Coltivazione di Lactobacillus plantarum e Lactococcus lactis in mezzo a base di estratto di soia: studio della cinetica di acidificazione, della crescita cellulare, dell’attività antimicrobica e dello stress gastrointestinale in vitro = Cultivo de Lactobacillus plantarum e Lactococcus lactis em meio contendo extrato de soja: estudo da cinética de acidificação, do crescimento celular, da atividade antimicrobiana e do estresse gastrointestinal in vitro

Currently, the idea of reducing dairy components as vehicles for probiotic agents has been promoted because of the high proportion of individuals who present lactose intolerance and allergy to milk protein components. Researchers suggest that lactose intolerance occurs in the sensitized intestinal mucosa, causing abdominal cramps, vomiting, intestinal constipation, fecal occult blood loss, and in more severe cases, intestinal obstruction and protein-losing enteropathy. Considering the pathologies related to food intolerance, new alternatives such as soy-based probiotic fermented beverages instead of dairy products have been emphasized in the diet, as they provide a beneficial modulation of the intestinal microbiota. The acidification kinetics was performed with the CINAC system of the different formulations at 42°C. The ternary co-culture composed of Lactococcus lactis (LL), Lactobacillus bulgaricus (LB), Streptococcus thermophilus (ST) was the highest acidification rate (Vmax 11.40 x 10-3 units pH / min) 10.12 hours to reach pH 4.5 (P <0.05), post acidification the Lactococcus lactis (LL) strain had the lowest significant acidification rate when compared to the others at 37ºC p <0.05. And the ternary co-culture Lactobacillus plantarum Lactobacillus bulgaricus (LB) and Streptococcus thermophilus (ST) showed the highest acidification rate when compared to the other p <0.05, at 42ºC, and the highest acidification rate was Lactococcus lactis (LL) with Lactobacillus plantarum (LP). In the microbiological count, all microorganisms at different temperatures and formulations maintained viability above 106 after 28 days of storage at 4ºC. The thermodynamic parameters estimated for nisin irreversible thermal inactivation were energy, enthalpy and Gibbs free energy of activation of 155.1, 152.1-152.3 and 86.2-90.4 kJ/mol, respectively, and an activation entropy of 177.9-186.2 J mol-1 K-1.