Abstract:
This study was conducted at the Department of Dairy Science and Technology,
College of Animal Production Science and Technology, Sudan University of
Science and Technology to evaluate the effect of adding different levels of
probiotic culture on the physicochemical and sensory properties of probiotic
Sudanese fermented milk during storage. Six liters of fresh cow’s milk were
purchased from dairy farm, College of Animal Production Science and
Technology. The milk was pasteurized at 85°Cfor 30min then cooled to 45°C. The
pasteurized milk divided into three equal portions. Three treatments were carried
out. The first treatment was the control sample in which fermented milk drinks was
processed by conventional yoghurt starter culture. In the second and third
treatments 75% and 100% of probiotics culture of (L. acidophillus, L.casei and
L.rhamnosus) were added respectively. The inoculated milk was incubated in all
treatments at 40 °C until coagulation occurred. After that sugar solution added
mixing with blender, packed into plastic bottles (250 ml capacity) in triplicates for
each treatment. There after samples from different treatments were cooled in
refrigeration at temperature (4°C). Chemical composition and sensory evaluation
were carried out for the fermented milk samples in all treatments at intervals of 1,
5 and 10 days. The results indicated that significant variations (P<0.05) were
observed in the fat%, acidity%, ash%, protein % and pH while total solids %
showed no significant difference (P>0.05). However, the storage period had
significant differences (P<0.05) on the acidity%, ash%, protein%, and pH while the
fat and total solids content were not affected by storage period. The sensory
characteristics of the fermented milk samples found to be not affected significantly
(P>0.05) by the addition of starter cultures except the texture. The color and flavor
affected significantly (P<0.05) by storage period.
