Samples of chokeberry, black currant, honeysuckle, Japanese quince and strawberry pomace were investigated for antioxidant characteristics. Free radical scavenging activity was determined using the DPPH• method in alcoholic extracts. Antioxidant activity was established in the ABTS•+ approach. The reducing power of the extracts was measured by the ferric reducing/antioxidant power (FRAP) technique. The Folin-Ciocalteu method and the Fuleki-Francis method was used to determine the total phenolics content and the amount of anthocyanins, respectively. All the samples examined display antioxidant properties that vary from one pomace type to another. The highest antioxidant activity (in terms of dry weight) is that of the chokeberry pomace (DPPH•, 199.4 mg×g-1; ABTS•+, 53.2 mg×g-1; FRAP, 12.53 mg×g-1). Black currant pomace displays a similar antioxidant activity although the FRAP values measured are surprisingly low (5.24 mg×g-1). The lowest antioxidant activity is that of the Japanese quince pomace (DPPH•, 18.21 mg×g-1; ABTS•+, 13.97 mg×g-1; FRAP, 6.12 mg×g-1). High correlation was observed (from r = 0,976 to r = 0,911) between total phenolic content and anthocyanins and antioxidant characteristics marked as DPPH• and ABTS•+ respectively. In sum, the antioxidant properties of all the pomace samples tested are high despite the drying process applied, during which the content of the compounds characterized by antioxidant characteristics decreases notably.
pomace fruits, antioxidant characteristics, DPPH•, ABTS•+, FRAP