EFFECT OF SOLIDS NON FAT AND SUCROSE CONCENTRATION ON ACIDIFICATION BY LACTIC ACID BACTERIA IN YOGURT

Abstract

The culture conditions influence the kinetics of growth and acidification of lactic acid bacteria. This study assessed the effect of adding different concentrations of sucrose and non fat milk solids in the production of lactic acid and pH variation in yogurt by thermophilic lactic acid bacteria. Yogurts were prepared from milk powder with concentrations of 6, 8, 10 and 12% solids non fat, 4, 6, 8 and 12% sucrose, was added to mixed lactic acid culture of Lactobacillus delbrueckii ssp bulgaricus and Streptococcus thermophilus. Samples were collected from yogurt in pre-determined for analysis of acidity and pH. The factors time, solids non fat and sucrose content were significant (p <0.05), except the concentration of sucrose in relation to variable pH. Therefore, pH and acidity behaved independently as a function of the factors studied. We observed a decrease in acidity as a function of sucrose concentration in milk. A signi? cant interaction between pH and concentrations of sucrose used in this study. So, although there may be differences in texture and viscosity of the clot, no differences were observed in relation to acid production and pH decrease.