Optimizing the quality and antimicrobial ability of yogurt through a combination of starter and dates puree at different levels

Research on the optimization of the quality and antimicrobial ability of yogurt using a combination of starters (Lactobacillus acidophilus and Streptococcus thermophilus) and dates puree with different levels has been carried out to determine the changes in the quality of yogurt in terms of lactic acid levels, protein content, syneresis and also looking for an antimicrobial ability which was measured based on of inhibition zone formed against the tested bacteria (E.coli and S aureus). A completely randomized design (CRD) factorial pattern was applied consisting of 2 factors, those are factor A which is the level of starter, a1 = 2.5 percent, a2 = 5 percent, and factor B which is the level of dates puree namely b0 = 0 percent, b1 = 10 percent, b2 = 20 percent and b3 = 30 percent. The results showed that the level of dates puree had a very significant effect on lactic acid levels but not so with the starter level. The combination of treatments (P <0.01) affects the protein content but there was no interaction between treatments. Furthermore, there is interaction between treatments and it decreases the syneresis value significantly. It can be concluded that the levels of lactic acid, protein and syneresis of yogurt still have the best quality obtained in the treatment of 5 percent starters and the addition of 20 percent of dates puree. On the other hand, it had a weaker antimicrobial ability