Improving probiotic survival through encapsulation in coconut oil in whey protein isolate emulsions during spray drying and gastrointestinal digestion

Abstract

Enhancing probiotic survival during spray drying and gastrointestinal transit is crucial for efficient probiotic production. In this study, whey protein isolate (WPI) alone and coconut oil (CO) in WPI emulsions at varying concentrations of CO, specifically 4% and 8% (referred to as 4CO-WPI and 8CO-WPI, respectively), were employed as encapsulants for spray drying Limosilactobacillus reuteri KUB-AC5. The proteins in the emulsions exhibited a higher degree of unfolding and surface hydrophobicity compared to WPI alone, leading to reduced contact angles with hydrophobic cells. Analysis through 13C Nuclear Magnetic Resonance spectroscopy revealed increased interactive sites of the unfolded proteins in 4CO-WPI and 8CO-WPI with peptidoglycan and protein-bound surfaces. Cells encapsulated in 4CO-WPI exhibited superior survival and minimal cell envelope injury. These encapsulated cells displayed the highest viability during simulated gastrointestinal digestion, with a final count of 8.76 log CFU/g. Both 4CO-WPI and 8CO-WPI experienced lower hydrolysis compared to WPI, indicating enhanced cell survival. These findings emphasize the importance of enhancing the interaction between the unfolded proteins in the emulsions, obtained through complexation with CO, and the cell wall. This enhancement results in increased cell survival throughout the entire process, emphasizing the potential for improved probiotic production methods.