evaluation of physicochemical changes of bezhi (special fried cookie) during deep-fat frying

bezhi (or beji) is a special sweet and fried cookie which is produced traditionally in west region of iran. in this study, the effect of different temperature levels (150, 165 and 180°c) and frying time (1 to 8 min) on physicochemical properties of bezhi was investigated. the obtained results showed that increasing frying time up to the first 3 minutes causes a significant increase in sample volume. although, further increase in frying time was not accompanied by volume increase but the mean volume was decreased significantly. generally any increase in the studied parameters (temperature and frying time) would increase the samples’ diameter while other dimensional characteristics remained unchanged. moreover, increasing temperature and frying time would increase the samples’ hardness as well as their color changes (∆e). l* value showed decrease when increasing studied parameters. the rate of decrease in l* in the studied temperature levels (150, 165 and 180 °c) were found to be 0.00987, 0.07665 and 0.11250 s-1 respectively. in addition a* value was increased by increasing the studied parameters while b* remained unchanged. the activation energy for the enzymatic reactions in bezhi samples was 31.12 kcal/mole which demonstrates the high effect of temperature on these reactions in the studied temperature range. temperature and frying time showed considerable effect on the crust formation of samples. while the maximum crust thickness at 150 °c was reached to 0.55 mm, the value of 1.45 mm was recorded as the maximum crust thickness at 165 and 180 °c. so oil temperature and frying time have an important effect on physiochemical properties of bezhi.