Vol. 7, Issue 12, Part H (2025)

The functional efficacy of probiotic foods depends on the delivery of adequate numbers of viable microorganisms to the intestine; however, probiotic bacteria such as Lactobacillus acidophilus are highly sensitive to heat stresses and adverse gastrointestinal conditions. Microencapsulation has therefore emerged as an effective strategy to enhance probiotic stability and targeted delivery. The present study aimed to develop a synbiotic microencapsulation system incorporating partially hydrolysed guar gum and to evaluate its protective effect on Lactobacillus acidophilus NCDC-15 under simulated gastric, intestinal, and thermal stress conditions. The probiotic culture was microencapsulated using a sodium alginate-corn starch matrix supplemented with partially hydrolysed guar gum at 3% and 5% (w/v) concentrations, with microcapsules formed by ionic gelation in calcium chloride solution. Survivability of encapsulated and non-encapsulated cells was assessed under simulated gastric pH conditions (pH 1.0, 1.5, and 2.0), bile salt concentrations ranging from 1.0 to 2.0%, and thermal treatments at 75 °C and 80 °C for 30 s. Microencapsulation significantly enhanced the survivability of L. acidophilus under all tested stress conditions, with PHGG-containing microcapsules, particularly at the 5% level, providing superior protection against acidic environments while maintaining viable counts above the recommended therapeutic threshold (≥10⁷-10⁸ CFU/g) even after prolonged exposure. Encapsulated cells also exhibited significantly higher tolerance to bile salts and thermal treatments compared with non-encapsulated controls, demonstrating a clear concentration-dependent protective effect of partially hydrolysed guar gum. Overall, incorporation of Partially hydrolysed guar gum into alginate-starch microencapsulation matrices markedly improves the resistance of Lactobacillus acidophilus NCDC-15 to gastrointestinal and thermal stresses, emphasizing the potential of this synbiotic encapsulation system for enhancing probiotic stability during food processing and digestion and supporting its application in functional foods, nutraceuticals, and sensitive formulations such as infant and medical nutrition products.