Physico-chemical Properties of Protein-Based Edible Films

Authors: Nidhi Parmar, Viraj Roghelia
Physico-chemical Properties of Protein-Based Edible Films
DOI
10.25125/ijoear-may-2026-13
DIN
IJOEAR-MAY-2026-13
Abstract

The present study focused on the development and characterization of protein-based edible films using soy protein isolate (SPI), mung bean protein (MBP), and their blends with corn starch (CS). A total of six formulations were prepared, namely SPI, MBP, corn starch–soy protein isolate blends (CSSP 40:60 and CSSP 50:50), and corn starch–mung bean protein blends (CSMBP 40:60 and CSMBP 50:50). The films were developed using the casting method with sorbitol as a plasticizer. The prepared films were evaluated for their physical properties including thickness, solubility, transparency, colour parameters (L*, a*, b*), mechanical properties such as tensile strength, and structural characteristics using Fourier-transform infrared spectroscopy (FTIR). The results revealed a significant (p ≤ 0.01) variation among all film formulations in terms of physical, optical, and mechanical properties. The thickness of the films ranged from 0.196 mm to 0.263 mm, with SPI-based films exhibiting the highest thickness (0.263 mm), while MBP films showed the lowest thickness (0.196 mm). Blended films displayed intermediate thickness values, indicating that incorporation of starch influenced film structure. Solubility values varied from 31.34% to 31.48%, with CSMBP 50:50 (31.48%) and CSSP 50:50 (31.34%) exhibiting significantly higher solubility compared to other formulations, suggesting improved interaction and dispersion of components in blended systems. Transparency also differed significantly among the films, ranging from 0.436 to 1.66. The highest transparency was observed in CSSP 40:60 (1.66), indicating better light transmittance and a more uniform film matrix, whereas MBP films exhibited the lowest transparency (0.436), reflecting higher opacity. Colour analysis demonstrated notable differences, with L* values ranging from 64.36 to 84.56. CSSP 40:60 films showed the highest lightness, while MBP and CSMBP 40:60 films appeared darker. The a* values ranged from 3.623 to 7.516, with MBP films exhibiting higher redness, whereas SPI films showed lower values. The b* values ranged from 4.356 to 14.196, indicating that MBP incorporation increased yellowness in the films. Mechanical analysis indicated significant differences (p ≤ 0.01) in tensile strength among formulations. The highest tensile strength was recorded for CSMBP 40:60 (4.093 MPa), followed by MBP (3.170 MPa), while SPI films showed the lowest value (1.24 MPa). Blended films generally exhibited improved mechanical performance due to enhanced intermolecular interactions between protein and starch components. FTIR analysis confirmed the presence of characteristic functional groups in all films. Strong O–H and N–H stretching bands around 3273–3278 cm⁻¹ indicated hydrogen bonding, while Amide I and II bands confirmed the protein structure. Additional peaks in starch-blended films verified the contribution of polysaccharides and improved compatibility within the matrix. Overall, the results suggest that blending proteins with corn starch significantly enhances the functional properties of edible films. Among all formulations, CSMBP 40:60 demonstrated superior mechanical strength, while CSSP 40:60 showed excellent optical properties, indicating their potential application in biodegradable and sustainable food packaging systems.

Keywords
Edible film soy protein isolate mung bean protein physical properties.
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Introduction

In recent years, the food packaging sector has been under increasing pressure to adopt sustainable and eco-friendly materials. Traditional packaging options, particularly plastics like polyethylene, are non-biodegradable and tend to accumulate in the environment, raising concerns about their impact on human health. As a result, significant progress has been made in the development of edible films and coatings, which are emerging as effective alternatives to conventional packaging. These biomaterials are especially suitable for perishable foods, as they help protect against chemical changes and microbial spoilage [1,2,3,4].

Edible films and coatings perform multiple functional roles in food preservation systems. They provide protection against ultraviolet (UV) radiation and regulate the mass transfer of solutes such as salts, additives, and pigments between the food matrix and the external environment. These materials also modulate the permeability of water vapor and respiratory gases, including oxygen (O₂), carbon dioxide (CO₂), nitrogen (N₂), and ethylene, thereby contributing to the establishment of a controlled or modified atmosphere around the product. In addition, they serve as protective barriers against mechanical damage during handling and distribution, ultimately extending the shelf life of food products. Furthermore, edible films and coatings can function as delivery systems for bioactive compounds, such as antioxidants and probiotic or bioprotective microorganisms, and may exhibit antimicrobial and antifungal activities that enhance both product safety and potential health benefits [5].

Protein-based edible films offer structural stability and are known for their good mechanical properties and high water vapor permeability [6]. Despite their hygroscopic nature, protein-based coatings (milk, soy, wheat, whey) help maintain the structure of perishable foods [7]. Protein-based coatings significantly improve the appearance, texture, and preservation of food. These films act as protective layers that shield food products from external environmental factors that could compromise their quality, safety, and stability. As effective physical barriers, protein-based films can reduce the permeation of oxygen, moisture, and microbial agents, thereby extending the shelf life of perishable food products [8].

Soybean is a major oilseed and protein crop valued for its high grain quality and substantial vegetative mass. It is widely utilized in food, feed, industrial applications, and medicine [9]. On average, soybean seeds contain 37–42% protein, 19–22% oil, and up to 30% carbohydrates. The vegetative biomass harvested during the pod-filling stage is also rich in proteins (16–18%), carbohydrates, and vitamins [10]. Soybeans, with their higher protein content compared to other legumes, are well positioned to help fulfill this demand [11]. Soy protein isolate (SPI) is an affordable, accessible, and nutritious biopolymer with low oxygen permeability, ideal for protecting against oxidative damage [12,13]. However, like other polar polymers, SPI films are poor moisture barriers [14]. Cross-linking treatments can improve their properties [15].

Mung bean (Vigna radiata), widely grown in Asia, contains 25–28% protein and numerous bioactive compounds [16]. Dry grains, sprouts, starch for noodle preparation, and paste are the main products of the mung bean market [17]. In the starch extraction process, the protein-rich byproduct is often discarded. This byproduct can be used for the preparation of edible films, thereby reducing waste disposal costs and enhancing sustainability [18]. It contains approximately 25–28% protein and serves as a rich source of bioactive constituents, including flavonoids, phenolic acids, organic acids, and polysaccharides [19]. These phytochemicals contribute to a range of health-promoting effects, such as antioxidant, antidiabetic, anti-hypercholesterolemic, anticancer, anti-tumor, and detoxifying activities [20,21].

Protein-based edible films exhibit superior mechanical strength, barrier performance, and nutritional benefits compared to those derived from polysaccharides and lipids [22]. Soy protein isolate and mung bean protein have been relatively less explored for the development of edible films. Therefore, the present study aims to develop and analyse edible films prepared from these protein sources at different concentrations. The films were fabricated using the casting method with sorbitol as a plasticizer, and subsequently evaluated for their thickness, solubility, opacity, colour characteristics, and mechanical properties.

Conclusion

In conclusion, the study demonstrated that protein-based edible films developed from soy protein isolate and mung bean protein, alone and in combination with corn starch, exhibit promising functional properties. Blending proteins with starch significantly improved the physical, optical, and mechanical characteristics of the films. Among the formulations, CSMBP 40:60 showed superior tensile strength, while CSSP 40:60 exhibited better transparency and overall appearance. The FTIR analysis confirmed strong intermolecular interactions contributing to film stability. Future studies should evaluate water vapor permeability, antimicrobial properties, and biodegradability of these films to further assess their potential for commercial food packaging applications. Overall, these protein–starch blend films have strong potential as biodegradable and sustainable alternatives for food packaging applications.

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References
  1. Amini, M., Aslani, R., Isvand, A., & Molaee-aghaee, E. (2025). Farsi gum (zedo gum) coating incorporated with Lactobacillus sakei; A novel shelf-life extension for Turkey breast during refrigerated storage. Food Control, 167, Article 110836. 

https://doi.org/10.1016/j.foodcont.2024.110836

  1. Andacheh, F., Moslehishad, M., Shojaee-Aliabadi, S., & Jannatyha, N. (2020). Production and characterization of antimicrobial carboxymethyl cellulose (CMC) films containing essential oils of Satureja khuzistanica, Zataria multiflora, Allium sativum and Bunium persicum. *Journal of Medicinal Plants and By-Products, 9*(Special), 35–45. 

https://doi.org/10.22092/JMPB.2020.121749

  1. García, A., Pérez, L. M., Piccirilli, G. N., & Verdini, R. A. (2020). Evaluation of antioxidant, antibacterial and physicochemical properties of whey protein-based edible films incorporated with different soy sauces. LWT, 117, Article 108587. 

https://doi.org/10.1016/j.lwt.2019.108587

  1. Otoni, C. G., Avena-Bustillos, R. J., Azeredo, H. M., Lorevice, M. V., Moura, M. R., Mattoso, L. H., & McHugh, T. H. (2017). Recent advances on edible films based on fruits and vegetables—A review. Comprehensive Reviews in Food Science and Food Safety, 16(5), 1151–1169. https://doi.org/10.1111/1541-4337.12281
  2. Pires, A. F., Díaz, O., Cobos, A., & Pereira, C. D. (2024). A review of recent developments in edible films and coatings—Focus on whey-based materials. Foods, 13(16), Article 2638.
  3. Galus, S. (2018). Functional properties of soy protein isolate edible films as affected by rapeseed oil concentration. Food Hydrocolloids, 85, 233–241.
  4. Lovera, M., Pérez, E., & Laurentin, A. (2017). Digestibility of starches isolated from stem and root tubers of arracacha, cassava, cush–cush yam, potato and taro. Carbohydrate Polymers, 176, 50–55.
  5. Kaur, A. P., Bhatia, S., & Alam, M. S. (2021). Influence of edible coatings and packaging on quality and shelf-life of carrot stored under ambient conditions. Agricultural Research Journal, 58(2), 280–290.
  6. Dubinkina, E. A., Shabalkin, A. V., & Makarov, M. R. (2023). Study of the treatment of soybean seeds and plants with inoculants and microbiological fertilizers in the Central Chernozem Region. Legumes and Groat Crops, 1(45).
  7. Khairullina, O. I., & Yarkova, T. M. (2018). Impact of economic sanctions on the food production and consumption in Russia. Вісник Національної академії керівних кадрів культури і мистецтв, (1).
  8. Messina, M. (2022). Perspective: Soybeans can help address the caloric and protein needs of a growing global population. Frontiers in Nutrition, 9, Article 909464.
  9. Brandenburg, A. H., Weller, C. L., & Testin, R. F. (1993). Edible films and coatings from soy protein. Journal of Food Science, 58(5), 1086–1089.
  10. Ma, M., Ren, Y., Xie, W., Zhou, D., Tang, S., Kuang, M., & Du, S. K. (2018). Physicochemical and functional properties of protein isolate obtained from cottonseed meal. Food Chemistry, 240, 856–862.
  11. Gennadios, A., Brandenburg, A. H., Weller, C. L., & Testin, R. F. (1993). Effect of pH on properties of wheat gluten and soy protein isolate films. Journal of Agricultural and Food Chemistry, 41(11), 1835–1839.
  12. Azeredo, H. M., & Waldron, K. W. (2016). Crosslinking in polysaccharide and protein films and coatings for food contact – A review. Trends in Food Science & Technology, 52, 109–122.
  13. Wang, L., Bai, P., Yuan, X., Chen, H., Wang, S., Chen, X., & Cheng, X. (2018). Genetic diversity assessment of a set of introduced mung bean accessions (Vigna radiata L.). The Crop Journal, 6(2), 207–213.
  14. Budseekoad, S., Yupanqui, C. T., Sirinupong, N., Alashi, A. M., Aluko, R. E., & Youravong, W. (2018). Structural and functional characterization of calcium and iron-binding peptides from mung bean protein hydrolysate. Journal of Functional Foods, 49, 333–341.
  15. Chai, W. M., Ou-Yang, C., Huang, Q., Lin, M. Z., Wang, Y. X., Xu, K. L., & Pang, D. D. (2018). Antityrosinase and antioxidant properties of mung bean seed proanthocyanidins: Novel insights into the inhibitory mechanism. Food Chemistry, 260, 27–36.
  16. Chandrasiri, S. D., Liyanage, R., Vidanarachchi, J. K., Weththasinghe, P., & Jayawardana, B. C. (2016). Does processing have a considerable effect on the nutritional and functional properties of mung bean (Vigna radiata)? Procedia Food Science, 6, 352–355.
  17. Du, M., Xie, J., Gong, B., Xu, X., Tang, W., Li, X., & Xie, M. (2018). Extraction, physicochemical characteristics and functional properties of mung bean protein. Food Hydrocolloids, 76, 131–140.
  18. Abdelhedi, O., Nasri, R., Jridi, M., Kchaou, H., Nasreddine, B., Karbowiak, T., & Nasri, M. (2018). Composite bioactive films based on smooth-hound viscera proteins and gelatin: Physicochemical characterization and antioxidant properties. Food Hydrocolloids, 74, 176–186.
  19. El-Adawy, T. A. (2000). Functional properties and nutritional quality of acetylated and succinylated mung bean protein isolate. Food Chemistry, 70(1), 83–91.
  20. Wu, J., Chen, S., Ge, S., Miao, J., Li, J., & Zhang, Q. (2013). Preparation, properties and antioxidant activity of an active film from silver carp (Hypophthalmichthys molitrix) skin gelatin incorporated with green tea extract. Food Hydrocolloids, 32(1), 42–51.
  21. Hazrol, M. D., Sapuan, S. M., Zainudin, E. S., Zuhri, M. Y. M., & Abdul Wahab, N. I. (2021). Corn starch (Zea mays) biopolymer plastic reaction in combination with sorbitol and glycerol. Polymers, 13, Article 242.
  22. Alves, M. M., Gonçalves, M. P., & Rocha, C. M. (2017). Effect of ferulic acid on the performance of soy protein isolate-based edible coatings applied to fresh-cut apples. LWT, 80, 409–415.
  23. Kumari, N., Bangar, S. P., Petrů, M., Ilyas, R. A., Singh, A., & Kumar, P. (2021). Development and characterization of fenugreek protein-based edible film. Foods, 10(9), Article 1976.
  24. Sultan, Z., Ashfaq, A., Jahan, K., Qadri, O. S., Younis, K., & Yousuf, O. (2024). pH shift extraction technique for plant proteins: A promising technique for sustainable development. Energy Nexus, 16, Article 100329.
  25. Zul'adhar, U. R., Awwaly, K. U. A., Widyastuti, E. S., Thohari, I., & Apriliyani, M. W. (2024). Physical quality of edible film with the addition of isolate whey protein on water content, solubility, thickness and transparency. Asian Food Science Journal, 23(10), 28–34.
  26. Bourtoom, T. (2008). Factors affecting the properties of edible film prepared from mung bean proteins. International Food Research Journal, 15(2), 167–180.
  27. Yoo, S., & Krochta, J. M. (2011). Whey protein–polysaccharide blended edible film formation and barrier, tensile, thermal and transparency properties. Journal of the Science of Food and Agriculture, 91(14), 2628–2636.
  28. Sun, B., Wang, W., Zhang, M., & Sain, M. (2018). Biomass-based edible film with enhanced mass barrier capacity and gas permeable selectivity. Cellulose, 25(10), 5919–5937.
  29. De Oliveira, M. M. G., de Souza Silva, K., & Mauro, M. A. (2021). Evaluation of interactions between carboxymethylcellulose and soy protein isolate and their effects on the preparation and characterization of composite edible films. Food Biophysics, 16(2), 214–228.
  30. Shroti, G. K., & Saini, C. S. (2022). Development of edible films from protein of brewer's spent grain: Effect of pH and protein concentration on physical, mechanical and barrier properties of films. Applied Food Research, 2(1), Article 100043.
  31. Moghadam, M., Salami, M., Mohammadian, M., Khodadadi, M., & Emam-Djomeh, Z. (2020). Development of antioxidant edible films based on mung bean protein enriched with pomegranate peel. Food Hydrocolloids, 104, Article 105735.
  32. Mihalca, V., Kerezsi, A. D., Weber, A., Gruber-Traub, C., Schmucker, J., Vodnar, D. C., & Pop, O. L. (2021). Protein-based films and coatings for food industry applications. Polymers, 13(5), Article 769.
  33. Cho, S. Y., Park, J. W., Batt, H. P., & Thomas, R. L. (2007). Edible films made from membrane processed soy protein concentrates. *LWT - Food Science and Technology, 40*(3), 418–423.
  34. Rosenbloom, R. A., & Zhao, Y. (2021). Hydroxypropyl methylcellulose or soy protein isolate-based edible, water-soluble, and antioxidant films for safflower oil packaging. Journal of Food Science, 86(1), 129–139.
  35. Miller, L. M., Bourassa, M. W., & Smith, R. J. (2013). FTIR spectroscopic imaging of protein aggregation in living cells. *Biochimica et Biophysica Acta (BBA) - Biomembranes, 1828*(10), 2339–2346.
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