Soybean Meal Protein Isolation Characterization Utilization in Edible Film Development and Its Application

Abstract

Soybeans (Glycine max L. Merr.) have long been valued for their nutritional richness, with soybean meal a by-product of oil extraction containing 45 50% protein and commonly used as animal feed. Due to increasing global demand for plant-based proteins, this study explores value addition by extracting soybean meal protein isolate using conventional and advanced methods, including enzymatic, microwave, and ultrasound-assisted techniques. Ultrasound-assisted extraction (UAE) yielded superior results, achieving 24.17±0.79% extraction yield and 91.6±1.08% purity under optimized conditions (1:15 solid-liquid ratio, 52% amplitude, 22°C, 3 s pulse, 11 min treatment). Extracted proteins often have poor functionality; thus, pH shifting was applied, with alkaline-treated isolates showing improved solubility, emulsifying ability, and amino acid profiles. newline newlineTo utilize the extracted protein, a bio-nanocomposite film was developed using soybean protein isolate, debittered kinnow peel powder (up to 20%), and montmorillonite nanoclay (up to 2%). This composite enhanced the film s mechanical strength, barrier capacity, antioxidant and antimicrobial activities, and thermal stability. Cytotoxicity tests confirmed its biocompatibility with 3T3L1 cells. When applied as packaging for chocolate bars, the protein-based film significantly extended shelf life by 21 days by reducing moisture loss, lipid oxidation, and microbial growth, compared to conventional packaging. The study highlights the potential of soybean meal as a sustainable, cost-effective protein source for producing functional, biodegradable films that support food preservation and reduce agricultural waste. newline newline