Evaluating the recovery of bioactive compounds and antioxidant activity of unripe red grape liquid extracts obtained by maceration

Abstract

This paper evaluates the results of extracting bioactive compounds using modern maceration technology, which transforms food products into a liquid extract, based on the example of unripe grapes and its by-product called verjuice. During the extraction process, the indicators of niacin and pyridoxine remained stable, while pantothenic acid and choline increased significantly. During the extraction, the extraction system produced 712 kg of liquid extract, which was characterized by a high content of phenolic compounds and water-soluble vitamins, as well as a high antioxidant activity compared to the measurement obtained for green juice from unripe grapes. Since the estimated liquid extract yield from 950 kg of crushed immature grapes is 847 kg, the actual liquid extract yield was about 80%. The advantages of the maceration extraction method included avoiding the use of solvents or preservatives, low temperature treatment and little oxidative damage. Besides, it enabled enhancing the extraction yield due to introduction of certain post-extraction steps.