Use of Lactulose as Prebiotic and Chitosan Coating for Improvement the Viability of Lactobacillus sp. FM4.C1.2 Microencapsulate with Alginate

Abstract

Lactic acid bacteria (LAB) constitute the microbial group most used as probiotics; however, many strains reduce their viability during their transit through the body. The objective of this study was to evaluate the effect of two microencapsulation techniques, as well as the incorporation of lactulose as a prebiotic and the use of chitosan coating on the microcapsules, on the viability of the Lactobacillus sp. strain FM4.C1.2. LAB were microencapsulated by extrusion or emulsion, using 2% sodium alginate as encapsulating matrix and lactulose (2 or 4%) as the prebiotic. The encapsulation efficiency was evaluated, and the capsules were measured for moisture and size. The encapsulation efficiency ranged between 80.64 and 99.32% for both techniques, with capsule sizes between 140.64 and 1465.65 µm and moisture contents from 88.23 to 98.04%. The microcapsules of some selected treatments (five) were later coated with chitosan and LAB survival was evaluated both in coated and uncoated microcapsules, through tolerance to pH 2.5, bile salts and storage for 15 days at 4 °C. The highest survival of the probiotic strain under the conditions of pH 2.5 (96.78–99.2%), bile salts (95.54%) and storage for 15 days (84.26%), was found in the microcapsules obtained by emulsion containing 4% lactulose and coated with chitosan. These results demonstrate the possible interaction of lactulose with alginate to form better encapsulating networks, beyond its sole probiotic effect. Additional research may shed more light on this hypothesis.