Protective Microencapsulation of Lactobacillus acidophilus for Gastrointestinal Stability and Development of Functional Juice

Abstract

Probiotics are widely recognized for their health-promoting effects; however, their viability is often challenged by harsh gastrointestinal conditions and food processing environments. This study evaluated the microencapsulation of Lactobacillus acidophilus through extrusion using alginate and carrageenan with different formulation i.e., T₀-free cells, T₂-2% alginate, T₃-2% alginate and 0.5 % carrageenan, T₃-2% alginate and 1% carrageenan, T₄-1.5% alginate and 1.5% carrageenan. The study was aimed to enhance bacterial survival under gastrointestinal conditions and develop a stable probiotic orange juice. Encapsulation efficiency ranged from 86.2% (T₁) to 94.5% (T₄), with higher carrageenan concentrations producing larger, more stable beads. Survival analysis showed that free cells suffered drastic reductions under bile salts (9.2 to 4.85 log CFU/mL) and simulated gastric juice (9.2 to 3.1 log CFU/mL), while encapsulated treatments exhibited significantly higher viability (≥7 log CFU/mL) with highest viability recorded for T₄. Similarly, under simulated intestinal fluid, encapsulated cells retained >6.5 log CFU/mL with highest viability recoded for T₄ (8.15 log CFU/mL) after 3 h compared to free cells showing 4.5 log reduction. Storage studies at 4 °C revealed that encapsulated probiotics-maintained counts above the therapeutic threshold (7 log CFU/mL) for 21 days, whereas free cells declined below acceptable levels. Probiotic orange juice formulated with encapsulated cells exhibited stable physicochemical properties, including controlled pH decline and slower sugar reduction, along with superior sensory acceptability (6-7 score) compared to juice containing free cells. These findings demonstrate that alginate-carrageenan encapsulation provides a promising strategy for improving probiotic stability and functionality in fruit-based beverages, thereby contributing to the development of consumer-acceptable functional drinks with extended shelf life.