Kinetics of hydrolysis reactions and triacylglycerols oxidation in olive oil during prolonged storage

Abstract

Abstract The article presents the results of studies on the effect of the antioxidant beta-carotene and storage temperature on hydrolytic and oxidative processes occurring during storage of extra virgin olive oil obtained from olives grown in the soil and climatic conditions in Syria. The research aims to study the effect of temperature and beta-carotene on the kinetics of the hydrolysis reactions of triglycerides and fatty acids oxidation in olive oil during storage. The object of the study was extra virgin olive oil obtained from olives grown in Syria according to the generally accepted technology in 2019. And beta-carotene, produced by Ekoresurs, has been used as a natural antioxidant. The kinetics of the hydrolysis and oxidation reaction was evaluated by studying the change in the content of saturated and unsaturated fatty acids during storage of the control sample from olive oil (sample No. 1), and experimental samples with the addition of beta-carotene at concentrations of 400 mg/L (sample No. 2) and 600 mg/L (sample No. 3). These samples were stored at 18 ° C. And sample No. 4 was stored without adding beta-carotene at 4 ° C. Upon receipt for storage and during this process, the content of saturated and unsaturated fatty acids in the test samples was determined periodically by gas chromatography on an LC-20 Shimadzu chromatograph, and organoleptic quality indicators were evaluated on a five-point scale. In addition, the content of triacylglycerols, saturated and unsaturated fatty acids were determined based on the change in beta-carotene dose, temperature, and period of storage. Also, the rate constants of the fatty acid oxidation reaction have been calculated. It was shown that the minimum rate of free fatty acids oxidation during storage of extra virgin olive oil for 7 months was in the olive oil sample stored at + 18 ° C with the addition of 400 mg/L of beta-carotene, as well as in the olive oil sample stored in the refrigerator at + 4 ° C without adding antioxidant.