Desing of autochthonous goat lactic ferments with probiotic activity

SALVA SUSANA; MARTA NUÑEZ DE KAIRUZ; GRACIELA FONT; ALICIA RABAZA; SUSANA ALVAREZ

San Miguel de Tucumán

Simposio; II Simposio Internacional de Bacterias Lácticas LAB- I encuentro Red BAL Argentina; 2006

Centro de Referencia para Lactobacilos CERELA-CONICET

Microflora isolated from goat milk products north western Argentina some lactic acid bacteria with interest technological and probiotic properties. In previous studies, using a murine model of malnutrition, we demonstrated that the addition of goat milk (GM) to a repletion diet allows early recovery of the biological parameters affected by malnutrition. On the other hand, we reported that Lactobacillus casei CRL 1506, isolated from GM, is able to stimulate the innate and adaptative immune response, and that this effect is dose dependent. The nutritional advantages of goat milk and the probiotic properties of L. casei CRL 1506 are an important resource for the prevention and/or the recovery of malnutrition. Considering these aspects we formulated and designed probiotic lactic ferments, with strains of lactic acid bacteria isolated from goat niches (CERELA), in order to develop a probiotic fermented lactic drink using differentiated goat milk (genotypification of CSN1S1 gen) provided by INTA-Leales. The protein and fat contents was analyzed in the raw milk (EKOMILK). Milk was pasteurized (85ºC, 15min) and fermented at controlled temperatures (37 and 42 ºC). Streptococcus thermophilus CRL 806 and CRL 728 were used as starter culture and L. casei CRL 1506 was used as adjunct. Different concentrations of lactic acid bacteria were evaluated with randomized factorial design and analyzed with a multivariate statistical method. During the manufacture (4 hours) acidification velocity (pH, ºD) and coagulation time were determined. At the end of fermentation and during the storage (4ºC, 10 days) 1) acid production; 2) total and differential count of lactic acid bacteria; 3) diacetil + acetoine production (King Test) and 4) rheological characteristics of the fermented milk (draining and consistency), were studied. The optimal results were obtained with 4:1 coco-bacilli relation. L. casei CRL 1506 counts reached a maximum of 1.6 106 CFU/ml at 4 h of incubation at 37ºC. Probiotic culture remained viable and rheological characteristics were constant during storage. In addition, pH and acidity were not modified during storage (p <0.05) which indicate that there was no post-acidification. The finished product had good sensorial properties (taste and aroma) due to diacetil and acetoine production during fermentation.