Enhanced viability and membrane lipid stability of cholesterol-lowering probiotics through spray drying encapsulation with whey protein isolate-coconut oil complex

Abstract This study assessed the effect of whey protein isolate (WPI) and its coconut oil complexes (CO-WPI) on the viability of Limosilactobacillus reuteri KUB-AC5 during spray drying and storage. Varied CO concentrations (0%, 4%, and 8%, w/w) and spray drying temperatures (110 °C and 130 °C) influenced secondary structures, free sulfhydryl groups, disulfide bonds, and DPPH• and ABTS•+ scavenging activities of WPI. Throughout the spray drying and storage processes, CO-WPI effectively reduced lipid peroxidation in the probiotic membranes, as detected by advanced 1H-nuclear magnetic resonance, compared to WPI alone. Microencapsulation in 4CO-WPI at 110 °C provided the highest cell viability during drying (1.34 × 1011 CFU g−1), coupled with the highest cholesterol assimilation (58.43%). After 12 months at 4 °C, viability remained high (5.57 ×1010 CFU g−1). This study demonstrated CO-WPI's potential in reducing oxidative damage and improving probiotic survival, highlighting its efficacy as a microencapsulant in spray drying.