Evaluation of Antioxidant Properties of Commercial Pomegranate Juices

Abstract

Background. Consumers consider pomegranate juice one of the most beneficial for health. The limited production of pomegranates in Russia cannot meet the needs of Russian consumers with juices of its own production. Pomegranate juices are produced from concentrates or pasteurized direct-squeezed juices imported from different countries, there is no information about their antioxidant properties.Purpose. Study of the content of the main biologically active substances and antioxidant activity of pomegranate juice of various brands on the consumer market, and their influence on the formation of antioxidant properties.Materials and Methods. The objects of research were freshly pressed juice from pomegranate fruits (control)and samples of commercial pomegranate juices produced using different technologies: «Grande», «Benature», «Grante» -direct-squeezed juice; «Swell», «O'keй», «Rich», «Gold Brand» - reconstituted pomegranate juice; «Nar» - reconstituted juice with the addition of direct-squeezed juice. In juices, the total content of phenolic compounds, anthocyanin, flavonoids, tannins and vitamin C was determined. The antioxidant activity of juices was determined by two methods: FRAP and coulometrictitration based on the measurement results of which the antioxidant index was calculated.Results. Juices of industrial production differed significantly in the amount of biologically active substances, the spread of values in their content between juices was 40-50%, they contained significantly less total anthocyanin and total flavonoids than freshly-pressed juice. Total tannins prevailed in the composition of phenolic compounds of all juices (40-75%). The antioxidant activity of juices varied depending on the method of determination. The FRAP test showed the highest values of antioxidant activity in the reconstituted pomegranate juice «Rich», and the coulometric titration showed the highest values in the direct-squeezed pomegranate juice «Benature». Juices had the highest antioxidant index Rich>Benature>Grante, the values of which were more than 85%. The antioxidant properties of pomegranate juices depend on the total amount of phenolic compounds (R2> 0.772) and total tannins (R2> 0.538).Conclusion. The formation of antioxidant properties of pomegranate juices depends on the amount of total phenolic compounds and total tannins. The results of the evaluation of the antioxidant properties of commercial pomegranate juices can be used in the development of functional beverages.