Biomass Conversion and Biorefinery

Prévia do material em texto

<p>Vol.:(0123456789)</p><p>Biomass Conversion and Biorefinery</p><p>https://doi.org/10.1007/s13399-024-06141-9</p><p>ORIGINAL ARTICLE</p><p>Optimization and characterization of active bio‑plastic film</p><p>from tamarind (Tamarindus indica L.) seed starch enriched with red</p><p>grape pomace extract</p><p>Tigist Girma Moges1 · Habtamu Shebabaw Kassa1,2 · Henock Woldemichael Woldemariam1,2</p><p>Received: 22 June 2024 / Revised: 27 August 2024 / Accepted: 7 September 2024</p><p>© The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature 2024</p><p>Abstract</p><p>Active biodegradable films offer a promising solution to the issue of food contamination and loss by providing suitable</p><p>packaging materials that help maintain food quality and extend shelf life. This study focused on optimizing and charac-</p><p>terizing active bio-plastic films made from modified tamarind seed starch enriched with red grape pomace extract. The</p><p>physical, mechanical, barrier, thermal, antioxidant, and antibacterial qualities of the films were assessed. Using response</p><p>surface methodology, modified tamarind seed starch (MTSC), glycerol (GC), and red grape pomace extract concentration</p><p>(RGPEC) were optimized to values of 3.5% w/v, 25% w/w, and 6% w/w, respectively, to develop active bio-plastic film</p><p>using solvent-casting techniques. The film’s optimal tensile strength was improved significantly (p < 0.05) from 11.87 ± 0.02</p><p>MPa for pure tamarind seed starch bio-plastic to 12.77 ± 0.02 MPa for active bio-plastic film, demonstrating improved the</p><p>mechanical characteristics. When compared to the pure tamarind seed starch-based film, which had a water vapor perme-</p><p>ability of 2.4 × 10–10 ± 0.005 gm−1h−1Pa−1, the optimized film enriched with red grape pomace had a water vapor perme-</p><p>ability of 2.35 × 10–10 ± 0.001 gm−1h−1Pa−1, which was notable (p < 0.05). The grape pomace extract exhibited higher anti-</p><p>oxidant activity (IC50 = 280.5 ± 0.042 µg mL−1) compared to the active film (IC50 = 556 ± 0.038 µg mL−1) and non-active</p><p>film (IC50 = 320067.3 ± 0.024 µg mL−1) in the DPPH assay. The extract also had larger zone of inhibition values against</p><p>Staphylococcus aureus (10.00 ± 0.01 mm) in contrast to the active bio-plastic film (8.2 ± 0.02 mm). For Escherichia coli,</p><p>the values were 8.5 ± 0.03 mm for the extract and 7.4 ± 0.05 mm for the active film. In non-active films (film without GPE),</p><p>no antimicrobial activity was seen. The active bio-plastic film decomposed to about 63% of its original weight after 30 days.</p><p>Overall, the active film exhibited positive mechanical, barrier, antibacterial, and antioxidant properties compared with pure</p><p>tamarind seed starch film, making it appropriate for applications in food packaging.</p><p>Keywords Active bio-plastic film · Grape pomace extract · Tamarind seed starch · Tensile strength · Water vapor</p><p>permeability</p><p>1 Introduction</p><p>Petroleum-based or synthetic plastics pose environmental</p><p>issues due to their difficulty in biodegradation [1]. Bio-plas-</p><p>tics derived from renewable sources offer environmentally</p><p>acceptable food packaging materials, advancing sustainable</p><p>production and consumption [2]. Since food packaging is</p><p>gaining importance in the food sector due to its functional</p><p>advancements, such as ease and portioning, and its ability</p><p>to protect food from adverse conditions [3].</p><p>Starch is the main source of carbohydrates, among the</p><p>several polysaccharides that are currently used in industry.</p><p>It is the most prevalent and widely used renewable resource.</p><p>They come from seeds, including those from corn, wheat,</p><p>rice, potatoes, sweet potatoes, and tubers cassava [4]. Since</p><p>native starch cannot develop appropriate functional qualities</p><p>on its own for films, even when combined with a plasticizer</p><p>or composite, it has been suggested that modified starch</p><p>be used to significantly modify its final properties [5]. A</p><p>* Henock Woldemichael Woldemariam</p><p>henock.woldemichael@aastu.edu.et</p><p>1 Department of Chemical Engineering, College</p><p>of Engineering, Addis Ababa Science and Technology</p><p>University, P.O.Box 16417, Addis Ababa, Ethiopia</p><p>2 Center of Excellence for Biotechnology and Bioprocess,</p><p>Addis Ababa Science and Technology University,</p><p>P.O.Box 16417, Addis Ababa, Ethiopia</p><p>http://crossmark.crossref.org/dialog/?doi=10.1007/s13399-024-06141-9&domain=pdf</p><p>http://orcid.org/0000-0001-8764-4834</p><p>Biomass Conversion and Biorefinery</p><p>polysaccharide known as tamarind starch is often sourced</p><p>from tropical and subtropical locations. It is made from the</p><p>seeds of the tamarind tree (Tamarindus indica L.). It was</p><p>discovered that the starch from tamarind seeds was found to</p><p>be an effective supplement matrix for film production [6].</p><p>Natural antioxidants derived from various sources hold</p><p>significant importance as bioactive substances that have</p><p>been shown to have applications in the food sector [7] and</p><p>it has been determined that grape pomace is a highly desir-</p><p>able and affordable source of polyphenolic compounds [8].</p><p>Consequently, there is great promise for using grape pomace</p><p>in active film development [9]. The bio-plastic films’ anti-</p><p>bacterial and antioxidant activities may be improved by the</p><p>inclusion of grape pomace extract. This study aims to opti-</p><p>mize and characterize active bio-plastic films using modified</p><p>tamarind seed starch, glycerol, and grape pomace extract as</p><p>bioactive agent.</p><p>2 Materials and methods</p><p>2.1 Sample collection and preparation</p><p>Tamarindus indica L. fruit was sourced locally from Ethio-</p><p>pia. The tamarind seeds were manually extracted, cleaned,</p><p>and inspected. After drying and roasting, the seeds were</p><p>dehulled as illustrated in Fig.  1. Sodium hypochlorite</p><p>(NaOCl) was used to modify native tamarind seed starch</p><p>and commercial corn starch was purchased locally for</p><p>comparison.</p><p>Red grape pomace (RGP) was donated by Awash Wine</p><p>(Lideta Winery) and extracted using ultrasound-assisted</p><p>extraction. Approximately 1.5 kg of grape pomace was</p><p>dried using an air circulation oven (BINDER, Germany)</p><p>and grinder (NIMA NM-124 GRINDER) was used to</p><p>obtain grape pomace flour illustrated in Fig. 2.</p><p>2.2 Experimental design</p><p>This study used OVAT and Box-Behnken design to study</p><p>the impact of MTSC, RGPEC, and GC on bio-plastic films.</p><p>Table 1 lists the independent variables and the appropriate</p><p>coded levels for the experimental design.</p><p>Fig. 1 Sample preparation of</p><p>dehulled tamarind seed: raw</p><p>tamarind fruit A, tamarind seed</p><p>B, roasted and dehulled tama-</p><p>rind seed C</p><p>A B C</p><p>Fig. 2 Sample preparation of</p><p>red grape pomace flour: red</p><p>grape pomace A and red grape</p><p>pomace flour B</p><p>A B</p><p>Table 1 Independent variables and their corresponding coded levels</p><p>used for the Box-Behnken design</p><p>* MTSC- modified tamarind seed starch concentration, RGPEC-red</p><p>grape pomace extract concentration, GC- glycerol concentration</p><p>Factors Name Levels</p><p>-1 0 + 1</p><p>A MTSC (% w/v) 2.50 3.00 3.50</p><p>B RGPEC (% w/w) 6.00 7.00 8.00</p><p>C GC (% w/w) 15.00 20.00 25.00</p><p>Biomass Conversion and Biorefinery</p><p>The experiment consisted of seventeen runs, and a sec-</p><p>ond-order model (Eq. 1) was employed in order to correlate</p><p>with the response variables.</p><p>where Y is the response (TS and WVP), k is the number of</p><p>factors, xi and xj are the coded factors, and β0, βi, βii, and</p><p>βij, are the regression coefficients for the intercept, linear,</p><p>quadratic and interaction terms, respectively.</p><p>2.2.1 Optimization of process variables and model</p><p>performance evaluation</p><p>A Box-Behnken Design (BBD) with three levels and</p><p>three variables was used to model and optimize the ratios</p><p>of MTSC, RGPEC, and GC for film production. TS and</p><p>WVP were two of the responses that were optimized using</p><p>response surface methodology (RSM).</p><p>2.3 Development of active bio‑plastic film</p><p>The development method was taken from [10] with slight</p><p>modification. Solvent-casting method was employed to</p><p>develop active bio-plastics using both tamarind seed starch</p><p>and corn starch as the control starch-based bio-plastic films.</p><p>The ingredients, including MTSC (at levels of 2.5, 3, and 3.5</p><p>com-</p><p>posites with treated oil palm empty fruit bunch fibers and citric</p><p>acid. Cellulose 28:4191–4210</p><p>58 Sudhakar MP, Magesh Peter D, Dharani G (2021) Studies on</p><p>the development and characterization of bioplastic film from the</p><p>red seaweed (Kappaphycus alvarezii). Environ Sci Pollut Res</p><p>28:33899–33913</p><p>59. Saliu O, Olatunji G, Olosho A, Adeniyi A, Azeh Y, Samo F, Ade-</p><p>bayo D, Ajetomobi O (2019) Barrier property enhancement of</p><p>starch citrate bioplastic film by an ammonium-thiourea complex</p><p>modification. J Saudi Chem Soc 23(2):141–149</p><p>60. Nowak AJ, Waśkiewicz S, Baszczeńska O, Niesporek K, Król M,</p><p>Hajnyš J (2021) DSC of biodegradable plastic composites mate-</p><p>rial. J Therm Anal Calorim, 1–11</p><p>61. Sangian HF, Maneking E, Tongkukut SH, Mosey HI, Suoth V,</p><p>Kolibu H, Tanauma A, Pasau G, As’ari A (2021) Masinambow.</p><p>Study of SEM, XRD, TGA, and DSC of cassava bioplastics cata-</p><p>lyzed by ethanol. in IOP Conference Series: Materials Science and</p><p>Engineering. IOP Publishing</p><p>62. Xiao W, Sun Z, Wang F, Dong J (2017) Preparation and DSC</p><p>Analysis of γ-Poly Glutamic Acid Ester. in Advanced Graphic</p><p>Communications and Media Technologies. Springer</p><p>63 Rajeshkumar L, Ramesh M, Bhuvaneswari V, Balaji D, Deepa C</p><p>(2023) Synthesis and thermo-mechanical properties of bioplas-</p><p>tics and biocomposites: A systematic review. J Mater Chem B</p><p>11(15):3307–37</p><p>64. Zhang X, Zhang H, Zhou G, Su Z, Wang X (2023) Flexible, ther-</p><p>mal processable, self-healing, and fully bio-based starch plastics</p><p>by constructing dynamic imine network. Green Energ Environ</p><p>65. Gazonato EC, Maia AA, Moris VA, Paiva JM (2019) Thermome-</p><p>chanical properties of corn starch based film reinforced with coffee</p><p>ground waste as renewable resource. Mater Res 22(2):e2019041</p><p>66. Reshmy R, Philip E, Vaisakh P, Raj S, Paul SA, Madhavan A,</p><p>Sindhu R, Binod P, Sirohi R, Pugazhendhi A (2021) Develop-</p><p>ment of an eco-friendly biodegradable plastic from jack fruit peel</p><p>Biomass Conversion and Biorefinery</p><p>cellulose with different plasticizers and Boswellia serrata as filler.</p><p>Sci Total Environ 767:144285</p><p>67. Fransiska D, Wahyuni T, Irianto H, Priambudi H, Abdullah H,</p><p>Nissa R, Firdiana B (2022) Physical properties of bioplastic agar/</p><p>chitosan blend. in IOP Conference Series: Earth and Environmen-</p><p>tal Science. IOP Publishing</p><p>68. Wagner CE, Richter JK, Dey D, Finnie S, Ganjyal GM (2023)</p><p>Impact of tamarind seed gum on the viscosity behavior, thermal</p><p>properties, and extrusion characteristics of native corn starch. J</p><p>Food Sci 88(4):1595–1609</p><p>69. Alemu N, Balakrishnan S, Debtera B (2022) Extraction and Char-</p><p>acterisation of Avocado Seed Starch, and Its Blend with Enset</p><p>Cellulosic. Adv Mater Sci Eng 2022</p><p>70. Zaky AA, Asiamah E, El-Faham S, Ashour M, and Sharaf A</p><p>(2020) Utilization of grape pomace extract as a source of natural</p><p>antioxidant in biscuits</p><p>71. Zhang X, Liu J, Yong H, Qin Y, Liu J, Jin C (2020) Develop-</p><p>ment of antioxidant and antimicrobial packaging films based on</p><p>chitosan and mangosteen (Garcinia mangostana L.) rind powder.</p><p>Int J Biol Macromol 145:1129–1139</p><p>72. Kanatt SR, Chawla S (2018) Shelf life extension of chicken packed</p><p>in active film developed with mango peel extract. J Food Saf</p><p>38(1):e12385</p><p>Publisher's Note Springer Nature remains neutral with regard to</p><p>jurisdictional claims in published maps and institutional affiliations.</p><p>Springer Nature or its licensor (e.g. a society or other partner) holds</p><p>exclusive rights to this article under a publishing agreement with the</p><p>author(s) or other rightsholder(s); author self-archiving of the accepted</p><p>manuscript version of this article is solely governed by the terms of</p><p>such publishing agreement and applicable law.</p><p>Optimization and characterization of active bio-plastic film from tamarind (Tamarindus indica L.) seed starch enriched with red grape pomace extract</p><p>Abstract</p><p>1 Introduction</p><p>2 Materials and methods</p><p>2.1 Sample collection and preparation</p><p>2.2 Experimental design</p><p>2.2.1 Optimization of process variables and model performance evaluation</p><p>2.3 Development of active bio-plastic film</p><p>2.4 Characterization of optimized and control bio-plastic films</p><p>2.4.1 Physical properties analysis</p><p>2.4.2 Mechanical properties analysis</p><p>2.4.3 Barrier properties</p><p>2.4.4 Thermal properties analysis</p><p>2.4.5 Functional group, structural and morphological analysis</p><p>2.4.6 Antioxidant determination of extract and films</p><p>2.4.7 Determination of antimicrobial properties of extract and films</p><p>2.5 Statistical data analysis</p><p>3 Results and discussion</p><p>3.1 Model equation and analysis of variance (ANOVA)</p><p>3.2 Interaction effects of factors on tensile strength and water vapor permeability</p><p>3.3 Optimization of the process parameters</p><p>3.4 Characterization of optimized and control bio-plastic films</p><p>3.4.1 Physical properties</p><p>3.4.2 Mechanical properties</p><p>3.4.3 Barrier properties</p><p>3.4.4 Thermal properties</p><p>3.4.5 Functional groups, structural and morphological analysis of films</p><p>3.4.6 Determination of antioxidant properties of extract and films</p><p>4 Conclusion</p><p>4.1 Future perspectives and commercial possibility</p><p>References</p><p>g/100 mL), GC (at levels of 15, 20, and 25% w/w on a starch</p><p>dry basis), and RGPEC (at levels of 6, 7, and 8% w/w on a</p><p>starch dry basis), were stirred and blended together using a</p><p>magnetic stirrer at 800 rpm for 30 min at 25 °C. The result-</p><p>ing suspension was heated to 65 °C for 15 min while stirring</p><p>at 800 rpm. The suspension was then poured onto a plastic</p><p>plate measuring 25 cm × 25 cm. The casted film was dried</p><p>for 2 days at 25°C. The poured film was left to dry at room</p><p>temperature for 2 days. Following drying, the bio-plastic</p><p>films were taken off from the plate and put in polyethylene</p><p>bags for further characterization.</p><p>2.4 Characterization of optimized and control</p><p>bio‑plastic films</p><p>2.4.1 Physical properties analysis</p><p>Thickness A digital outside micrometer (Insize, SL-M,</p><p>India) was used to measure the bio-plastic’s thickness</p><p>depend on the method described by Oluwasina, Falola [11]</p><p>as specified by Eq. 2. The average of ten measurements that</p><p>were made at different points across the film was determined.</p><p>(1)</p><p>Y = �o +</p><p>∑k</p><p>i=1</p><p>�ixi +</p><p>∑k</p><p>i=1</p><p>�iix2ii +</p><p>∑k</p><p>i=1</p><p>∑k</p><p>j=i+1</p><p>�ijxixj</p><p>Moisture content The initial weight (W1) of each film sam-</p><p>ples, which was obtained from a digital weighing scale,</p><p>was used to calculate the moisture content of the film sam-</p><p>ples. After drying the samples for 24 h at 100℃ in an oven</p><p>(BINDER, Germany), they were reweighed to obtain the</p><p>final weight (W2). The moisture content (MC) of each film</p><p>sample is determined using the following Eq. 3, as described</p><p>by Sanyang, Sapuan [12].</p><p>Film water solubility Solubility was determined using the</p><p>formula provided by Sanyang, Sapuan [12] as described in</p><p>Eq. 4. Small sample pieces (2 cm2) were left to dry for a full</p><p>day at 100℃ and weighed in order to obtain their initial dry</p><p>matter (W1). After that, each specimen was submerged in</p><p>50 ml of distilled water at room temperature with periodic</p><p>stirring over 24 h. After filtering the water, the remaining</p><p>bio-plastic residue was dried at 100℃ for an additional 24</p><p>h. The dried residue was weighed to determine the weight</p><p>of the soluble dry matter (W2).</p><p>Transparency and optical property Transmittance and opac-</p><p>ity were determined depend on method of from spectropho-</p><p>tometer readings. A spectrophotometer was used to measure</p><p>the films’ transparency [13]. Films were cut into rectangles,</p><p>stored in cuvettes, and put into the spectrophotometer cell.</p><p>The transparency of the films was determined by calculat-</p><p>ing the percentage of transmission at visible light [14]. The</p><p>opacity is calculated using Eq. 5, by measuring films light</p><p>transmittance at 600 nm using a UV–VIS spectrophotometer</p><p>(JASCO V-770, Japan).</p><p>where O is the opacity, Abs600 is the absorbance value at 600</p><p>nm, and L is the thickness of the film (mm).</p><p>Biodegradability test To calculate the percentage of bio-</p><p>degradation, the method of [15] with slight modifications as</p><p>shown in Eq. 6 was used. To assess the biodegradability of</p><p>the bio-plastic, 2-cm2 pieces of films were initially weighed</p><p>(W1) prior to composting. The weight of the remaining resi-</p><p>dues was then cleaned and subsequently reweighed to deter-</p><p>mine the final weight (W2) after 1 month of storage period</p><p>at room temperature in compost.</p><p>(2)Thickness =</p><p>Sum of Measured Values</p><p>10</p><p>(3)Moisture Content% =</p><p>W1 −W2</p><p>W1</p><p>× 100</p><p>(4)Solubility% =</p><p>W2 −W1</p><p>W2</p><p>× 100</p><p>(5)O =</p><p>(Abs600)</p><p>L</p><p>Biomass Conversion and Biorefinery</p><p>2.4.2 Mechanical properties analysis</p><p>Tensile strength (MPa) A texture analyzer (AMETEK, Tex-</p><p>ture Analyzer TA1, USA) was used to evaluate the film’s</p><p>mechanical characteristics following the procedure out-</p><p>lined by Yadav, Kumar [16]. The film samples, measuring</p><p>approximately 1.5 cm by 5 cm, were held in place by tensile</p><p>grips. During extension, measurements of the force (N) and</p><p>deformation (mm) were made. The force (N) and defor-</p><p>mation (mm) were recorded during extension. The tensile</p><p>strength (TS) was calculated by dividing the maximum force</p><p>by the specimen's original average cross-sectional area. The</p><p>results were expressed in mega pascal (MPa) using a formula</p><p>described in Eq. 7, reporting to three significant digits.</p><p>where A is the sample’s cross-sectional area (mm2) and</p><p>Fmax is the maximum stress (N) required to tear it apart.</p><p>Percent of elongation at the break Percentage of elongation</p><p>at the break was calculated according to method of [17].</p><p>As described in Eq. 8 The extension at the time of the bio-</p><p>plastic film rupture is divided by the bio-plastic’s initial gage</p><p>length, and the result is multiplied by 100 to determine the</p><p>percentage of elongation at the break.</p><p>2.4.3 Barrier properties</p><p>Absorption of water To measure the water absorption of</p><p>the bio-plastic samples, they were dried in an oven at 100℃</p><p>for 24 h to determine their initial dry weight (W1). Subse-</p><p>quently, the samples were placed in a beaker with 50 mL of</p><p>distilled water and left at room temperature for 24 h. After</p><p>filtering the water, the bio-plastic residue was weighed</p><p>to determine its final weight (W2). The amount of water</p><p>absorbed by the bio-plastic film was calculated using Eq. 9.</p><p>Water vapor permeability (WVP) The desiccant method in</p><p>ASTM E 96 method was used to test the films water vapor</p><p>transfer rate (WVTR) gravimetrically [18]. A desiccator</p><p>with silica gel was set up at 30 °C and 0% RH (0 Pa water</p><p>(6)Biodegradability% =</p><p>W1 − W2</p><p>W1</p><p>× 100</p><p>(7)Tensile Strength (MPa) =</p><p>Fmax</p><p>A</p><p>(8)</p><p>%Elongation at the Break =</p><p>Extension at rapture (mm)</p><p>Initial Gage Length (mm)</p><p>× 100</p><p>(9)Waterabsorption% =</p><p>W2 −W1</p><p>W2</p><p>× 100</p><p>vapor pressure) with the film sealed on top of a permeation</p><p>cell filled with distilled water (100% RH; 4245 Pa vapor</p><p>pressure at 30 °C). Throughout 10 h, the cells were weighted</p><p>every 2 h. Following the permeation tests, the film thickness</p><p>(mm) was determined, and Eq. 10 is used to compute WVP</p><p>(g m−1 Pa−1 h−1).</p><p>where ΔP (Pa) is the variation in vapor pressure across the</p><p>film and d is the average thickness of each sample (m).</p><p>2.4.4 Thermal properties analysis</p><p>Differential scanning calorimeter (DSC) analysis bio‑plastic</p><p>film Thermal characteristics of the biofilm were evaluated</p><p>according to the procedure of [19]. By heating the sample</p><p>at a rate of 10 °C per minute, the differential scanning calo-</p><p>rimeter was utilized to examine the results of the DSC test.</p><p>Next, the sample pan was heated in an atmosphere of nitro-</p><p>gen from 20 to 250˚C at a rate of 10˚C each minute.</p><p>2.4.5 Functional group, structural and morphological</p><p>analysis</p><p>FTIR analysis The FTIR analysis was conducted following</p><p>the method described by Taddele [20] and Contessa, da Rosa</p><p>[21]. The samples were pressed into pellets and placed on</p><p>the sample holder. IR light was applied, and data was col-</p><p>lected at 32 resolutions and 16 scans. The 400–4000 cm−1</p><p>range was used to record the spectra.</p><p>SEM analysis Scanning electron microscopy (SEM) was</p><p>used to assess the microstructure of the optimized film. The</p><p>film sample was dehydrated for three weeks using silica gel</p><p>in a desiccator. Tiny fragments were extracted from the dried</p><p>sample and secured onto aluminum stubs using double-sided</p><p>tape. A layer of gold was applied using a Sputter Coater, and</p><p>the coated sample was examined using a scanning electron</p><p>microscope operating at a 10 kV acceleration voltage [22].</p><p>XRD analysis The X-ray diffraction analysis was performed</p><p>following the procedure outlined by [23]. A 40-kV X-ray</p><p>diffractometer with a 40-mA current was utilized for this</p><p>purpose. Prior to analysis, the film samples were left in a</p><p>saturated relative humidity chamber overnight to adjust</p><p>to the room temperature. The films were then subjected to</p><p>scanning in the range of 5° to 60° 2θ, using X-ray radiation</p><p>with a wavelength of 1.57 Å, specifically Co Kα radiation.</p><p>(10)WVP =</p><p>WVTR</p><p>ΔP</p><p>× d</p><p>Biomass Conversion and Biorefinery</p><p>2.4.6 Antioxidant determination of extract and films</p><p>Determination of TPC The total phenolic content (TPC) of</p><p>the grape pomace extract was determined using</p><p>the Folin–</p><p>Ciocalteau assay, based on the method described by Single-</p><p>ton, Orthofer [24] with modification by Ikram, Eng [25]. For</p><p>the film, the TPC was evaluated according to the method</p><p>of Saurabh, Gupta [9]. A 500 mL of ethanol was used to</p><p>dissolve the 3.2 mg of film sample. In both cases, TPC was</p><p>calculated using Eq. 11. A diluted extract aliquot (0.2 mL)</p><p>was mixed with 1.5 mL of tenfold diluted Folin–Ciocalteau</p><p>reagent in a 25-mL volumetric flask. A 6% (w/v) Na2CO3</p><p>solution containing 1.5 mL was added to the mixture after</p><p>it had been left to sit for 5 min. Once the mixture was well</p><p>combined, it was allowed to stand for 90 min. A UV–VIS</p><p>spectrophotometer was used to detect the absorbance at</p><p>725 nm. Gallic acid solution at varying concentrations was</p><p>used to create a standard curve, and TPC was represented</p><p>as milligrams of gallic acid equivalents (GAE) per 100 g or</p><p>per 100 g of film.</p><p>where C is concentration obtained from the calibration curve</p><p>(mg/mL), V is volume of stock solution of extract (mL), M</p><p>is dry weight of extract found in the stock solution (g), and</p><p>TPC is total phenol content.</p><p>Determination of TFC The total flavonoid content (TFC) of</p><p>the grape pomace extract was quantified using the colori-</p><p>metric method with aluminum chloride, following the meth-</p><p>odology described in Casagrande, Zanela [26]. For the film</p><p>samples, the Al2Cl3 procedure described by Ferreira, Nunes</p><p>[27] was used to determine the total flavonoid content. To</p><p>make the film extract, a 50-mg film sample was dissolved in</p><p>500 mL of ethanol. The TFC was calculated using Eq. 12.</p><p>An aliquot of 0.5 mL of the extract (at a concentration of</p><p>20 g L−1) was mixed with ethanol, aluminum chloride, and</p><p>potassium acetate. The mixture was allowed to stand for</p><p>60 min at room temperature. After 60 min, absorbance was</p><p>measured at 415 nm using a UV–VIS spectrophotometer.</p><p>A calibration curve was created using an ethanol solution</p><p>of quercetin. TFC was measured in milligrams of quercetin</p><p>equivalent (QE) per 100 g of film or grape pomace extract.</p><p>where TFC is total flavonoid content (mg QE/g sample), V</p><p>is the volume of the grape pomace extract solution (mL), M</p><p>is the weight of the sample found in the stock solution (g),</p><p>and C is the concentration determined from the calibration</p><p>curve (mg/ml).</p><p>(11)TPC = C ×</p><p>V</p><p>M</p><p>(12)TFC =</p><p>C × V</p><p>M</p><p>DPPH assay The method described by Baba and Malik</p><p>[28] was followed for the extract, while the methodology</p><p>reported by Merino, Bertolacci [29] was used for the films.</p><p>Bio-plastic film samples were made at a concentration of</p><p>(50–300  µg/mL) and mixed with 1  mL DPPH solution</p><p>(2.00 mg DPPH solution in ethanol). A 3.2-mg film was</p><p>immersed in 500 mL of ethanol and 1000 µg/mL of stock</p><p>solution of grape pomace extract of ethanol. Serially dilute</p><p>the stock solution to give solutions with concentrations of</p><p>(50–300 μg/ml) respectively and incubated for 30 min at</p><p>room temperature in the dark. As a positive control, ascorbic</p><p>acid was utilized at concentrations of 50–300 µg/mL. The</p><p>decrease in absorbance after a 30-min incubation was used</p><p>to calculate radical scavenging activity (RSA) using Eq. 13.</p><p>where; I% represents the percentage of DPPH inhibition, AS</p><p>represents the sample solution’s absorbance, and AC repre-</p><p>sents the control’s absorbance.</p><p>FRAP assay Ferric reducing power assay of extract was</p><p>determined according to method of [28] and for films method</p><p>of [27] was used. Briefly, 100 µL of the extract and film at</p><p>concentration of (50–300 µg/mL) was prepared. A 0.25 cm2</p><p>film was incubated at 50 °C for 20 min after being sub-</p><p>merged in 3 mL of FRAP solution, 2.5 mL of 200 mmol/L</p><p>phosphate buffer (pH 6.6), and 2.5 mL of 1% potassium</p><p>ferricyanide. After adding 2.5 mL of 10% trichloroacetic</p><p>acid, the tubes were centrifuged for 10 min at 10,000 rpm.</p><p>A mixture of 5.0 mL distilled water and 1 mL 0.1% ferric</p><p>chloride was added to the top layer (5 mL). The absorbance</p><p>of the reaction mixtures was measured at 700 nm using a</p><p>UV–VIS spectrophotometer (JASCO V-770, Japan). Ascor-</p><p>bic acid served as a positive control, and the reducing power</p><p>was expressed as an EC50 (µg/mL) value.</p><p>2.4.7 Determination of antimicrobial properties of extract</p><p>and films</p><p>Using the disk diffusion method, the antibacterial activ-</p><p>ity of the bio-plastic film and grape pomace extract (GPE)</p><p>was assessed. Staphylococcus aureus and Escherichia coli</p><p>were used as test microorganisms. The media form Muller</p><p>Hinton Agar was prepared and added to petri dishes. The</p><p>microorganisms were inoculated on the agar surface. Bio-</p><p>plastic films and filter paper disks soaked in the grape pom-</p><p>ace extract were placed on the agar plates. The antibacterial</p><p>activity of the petri dish plates was evaluated by measuring</p><p>the zone of inhibition surrounding the disks following a 24-h</p><p>incubation period. The size of the zone indicates the effec-</p><p>tiveness in inhibiting bacterial growth.</p><p>(13)% =</p><p>Ac − As</p><p>Ac</p><p>× 100</p><p>Biomass Conversion and Biorefinery</p><p>2.5 Statistical data analysis</p><p>The data from the bioplastics characterization was subjected</p><p>to a statistical analysis using analysis of variance (ANOVA).</p><p>The analysis included triplicate measurements. The validity</p><p>of the model was assessed using ANOVA, as well as the</p><p>coefficient of determination (R2) and adjusted coefficient of</p><p>determination (Adj-R2). Significant differences among the</p><p>mean values were determined using one-way ANOVA and</p><p>Tukey’s test at a significance level of 0.05, utilizing Minitab</p><p>statistical software. The mean ± standard deviation (SD) was</p><p>used to report the results.</p><p>3 Results and discussion</p><p>3.1 Model equation and analysis of variance</p><p>(ANOVA)</p><p>The coefficients of the polynomial equation models utilized</p><p>for predicting the water vapor permeability and tensile</p><p>strength were given in Eqs. 14 and 15.</p><p>where TS is tensile strength, WVP is water vapor permeabil-</p><p>ity, and A, B, and C are symbol for coded factors.</p><p>In Table 2, the results obtained from the independent var-</p><p>iables, namely, A, MTSC (2.5–3.5% w/v); B, RGPEC (6–8%</p><p>w/w); and GC, (15–25% w/w), are presented. Water vapor</p><p>permeability (gm−1h−1pa−1) and tensile strength (MPa) are</p><p>the two responses in this study.</p><p>3.2 Interaction effects of factors on tensile strength</p><p>and water vapor permeability</p><p>The response characteristics observed in this study demon-</p><p>strate a maximum response, as depicted in Fig. 3. Figure 3A</p><p>illustrates that the tensile strength of the bio-plastic film</p><p>increases as the MTSC (2.5–3.5% w/v) rises, while the TS</p><p>value decreases with an increase in red grape pomace extract</p><p>concentration (6–8% w/w). Therefore, 3.5% w/v starch con-</p><p>centration and 6% w/w pomace extract concentration were</p><p>(14)</p><p>TS = 10.89 + 1.46A − 0.6489B − 1.53C + 0.6335AB</p><p>+ 1.90AC − 2.97BC − 0.7663A</p><p>2 − 1.32B</p><p>2</p><p>− 0.1700C</p><p>2</p><p>(15)</p><p>WVP = 2.623 × 10</p><p>−10 − 5.250 × 10</p><p>−12</p><p>A + 2.488 × 10</p><p>−11</p><p>B</p><p>+ 1.313 × 10</p><p>−11</p><p>C − 2.600 × 10</p><p>−11</p><p>AB − 3.400</p><p>× 10</p><p>−11</p><p>AC + 1.325 × 10</p><p>−11</p><p>BC − 7.850 × 10</p><p>−13</p><p>A</p><p>2</p><p>+ 9.650 × 10</p><p>−13</p><p>B</p><p>2 − 2.035 × 10</p><p>−12</p><p>C</p><p>2</p><p>chosen as the goal point to reach the highest tensile strength.</p><p>Figure 3B shows that the tensile strength of the bio-plas-</p><p>tic film increases with higher MTSC (2.5–3.5% w/v) and</p><p>decreases with increasing glycerol concentration (15–25%</p><p>w/w). Similarly, Fig. 3C illustrates that increasing the glyc-</p><p>erol concentration (15–25% w/w) causes the TS of the bio-</p><p>plastic film to rise and increasing RGPEC from (6–8) %</p><p>w/w results in a decreases in the TS of bio-plastic film. So,</p><p>25% w/v of glycerol concentration was selected to attain the</p><p>maximum of TS.</p><p>The response characteristics exhibited a minimum</p><p>response pattern, as depicted in Fig. 4. Figure 4A dem-</p><p>onstrates that increasing the MTSC (2.5–3.5% w/v) and</p><p>RGPEC (6–8% w/w) leads to rise in water vapor permeabil-</p><p>ity ( WVP). Therefore, 3.5% w/v MTSC starch and 6% w/w</p><p>RGPEC were chosen as the goal point to reach the minimum</p><p>WVP. Similarly, Fig. 4B shows that as the glycerol concen-</p><p>tration (GC) increases</p><p>from 15 to 25% w/w, the WVP of the</p><p>bio-plastic film also increases. Figure 4C further illustrates</p><p>that both increasing GC and RGPEC result in higher water</p><p>vapor permeability in the bio-plastic film in case of this</p><p>study 25% w/v of glycerol concentration and 6%w/w of red</p><p>grape pomace extract concentration was selected to attain</p><p>the minimum WVP.</p><p>Table 2 Box–Behnken design employed for formulation of active</p><p>bio-plastic film composition</p><p>* MTSC modified tamarind seed starch concentration, RGPEC red</p><p>grape pomace extract concentration, GC glycerol concentration, TS</p><p>tensile strength, WVP water vapor permeability</p><p>Input variables Films properties</p><p>MTSC</p><p>(% w/v)</p><p>RGPEC</p><p>(% w/w)</p><p>GC</p><p>(% w/w)</p><p>TS (MPa)</p><p>WVP × 10–10</p><p>(g/m.h.Pa)</p><p>3 7 20 10.941 2.61</p><p>2.5 6 20 8.695 2.17</p><p>3 6 15 8.628 2.36</p><p>3 8 25 4.236 3.13</p><p>3 7 20 10.774 2.63</p><p>3.5 7 15 11.028 2.75</p><p>3.5 7 25 11.884 2.33</p><p>3 7 20 10.911 2.62</p><p>3.5 8 20 10.187 2.56</p><p>3 6 25 11.417 2.36</p><p>2.5 8 20 6.070 3.18</p><p>3.5 6 20 10.278 2.59</p><p>2.5 7 15 11.830 2.18</p><p>2.5 7 25 5.068 3.12</p><p>3 8 15 13.334 2.60</p><p>3 7 20 10.894 2.63</p><p>3 7 20 10.924 2.626</p><p>Biomass Conversion and Biorefinery</p><p>Fig. 3 Response surface plots</p><p>illustrating the effects of process</p><p>variables on tensile strength</p><p>(TS)</p><p>Fig. 4 Response surface plots</p><p>illustrating the effects of process</p><p>variables on WVP</p><p>Biomass Conversion and Biorefinery</p><p>3.3 Optimization of the process parameters</p><p>Optimal conditions were identified as 3.5% w/v of tama-</p><p>rind starch, 6% w/w grape pomace extract, and 25% w/w</p><p>glycerol, yielding the desired film characteristics. Table 3</p><p>displays the mean values with standard deviations, and</p><p>the absolute residual error ranged from 5.4 to 5.53%.</p><p>These results confirm the efficacy of the optimization</p><p>methodology and the reliability of the surface responses</p><p>derived from the Box-Behnken experimental design.</p><p>3.4 Characterization of optimized and control</p><p>bio‑plastic films</p><p>The films showed uniform and high-quality dispersion</p><p>of particles, with no bubbles or cracks after drying. The</p><p>tamarind seed starch-based biofilms were smooth, easy to</p><p>Table 3 Findings from an</p><p>experimental validation of</p><p>the optimal conditions for</p><p>development of an active</p><p>bioplastic film based on</p><p>tamarind seed starch</p><p>* MTSC modified tamarind seed starch concentration, RGPEC red grape pomace extract concentration, GC</p><p>glycerol concentration, TS tensile strength, WVP water vapor permeability</p><p>Input variables Film properties</p><p>MTSC</p><p>(% w/v)</p><p>GPEC</p><p>(% w/w)</p><p>GC</p><p>(% w/w)</p><p>TS</p><p>(MPa)</p><p>WVP × 10–10</p><p>(gm−1h−1Pa−1)</p><p>Predicted Values 3.5 6 25 13.46 2.22</p><p>Experimental Values 3.5 6 25 12.77 ± 0.02 2.35 ± 0.001</p><p>Absolute residual error (%) 0 0 0 5.4 5.53</p><p>Fig. 5 Process of Film Develop-</p><p>ment and developed bio-plastic</p><p>films: mixing of ingredients</p><p>A, starch gelatinization B, film</p><p>casting C, and dried bio-plastic</p><p>films (modified tamarind seed</p><p>starch with GPE D, pure starch</p><p>(without GPE) E, corn starch F</p><p>A B C</p><p>DEG F</p><p>Table 4 Overall summary of each bio-plastic films properties and effect of grape pomace extract</p><p>The mean ± SD of three replicates is used for all data. The same column’s mean that is followed by different letters differs significantly (p ≤ 0.05)</p><p>Films WVP × 10–10</p><p>g/m.h.pa</p><p>MC (%) Opacity at 600</p><p>nm</p><p>Solubility (%) Thickness (mm) Tensile</p><p>Strength</p><p>(MPa)</p><p>Elongation</p><p>(%)</p><p>Water</p><p>absorption</p><p>(%)</p><p>Film with GPE 2.35d ± 0.001 6.50d ± 0.01 1.26c ± 0.005 0.56d ± 0.002 0.052a ± 0.0005 12.77a ± 0.02 10.9b ± 0.05 83c ± 0.03</p><p>Film without</p><p>GPE</p><p>2.4b ± 0.005 7.00c ± 0.03 1.2d ± 0.001 0.7c ± 0.008 0.049c ± 0.0005 11.87b ± 0.02 11.2a ± 0.03 88.00a ± 0.03</p><p>Native Starch</p><p>Based Film</p><p>2.5a ± 0.01 7.8b ± 0.01 1.9b ± 0.01 0.8b ± 0.01 0.05b ± 0.0005 11.00c ± 0.03 4.5c ± 0.03 86b ± 0.04</p><p>Corn starch</p><p>Based Film</p><p>2.4c ± 0.002 8.00a ± 0.01 3.5a ± 0.01 0.84a ± 0.05 0.045d ± 0.0003 11.6d ± 0.03 4d ± 0.03 76d ± 0.025</p><p>Biomass Conversion and Biorefinery</p><p>remove, and soluble in water, indicating good performance</p><p>as shown in Fig. 5 and overall summary of each developed</p><p>bio-plastic films are presented in Table 4. The numbers are</p><p>all means ± standard deviations, and there is a significant</p><p>difference (p < 0.05).</p><p>3.4.1 Physical properties</p><p>Thickness The film thickness was measured using digi-</p><p>tal micrometer as shown in Fig. 6 and varied among the</p><p>different types of films analyzed. Pure starch-based films</p><p>had a thickness of 0.049 ± 0.0005 mm, while films with</p><p>grape pomace extract had a significantly higher thickness</p><p>of 0.052 ± 0.0005 mm. Native-based starch films were</p><p>0.05 ± 0.0005 mm thick, and corn starch-based films were</p><p>0.045 ± 0.0003 mm thick. Adding grape pomace extract</p><p>increased the film thickness, which can improve mechanical</p><p>properties and barrier performance. Film thickness directly</p><p>affects properties like water vapor permeability, opacity, ten-</p><p>sile strength, and elongation [30].</p><p>Moisture content The moisture content of the analyzed</p><p>films varied. The moisture content of the corn starch film</p><p>was 8.00 ± 0.01%, while the oxidized tamarind seed starch</p><p>film had a moisture level of 6.50 ± 0.01%. The moisture</p><p>percentage of the pure film was 7.00 ± 0.03%, whereas the</p><p>native tamarind seed starch-based film had a moisture value</p><p>of 7.8 ± 0.01%. The reduced moisture content in the modi-</p><p>fied tamarind seed starch film may contribute to improved</p><p>mechanical strength and barrier effectiveness. Based on the</p><p>findings of Fonseca, Henkes [31] the moisture content of the</p><p>films derived from native and oxidized potato starch ranged</p><p>from 15.35 ± 1.31 to 21.78 ± 0.49%, with the highest mois-</p><p>ture content observed in the films plasticized with sorbitol.</p><p>another study conducted by Sondari, Triwulandari [32] men-</p><p>tions that the moisture content of films made from modified</p><p>sago starch is lower compared to films made from pure sago</p><p>starch which fits with this studies. Moisture from the food</p><p>itself or moisture entering the packaging material from the</p><p>outside might accelerate food decomposition. As a result,</p><p>it is expected that high-quality packaging materials do not</p><p>cause their packed materials' moisture content to rise [33].</p><p>Film solubility In this study, the solubility of modi-</p><p>fied tamarind seed starch-based film (film with GPE)</p><p>was 0.56 ± 0.002%, for the native starch-based film was</p><p>0.80 ± 0.01% and for control film was 0.84 ± 0.05% and for</p><p>pure film solubility was observed as 0.70 ± 0.008%. The sol-</p><p>ubility of active film was lower than non-active film because</p><p>of addition of GPE and oxidation of tamarind starch. Grape</p><p>pomace extract (GPE) decreases the solubility of films made</p><p>from starch by increasing the water content and acting as a</p><p>plasticizer, which reduces the molecular interactions of the</p><p>polymer chain and favors its solubilization [34] and starch</p><p>oxidation decreases the solubility of films made from starch</p><p>by introducing hydrophobic carboxyl groups into the starch</p><p>molecule chain, resulting in increased hydrophobicity of the</p><p>modified starch films [35]. This increased hydrophobicity</p><p>leads to lower moisture content and reduced water solubility</p><p>in the films [31, 36]. Reduced solubility in the development</p><p>of biodegradable films or coatings can improve their mois-</p><p>ture resistance, offering packaged goods better protection</p><p>and a longer shelf life. In general, the water solubility can be</p><p>used to determine the films' water resistance [37].</p><p>Transparency and opacity Oxidized starch-based films</p><p>exhibit higher transparency [38]. Thus, the opacity of oxi-</p><p>dized starch film with GPE was 1.26 ± 0.005, for Native</p><p>starch-based film it was 1.9 ± 0.01 and for the corn starch-</p><p>based film the opacity was 3.5 ± 0.01 at for pure film (with-</p><p>out GPE) opacity 1.2 ± 0.001 at 600 nm absorbance. Films</p><p>absent of extract were the most transparent, while those con-</p><p>taining 6% w/w of grape extract were the least transparent</p><p>[39]. A low opacity value is associated with high transpar-</p><p>ency. This study has similarities to another one that demon-</p><p>strated how the addition of GPE reduced film transparency</p><p>[40]. A study by Pirouzifard,</p><p>Yorghanlu [41]. found that the</p><p>films developed from pure starch (control film) showed a</p><p>higher transparency than other films (p < 0.05). When com-</p><p>pared to films without GPE, films with GPE were shown to</p><p>have a higher opacity because of the interaction between the</p><p>biopolymer matrix and the polyphenols found in the GPE,</p><p>which decreased the amount of light that passed through</p><p>the films. Consistent with the theories proposed by Thivya,</p><p>Bhosale [42], it was observed that the opacity of XG and</p><p>pectin films containing SSP was greater than that of control</p><p>films.This was attributed to the interaction of the biopolymer Fig. 6 Thickness measurement of developed bio-plastic films</p><p>Biomass Conversion and Biorefinery</p><p>matrix with the polyphenols contained in the SSP, which</p><p>decreased the amount of light that passed through the films.</p><p>Biodegradability Figure 6 shows that biodegradability test</p><p>of all developed films. The bio-plastic films showed varying</p><p>biodegradation rates: 63% for modified starch-based film</p><p>with grape pomace extract, 60.5% for pure starch-based</p><p>film, 58% for native starch-based film, and 45.8% for corn</p><p>starch-based film after 30 days in soil. Starch modification</p><p>improved biodegradability, and films without grape pom-</p><p>ace extract degraded slower. These films have potential as</p><p>eco-friendly alternatives to conventional plastics. In another</p><p>study by Chowdhury, Hossain [43], a significant biodegra-</p><p>dation rate of 73% was observed within 30 days as shown</p><p>in Fig. 7.</p><p>3.4.2 Mechanical properties</p><p>Tensile strength The tensile strength results of film sam-</p><p>ples are given Table 4. The bio-plastic film containing</p><p>6% w/w grape pomace extract (GPE) showed the high-</p><p>est tensile strength of 12.77 ± 0.02 MP compared to the</p><p>non-active film of 11.87 ± 0.02 Mpa. The same result was</p><p>obtained by Sutthiparinyanont, Panrattanasukkul [44],</p><p>they discovered that the mechanical properties were sig-</p><p>nificantly different (P < 0.05) from the original film without</p><p>the extract (2.93 MPa and 21.5% elongation), with 0.92</p><p>MPa of puncture strength and 37.7% elongation. Rakhavan,</p><p>Sudharsan [6], studied the design and characterization of</p><p>spice fused tamarind starch edible packaging film and</p><p>found that 5 g/100 mL of tamarind seed starch, 0.2 g/100</p><p>mL of xanthan gum, and 5 mL/100 mL of glycerol as plas-</p><p>ticizer and elongation at break (18.64 ± 4.86%) produced</p><p>the best tensile strength (67.76 ± 5.38 MPa). The inclu-</p><p>sion of GPE increased the tensile strength compared to</p><p>the film without the extract. Statistical analysis revealed</p><p>a significant (p < 0.05) difference in mechanical proper-</p><p>ties among the samples. Adding oxidized starch to the film</p><p>improved its tensile strength, as observed by Oluwasina,</p><p>Olaleye [30] this is because the presence of carbonyl and</p><p>carboxyl groups in the oxidized starch promotes stronger</p><p>interactions, such as hydrogen bonding or Van der Waals</p><p>interactions, which contribute to the overall strength of</p><p>the film [45]. Glycerol plays a crucial role in strengthen-</p><p>ing the film by promoting stronger intermolecular interac-</p><p>tions and reducing internal hydrogen bonds. This leads to</p><p>a more robust and resistant film structure, contributing to</p><p>its enhanced tensile strength [46].</p><p>Percent of elongation at the break (EAB) Table 4 shows the</p><p>percent of elongation at break (EAB) results of all film sam-</p><p>ples. EAB was determined as a percentage by dividing the</p><p>final length of each film sample by its initial length [47]. In</p><p>this study, the EAB at the optimal position was 10.9 ± 0.05%</p><p>for MF with GPE, 11.2 ± 0.03% for MF without GPE,</p><p>4.5 ± 0.03% for NF, and 4.00 ± 0.03% for the control film</p><p>(CF). Compared to films without extract, films containing</p><p>grape pomace extract were easier to handle [34]. Recent</p><p>reports on the synthesis of bio-plastic developed from dif-</p><p>ferent polysaccharides and their improved film properties are</p><p>summarized in Table 5.</p><p>3.4.3 Barrier properties</p><p>Water absorption The water absorption results of film sam-</p><p>ples are displayed in Table 4. In this study, the films’ ability</p><p>to absorb water at the optimal position was 83.00 ± 0.03% for</p><p>GPE-based films, 88.00 ± 0.03% for non-GPE-based films,</p><p>86 ± 0.04% for native films, and 76 ± 0.03% for corn starch-</p><p>based films. The addition of oxidized starch and grape pom-</p><p>ace extract give low water absorption of film.</p><p>Water vapor permeability (WVP) For films to be used in</p><p>critical applications, their WVP must be lowered [19]. The</p><p>WVP of all film samples are given in Table 4. The WVP</p><p>at optimum point for developed film was assessed in this</p><p>investigation, the modified tamarind seed starch-based</p><p>film enriched with grape pomace extract (GPE) showed</p><p>significantly minimum WVP compared to native tama-</p><p>rind seed starch and corn starch based films. The starch</p><p>oxidation process and the addition of GPE enhanced</p><p>the film’s barrier qualities. The modified tamarind seed</p><p>starch-based film with GPE exhibited the minimum WVP</p><p>value (2.35 × 10–10 ± 0.001 g m−1h−1pa−1) compared to</p><p>the film without GPE (2.4 × 10–10 ± 0.005 g m−1h−1pa−1),</p><p>native starch film (2.5 × 10–10 ± 0.01 g m−1h−1pa−1), and</p><p>corn film (2.4 × 10–10 ± 0.002 g m−1h−1pa−1). Because the</p><p>oxidation of starch formed carbonyl and carboxyl groups,</p><p>which had a larger affinity for water, the oxidation of Fig. 7 Biodegradability test</p><p>Biomass Conversion and Biorefinery</p><p>Ta</p><p>bl</p><p>e</p><p>5</p><p>C</p><p>ur</p><p>re</p><p>nt</p><p>re</p><p>po</p><p>rts</p><p>o</p><p>n</p><p>th</p><p>e</p><p>sy</p><p>nt</p><p>he</p><p>si</p><p>s o</p><p>f b</p><p>io</p><p>-p</p><p>la</p><p>sti</p><p>c</p><p>de</p><p>ve</p><p>lo</p><p>pe</p><p>d</p><p>fro</p><p>m</p><p>d</p><p>iff</p><p>er</p><p>en</p><p>t p</p><p>ol</p><p>ys</p><p>ac</p><p>ch</p><p>ar</p><p>id</p><p>es</p><p>Po</p><p>ly</p><p>sa</p><p>cc</p><p>ha</p><p>rid</p><p>es</p><p>Pl</p><p>as</p><p>tic</p><p>iz</p><p>er</p><p>Pr</p><p>oc</p><p>es</p><p>si</p><p>ng</p><p>Re</p><p>su</p><p>lt/</p><p>Im</p><p>pr</p><p>ov</p><p>ed</p><p>F</p><p>ilm</p><p>p</p><p>ro</p><p>pe</p><p>rti</p><p>es</p><p>Re</p><p>fe</p><p>re</p><p>nc</p><p>es</p><p>ce</p><p>llu</p><p>lo</p><p>se</p><p>e</p><p>xt</p><p>ra</p><p>ct</p><p>ed</p><p>fr</p><p>om</p><p>P</p><p>ro</p><p>so</p><p>pi</p><p>s j</p><p>ul</p><p>ifl</p><p>or</p><p>a</p><p>G</p><p>ly</p><p>ce</p><p>ro</p><p>l a</p><p>nd</p><p>c</p><p>itr</p><p>ic</p><p>a</p><p>ci</p><p>d</p><p>C</p><p>as</p><p>tin</p><p>g</p><p>B</p><p>io</p><p>-p</p><p>la</p><p>sti</p><p>c</p><p>fil</p><p>m</p><p>s h</p><p>av</p><p>e</p><p>fa</p><p>vo</p><p>ra</p><p>bl</p><p>e</p><p>pr</p><p>op</p><p>er</p><p>tie</p><p>s l</p><p>ik</p><p>e</p><p>hi</p><p>gh</p><p>te</p><p>n-</p><p>si</p><p>le</p><p>st</p><p>re</p><p>ng</p><p>th</p><p>, b</p><p>ur</p><p>sti</p><p>ng</p><p>st</p><p>re</p><p>ng</p><p>th</p><p>, b</p><p>io</p><p>de</p><p>gr</p><p>ad</p><p>ab</p><p>ili</p><p>ty</p><p>, a</p><p>nd</p><p>he</p><p>at</p><p>st</p><p>ab</p><p>ili</p><p>ty</p><p>c</p><p>om</p><p>pa</p><p>re</p><p>d</p><p>to</p><p>o</p><p>th</p><p>er</p><p>b</p><p>io</p><p>-p</p><p>la</p><p>sti</p><p>cs</p><p>M</p><p>K</p><p>, P</p><p>[4</p><p>8]</p><p>Ya</p><p>m</p><p>S</p><p>ta</p><p>rc</p><p>h,</p><p>ti</p><p>ta</p><p>ni</p><p>um</p><p>d</p><p>io</p><p>xi</p><p>de</p><p>n</p><p>an</p><p>ofi</p><p>lle</p><p>r</p><p>G</p><p>ly</p><p>ce</p><p>ro</p><p>l</p><p>C</p><p>as</p><p>tin</p><p>g</p><p>A</p><p>dd</p><p>in</p><p>g</p><p>tit</p><p>an</p><p>iu</p><p>m</p><p>d</p><p>io</p><p>xi</p><p>de</p><p>n</p><p>an</p><p>ofi</p><p>lle</p><p>rs</p><p>c</p><p>an</p><p>im</p><p>pr</p><p>ov</p><p>e</p><p>bi</p><p>o-</p><p>pl</p><p>as</p><p>tic</p><p>fi</p><p>lm</p><p>p</p><p>ro</p><p>pe</p><p>rti</p><p>es</p><p>, i</p><p>nc</p><p>lu</p><p>di</p><p>ng</p><p>a</p><p>nt</p><p>ib</p><p>ac</p><p>te</p><p>ria</p><p>l a</p><p>ct</p><p>iv</p><p>ity</p><p>,</p><p>ba</p><p>rr</p><p>ie</p><p>r q</p><p>ua</p><p>lit</p><p>ie</p><p>s,</p><p>te</p><p>ns</p><p>ile</p><p>st</p><p>re</p><p>ng</p><p>th</p><p>, a</p><p>nd</p><p>th</p><p>er</p><p>m</p><p>al</p><p>st</p><p>ab</p><p>ili</p><p>ty</p><p>C</p><p>he</p><p>m</p><p>iru</p><p>a</p><p>nd</p><p>G</p><p>on</p><p>fa</p><p>[4</p><p>9]</p><p>Sw</p><p>ee</p><p>t P</p><p>ot</p><p>at</p><p>o</p><p>st</p><p>ar</p><p>ch</p><p>(S</p><p>PS</p><p>)</p><p>G</p><p>ly</p><p>ce</p><p>ro</p><p>l</p><p>C</p><p>as</p><p>tin</p><p>g</p><p>Th</p><p>e</p><p>1:</p><p>3</p><p>SP</p><p>S-</p><p>ge</p><p>la</p><p>tin</p><p>fi</p><p>lm</p><p>e</p><p>xh</p><p>ib</p><p>ite</p><p>d</p><p>de</p><p>si</p><p>ra</p><p>bl</p><p>e</p><p>qu</p><p>al</p><p>iti</p><p>es</p><p>lik</p><p>e</p><p>hi</p><p>gh</p><p>m</p><p>oi</p><p>stu</p><p>re</p><p>c</p><p>on</p><p>te</p><p>nt</p><p>, l</p><p>ow</p><p>so</p><p>lu</p><p>bi</p><p>lit</p><p>y,</p><p>lo</p><p>w</p><p>w</p><p>at</p><p>er</p><p>va</p><p>po</p><p>r p</p><p>er</p><p>m</p><p>ea</p><p>bi</p><p>lit</p><p>y,</p><p>h</p><p>ig</p><p>h</p><p>op</p><p>ac</p><p>ity</p><p>, a</p><p>nd</p><p>g</p><p>oo</p><p>d</p><p>po</p><p>ly</p><p>m</p><p>er</p><p>co</p><p>m</p><p>pa</p><p>tib</p><p>ili</p><p>ty</p><p>G</p><p>ho</p><p>sh</p><p>al</p><p>a</p><p>nd</p><p>K</p><p>au</p><p>r [</p><p>50</p><p>]</p><p>M</p><p>an</p><p>go</p><p>S</p><p>ee</p><p>d</p><p>St</p><p>ar</p><p>ch</p><p>G</p><p>ly</p><p>ce</p><p>ro</p><p>l (</p><p>G</p><p>),</p><p>so</p><p>rb</p><p>ito</p><p>l (</p><p>S)</p><p>a</p><p>nd</p><p>1</p><p>:1</p><p>m</p><p>ix</p><p>tu</p><p>re</p><p>o</p><p>f g</p><p>ly</p><p>ce</p><p>ro</p><p>l a</p><p>nd</p><p>so</p><p>rb</p><p>ito</p><p>l</p><p>(G</p><p>S)</p><p>C</p><p>as</p><p>tin</p><p>g</p><p>G</p><p>-p</p><p>la</p><p>sti</p><p>ci</p><p>ze</p><p>d</p><p>fil</p><p>m</p><p>s h</p><p>av</p><p>e</p><p>hi</p><p>gh</p><p>er</p><p>m</p><p>oi</p><p>stu</p><p>re</p><p>, l</p><p>ow</p><p>er</p><p>te</p><p>ns</p><p>ile</p><p>,</p><p>hi</p><p>gh</p><p>er</p><p>e</p><p>lo</p><p>ng</p><p>at</p><p>io</p><p>n,</p><p>lo</p><p>w</p><p>er</p><p>g</p><p>la</p><p>ss</p><p>tr</p><p>an</p><p>si</p><p>tio</p><p>n,</p><p>a</p><p>nd</p><p>h</p><p>ig</p><p>he</p><p>r</p><p>tra</p><p>ns</p><p>pa</p><p>re</p><p>nc</p><p>y</p><p>co</p><p>m</p><p>pa</p><p>re</p><p>d</p><p>to</p><p>S</p><p>- a</p><p>nd</p><p>G</p><p>S-</p><p>pl</p><p>as</p><p>tic</p><p>iz</p><p>ed</p><p>fi</p><p>lm</p><p>s.</p><p>In</p><p>cr</p><p>ea</p><p>si</p><p>ng</p><p>p</p><p>la</p><p>sti</p><p>ci</p><p>ze</p><p>r i</p><p>m</p><p>pr</p><p>ov</p><p>es</p><p>c</p><p>ol</p><p>or</p><p>, d</p><p>ec</p><p>re</p><p>as</p><p>es</p><p>c</p><p>ry</p><p>s-</p><p>ta</p><p>lli</p><p>ni</p><p>ty</p><p>, a</p><p>nd</p><p>e</p><p>nh</p><p>an</p><p>ce</p><p>s U</p><p>V</p><p>b</p><p>ar</p><p>rie</p><p>r i</p><p>n</p><p>al</p><p>l fi</p><p>lm</p><p>s</p><p>N</p><p>aw</p><p>ab</p><p>, A</p><p>la</p><p>m</p><p>[5</p><p>1]</p><p>Po</p><p>ta</p><p>to</p><p>p</p><p>ee</p><p>l s</p><p>ta</p><p>rc</p><p>h</p><p>G</p><p>ly</p><p>ce</p><p>ro</p><p>l a</p><p>nd</p><p>S</p><p>or</p><p>bi</p><p>to</p><p>l</p><p>C</p><p>as</p><p>tin</p><p>g</p><p>Th</p><p>e</p><p>op</p><p>tim</p><p>iz</p><p>ed</p><p>b</p><p>io</p><p>-p</p><p>la</p><p>sti</p><p>c</p><p>fil</p><p>m</p><p>h</p><p>ad</p><p>te</p><p>ns</p><p>ile</p><p>st</p><p>re</p><p>ng</p><p>th</p><p>o</p><p>f</p><p>6.</p><p>44</p><p>9</p><p>M</p><p>Pa</p><p>, e</p><p>lo</p><p>ng</p><p>at</p><p>io</p><p>n</p><p>of</p><p>1</p><p>9.</p><p>87</p><p>%</p><p>, b</p><p>io</p><p>de</p><p>gr</p><p>ad</p><p>ab</p><p>ili</p><p>ty</p><p>o</p><p>f</p><p>83</p><p>.9</p><p>2%</p><p>, a</p><p>nd</p><p>w</p><p>at</p><p>er</p><p>a</p><p>bs</p><p>or</p><p>pt</p><p>io</p><p>n</p><p>of</p><p>5</p><p>9.</p><p>94</p><p>%</p><p>—</p><p>su</p><p>pe</p><p>rio</p><p>r t</p><p>o</p><p>ot</p><p>he</p><p>r s</p><p>ta</p><p>rc</p><p>h-</p><p>ba</p><p>se</p><p>d</p><p>bi</p><p>o-</p><p>pl</p><p>as</p><p>tic</p><p>s</p><p>C</p><p>ha</p><p>ffa</p><p>, M</p><p>es</p><p>he</p><p>sh</p><p>a</p><p>[1</p><p>7]</p><p>Ta</p><p>m</p><p>ar</p><p>in</p><p>ds</p><p>ee</p><p>d</p><p>st</p><p>ar</p><p>ch</p><p>a</p><p>nd</p><p>A</p><p>rju</p><p>na</p><p>p</p><p>ow</p><p>de</p><p>r</p><p>vi</p><p>ne</p><p>ga</p><p>r a</p><p>nd</p><p>gl</p><p>yc</p><p>er</p><p>ol</p><p>C</p><p>as</p><p>tin</p><p>g</p><p>Th</p><p>e</p><p>bi</p><p>o-</p><p>pl</p><p>as</p><p>tic</p><p>fi</p><p>lm</p><p>s s</p><p>ho</p><p>w</p><p>ed</p><p>7</p><p>3%</p><p>b</p><p>io</p><p>de</p><p>gr</p><p>ad</p><p>at</p><p>io</p><p>n</p><p>in</p><p>3</p><p>0</p><p>da</p><p>ys</p><p>, h</p><p>ig</p><p>h</p><p>te</p><p>ns</p><p>ile</p><p>st</p><p>re</p><p>ng</p><p>th</p><p>, t</p><p>he</p><p>rm</p><p>al</p><p>st</p><p>ab</p><p>ili</p><p>ty</p><p>, a</p><p>nd</p><p>a</p><p>nt</p><p>i-</p><p>ba</p><p>ct</p><p>er</p><p>ia</p><p>l a</p><p>ct</p><p>iv</p><p>ity</p><p>. T</p><p>he</p><p>y</p><p>ar</p><p>e</p><p>ec</p><p>on</p><p>om</p><p>ic</p><p>al</p><p>, e</p><p>co</p><p>-f</p><p>rie</p><p>nd</p><p>ly</p><p>,</p><p>an</p><p>d</p><p>su</p><p>ita</p><p>bl</p><p>e</p><p>fo</p><p>r f</p><p>oo</p><p>d</p><p>pa</p><p>ck</p><p>ag</p><p>in</p><p>g</p><p>C</p><p>ho</p><p>w</p><p>dh</p><p>ur</p><p>y,</p><p>H</p><p>os</p><p>sa</p><p>in</p><p>[4</p><p>3]</p><p>Po</p><p>ta</p><p>to</p><p>S</p><p>ta</p><p>rc</p><p>h</p><p>G</p><p>ly</p><p>ce</p><p>ro</p><p>l a</p><p>nd</p><p>so</p><p>rb</p><p>ito</p><p>l</p><p>C</p><p>as</p><p>tin</p><p>g</p><p>A</p><p>dd</p><p>in</p><p>g</p><p>pl</p><p>as</p><p>tic</p><p>iz</p><p>er</p><p>s i</p><p>nc</p><p>re</p><p>as</p><p>es</p><p>w</p><p>at</p><p>er</p><p>v</p><p>ap</p><p>or</p><p>p</p><p>er</p><p>m</p><p>ea</p><p>bi</p><p>lit</p><p>y</p><p>an</p><p>d</p><p>fle</p><p>xi</p><p>bi</p><p>lit</p><p>y,</p><p>b</p><p>ut</p><p>d</p><p>ec</p><p>re</p><p>as</p><p>es</p><p>te</p><p>ns</p><p>ile</p><p>st</p><p>re</p><p>ng</p><p>th</p><p>. G</p><p>ly</p><p>ce</p><p>ro</p><p>l</p><p>pl</p><p>as</p><p>tic</p><p>iz</p><p>er</p><p>g</p><p>iv</p><p>es</p><p>h</p><p>ig</p><p>he</p><p>r W</p><p>V</p><p>TR</p><p>a</p><p>nd</p><p>w</p><p>at</p><p>er</p><p>a</p><p>bs</p><p>or</p><p>pt</p><p>io</p><p>n</p><p>th</p><p>an</p><p>so</p><p>rb</p><p>ito</p><p>l.</p><p>B</p><p>io</p><p>de</p><p>gr</p><p>ad</p><p>ab</p><p>ili</p><p>ty</p><p>d</p><p>ec</p><p>re</p><p>as</p><p>es</p><p>w</p><p>ith</p><p>h</p><p>ig</p><p>he</p><p>r</p><p>pl</p><p>as</p><p>tic</p><p>iz</p><p>er</p><p>c</p><p>on</p><p>ce</p><p>nt</p><p>ra</p><p>tio</p><p>n</p><p>N</p><p>g,</p><p>K</p><p>ie</p><p>w</p><p>[5</p><p>2]</p><p>B</p><p>le</p><p>nd</p><p>o</p><p>f r</p><p>ic</p><p>e</p><p>an</p><p>d</p><p>po</p><p>ta</p><p>to</p><p>st</p><p>ar</p><p>ch</p><p>G</p><p>ly</p><p>ce</p><p>ro</p><p>l</p><p>C</p><p>as</p><p>tin</p><p>g</p><p>Th</p><p>e</p><p>cr</p><p>os</p><p>s-</p><p>lin</p><p>ke</p><p>d</p><p>bi</p><p>o-</p><p>pl</p><p>as</p><p>tic</p><p>sh</p><p>ow</p><p>ed</p><p>e</p><p>nh</p><p>an</p><p>ce</p><p>d</p><p>m</p><p>ec</p><p>ha</p><p>ni</p><p>-</p><p>ca</p><p>l s</p><p>tre</p><p>ng</p><p>th</p><p>, t</p><p>he</p><p>rm</p><p>al</p><p>st</p><p>ab</p><p>ili</p><p>ty</p><p>, a</p><p>nt</p><p>ib</p><p>ac</p><p>te</p><p>ria</p><p>l a</p><p>ct</p><p>iv</p><p>ity</p><p>,</p><p>an</p><p>d</p><p>bi</p><p>od</p><p>eg</p><p>ra</p><p>da</p><p>bi</p><p>lit</p><p>y</p><p>co</p><p>m</p><p>pa</p><p>re</p><p>d</p><p>to</p><p>n</p><p>on</p><p>-c</p><p>ro</p><p>ss</p><p>-li</p><p>nk</p><p>ed</p><p>,</p><p>w</p><p>hi</p><p>le</p><p>h</p><p>ig</p><p>he</p><p>r C</p><p>A</p><p>c</p><p>on</p><p>ce</p><p>nt</p><p>ra</p><p>tio</p><p>n</p><p>re</p><p>du</p><p>ce</p><p>d</p><p>m</p><p>oi</p><p>stu</p><p>re</p><p>,</p><p>w</p><p>at</p><p>er</p><p>v</p><p>ap</p><p>or</p><p>tr</p><p>an</p><p>sm</p><p>is</p><p>si</p><p>on</p><p>, a</p><p>nd</p><p>su</p><p>rfa</p><p>ce</p><p>ro</p><p>ug</p><p>hn</p><p>es</p><p>s</p><p>C</p><p>ha</p><p>kr</p><p>ab</p><p>or</p><p>ty</p><p>, N</p><p>[5</p><p>3]</p><p>Ya</p><p>m</p><p>st</p><p>ar</p><p>ch</p><p>G</p><p>ly</p><p>ce</p><p>ro</p><p>l</p><p>So</p><p>lu</p><p>tio</p><p>n</p><p>ca</p><p>sti</p><p>ng</p><p>Th</p><p>e</p><p>ad</p><p>di</p><p>tio</p><p>n</p><p>of</p><p>1</p><p>.5</p><p>%</p><p>(w</p><p>/w</p><p>) b</p><p>en</p><p>to</p><p>ni</p><p>te</p><p>e</p><p>nh</p><p>an</p><p>ce</p><p>d</p><p>th</p><p>e</p><p>bi</p><p>o-</p><p>pl</p><p>as</p><p>tic</p><p>fi</p><p>lm</p><p>s'</p><p>m</p><p>ec</p><p>ha</p><p>ni</p><p>ca</p><p>l s</p><p>tre</p><p>ng</p><p>th</p><p>, r</p><p>es</p><p>ist</p><p>an</p><p>ce</p><p>to</p><p>so</p><p>il</p><p>de</p><p>gr</p><p>ad</p><p>at</p><p>io</p><p>n,</p><p>w</p><p>at</p><p>er</p><p>re</p><p>si</p><p>st</p><p>an</p><p>ce</p><p>, a</p><p>nd</p><p>re</p><p>du</p><p>ce</p><p>d</p><p>w</p><p>at</p><p>er</p><p>v</p><p>ap</p><p>or</p><p>tra</p><p>ns</p><p>m</p><p>is</p><p>si</p><p>on</p><p>ra</p><p>te</p><p>B</p><p>eh</p><p>er</p><p>a,</p><p>M</p><p>oh</p><p>an</p><p>ta</p><p>[5</p><p>4]</p><p>O</p><p>ra</p><p>ng</p><p>e</p><p>pe</p><p>el</p><p>G</p><p>ly</p><p>ce</p><p>ro</p><p>l</p><p>C</p><p>as</p><p>tin</p><p>g</p><p>Th</p><p>e</p><p>re</p><p>su</p><p>lti</p><p>ng</p><p>b</p><p>io</p><p>-p</p><p>la</p><p>sti</p><p>c</p><p>fil</p><p>m</p><p>is</p><p>tr</p><p>an</p><p>sl</p><p>uc</p><p>en</p><p>t a</p><p>nd</p><p>ri</p><p>gi</p><p>d,</p><p>w</p><p>ith</p><p>g</p><p>oo</p><p>d</p><p>oi</p><p>l a</p><p>nd</p><p>w</p><p>at</p><p>er</p><p>re</p><p>te</p><p>nt</p><p>io</p><p>n,</p><p>h</p><p>ig</p><p>h</p><p>m</p><p>ec</p><p>ha</p><p>ni</p><p>ca</p><p>l</p><p>str</p><p>en</p><p>gt</p><p>h,</p><p>th</p><p>er</p><p>m</p><p>al</p><p>st</p><p>ab</p><p>ili</p><p>ty</p><p>, a</p><p>nd</p><p>2</p><p>3.</p><p>76</p><p>%</p><p>d</p><p>eg</p><p>ra</p><p>da</p><p>tio</p><p>n</p><p>in</p><p>31</p><p>d</p><p>ay</p><p>s u</p><p>nd</p><p>er</p><p>n</p><p>at</p><p>ur</p><p>al</p><p>so</p><p>il</p><p>co</p><p>nd</p><p>iti</p><p>on</p><p>s</p><p>Ya</p><p>ra</p><p>do</p><p>dd</p><p>i,</p><p>B</p><p>an</p><p>ap</p><p>ur</p><p>m</p><p>at</p><p>h</p><p>[5</p><p>5]</p><p>Biomass Conversion and Biorefinery</p><p>Ta</p><p>bl</p><p>e</p><p>5</p><p>(c</p><p>on</p><p>tin</p><p>ue</p><p>d)</p><p>Po</p><p>ly</p><p>sa</p><p>cc</p><p>ha</p><p>rid</p><p>es</p><p>Pl</p><p>as</p><p>tic</p><p>iz</p><p>er</p><p>Pr</p><p>oc</p><p>es</p><p>si</p><p>ng</p><p>Re</p><p>su</p><p>lt/</p><p>Im</p><p>pr</p><p>ov</p><p>ed</p><p>F</p><p>ilm</p><p>p</p><p>ro</p><p>pe</p><p>rti</p><p>es</p><p>Re</p><p>fe</p><p>re</p><p>nc</p><p>es</p><p>Ta</p><p>ro</p><p>, S</p><p>ta</p><p>rc</p><p>h</p><p>G</p><p>ly</p><p>ce</p><p>ro</p><p>l</p><p>C</p><p>as</p><p>tin</p><p>g</p><p>B</p><p>io</p><p>-p</p><p>la</p><p>sti</p><p>c</p><p>fil</p><p>m</p><p>s w</p><p>ith</p><p>a</p><p>dd</p><p>ed</p><p>b</p><p>en</p><p>to</p><p>ni</p><p>te</p><p>e</p><p>xh</p><p>ib</p><p>it</p><p>ex</p><p>ce</p><p>lle</p><p>nt</p><p>m</p><p>ec</p><p>ha</p><p>ni</p><p>ca</p><p>l p</p><p>ro</p><p>pe</p><p>rti</p><p>es</p><p>, u</p><p>ni</p><p>fo</p><p>rm</p><p>ity</p><p>, a</p><p>nd</p><p>b</p><p>io</p><p>de</p><p>gr</p><p>ad</p><p>ab</p><p>il-</p><p>ity</p><p>, a</p><p>s w</p><p>el</p><p>l a</p><p>s r</p><p>ed</p><p>uc</p><p>ed</p><p>re</p><p>tro</p><p>gr</p><p>ad</p><p>at</p><p>io</p><p>n</p><p>an</p><p>d</p><p>im</p><p>pr</p><p>ov</p><p>ed</p><p>re</p><p>si</p><p>st</p><p>an</p><p>ce</p><p>to</p><p>sa</p><p>lts</p><p>a</p><p>nd</p><p>a</p><p>ci</p><p>ds</p><p>Sh</p><p>an</p><p>m</p><p>at</p><p>hy</p><p>, M</p><p>oh</p><p>an</p><p>ta</p><p>[5</p><p>6]</p><p>Po</p><p>ta</p><p>to</p><p>st</p><p>ar</p><p>ch</p><p>G</p><p>ly</p><p>ce</p><p>ro</p><p>l</p><p>So</p><p>lu</p><p>tio</p><p>n</p><p>ca</p><p>sti</p><p>ng</p><p>m</p><p>et</p><p>ho</p><p>d</p><p>Th</p><p>e</p><p>bi</p><p>o-</p><p>pl</p><p>as</p><p>tic</p><p>c</p><p>om</p><p>po</p><p>si</p><p>te</p><p>s o</p><p>ut</p><p>pe</p><p>rfo</p><p>rm</p><p>n</p><p>on</p><p>-c</p><p>ro</p><p>ss</p><p>-</p><p>lin</p><p>ke</p><p>d</p><p>bi</p><p>o-</p><p>pl</p><p>as</p><p>tic</p><p>in</p><p>m</p><p>ec</p><p>ha</p><p>ni</p><p>ca</p><p>l,</p><p>th</p><p>er</p><p>m</p><p>al</p><p>, s</p><p>tru</p><p>ct</p><p>ur</p><p>al</p><p>,</p><p>an</p><p>d</p><p>w</p><p>at</p><p>er</p><p>-r</p><p>es</p><p>ist</p><p>an</p><p>t p</p><p>ro</p><p>pe</p><p>rti</p><p>es</p><p>, w</p><p>ith</p><p>re</p><p>du</p><p>ce</p><p>d</p><p>m</p><p>oi</p><p>stu</p><p>re</p><p>ab</p><p>so</p><p>rp</p><p>tio</p><p>n/</p><p>re</p><p>le</p><p>as</p><p>e,</p><p>h</p><p>ig</p><p>he</p><p>r t</p><p>en</p><p>si</p><p>le</p><p>st</p><p>re</p><p>ng</p><p>th</p><p>, m</p><p>el</p><p>tin</p><p>g</p><p>po</p><p>in</p><p>t,</p><p>th</p><p>er</p><p>m</p><p>al</p><p>st</p><p>ab</p><p>ili</p><p>ty</p><p>, a</p><p>nd</p><p>g</p><p>oo</p><p>d</p><p>bi</p><p>od</p><p>eg</p><p>ra</p><p>da</p><p>bi</p><p>lit</p><p>y</p><p>in</p><p>so</p><p>il</p><p>Ya</p><p>ng</p><p>, C</p><p>hi</p><p>ng</p><p>[5</p><p>7]</p><p>Re</p><p>d</p><p>se</p><p>aw</p><p>ee</p><p>d</p><p>K</p><p>ap</p><p>pa</p><p>ph</p><p>yc</p><p>us</p><p>a</p><p>lv</p><p>ar</p><p>ez</p><p>ii</p><p>Po</p><p>ly</p><p>et</p><p>hy</p><p>le</p><p>ne</p><p>g</p><p>ly</p><p>co</p><p>l (</p><p>PE</p><p>G</p><p>-3</p><p>00</p><p>0)</p><p>So</p><p>lu</p><p>tio</p><p>n</p><p>C</p><p>as</p><p>tin</p><p>g</p><p>Th</p><p>e</p><p>4%</p><p>se</p><p>aw</p><p>ee</p><p>d</p><p>ex</p><p>tra</p><p>ct</p><p>b</p><p>io</p><p>-p</p><p>la</p><p>sti</p><p>c</p><p>fil</p><p>m</p><p>h</p><p>ad</p><p>th</p><p>e</p><p>hi</p><p>gh</p><p>es</p><p>t</p><p>te</p><p>ns</p><p>ile</p><p>st</p><p>re</p><p>ng</p><p>th</p><p>, w</p><p>hi</p><p>le</p><p>th</p><p>e</p><p>3%</p><p>fi</p><p>lm</p><p>h</p><p>ad</p><p>th</p><p>e</p><p>lo</p><p>w</p><p>es</p><p>t</p><p>ox</p><p>yg</p><p>en</p><p>a</p><p>nd</p><p>w</p><p>at</p><p>er</p><p>v</p><p>ap</p><p>or</p><p>tr</p><p>an</p><p>sm</p><p>is</p><p>si</p><p>on</p><p>ra</p><p>te</p><p>s.</p><p>Th</p><p>e</p><p>gl</p><p>as</p><p>s</p><p>tra</p><p>ns</p><p>iti</p><p>on</p><p>a</p><p>nd</p><p>m</p><p>el</p><p>tin</p><p>g</p><p>te</p><p>m</p><p>pe</p><p>ra</p><p>tu</p><p>re</p><p>s r</p><p>an</p><p>ge</p><p>d</p><p>fro</p><p>m</p><p>84</p><p>.5</p><p>–8</p><p>9.</p><p>1</p><p>°C</p><p>a</p><p>nd</p><p>2</p><p>20</p><p>–4</p><p>00</p><p>°C</p><p>, r</p><p>es</p><p>pe</p><p>ct</p><p>iv</p><p>el</p><p>y</p><p>Su</p><p>dh</p><p>ak</p><p>ar</p><p>, M</p><p>ag</p><p>es</p><p>h</p><p>Pe</p><p>te</p><p>r [</p><p>58</p><p>]</p><p>Po</p><p>ta</p><p>to</p><p>st</p><p>ar</p><p>ch</p><p>C</p><p>itr</p><p>ic</p><p>a</p><p>ci</p><p>d</p><p>C</p><p>as</p><p>tin</p><p>g</p><p>Th</p><p>e</p><p>bi</p><p>o-</p><p>pl</p><p>as</p><p>tic</p><p>fi</p><p>lm</p><p>e</p><p>xh</p><p>ib</p><p>ite</p><p>d</p><p>en</p><p>ha</p><p>nc</p><p>ed</p><p>b</p><p>ar</p><p>rie</p><p>r p</p><p>ro</p><p>pe</p><p>r-</p><p>tie</p><p>s l</p><p>ik</p><p>e</p><p>lo</p><p>w</p><p>m</p><p>oi</p><p>stu</p><p>re</p><p>a</p><p>bs</p><p>or</p><p>pt</p><p>io</p><p>n,</p><p>re</p><p>fle</p><p>ct</p><p>iv</p><p>ity</p><p>, a</p><p>nd</p><p>w</p><p>at</p><p>er</p><p>v</p><p>ap</p><p>or</p><p>re</p><p>le</p><p>as</p><p>e,</p><p>a</p><p>s w</p><p>el</p><p>l a</p><p>s g</p><p>oo</p><p>d</p><p>th</p><p>er</p><p>m</p><p>al</p><p>st</p><p>ab</p><p>ili</p><p>ty</p><p>Sa</p><p>liu</p><p>, O</p><p>la</p><p>tu</p><p>nj</p><p>i [</p><p>59</p><p>]</p><p>Ta</p><p>m</p><p>ar</p><p>in</p><p>d</p><p>se</p><p>ed</p><p>st</p><p>ar</p><p>ch</p><p>G</p><p>ly</p><p>ce</p><p>ro</p><p>l</p><p>C</p><p>as</p><p>tin</p><p>g</p><p>Th</p><p>e</p><p>op</p><p>tim</p><p>al</p><p>b</p><p>io</p><p>-b</p><p>as</p><p>ed</p><p>fi</p><p>lm</p><p>c</p><p>om</p><p>po</p><p>si</p><p>tio</p><p>n</p><p>w</p><p>as</p><p>0.</p><p>2</p><p>g/</p><p>10</p><p>0</p><p>m</p><p>L</p><p>xa</p><p>nt</p><p>ha</p><p>n</p><p>gu</p><p>m</p><p>, 5</p><p>m</p><p>L/</p><p>10</p><p>0</p><p>m</p><p>L</p><p>gl</p><p>yc</p><p>er</p><p>ol</p><p>,</p><p>an</p><p>d</p><p>5</p><p>g/</p><p>10</p><p>0</p><p>m</p><p>L</p><p>ta</p><p>m</p><p>ar</p><p>in</p><p>d</p><p>se</p><p>ed</p><p>st</p><p>ar</p><p>ch</p><p>, y</p><p>ie</p><p>ld</p><p>in</p><p>g</p><p>hi</p><p>gh</p><p>te</p><p>ns</p><p>ile</p><p>st</p><p>re</p><p>ng</p><p>th</p><p>(4</p><p>8.</p><p>24</p><p>±</p><p>2.</p><p>57</p><p>M</p><p>Pa</p><p>) a</p><p>nd</p><p>m</p><p>od</p><p>er</p><p>at</p><p>e</p><p>el</p><p>on</p><p>ga</p><p>tio</p><p>n</p><p>(2</p><p>7.</p><p>32</p><p>±</p><p>1.</p><p>75</p><p>%</p><p>).</p><p>Th</p><p>e</p><p>fil</p><p>m</p><p>a</p><p>ls</p><p>o</p><p>ex</p><p>hi</p><p>bi</p><p>te</p><p>d</p><p>an</p><p>tib</p><p>ac</p><p>te</p><p>ria</p><p>l,</p><p>an</p><p>tio</p><p>xi</p><p>da</p><p>nt</p><p>, a</p><p>nd</p><p>g</p><p>as</p><p>b</p><p>ar</p><p>rie</p><p>r p</p><p>ro</p><p>pe</p><p>rti</p><p>es</p><p>R</p><p>ak</p><p>ha</p><p>va</p><p>n,</p><p>S</p><p>ud</p><p>ha</p><p>rs</p><p>an</p><p>[6</p><p>]</p><p>Biomass Conversion and Biorefinery</p><p>starch increased its hydrophilic character. As a result,</p><p>more water molecules were transported via the film. Tam-</p><p>arind seed starch oxidation reduces water vapor perme-</p><p>ability because it increases hydrophobicity, which is con-</p><p>sistent with research by Zamudio‐Flores, Bautista‐Baños</p><p>[45]. It has been discovered that grape pomace extract</p><p>(GPE) reduces the water vapor permeability of starch-</p><p>based films. The addition of GPE to starch films increases</p><p>their water vapor barrier properties, making them less</p><p>permeable to water vapor. This is due to the hydrophilic</p><p>nature of GPE, which increases the hydrophilic portion of</p><p>the film and acts as a plasticizer, reducing the molecular</p><p>interactions of the polymer chain [34].</p><p>3.4.4 Thermal properties</p><p>Differential scanning calorimetric analysis of bio‑plastic The</p><p>study employed differential scanning calorimetry (DSC) to</p><p>quantify the heat transfer and variations in the thermal char-</p><p>acteristics of the starch films, including melting, crystalliza-</p><p>tion, and glass transition [60]. Understanding the behavior of</p><p>bioplastics under temperature fluctuations and determining</p><p>their suitability for packaging applications requires analyz-</p><p>ing the thermal parameters, such as melting points and heat</p><p>capacities, using DSC [61, 62].</p><p>In this study, DSC was used to compare the thermal prop-</p><p>erties of three different films: modified tamarind seed starch</p><p>film, native tamarind seed starch film, and corn starch film. It</p><p>was used as a method for analyzing and evaluating these films</p><p>thermal behavior. Bio-plastics thermal characteristics are sig-</p><p>nificant for a number of uses. For example, plastics low heat</p><p>conductivity and insulating qualities are essential for preserv-</p><p>ing food quality in food packaging [63]. Because of the strong</p><p>hydrogen bonding between its molecular chains, native starch</p><p>has significant stiffness, which presents difficulties during heat</p><p>processing [64]. In comparison to native and control films,</p><p>modified starch-based film exhibits better thermal stability,</p><p>indicating the significance of starch modification as shown in</p><p>Fig. 8. Starch is frequently changed to increase film qualities</p><p>and to improve its properties [38].</p><p>For CF, NF, and MF, the bio-plastic melting temperatures</p><p>are 337 °C, 306 °C, and 309 °C, respectively. When compared</p><p>to non-oxidized and oxidized tamarind seed starch films, the</p><p>control film showed a higher melting temperature; so, corn</p><p>films have a high Tm as well as better thermal stability. When</p><p>compared to native starch bio-plastic, oxidized tamarind starch</p><p>bio-plastic has better thermal characteristics. In the same way,</p><p>corn film might not be as biodegradable as starch-based bio-</p><p>plastics even though it might have great heat stability. One way</p><p>to evaluate the thermal stability of the films is to observe them</p><p>at the melting</p><p>and thermal decomposition temperatures of the</p><p>crystalline structure [65].</p><p>3.4.5 Functional groups, structural and morphological</p><p>analysis of films</p><p>FTIR analysis The modified tamarind seed starch based film</p><p>(MF), native starch based film (NF), and corn starch based</p><p>film (CF) broad peaks, which measure 3278.61, 3286.73, and</p><p>3270.71, respectively, indicate the secondary NH stretching</p><p>in this investigation. The spectra of CO (amide I) and NH2</p><p>def(amide II), Primary (1650–1620  cm−1), and inorganic</p><p>phosphates are highly distinctive. The accompanying Fig. 9</p><p>shows two distinct bands that are located at approximately</p><p>1000  cm−1 and 550  cm−1 for reference.</p><p>Fig. 8 DSC thermograms of modified tamarind seed starch (MF),</p><p>native tamarind seed starch (NF) and corn starch (CF) based films</p><p>Fig. 9 FTIR for control (CF), native (NF), and modified (MF) starch-</p><p>based film</p><p>Biomass Conversion and Biorefinery</p><p>The addition of glycerol and grape pomace extract</p><p>resulted in changes in absorption strengths and peak posi-</p><p>tions, indicating modifications in polysaccharide bonding.</p><p>According to study of [27] incorporating grape pomace</p><p>extract into chitosan films led to alterations in peak intensi-</p><p>ties, suggesting increased hydrophilicity.</p><p>The interaction of starches with glycerol and polyphenols</p><p>during film development was the cause of the peaks shift-</p><p>ing from 996.08, 1016.37, and 1017.77 cm−1 for CS, MS,</p><p>and NS to 996.79, 1029.63, and 1027.41 cm−1 for starch-</p><p>based film. Results from [66] showed that the addition of</p><p>additional -OH functionalities from plasticizers and BS was</p><p>responsible for the peaks rising absorption strength in the</p><p>range of 3400 cm−1.</p><p>SEM analysis Determining the surface structure, cracks, and</p><p>smoothness was the aim of the surface morphology exami-</p><p>nation [61]. The study used scanning electron microscopy</p><p>to examine starch films that had been incorporated with 6%</p><p>w/w crude extract of grape pomace. The SEM micrograph</p><p>revealed particles of approximately 50 μm in size as pre-</p><p>sented in Fig. 10. Compared to native tamarind starch and</p><p>corn starch-based films, the modified tamarind starch-based</p><p>active film had exhibited a greater degree of homogeneity,</p><p>indicating that it had preserved the denser internal micro-</p><p>structures, including the distribution and arrangement of the</p><p>starch and grape pomace extract components. The modified</p><p>tamarind seed starch matrix had adhered well to the grape</p><p>pomace particles, while the films made from native tamarind</p><p>seed starch were less smooth, significantly rougher, and had</p><p>exhibited fractures and other irregularities.</p><p>SEM study of bioplastics from several research pro-</p><p>vided useful details about their shape and microstructure.</p><p>According to the study of Fransiska, Wahyuni [67], the SEM</p><p>analysis of a thermoplastic agar/chitosan blend showed a</p><p>rougher and more inhomogeneous surface compared to pure</p><p>bioplastic agar and the SEM analysis of cassava bioplastics,</p><p>as reported by Sangian, Maneking [61], revealed a flat sur-</p><p>face morphology, indicating a consistent structure between</p><p>samples. The study also observed a significant reduction in</p><p>mass during the heating process.</p><p>X‑ray diffraction (XRD) analysis X-ray diffraction (XRD)</p><p>analysis is a powerful technique that can provide valuable</p><p>information about the crystalline structure and composition</p><p>of the bioplastic films developed from wild tamarind (Tam-</p><p>arindus indica L.) seed starch and grape pomace extract.</p><p>Broader and less intense peaks are typically indicative of</p><p>a more amorphous structure, whereas sharper and more</p><p>intense peaks typically show a higher degree of crystallinity.</p><p>The crystallinity of the modified tamarind seed starch-based</p><p>film is higher than that of the unmodified corn starch-based</p><p>film. This analysis demonstrates that the starch modification</p><p>can improve the crystallinity of the film [68].</p><p>Perez Sira and Dufour [5] reported that whereas the starch</p><p>extracted from tamarind seeds displayed an A-type pattern,</p><p>all other starch-based films displayed a B-type X-ray pattern.</p><p>Diffraction peaks, crystal patterns, and relative crystallinity</p><p>are the characteristics of the XRD spectra [69]. Figure 11</p><p>A B C</p><p>Fig. 10 The SEM pictures of films at 50 µm magnification levels based: A native tamarind seed starch, B modified tamarind seed starch and</p><p>corn starch C</p><p>0 10 20 30 40 50 60 70</p><p>0</p><p>200</p><p>400</p><p>600</p><p>800</p><p>1000</p><p>1200</p><p>1400</p><p>1600</p><p>)u.a(I</p><p>2 Theta (o)</p><p>MF</p><p>NF</p><p>CF</p><p>Fig. 11 XRD of film-based modified tamarind seed starch (MF),</p><p>native tamarind seed starch (NS) and corn starch (CS)</p><p>Biomass Conversion and Biorefinery</p><p>demonstrates that the modified tamarind seed starch-based</p><p>film, the unmodified (native) tamarind seed starch-based</p><p>film, and the corn starch showed the characteristic peaks</p><p>of B-type film, respectively. The film samples also showed</p><p>strong diffraction 2θ-peak values of 19.78º, 19.73º, and 19.2º</p><p>for MF, NF and CF films, respectively.</p><p>3.4.6 Determination of antioxidant properties of extract</p><p>and films</p><p>Total phenolic and flavonoid content determination The</p><p>total phenolic content of the ethanol grape pomace extract</p><p>for Syrah variety, was obtained from the calibration curve</p><p>with equation of Y = 0.0004x—0.018 (R2 = 0.997), was</p><p>282 ± 0.003 mg GAE/100g of extract and 133.5 ± 0.002 mg</p><p>QE/100 g flavonoid content of extract, was obtained from</p><p>the calibration curve with equation of Y = 0.0007x + 0.0453</p><p>(R2 = 0.993) which was extracted at solid to liquid ratio of</p><p>1:10 (g/mL) 50% ethanol/water as the solvent. This value</p><p>was fit with the result (205.53 ± 0.11 mg GAE/g 100 g−1</p><p>dry weight) obtained by [70]. TPC and TFC of active film</p><p>(containing 6% w/w grape pomace extract) was found to be</p><p>158.5 ± 0.001 mg GAE/100g of film and 65.57 ± 0.0153 mg</p><p>QE/100g of film, respectively.</p><p>DPPH radical scavenging activity and ferric reducing antioxi‑</p><p>dant power assay The presence of RGPE in the film dem-</p><p>onstrated antioxidant action, while control (with out RGPE)</p><p>films lacked antioxidant activity. The optimized film with 6%</p><p>w/w grape pomace extract exhibited inhibition percentages</p><p>ranging from 42.7 to 45.7% as plotted in Fig. 12. Additional</p><p>research conducted by Santos, Siqueira [22] and Zhang,</p><p>Liu [71] also reported similar inhibition levels in films with</p><p>natural extracts, indicating that polyphenols contribute to the</p><p>film's antioxidant capacity. The IC50 value for the extract in</p><p>the DPPH assay was 280.5 ± 0.042 µg mL−1, while the active</p><p>film had an IC50 of 556 ± 0.038 µg mL−1. Similarly, in the</p><p>FRAP assay, the EC50 of the extract was 341 ± 0.045 µg/</p><p>mL, higher than the EC50 of the film (762 ± 0.0125 µg/mL).</p><p>Antimicrobial analysis Affordable, natural, and power-</p><p>ful antimicrobial agents are essential for both food pres-</p><p>ervation and safe human consumption [72]. Antibacterial</p><p>activity against several pathogens was investigated in this</p><p>study, and Gram-positive bacteria (Staphylococcus aureus</p><p>ATCC-25923) and Gram-negative bacteria (Escherichia coli</p><p>ATCC 25922) were used as test microorganisms as shown</p><p>in Fig. 13.</p><p>The antibacterial properties of the films were effective</p><p>against both gram-positive and gram-negative bacteria.</p><p>The ethanolic grape pomace extract exhibited significantly</p><p>higher antibacterial activity compared to the grape pomace</p><p>extract-based film (Table 6). The presence of inhibition</p><p>zones indicated the films’ ability to inhibit bacterial growth.</p><p>The most susceptible bacteria were Staphylococcus aureus</p><p>and Escherichia coli.</p><p>The active films showed good antimicrobial action, mak-</p><p>ing them suitable for product packaging. Similar research</p><p>conducted by Saurabh, Gupta [9] using grape pomace extract</p><p>in guar gum-based films showed a significant reduction in</p><p>the growth of foodborne pathogens.</p><p>Fig. 12 Plot of radical scaveng-</p><p>ing percentage between ascorbic</p><p>acid and samples</p><p>Ascorbic Acid Active Film (with RGPE)</p><p>Grape Pomace Extract Film without RGPE</p><p>Biomass Conversion and</p><p>Biorefinery</p><p>4 Conclusion</p><p>In this study Tamarindus indica L. seed starch-based active</p><p>films enriched with grape pomace extract was successfully</p><p>developed and optimized using solvent-casting methods.</p><p>The optimized bio-plastic film had satisfactory physical,</p><p>mechanical, and barrier properties. The tensile strength of</p><p>the optimized film increased significantly (p < 0.05) from</p><p>11.87 ± 0.02 MPa for pure tamarind seed starch bio-plastic</p><p>to 12.77 ± 0.02 MPa for active bio-plastic film, demon-</p><p>strating improved mechanical properties. Oxidized tama-</p><p>rind seed starch decreases the water vapor permeability</p><p>due to increased hydrophobicity. GPE has been shown to</p><p>improve the mechanical properties and reduce the water</p><p>solubility of starch-based films, further contributing to</p><p>the decrease in water vapor permeability and the addi-</p><p>tion of grape pomace extract provided antibacterial and</p><p>antioxidant properties, making the films suitable for active</p><p>packaging of high-fat food products. Films developed in</p><p>this studies were also biodegradable with a rate of 63%</p><p>and environmentally friendly. Generally, it was observed</p><p>that tamarind seed starch has comparable property to corn</p><p>starch. Therefore, tamarind seed starch could be functional</p><p>as a potential alternative source of starch being used for</p><p>packaging applications in the food and other industries.</p><p>4.1 Future perspectives and commercial possibility</p><p>The research study on the optimization and characterization</p><p>of active bio-plastic film from tamarind (Tamarindus indica</p><p>L.) seed starch enriched with red grape pomace extract has</p><p>shown promising results. The film has good mechanical</p><p>properties, thermal stability, and water resistance. It also</p><p>has antimicrobial and antioxidant properties. These proper-</p><p>ties make it a potential candidate for use in food packaging,</p><p>medical applications, and other industrial applications.</p><p>The use of industrial machines in the production of active</p><p>bio-plastic film from tamarind seed starch enriched with red</p><p>grape pomace extract could improve the efficiency and qual-</p><p>ity of the film. Industrial machines could be used to auto-</p><p>mate the process of film production, which would reduce</p><p>the cost of production and make the film more affordable.</p><p>Industrial machines could also be used to control the quality</p><p>of the film, ensuring that it meets the desired specifications.</p><p>The commercial potential of active bio-plastic film from</p><p>tamarind seed starch enriched with red grape pomace extract</p><p>is high. The film has a number of advantages over traditional</p><p>plastic films, including its biodegradability, biocompatibil-</p><p>ity, and antimicrobial and antioxidant properties. These</p><p>advantages make it a good choice for a variety of applica-</p><p>tions, including food packaging, medical applications, and</p><p>other industrial applications.</p><p>The research study on the optimization and characteri-</p><p>zation of active bio-plastic film from tamarind seed starch</p><p>enriched with red grape pomace extract is a significant step</p><p>forward in the development of sustainable and biodegradable</p><p>materials. The use of industrial machines in the production</p><p>of this film could further improve its efficiency and quality,</p><p>making it a more viable option for commercial applications.</p><p>Fig. 13 Antimicrobial test</p><p>plates</p><p>Table 6 Zone of inhibition of GPE and oxidized tamarind starch-</p><p>based active film</p><p>Each value is expressed as a mean ± standard deviation, and values</p><p>that do not share a superscript letter in the same row indicate a sig-</p><p>nificant difference (p ≤ 0.05)</p><p>Tested Bacteria’s Zone of Inhibition (mm)</p><p>Samples</p><p>GPE MF</p><p>Staphylococcus aureus 10.00a ± 0.01 8.2b ± 0.02</p><p>Escherichia coli 8.5a ± 0.03 7.40b ± 0.05</p><p>Biomass Conversion and Biorefinery</p><p>Author contribution Tigist Girma Moges: Conceptualization, Meth-</p><p>odology, Formal analysis and investigation, Writing—original draft</p><p>preparation. Habtamu Shebabaw Kassa: Methodology, Resources,</p><p>Writing—review and editing. Henock Woldemichael Woldemariam:</p><p>Conceptualization, Methodology, Writing—review and editing,</p><p>Resources, Supervision.</p><p>Data availability Data can be made available on request to the cor-</p><p>responding author.</p><p>Declarations</p><p>Competing interests The authors declare no competing interests.</p><p>References</p><p>1. Mohan CC, Harini K, Aafrin BV, Babuskin S, Karthikeyan S,</p><p>Sudarshan K, Renuka V, Sukumar M (2018) Extraction and char-</p><p>acterization of polysaccharides from tamarind seeds, rice mill res-</p><p>idue, okra waste and sugarcane bagasse for its Bio-thermoplastic</p><p>properties. Carbohyd Polym 186:394–401</p><p>2. Hamid L, Elhady S, Abdelkareem A, Fahim I (2022) Fabricat-</p><p>ing Starch-Based Bioplastic Reinforced with Bagasse for Food</p><p>Packaging. Circ Econ Sustain 2(3):1–12</p><p>3. Mihindukulasuriya S, Lim L-T (2014) Nanotechnology devel-</p><p>opment in food packaging: A review. Trends Food Sci Technol</p><p>40(2):149–167</p><p>4. BeMiller JN (2007) Starches, modified food starches, and other</p><p>products from starches. In: Carbohydrate chemistry for food sci-</p><p>entists, 2nd edn. AACC International. pp 173–223</p><p>5. Perez Sira EE, Dufour D (2017) Native and modified starches as</p><p>matrix for edible films and covers. Nutri Food Sci Int J 3(3):1–15</p><p>6. Rakhavan K, Sudharsan K, Babuskin S, Sukumar M (2016)</p><p>Design and characterization of spice fused tamarind starch edible</p><p>packaging films. LWT-Food Sci Technol 68:642–652</p><p>7. Lourenco SC, Moldao-Martins M, Alves VD (2019) Antioxidants</p><p>of natural plant origins: From sources to food industry applica-</p><p>tions. Molecules 24(22):4132</p><p>8. Tournour HH, Segundo MA, Magalhaes LM, Barreiros L, Queiroz</p><p>J, Cunha LM (2015) Valorization of grape pomace: Extraction of</p><p>bioactive phenolics with antioxidant properties. Ind Crops Prod</p><p>74:397–406</p><p>9. Saurabh CK, Gupta S, Variyar PS (2018) Development of guar</p><p>gum based active packaging films using grape pomace. J Food Sci</p><p>Technol 55:1982–1992</p><p>10. Aldawsari HM, Kotta S, Asfour HZ, Vattamkandathil S, Elfaky</p><p>MA, Ashri LY, Badr-Eldin SM (2023) Development and evalu-</p><p>ation of quercetin enriched bentonite-reinforced starch-gelatin</p><p>based bioplastic with antimicrobial property. Saudi Pharm J</p><p>31(12):101861</p><p>11. Oluwasina OO, Falola T, Wahab OJ, Idahagbon NB (2018)</p><p>Enhancement of physical and mechanical properties of dioscorea</p><p>dumetorum starch films with dialdehyde starch solution. Starch-</p><p>Stärke 70(3–4):1700148</p><p>12. Sanyang ML, Sapuan SM, Jawaid M, Ishak MR, Sahari J (2015)</p><p>Effect of glycerol and sorbitol plasticizers on physical and thermal</p><p>properties of sugar palm starch based films. Recent Adv Environ</p><p>Ecosyst Dev 3(2):157–162</p><p>13. Leuangsukrerk M, Phupoksakul T, Tananuwong K, Borompichai-</p><p>chartkul C, Janjarasskul T (2014) Properties of konjac glucoman-</p><p>nan–whey protein isolate blend films. LWT-Food Sci Technol</p><p>59(1):94–100</p><p>14. Shankar S, Reddy JP, Rhim J-W, Kim H-Y (2015) Preparation,</p><p>characterization, and antimicrobial activity of chitin nanofibrils</p><p>reinforced carrageenan nanocomposite films. Carbohyd Polym</p><p>117:468–475</p><p>15. Chapagain S (2021) Biodegradable polymer synthesis from renew-</p><p>able sources. Ammattikorkeakoulut Yrkeshögskolan Arcada Opin-</p><p>näytetyöt 3(2):157–162</p><p>16 Yadav A, Kumar N, Upadhyay A, Pratibha, Anurag RK (2023)</p><p>Edible packaging from fruit processing waste: A comprehensive</p><p>review. Food Rev Int 39(4):2075–2106</p><p>17. Chaffa TY, Meshesha BT, Mohammed SA, Jabasingh SA (2022)</p><p>Production, characterization, and optimization of starch-based</p><p>biodegradable bioplastic from waste potato (Solanum tuberosum)</p><p>peel with the reinforcement of false banana (Ensete ventricosum)</p><p>fiber. Biomass Conver Biorefinery 1:1–13</p><p>18. Karkhanis SS, Stark NM, Sabo RC, Matuana LM (2018) Water</p><p>vapor and oxygen barrier properties of extrusion-blown poly (lac-</p><p>tic acid)/cellulose nanocrystals nanocomposite films. Compos A</p><p>Appl Sci Manuf 114:204–211</p><p>19. Tarique J, Sapuan S, Khalina A (2021) Effect of glycerol plasti-</p><p>cizer loading on the physical, mechanical, thermal, and barrier</p><p>properties of arrowroot (Maranta arundinacea) starch biopoly-</p><p>mers. Sci Rep 11(1):13900</p><p>20. Taddele A (2019) Synthesis, process parameters optimization and</p><p>characterization of banana peel based bio-plastic. Addis Ababa</p><p>University. pp 1–94</p><p>21. Contessa CR, da Rosa GS, Moraes CC (2021) New active pack-</p><p>aging based on biopolymeric mixture added with bacteriocin as</p><p>active compound. Int J Mol Sci 22(19):10628</p><p>22. Santos FH, Siqueira LE, Cardoso GP, Molina G, Pelissari FM</p><p>(2021) Antioxidant packaging development and optimization</p><p>using agroindustrial wastes. J Appl Polym Sci 138(35):50887</p><p>23. Vilas Dhumal C, Pal K, Sarkar P (2019) Synthesis, characteriza-</p><p>tion, and antimicrobial efficacy of composite films from guar gum/</p><p>sago starch/whey protein isolate loaded with carvacrol, citral and</p><p>carvacrol-citral mixture. J Mater Sci Mater Med 30(10):1–14</p><p>24. Singleton VL, Orthofer R, Lamuela-Raventós RM (1999) [14]</p><p>Analysis of total phenols and other oxidation substrates and anti-</p><p>oxidants by means of folin-ciocalteu reagent. Methods in enzy-</p><p>mology. Elsevier, pp 152–178</p><p>25. Ikram EHK, Eng KH, Jalil AMM, Ismail A, Idris S, Azlan A,</p><p>Nazri HSM, Diton NAM, Mokhtar RAM (2009) Antioxidant</p><p>capacity and total phenolic content of Malaysian underutilized</p><p>fruits. J Food Compos Anal 22(5):388–393</p><p>26. Casagrande M, Zanela J, Pereira D, de Lima VA, Oldoni TLC,</p><p>Carpes ST (2019) Optimization of the extraction of antioxidant</p><p>phenolic compounds from grape pomace using response surface</p><p>methodology. J Food Measur Charact 13:1120–1129</p><p>27. Ferreira AS, Nunes C, Castro A, Ferreira P, Coimbra MA (2014)</p><p>Influence of grape pomace extract incorporation on chitosan films</p><p>properties. Carbohyd Polym 113:490–499</p><p>28. Baba SA, Malik SA (2015) Determination of total phenolic and</p><p>flavonoid content, antimicrobial and antioxidant activity of a</p><p>root extract of Arisaema jacquemontii Blume. J Taibah Univ Sci</p><p>9(4):449–454</p><p>29. Merino D, Bertolacci L, Paul UC, Simonutti R, Athanassiou A</p><p>(2021) Avocado peels and seeds: processing strategies for the</p><p>development of highly antioxidant bioplastic films. ACS Appl</p><p>Mater Interfaces 13(32):38688–38699</p><p>30. Oluwasina OO, Olaleye FK, Olusegun SJ, Oluwasina OO, Mohal-</p><p>lem ND (2019) Influence of oxidized starch on physicomechani-</p><p>cal, thermal properties, and atomic force micrographs of cassava</p><p>starch bioplastic film. Int J Biol Macromol 135:282–293</p><p>31. Fonseca LM, Henkes AK, Bruni GP, Viana LAN, de Moura CM,</p><p>Flores WH, Galio AF (2018) Fabrication and characterization of</p><p>Biomass Conversion and Biorefinery</p><p>native and oxidized potato starch biodegradable films. Food Bio-</p><p>phys 13:163–174</p><p>32. Sondari D, Triwulandari E, Ghozali M, Sampora Y, Iltizam</p><p>I, Masruchin N (2018) The effect of oxidation on sago starch</p><p>and its application as edible film. Jurnal Sains Materi Indonesia</p><p>20(1):1–7</p><p>33. Oluwasina OO, Akinyele BP, Olusegun SJ, Oluwasina OO,</p><p>Mohallem ND (2021) Evaluation of the effects of additives on</p><p>the properties of starch-based bioplastic film. SN Appl Sci 3:1–12</p><p>34. Nogueira GF, Soares IHBT, Soares CT, Fakhouri FM, de Oliveira</p><p>RA (2022) Development and characterization of arrowroot starch</p><p>films incorporated with grape pomace extract. Polysaccharides</p><p>3(1):250–263</p><p>35. Kalu AO, Egwim EC, Jigam AA, Muhammad HL (2022) Effect</p><p>of oxidized sucrose, citric acid crosslinking and dual modification</p><p>on some physicochemical properties of cassava starch for potential</p><p>application in packaging films. BIOMED Nat Appl Sci 2(2):10–24</p><p>36. Nguyen VT (2021) Physical properties of films based on gelatin</p><p>and dialdehyde starch with different oxidation degrees. Orient J</p><p>Chem 37(1):103</p><p>37. Yanti NA, Ahmad SW, Ramadhan LO, Jamili Muzuni, Walhi-</p><p>dayah T, Mamangkey J (2021) Properties and application of edible</p><p>modified bacterial cellulose film based sago liquid waste as food</p><p>packaging. Polymers 13(20):3570</p><p>38. Cahyana Y, Verrell C, Kriswanda D, Aulia GA, Yusra NA, Marta</p><p>H, Sukri N, Esirgapovich SJ, Abduvakhitovna SS (2023) Proper-</p><p>ties Comparison of Oxidized and Heat Moisture Treated (HMT)</p><p>Starch-Based Biodegradable Films. Polymers 15(9):2046</p><p>39. Pelissari FM, Ferreira DC, Louzada LB, dos Santos F, Corrêa AC,</p><p>Moreira FK, Mattoso LH (2019) Starch-based edible films and</p><p>coatings: an eco-friendly alternative for food packaging. In: Silva</p><p>Clerici MTP, Schmiele MBT (eds.) Starches for food application.</p><p>Academic Press, pp 359–420</p><p>40. Xu Y, Scales A, Jordan K, Kim C, Sismour E (2017) Starch nano-</p><p>composite films incorporating grape pomace extract and cellulose</p><p>nanocrystal. J Appl Polym Sci 134(6):44438</p><p>41. Pirouzifard M, Yorghanlu RA, Pirsa S (2020) Production of</p><p>active film based on potato starch containing Zedo gum and</p><p>essential oil of Salvia officinalis and study of physical, mechani-</p><p>cal, and antioxidant properties. J Thermoplast Compos Mater</p><p>33(7):915–937</p><p>42. Thivya P, Bhosale Y, Anandakumar S, Hema V, Sinija V (2021)</p><p>Exploring the effective utilization of shallot stalk waste and tama-</p><p>rind seed for packaging film preparation. Waste Biomass Valoriza-</p><p>tion 12:5779–5794</p><p>43. Chowdhury M, Hossain N, Noman TI, Hasan A, Shafiul A, Abul</p><p>KM (2022) Biodegradable, physical and microbial analysis of</p><p>tamarind seed starch infused eco-friendly bioplastics by different</p><p>percentage of Arjuna powder. Results Eng 13:100387</p><p>44 Sutthiparinyanont S, Panrattanasukkul N, Katasila S, Panyajai S,</p><p>Kamkeaw A, Chitropas P (2016) Preparation of antioxidant film</p><p>from Musa sapientum Linn. peel extract and fruit. Asian J Pharm</p><p>Sci 11:116–117</p><p>45. Zamudio-Flores PB, Bautista-Baños S, Salgado-Delgado R, Bello-</p><p>Pérez LA (2009) Effect of oxidation level on the dual modification</p><p>of banana starch: The mechanical and barrier properties of its</p><p>films. J Appl Polym Sci 112(2):822–829</p><p>46 Rumyaan M, Polnaya FJ, Tuhumury HC (2022) Characteristics</p><p>of Edible Film Made from Bitter Cassava Starch with Glycerol.</p><p>AGRITEKNO: Jurnal Teknologi Pertanian 11(2):102–107</p><p>47. Souza MP, Vaz AF, Silva HD, Cerqueira MA, Vicente AA, Car-</p><p>neiro-da-Cunha MG (2015) Development and characterization</p><p>of an active chitosan-based film containing quercetin. Food Bio-</p><p>process Technol 8:2183–2191</p><p>48 MK M, P M, Khan A, K K, Abduljabbar AH, Syafri E, Waz-</p><p>zan MA, Wazzan H, Khan W (2023) Development and</p><p>Characterization of Sustainable Bioplastic Films Using Cellulose</p><p>Extracted from Prosopis juliflora. J Nat Fib 20(2):2231271</p><p>49. Chemiru G, Gonfa G (2023) Preparation and characterization</p><p>of glycerol plasticized yam starch-based films reinforced with</p><p>titanium dioxide nanofiller. Carbohydrate Polym Technol Applic</p><p>5:100300</p><p>50. Ghoshal G, Kaur M (2023) Optimization of extraction of starch</p><p>from sweet potato and its application in making edible film. Food</p><p>Chem Adv 3:100356</p><p>51. Nawab A, Alam F, Hadi A, Lutfi Z (2022) Development and char-</p><p>acterization of edible film made from mango kernel starch. J Pack</p><p>Technol Res 6(1):63–72</p><p>52. Ng JS, Kiew PL, Lam MK, Yeoh WM, Ho MY (2022) Preliminary</p><p>evaluation of the properties and biodegradability of glycerol-and</p><p>sorbitol-plasticized potato-based bioplastics. Int J Environ Sci</p><p>Technol, 1–10</p><p>53. Chakraborty I (2022) N P, Banik S, Govindaraju I, Das K, Mal</p><p>SS, Zhuo GY, Rather MA, Mandal M, Neog A, Synthesis and</p><p>detailed characterization of sustainable starch-based bioplastic. J</p><p>Appl Polym Sci 139(39):e52924</p><p>54. Behera L, Mohanta M, Thirugnanam A (2022) Intensification of</p><p>yam-starch based biodegradable bioplastic film with bentonite for</p><p>food packaging application. Environ Technol Innov 25:102180</p><p>55. Yaradoddi JS, Banapurmath NR, Ganachari SV, Soudagar MEM,</p><p>Sajjan AM, Kamat S, Mujtaba M, Shettar AS, Anqi AE, Safaei</p><p>MR (2022) Bio-based material from fruit waste of orange peel for</p><p>industrial applications. J Market Res 17:3186–3197</p><p>56. Shanmathy M, Mohanta M, Thirugnanam A (2021) Development</p><p>of biodegradable bioplastic films from Taro starch reinforced with</p><p>bentonite. Carbohydrate Polym Technol Applic 2:100173</p><p>57. Yang J, Ching YC, Chuah CH, Hai ND, Singh R, Nor ARM (2021)</p><p>Preparation and characterization of starch-based bioplastic</p>