Optimization of Bioemulsifier Extraction from <i>Candida tropicalis</i> Isolated from Overripe Banana and its Potential as a Food Additive

Background: Improvement in food processing can be achieved by applying a bioemulsifier produced from microorganisms isolated from overripe fruit Objective: The study aims to isolate, optimize, characterize, and determine the application of a bioemulsifier from Candida tropicalis MN450877.1, obtained from overripe bananas. Method: Candida tropicalis MN450877.1 was identified using 16S rRNA sequencing and BLAST analysis. The autoclaving extraction procedure was optimized using a 5-level, 2-factor central composite design (CCD). Purification was conducted via Sephadex G-50 gel filtration chromatography. Comprehensive characterization was performed using HPLC, SEM-EDX, FTIR, 1 H and 13C NMR, and SDS-PAGE. The bioemulsifier was applied as a food additive in mayonnaise production at a concentration of 0.5% (w/v) and evaluated for its sensory and toxicological properties Results: The bioemulsifier composition exhibited similarity to structural mannoprotein, with 11.32% protein and 88.68% carbohydrate. The optimized conditions, at 121 ºC for 120 min, yielded 0.232 g per 0.3 g dry cells, with an emulsification index of 55.5%, a protein content of 0.488 mg/mL, and a carbohydrate content of 5.4 mg/g. SDS-PAGE revealed a molecular mass of 38 kDa. FTIR confirmed the presence of glycoprotein, while HPLC revealed various molecular weight fractions, including monosaccharides, polysaccharides, and glycoproteins. SEM-EDX analysis confirmed porous, aggregated biopolymer structures with an elemental composition predominantly consisting of carbon, oxygen, nitrogen, and phosphorus. ¹H NMR validated glycoprotein structures with characteristic functional groups. Toxicity evaluation indicated an LD50 above 5000 mg/kg. Sensory analysis demonstrated functional properties comparable to those of commercial emulsifiers. Discussion: Physicochemical, structural, and functional analyses jointly support the classification of the purified compound as a glycoprotein-based bioemulsifier. The absence of toxicity at high doses supports its safety; however, long-term assessments and broader application across food matrices are recommended. Conclusion: The bioemulsifier from Candida tropicalis MN450877.1 demonstrates promising emulsification, physicochemical, toxicological, and sensory properties, supporting its potential use as a food additive.