Influence of temperature and beta-carotene on the processes of hydrolysis and oxidation of triacylglycerins in extra virgin olive oil during storage

Abstract

The article presents the results of studies on the effect of 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 of Syria. The aim is to study the effect of temperature and beta-carotene on the kinetics of reactions of hydrolysis of triacylglycerides (TAG) and oxidation of free fatty acids (FFA) of olive oil during storage. The object of the study was extra virgin olive oil obtained from olives grown in the soil and climatic conditions of Syria according to the generally accepted technology (harvest 2019). Control sample № 1 (without the addition of antioxidant) and experimental samples with the addition of beta-carotene in the amount of 400 (№ 2) and 600 mg/100 g (№ 3) were stored at a temperature of 18 °C for 7 months. Oil sample № 4 without the addition of antioxidants was stored at 4 °C. In the samples under study, the acid value was periodically determined by the titration method, according to the change in which the formation of free fatty acids during the hydrolysis of TAG, as well as the peroxide value characterizing the formation of FFA oxidation products, was estimated. The organoleptic assessment of the oil quality indicators according to the studied descriptors was 5 points. The rate constants of TAG hydrolysis and oxidation of FFA in olive oil have been calculated. It has been shown that during the storage of experimental oil samples the hydrolytic and oxidative processes of TAG significantly slow down with the addition of the antioxidant beta-carotene. It was found that minimal changes in the content of TAG hydrolysis products and FFA oxidation during storage of olive oil at a temperature of + 18 °C are characteristic for samples containing 400 mg/L of beta-carotene and for oil samples stored at a temperature of + 4 °C without the addition of an antioxidant. Expiration dates of olive oil are substantiated depending on the dose of beta-carotene and storage temperature