The biologically active compounds, especially fruit phenolics, are responsible for reduced risk of developing chronic diseases (cardiovascular disease, cancer, diabetes, etc.), due to their antioxidant activities. Th is study summarized some chemical principles of antioxidant capacity assays and the antioxidant capacity of selected fruit varieties (strawberry, sour cherry, cornelian cherry, blackthorn). We determined the contents of total phenolics (TPC), total flavonoids (TF), total non-flavonoids (TNF) and total anthocyanins (TA) in selected fruits. The content of TPC, TF and TNF in fruits was analyzed by Folin-Ciocalteu colorimetric method, while the TA content of extracts was determined by bisulphite bleaching method. Total antioxidant capacity (TAC) of selected fruits were analyzed using 2,2-azinobis(3-ethylbenzothiazoline- 6-sulfonic acid) radical cation (ABTS), 2,2-diphenil-1-picrylhydrazyl radical scavenging capacity (DPPH), ferric ion reducing antioxidant power (FRAP) and oxygen radical absorbance capacity (ORAC). Cornelian cherry had the highest content of TPC, while sour cherry cv. Marasca had the highest content of TA. TAC was the highest in cornelian cherry fruits and decreased in other fruits as follow: sour cherry, blackthorn and strawberry. The fruit extracts had different TAC in relation to the method applied, and the different TAC of fruits can be ascribed to their TPC, TF, TNF or TA content. There was a direct correlation between the TAC determined using DPPH and ORAC methods and the TA content of fruit extracts. Using FRAP method correlation was weaker, but using ABTS method correlation was not observed. The ripping correlation between TF or TNF and TAC was observed using ABTS and ORAC methods.

antioxidant capacity; phenolics; anthocyanins; fruits

Published by University of Zagreb, Faculty of Agriculture, Zagreb, CROATIA
Sponsored by Ministry Science and Education of the Republic of Croatia