Effect of fermentation on physico-chemical, textural properties and yoghurt bacteria in mango soy fortified yoghurt

摘要

Mango soy fortified yoghurt (MSFY) samples were prepared by using blends of 78.3% milk containing 3% fat, 14.5% soymilk containing 8.2% total solids and 7.2% mango pulp containing 18% total solids. The physico-chemical, textural properties and yoghurt bacteria counts of MSFY were analyzed at an interval of 30 min during fermentation upto 270 min. The fermentation time had a positive effect on acidity but a negative effect on pH, total solids and sugars in MSFY. Quadratic model were well fitted into different physico-chemical properties of MSFY during fermentation. Textural profile data of MSFY during fermentation were: hardness (46.44 - 154.6 g), cohesiveness (0.4133 - 0.8137), adhesiveness (-2.57 to -59.77 g.s), springiness (1.037 - 1.416) and gumminess (26.22 - 93.80 g). TheStreptococcus thermophiluscounts increased from 1.3 × 108to 1.75 × 109cfu/ml andLactobacillus bulgaricusfrom 0.9 × 108to 1.17 × 109cfu/ml. Specific growth rate ofS. thermophilusis higher than that ofL. bulgaricusduring MSFY fermentation.