Comparative study of the influence of ultrasonic influ-ences on the extraction of antioxidant compounds of blackberry berries (vaccinium myr-tillus l.)

Abstract

The interest in berries from food manufacturers is huge, which is explained by good organoleptic characteristics and high biological activity of berries. One way to preserve the properties of berries throughout the year is to obtain extracts. Determining the conditions and type of optimal extraction technology to obtain biologically active substances from plant materials is an im-portant stage in the production of new natural preventive additives. The aim of this work is to study the chemical composition and antioxidant activity of blueberry extracts (Vaccinium myrtillus L.) obtained by various methods: Maceration, ultrasonic and microwave extraction. The use of ultrasonic extraction as a method of intensifying the process of extracting biologically active compounds from blueberries is very effective. This proves an almost 2-fold increase in the flavonoid content in the extracts. However, the content of anthocyanins in the extracts of blueberries is not the highest for ultrasonic extraction (a decrease by 3.3 times compared with maceration), in all likelihood due to the instability of this class of compounds in this type of processing. Among the extracts of blueberries obtained by three technologies (maceration, microwave and ultrasound treatment), it is the ultrasound extract that has the highest antioxidant activity (9.5±0.1 mg/cm3, 18.18 mmol±0.24 Fe2+/1 kg, 58.6%), determined by three methods: DPPH method, FRAP method, method for assessing antioxidant properties using a model system with linoleic acid. Ultrasonic extraction was chosen as a technology for obtaining a concentrated blueberry extract.