Utilization of sweet whey and Ultra Filtration-milk permeate in manufacture of yoghurt drink

Sweet whey and UF-milk permeate, the nutritional and valuable dairy by-products were successfully used in yoghurt drink manufacture. Sweet whey, UF-milk permeate or water were added to fresh cow’s milk in a ratio of (1:1). Yoghurt drink cultures: ABT probiotic yoghurt culture (Lactobacillus acidophilus, Bifidobacterium bifidum, & Streptococcus thermophilus) and YCX11 thermophilic yoghurt culture (Streptococcus thermophilus & Lactobacillus delbrueckii subsp. bulgaricus) were also used. The higher total solid (TS) content were shown in sweet whey yoghurt drink samples meanwhile, water samples were the lowest. ABT yoghurt drink samples exhibited pH values slightly lower than that of YC-X11 when compared at the same order. Lb. acidophilus was recorded a developing count in water yoghurt drink treatment along 14 days meanwhile; sweet whey yoghurt drink treatment recorded the highest developing count up to 21 days of storage at (4 ± 1°C). The lower TS content the lower developing count of Lb. acidophilus. The joint growth of S. thermophilus and (B. bifidum & Lb. acidophilus) was better more than that with Lb. bulgaricus even at the low levels of the TS. No yeast and mold counts were detected in all treatments when fresh and during storage up to the day 21. For the sensory character assessed sweet whey yoghurt drink treatments were the most preferred and UF-milk permeate yoghurt drink was slightly less acceptable. Three replicates were carried out for each treatment and the data obtained were statistically analyzed at p ≤ 0.05.