Determination of the effects of frying process in oil used in making ring dessert

Halka dessert is one of the most preferred street desserts in our country. It is a dessert served by frying the prepared dough mixture in oil. During the deep-frying process, the oil goes through chemical reactions. These are reactions such as lipid hydrolysis, oxidation, polymerization and isomerization. These reactions produce harmful compound that degrades frying oil quality. After frying, fatty acids and trans isomers are formed. In the degree of formation of trans fatty acids; the temperature and hydrogen health of the environment, the pressure and distribution degree of the gas, the activity and amount of the catalyst type are effective. In this study, the physical and chemical properties and trans fatty acids of the frying oils used in making halka desserts, which change with the frying process, were determined. For this purpose, oil samples were collected before and after frying from 15 different halka dessert producers. The physical and chemical properties of the obtained oil samples were evaluated in terms of quality. Within the scope of the study, the refractive index, free fatty acid, peroxide amount, colour analysis, iodine analysis, saponification amount and fatty acid profiles of the oils were analysed. As a result of the analysis, the refractive index value increased from 1.4735 to 1.4744, the amount of free oil increased from 0.43 mg KOH/g oil to 2.32 mg KOH/g oil, the amount of peroxide increased from 4.25meq g O2/kg oil to 6.52 meq g O2/kg oil, the saponification amount increased from 193.52 mg KOH/g oil to 256.90 mg KOH/g oil, the b* value increased from 10.53, c value increased regularly from 10.81 to 33.56, the amount of elaidic acid, which is a trans fat, increased from %0.1969 to %0.3109, the amount of linolelaidic acid increased from %0.2724 to %0.2858, the a* value decreased from -2.38 to -3.24, L* value decreased from 95.83 to 91.68, and h value decreased from 102.82 to 98.64. At the same time, the iodine count decreased from 121.58 to 117.38. After the study, it was determined that the frying process in the halka dessert caused a significant decrease in the oil quality values. These transformations have negative effects on human health. For this reason, it is recommended to limit the consumption of halka dessert to the public.