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

Abstract

Lactic beverage (sample 1), with 70% of milk and 30% of cheese whey, and fermented milk (sample 2), with 100% of milk, added of Lactobacillus acidophilus La-5, Bifidobacterium Bb-12 and Streptococcus thermophilus, were evaluated about physico-chemical composition, enumeration of viable cells of probiotic bacteria and rheological measurements, in the temperatures of 2.0 ± 0.1 ºC; 4.0 ± 0.1 ºC; 6.0 ± 0.1 ºC and 8.0 ± 0.1 ºC. The whey addition resulted in lactic beverage with lesser contents (p < 0.05) of total solids (18.08 ± 0.08% m/m), proteins (2,23 ± 0.10% m/m), lipids (1.91 ± 0.02% m/m) and caloric value (79.27 ± 0.37 Kcal/ 100 g), when compared with those presented in fermented milk, respectively. While, the contents of ashes, carbohydrates, the acidity and pH of the lactic beverage and fermented milk weren't different (p > 0.05). According to Brazilian legislation the lactic beverage and fermented milk were considered probiotic (> 106 CFU/mL). The two samples (1 and 2) had behaved as pseudoplastic fluids, confirming the non- Newtonian behavior and had presented thixotropy. The values for the activation energy were equal to 1.89 Kcal.mol-1, for the lactic beverage, and 1.84 Kcal.mol-1, for the fermented milk, indicating that the activation energy was not influenced by the amount of whey used, as well as the temperature also did not influence on the apparent viscosity of samples 1 and 2.