Abstract
Mish is a soft pickled cheese produced traditionally in Jordan and Palestine. The influence of Mish cheese processing and storage on fat and cholesterol oxidation and hydrolytic rancidity was evaluated by determining peroxide value (PV), 7-ketocholesterol, and free fatty acid (FFA) content. Changes in Mish cheese acidity, salt, moisture, the antioxidant activity of water soluble nitrogen (WSN) measured by a super oxide dismutase (SOD) test and organoleptic evaluation were also evaluated. The results indicate that the extent of oxidation of fat and cholesterol was very low, fine PV and 7-ketocholesterol content after 20 weeks of storage were in the ranges 1.42-2.88 meqO(2)/kg and 2.02-4.81 mu g/g, respectively. The effect of storage was greater on hydrolytic rancidity i.e. the FFA content at the end period of storage ranged from 1.87-3.64%. There was a significant decrease in moisture and salt contents throughout the storage period, i.e. moisture decreased by 9-14% and salt decreased by approximately 5%. The WSN increased significantly with storage period, which increased the antioxidant activity. The aforementioned changes had no significant effect on the characteristic flavour and colour of the Mish cheese during the 20 months of storage.