The manufacturing of lactobacillus microcapsules by freezing with egg yolk: The analysis of microstructure and the preservation effect against freezing and acid treatments

Abstract

Encapsulation is an effective strategy to prevent probiotics from environmental damages. The survivability of Lactobacillus is generally reduced under frozen or acid environments. In this study, an attempt was made to encapsulate Lactobacillus into the egg yolk aggregates formed upon freezing. Lactobacillus broth was mixed with liquid egg yolk and frozen at selected temperatures and time periods. After thawing, the number of surviving bacteria was determined. The results showed that freezing with the addition of egg yolk improved Lactobacillus survivability. It was confirmed that freezing increased the number of egg yolk aggregates, and those aggregates coated Lactobacillus after freezing. The encapsulated Lactobacillus was treated at pH 2.5 for 10 min, and the results showed that the encapsulation process increased the acid resistance of Lactobacillus . These results indicate that freezing-induced encapsulation with egg yolk could effectively protect Lactobacillus against freezing and acid treatment. This finding could be useful for the design and preservation of probiotics-based food products. • Lactobacillus was encapsulated by freeze-induced aggregation of egg-yolk. • The present microencapsulation technique improved the survivability of lactobacillus. • Acid tolerance of lactobacillus was enhanced by the present encapsulation method. • The number concentration of egg-yolk aggregates increased under frozen environment. • Aggregate formation would correlate to the microencapsulation efficiency.