Physico-chemical, microbiological and rheological evaluation of dairy beverage and fermented milk added of probiotics.

摘要

Lactic beverage (sample 1, with 70% of milk and 30% of cheese whey) and fermented milk (sample 2, with 100% of milk) added with Lactobacillus acidophilus La-5, Bifidobacterium Bb-12 and Streptococcus thermophilus were evaluated for physicochemical composition, number of viable cells of probiotic bacteria and rheological parameters at 2.0+or-0.1 4.0+or-0.1, 6.0+or-0.1 and 8.0+or-0.1 degrees C. The whey addition resulted to a lactic beverage with less (p<0.05) total solids (18.08+or-0.08% m/m), proteins (2.23+or-0.10% m/m), lipids (1.91+or-0.02% m/m) and caloric value (79.27+or-0.37 kcal/100 g) compared to fermented milk. The ash and carbohydrate contents, acidity and pH of the lactic beverage and fermented milk were not different (p>0.05). According to Brazilian legislation, the lactic beverage and fermented milk were considered probiotic (>106 cfu/ml). The two samples behaved as pseudoplastic fluids, confirming the non-Newtonian behaviour. Moreover, the samples presented thixotropy. The values for the activation energy were equal to 1.89 kcal/mol for the lactic beverage and 1.84 kcal/mol for the fermented milk, indicating that the activation energy was not influenced by the amount of whey used. The temperature did not also influence the apparent viscosity of samples 1 and 2.