ABSTRACT
Microalgae and probiotics such as Bifidobacterium and Lactobacillus genera are associated with human beneficial effects. The aim of this study was to evaluate the activity of Chlorella sorokiniana on Bifidobacterium longum and Lactobacillus plantarum viability in a dairy product (flan) and its microbial effect against rotavirus, which is one of the major diarrhea-causing pathogens worldwide. Microalge were isolated from a Mexican river and characterized by molecular tools. Their prebiotic activity was evaluated by determining Bifidobacterium longum and Lactobacillus plantarum shelf-life after incorporation in the food matrix. In addition, HT-29 cells were infected with rotavirus Wa and treated with 1 × 109 CFU/mL L. plantarum and B. longum metabolites alone or in combination with 1 × 109 cells/mL Chlorella sorokiniana; viral titers in probiotics- and/or microalgae-treated cells were evaluated for antiviral activity. Results indicated that C. sorokiniana not only significantly (p < 0.05) improved L. plantarum and B. longum viability in flan, but also increased their antiviral activity; potent anti-rotavirus effect of C. sorokiniana alone was observed. Although more studies are needed, results suggest that incorporation of this microalga into a dairy product confers enhanced viability and antiviral effects, which indicates that C. sorokiniana might be used as an ingredient to design products with additional health benefits.
ABSTRACT
BACKGROUND: The selection of the food matrix to be used as a vehicle for a probiotic culture is important because its chemical composition and physicochemical characteristics can affect probiotic survival during the shelf-life of the product and under simulated gastrointestinal conditions (SGIC). The present study aimed to evaluate the influence of the dairy matrix (chocolate fermented milk beverage, chocolate flan or passion fruit flan) on the survival of Lactobacillus casei Lc-1 during refrigerated storage (4 °C for 21 days) and SGIC. RESULTS: Chocolate fermented milk beverage and chocolate and passion fruit flans could be considered as matrices for the incorporation of L. casei, providing suitable counts (6.38-7.84 log cfu g-1 ) during storage. The type of matrix had an impact on the inicial probiotic counts in the products and on the probiotic resistance to the SGIC. The chocolate fermented milk beverage presented higher initial probiotic counts (7.72 versus 6.65-7.28 log cfu g-1 ). The higher pH (5.3-6.8), solid matrix and increased fat content (65.0-72.9 g 100 g-1 ) contributed to the higher resistance to the SGIC of the chocolate and passion fruit flans, allowing recovery of viability during the enteric phase (increases of 1-1.5 log cycles). CONCLUSION: The type of dairy matrix has an impact on the inicial probiotic counts in the products and on the probiotic resistance to the SGIC. Chocolate and passion fruit flans proved to be more suitable options than chocolate fermented milk beverage for the incorporation of Lactobacillus casei Lc-1. © 2019 Society of Chemical Industry.