Viability of Lactobacillus acidophilus in synbiotic guava mousses and its survival under in vitro simulated gastrointestinal conditions

The effects of refrigeration, freezing and substitution of milk fat by inulin and whey protein concentrate (WPC) on Lactobacillus acidophilus La-5 viability and resistance to gastric and enteric simulated conditions in synbiotic guava mousses effects were investigated. Refrigerated mousses supplemented with WPC presented the best probiotic viability. ranging from 7.77 to 6.24 log cfu/g during 28 days of storage. The highest probiotic populations, above 7.45 log cfu/g, were observed for all frozen mousses during 112 days of storage. Decreased L acidophilus survival during the in vitro gastrointestinal simulation was observed both for refrigerated and frozen mousses. Nonetheless, for the refrigerated mousses, the addition of inulin enhanced the probiotic survival during the in vitro assays in the first week of storage. L acidophilus survival in simulated gastrointestinal fluids was also improved through freezing. The frozen storage may be used to provide increased shelf-life for synbiotic guava mousses. Even though the protective effect of inulin and WPC on the probiotic microorganism tested was shown to be more specific for the refrigerated products, the partial replacement of milk fat by these ingredients may also help, as it improves the nutritional value of mousses in both storage conditions. (C) 2009 Elsevier B.V. All rights reserved.