Effect of Probiotics and storage stability on quality of Bio-Fruit Yoghurt

Abstract

Freshly drawn buffalo milk after clarification, standardization (3% fat), addition of skim milk powder (SMP) (4 %), sugar (7 %) and sodium alginate (0.4%) was pasteurized (900C, 5 min), cooled (360C), mixed with papaya (10%) and mango (20%) pulp and then inoculated with 1.5 % Lactobacillus delbrukii spp. bulgaricus + 1.5 % Streptococcus thermophilus and Biofidobacterium (1 %) for preparing bio-fruit yoghurt. Incubation was carried out at 42 ± 10C for 3-3.5 h. The control and experimental samples were kept at 30 ± 1 and 4 ± 10C to study the effects of probiotics, fruit pulp and storage temperatures on the quality parameters of products. Results indicated that curd tension, viscosity, pH and acetaldehyde content registered a declining trend while syneresis, acidity and content of soluble nitrogen and free fatty acids (FFA) followed an increasing trend irrespective of storage temperature, fruit pulp and culture. Total plate count increased during storage at 30 ± 10C but an opposite trend was observed at 4 ± 10C. Yeast and mold, and coliforms were not detected during the entire period of storage at the either temperature. Overall acceptability of all the three samples was maintained only upto 4 h when stored at 30 ± 10C while control, papaya and mango yoghurt were acceptable upto 3, 3 and 6 days of storage, respectively at 4 ± 10C. Statistically, the effects of storage on the quality attributes was found significant