Determining the effect of addition of cheese slurry on proteolysis and forming of bioactive peptides in the model cheese

In this study, in the production of model cheese It is aimed to accelerate the ripening by using moldy cheese slurry. The hypothesis of the study is that the extracellular proteinases originating from Penicillum roqueforti contained in moldy cheese can accelerate the ripening of the model cheese. In the first stage of the study, the slurry ratio (0, 1, 3 and 5%) salt ratio (1, 2 and 3%) and depending on the ripening temperature (5 ºC, 10 ºC and 15 ºC) factors trial model cheese was produced. Cheeses produced using the Response Surface Method (RSM) were ripened for 30 days. Cheeses produced under optimized conditions according to RSM results were ripened for 60 days and analyzed on the 1st, 15th, 30th and 60th days of ripening. Significant differences were found in the titratable acidity and pH values of the cheeses. The nitrogen values of the control sample, which were dissolved in water and 12% TCA in 60 days, were reached in about 30 days with the addition of 5% slurry. The use of slurry had a significant effect on free amino acid composition (P<0.01), there was caused an increase in the amount of Ile, Leu, Phe and Val, especially with the use of the slurry. It was observed that the addition of slurry had a significant effect on RP-HPLC peptide profiles and urea-PAGE electrophoretograms during all ripening periods of cheeses. Accordingly, cheeses with slurry added to the level of proteolysis It has been found that its biochemical activity is significantly affected. As antioxidant activity; ABTS*+ While finding differences between samples in values (P<0.05), The difference between DPPH* values was not significant (P>0.05). The effect of slurry addition in terms of volatile compounds among cheeses was significant. On the 60th day of ripening, the number and amounts of other volatile compounds were found to be higher than the control sample except for various compounds and aldehydes. The highest aminopeptidase activity was reached on the 15th day of ripening with the use of slurry. Only the aminopepdidase enzyme activity value of the sample with low storage temperature increased during storage. ACE-inhibitory activity was found to be higher in slurry added cheeses and increased during storage. Depending on the slurry addition rate, while there was a decrease in the lightness values during the storage, there was an increase in the a* and b* values. With the addition of slurry, the sensory properties of model cheeses decreased, but they were considered to be generally acceptable. As a result, it was determined that the model cheese using 5% slurry and 1% salt and having a ripening temperature of 15 ºC gave the most suitable results in terms of quality in other analysis parameters except for the sensory properties. Keywords: Model cheese, Moldy cheese of Konya, Slurry, RSM, Proteolysis, Enzymatic activity