Is there an impact of the dairy matrix on the survival of Lactobacillus casei Lc-1 during shelf life and simulated gastrointestinal conditions?

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 degrees 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. (c) 2019 Society of Chemical Industry