Effects of storage conditions, microencapsulation and inclusion in chocolate particles on the stability of probiotic bacteria in ice cream

Abstract

Three technological approaches to enhance viable counts of probiotic bacteria in ice cream were examined: post-freezing inoculation, use of a microencapsulated culture (spray-coating technology) and inclusion of cultures in chocolate or tablet particles. When a free-cell powder (FCP) of Bifidobacterium longum R0175 was added to the soft ice cream before hardening, a drop of almost 3 log cfu g−1 occurred during production and storage, while it was of only 0.43 log cfu g−1 for Lactobacillus rhamnosus R0011. However, inoculation with a powder of microencapsulated cells (MEP) improved stability of B. longum. The viability of probiotics was further improved when the MEP was incorporated into chocolate particles, which were subsequently blended into the ice cream. Viability losses of the FCP culture during storage at −16 °C in a household freezer having periodic defrost cycles were 10 times higher than when constantly maintained at −20 °C.