Resumo

The different composition of food matrix can exert variable and protective effect on probiotic bacteria and enhance their survival during passage through the gastrointestinal tract. Thus, the objective of this study was to evaluate the functionality of a dairy dessert as food matrix supplemented with probiotic bacteria (Lactobacillus acidophilus) during chilling storage. Three different formulations of dairy desserts were processed: F1 – added of 10^4 CFU/g of L. innocua, F2 – added of 10^8 CFU/g of L. acidophilus only and F3 – added of both L. acidophilus (10^8 CFU/g) and L. innocua (10^4 CFU/g). The functionality of probiotic dairy dessert was evaluated at 0, 7, 14, 21 and 28 days of storage. The functionality was assessed through collection of 1 mL of samples, further added to 9 mL of gastric solution (pH 2.0, 0.2% NaCl). The resulting solution was incubated at 37°C for 30 min, following transference of 1 mL to 9 mL of the intestinal solution (pH 7.0, 0.6% of bile salts), which was incubated at 37°C for 60 min. The survival rate (%) of L. acidophilus was determined by the formula SR (%) = log CFU nf/log CFUno × 100, where, nf = total viable count of L. acidophilus after exposure to gastrointestinal juices and no = total viable count of L. acidophilus before the exposure to gastrointestinal juices. L. acidophilus was enumerated using MRS agar supplemented with 0.15% bile salts. Statistical difference was assessed through analysis of variance and Tukey’s test using the XLSTAT for Window 2011. The storage time affected the survival rate of L. innocua inoculated in F1, with a decrease in populations from 89.3 to 58.8% being observed. On the other hand, in F3 inoculated with L. inoocua and L. acidophilus, this effect was not observed (p>0.05). The results of this study suggest the existence of cooperation between L. innocua and L. acidophilus, resulting in positive effects for both microorganisms. This effect reflected in the functionality of the product, with probiotic microorganism presenting in F3 showing higher tolerance to gastric and intestinal conditions studied. Our results indicate that the dairy dessert is an adequate matrix for the survival of probiotic microorganism (L. acidophilus), however, the enhanced survival of L. innocua may impact food safety.