Manufacture of set yoghurt with probiotic Bifidobacteruim longum BB 536 and Bifidobacteruim infantis 20088

Abstract

This study was carried out to evaluate the potential of producing probiotic set type yoghurt in Sudan. Yogurt culture (lactic acid bacteria (LAB), Bifidobacterium longum BB536, Bifidobacterium infantis 20088 and mix Bifidobacterium cultures were used for processing. Fresh milk was standardized; heat (at 95 ᵒC for 5 minutes), inculcated (with yoghurt starter cultures at 43 ◦C and at 37 ◦C for Bifidobacterium strains) and then cooled after the pH reach 4.60. Different analysis were carried out including: physiochemical (TSS, TA, pH and water holding capacity), chemical (fat, protein, lactose, ash, moisture, and mineral), microbial (lactic acid bacteria, bifidobacteria, yeast &mould, coliform and viability of cultures) and sensory (taste, flavour, appearance, consistency and overall acceptabitity). The results obtained for the fresh milk used in this study did not deviate from standard values of each specific quality parameter for raw milk. During mixing process fat, solid nonfat, total solid content, titarable acidity and specific gravity were not significantly (p˂ 0.05) difference than the standard parameters of milk yoghurt. For the final product the pH, acidity and mineral were not significantly (p˂0.05) difference between formulated yoghurt. The total viable count of different bacterial strains were ranged between 8.0 – 8.9 log CFU /ml between yoghurt products; exceeding the number required to presence in probiotic foods which at least 6 log CFU/ ml. However, during shelf life of different set yoghurt at refrigeration for 15 days, there were significant (p˂0.05) decreases in viable number of strains. In general, the levels of the strains in set yoghurt were still maintained above 6 log CFU/ml. Sensory characteristics of set yoghurts types revealed no significant (P˂0.05) differences in appearance, flavor, consistency and overall acceptability between different types of yogurt. Overall scalding manufacture of probiotic set yoghurt fulfilling probiotic products requirements was successful.