Effect of yeast cell wall and β-glucan on survival of Lactobacillus acidophilus LA-5 encapsulated in spray-dried cross-linked alginate microcapsules

Abstract

Growing number of evidence suggests that probiotics may offer health benefits for humans. The effectiveness of probiotic depends on the bacteria viability throughout storage and gastrointestinal environment. Encapsulation is the main strategy to protect probiotics . The rapid release of encapsulated probiotics within alginate is an important challenge and various types of materials has been studied to address this issue. Therefore, this study was designed to evaluate the effects of yeast cell wall or β-glucan cross-linked with alginate on the survival of spray-dried encapsulated L. acidophilus LA-5. Survivability and morphology studies were conducted on three spray-dried alginate formulations: pure calcium alginate (Alg), calcium alginate with 3 % yeast cell wall (Alg-Y3), and calcium alginate with 5 % β-glucan (Alg-βGlu5). Alg-Y3 demonstrated the lowest mean diameter (0.65 μm) and the highest encapsulation efficiency (97.6 ± 0.14 %) (P < 0.05). Alg-Y3 microcapsules also had a showed a significantly higher survival rate in simulated gastrointestinal fluid, reaching 8.77 log CFU/mL compared to free cells at 4 log CFU/mL (P < 0.05). Storage stability was assessed by monitoring the viability of microencapsulated L. acidophilus LA-5 over a period of 56 days at different temperatures. The viability remained above 6 log units after 56 days of storage in both Alg-Y3 and Alg-βGlu5 formulations. Notably, the microencapsulated probiotics exhibited the longest shelf life when stored at 4 °C, with predicted viability up to 200 days for Alg-Y3 microcapsules. These findings highlight the potential of yeast cell wall and β-glucan to enhance the viability of Lactobacillus acidophilus LA-5 within simulated gastrointestinal conditions and during storage.

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