Composition and Antioxidant Activity of Aronia Melanocarpa Fruit Juice

Abstract

Aronia melanocarpa is a woody shrub of the Rosaceae family. Its fruits are used for consumption either fresh, or as juice, jam and wine. The aim of the present study was to measure the concentration of some biologically active substances and the antioxidant activity of two samples of Aronia melanocarpa fruit juice (AMFJ). The juice was prepared from fresh fruits. One of the samples was produced using a juice centrifuge and was preserved with potassium sorbate (1.0 g/l). The other sample was produced by crushing and squeezing of fruits after which the juice was filtered and sterilized at 100 °C for 10 min. The contents of biologically active substances in the juice samples were measured by spectrophotometric and high-performance liquid chromatography methods. The antioxidant activity of the two juice samples was measured by the ORAC (oxygen radical absorbance capacity) and HORAC (hydroxyl radical аverting capacity) methods. The results showed that both samples were extremely rich in polyphenolic substances, amongst which the highest was the concentration of procyanidins followed by phenolic acids (chlorogenic and neochlorogenic) and anthocyanins. Sample 1 had higher concentration of total phenolics and contained higher quantities of most polyphenolic substances with the exception of anthocyanins. It also contained micro-quantities of cyanogens. The variations in the composition of the two samples could be attributed to the different methods of juice production and conservation. Both juice samples showed very high ORAC and HORAC values which were higher for sample 1 (the sample with the higher concentration of polyphenolic substances). The high antioxidant activity of the two AMFJ samples could be attributed to their polyphenolic ingredients.