Optimization of production technology of keş for frying

The study was aimed to optimize the production steps of keş for frying produced by traditional methods arounds Bolu province. In order to determine the ideal parameters in the production steps chemical, textural, sensory and color properties of the products were investigated. Ideal fat percentage of milk used in the production was optimized as 3%. With the increase of fat percentage in milk (from 1% to 3%), hardness decreased in the keş samples (p<0.05), adhesiveness and cohesiveness values increased (p>0.05), preference in the sensory evaluation increased. Optimum pH value to end incubation point of yoghurt was best at 4.80. The pH values below 4.80, the yield decreased (p<0.05) in the keş samples. Hovewer hardness values increased (p>0.05), adhesiveness and cohesiveness values decreased (p>0.05), preference in the sensory analysis decreased in the keş samples. The most ideal method for removing yoghurt serum was found to be Quick-1 method (200 rpm for 1 h centrifugation, then 400 rpm for 1 h centrifugation and finally 600 rpm for 1 h centrifugation). Thus, the required time was reduced from 2 days to 3 hours to remove the yoghurt serum. Optimum salt level added by weight into centrifuged yoghurt was determined as 1%. The salt content of the keş samples produced in this way became 1.78%. In the drying process using industrial type drier the ideal temperature was determined as 25°C, the ideal drying fan speed was 0.5 m/sec and 10 h was determined as the optimum drying time. Increasing the drying temperature (>25°C) caused hard layer outside of the samples and prevented drying of internal surface of the keş molds. Accelerating the drying fan speed (>0.5 m/sec) and the drying period for over 10 hours increased splitting in the samples. The keş samples produced according to optimal parameters determined in the optimization studies were stored in vacuum packages under refrigerator conditions (3±1°C) for 120 days. The chemical, biochemical, microbiological, textural and sensory properties of the samples were investigated on the 1st, 30th, 60th, 90th and 120th days of storage time. The changes in the dry matter, fat, acidity, water-soluble nitrogen, hardness, springiness, gumminess, chewiness values, yeast and mold counts of the keş samples were found significant (p<0.05) during storage. General acceptability on days of 1, 30 and 60 were above 4 point. Hovewer general acceptability on days 90 and 120 was found to be lower. Hovewer the difference between the means was not statistically significant (p>0.05). As a result of storage findings, it could be suggested for the keş samples that they may be stored under refrigerator conditions (3±1°C) at least 4 months.