Identification of Microbial Profile of Pegah Golpayegan Shahri Cheese and Optimization of Its Bitter Taste Reduction Process by Adding Prebiotic Compounds

The aim of this study was to identify the microbial profile of Shahri cheese of Pegah Golpayegan and reduce its bitter taste by adding prebiotic compounds of whey and maltodextrin. Microorganisms were identified by macroscopic, microscopic, biochemical and molecular tests. Prebiotic compounds of whey and maltodextrin were used to reduce bitter taste of cheese. Cheese production was optimized by CCD method using RSM software. Sensory evaluation was performed by panelist and proteolysis assay by measuring soluble nitrogen to total nitrogen and non-protein nitrogen to total nitrogen . Based on the results, three bacterial isolates, one fungal isolate and one yeast isolate were identified in Shahri cheese. The results of response level test in proteolysis assay showed that with increasing maltodextrin and whey the amount of proteolysis increased and in sensory evaluation with increasing maltodextrin and whey decreased the amount of sensory evaluation. The effect of maltodextrin and whey on proteolysis evaluation and sensory evaluation was significan. The optimum values for maltodextrin and whey were 0.894 and 1.668, respectively. In the sensory evaluation, the two treatments received the highest score from the panelists . . The amount of maltodextrin and whey in the two treatments were (0.5% and 1.75%) and (1.75% and 0.5%), respectively. Both treatments showed a 22% reduction in proteolysis compared to the control sample. The effect of cheese ripening time and number of microorganisms on proteolysis and bitter taste were significant. The results showed that prebiotic compounds could be effective in reducing proteolysis and bitter taste of cheese.