Study of the Content of Antioxidants and Their Activity in Concentrated Extracts of Cranberry (Vaccinium oxycoccus), Sea Buckthorn (Hippophae rhamnoides L.), Blackberry (Rubus fruticosus), Guelder Rose (Viburnum opulus L.) and Mountain Ash (Sorbus aucuparia L.)

Extracts and their concentrates can be considered as a source of biologically active ingredients of food products and as food additives to increase the consumption of useful substances of berries. The benefits gained from their use lead to the development of advanced technologies that can allow them to be extracted from the feedstock without significantly compromising the biological activity of the feedstock. In this paper, we studied the content of antioxidants and their activity in concentrated extracts of cranberry (Vaccinium oxycoccus), sea buckthorn (Hippophae rhamnoides L.), blackberry (Rubus fruticosus), guelder rose (Viburnum opulus L.) and mountain ash (Sorbus aucuparia L.) berries. For all extracts, the total content of phenolic compounds, flavonoids and anthocyanins, antioxidant activity according to the DPPH method and iron-reducing antioxidant activity (FRAP) were determined. Concentrated extracts of guelder rose contain the largest amount of phenolic compounds (9.3 +/- 0.3 mol HA/L) , flavonoids (1.96 +/- 0.08 mol K/L) and anthocyanins (0.26 +/- 0.02 mol CG/L) among the studied extracts. There is also a high total content of phenolic substances and flavonoids in blackberry and rowan extracts (5.7 mol HA/L, 1.33 mol K/L and 4.7 mol HA/L, 192 mol K/L, respectively) . The antioxidant activity of the extract of guelder rose berries showed a directly proportional dependence on the content of biologically active compounds in it: DPPH-method, 2.4 mg/mL; FRAP-method, 39.99 mmol Fe2+/kg. Also, high levels were found in concentrated extracts of blackberries, sea buckthorn and mountain ash. It is the extracts of guelder rose, blackberry and mountain ash that are recommended to be used in the production of food products to enrich them with biologically active substances and give them antioxidant properties. Cranberry and sea buckthorn extracts can be used in combination with other extracts.