Abstract:
This study was conducted to explore the potential of fermenting none-dairy medium based on sorghum tabat milk and peanut milk with probiotic bacterium. The commercial probiotic strain Bifidobacterium longum BB536 was used for fermentation. Growth medium were formulated from pure tabat milk, pure peanut milk, mix mil mix (50% peanut milk and 50% tabat milk), and re-constituted skin milk. The strain viable count, physiochemical changes (TSS, pH, viscosity), chemical composition (moisture, fat, protein, fiber, and ash, sugars) were also determined during the research. The results obtained showed that the highest levels of moisture, fat, and fiber were in peanut as compared to their levels in tabat and skim milk. Protein highest level was in the skim milk followed by peanut. While the highest values of ash and carbohydrates were in tabat. During fermentation there were increases in protein and ash at maximum growth of strain BB 536 in different milks. The increase in protein could be due to the increase in microbial mass. While moisture, fat, carbohydrate and sugar decreased by fermentation due to breakdown of macro-components and fermentation of sugar. The results also revealed decreases in viscosity, total solids (TS) by fermentation as results of breakdown of macro- components and release of water, utilization of sugar by strain BB 536 and production of organic acids which caused pH reduction. On the other hand, the increases in viable count of strain BB 536 in different milk by extend fermentation were significant (p ˂ 0.05). The maximum growth of the strain BB 536 was attained at 36 h fermentation in all types of fermented milks ranged between 8.90 – 9.72 log CFU/ml, these viable counts exceed the minimum number of probiotic microorganism required to presence in food which at least 6 log CFU/ml. The growth of strain BB 536 accompanied by significant (P<0.05) decreases in pH levels because of increased acids production from sugar fermentation. During refrigeration storage for two weeks there were significant (p<0.05) reduction in strain BB536 viable count in all types of fermented milks which ranged between 6.53 – 7.97 log CFU/ml which fulfilling probiotic requirement even after two weeks storage under refrigeration. Therefore, it's possible to develop strain BB 536 fermented sorghum tabat and peanut milk having high viable count of Bifidobacterium longum BB 536 comparable to the reference reconstituted skim milk fermented with strain BB536.
