Valorization of Bael Fruit Shell to Natural Emulsifiers: Formulation of Emulsifier Stabilized Chia Seed Oil-Loaded Antimicrobial Nanoemulsion Against Food Pathogenic Microorganisms

Natural emulsifiers originating from unconventional sources have attracted attention due to their exceptional functional properties. Bael fruit shell is typically considered an agricultural byproduct and is often discarded as waste. This research, therefore, focuses on valorizing it by developing bael fruit shell extract (BFSE). The utilization of bael fruit shells makes this approach both a sustainable and functional innovation. Proximate analysis showed that bael fruit shell powder (BFSP) is rich in carbohydrates (57.89 ± 0.32%) and proteins (7.53 ± 0.90%). Compounds, including polysaccharides, proteins, and other bioactive components, were extracted from BFSP at different pH levels (4, 5, 6, and 7) with microwave treatment (950 W for 3 min). The optimal pH was identified as 5, yielding the highest soluble fractions (80.08 ± 0.46%), polysaccharide, and protein content (180.98 ± 0.34 and 56.98 ± 0.37 mg/g). The optimized BFSE powder (pH 5) showed a porous structure, excellent thermal stability, high water and oil absorption capacities, and excellent emulsifying activity and stability. The BFSE nanoemulsion showed excellent stability compared to the conventional lecithin-based nanoemulsion. The BFSE-based nanoemulsion effectively reduced the viability of S. aureus, E. coli, and Candida albicans, suggesting its potential as an antimicrobial agent that could be utilized for enhancing food safety and extending shelf life in food preservation.