Investigation of the Survival of Probiotic Bacteria Lactobacillus plantarum in Free and Microencapsulated Forms in Barley Malt Extract

Abstract

Background: Probiotic products with valuable nutritional and therapeutic properties have attracted great attention in the fields of industry, nutrition, and medicine. Objectives: The present study aimed to investigate the survival of Lactobacillus plantarum probiotic bacteria in capsulated and non-capsulated forms in malt products during storage. We also evaluated the pH, brix, sugar content, and organoleptic properties of the three products, a control malt (non-probiotic extract), an extract containing the probiotic bacteria without capsules, and an extract containing encapsulated probiotic bacteria. Methods: The probiotic strain of L. plantarum was inoculated into a barley malt extract in free and encapsulated forms. Bacterial microencapsulation was performed using the extrusion technique with sodium alginate. In addition, bacterial viability was determined using the mixed culture method in MRS agar medium at the temperature of 37°C for 48 hours. Data analysis was performed using one-way analysis of variance (ANOVA) in the Minitab 16 software. Results: The count of L. plantarum in the non-capsulated form did not change significantly although it increased in the capsulated form. No significant changes were observed in the sugar content, pH, and brix during the storage of the three products. Moreover, the sensory acceptance of malt with capsulated bacteria was higher compared to the other samples. Conclusions: According to the results, the probiotic strain of L. plantarum in the free and microencapsulated forms was maintained in the barley malt extract for two months of storage at the temperature of 4°C. Therefore, it seems that barley malt extract may be a favorable environment for the preservation of probiotic L. plantarum.