A comparative study on the correlation between phenolic compound contents and antioxidant activities in ‘Seol-hyang’ and breed-improved strawberry extracts

We compared the phenolic compound contents and antioxidant activities of the widely cultivated 'Seol-hyang' strawberry and four newly bred cultivars (1643-27, 1646-44, 1665-97, 1611-105), developed through a targeted breeding program aimed at enhancing antioxidant potential. The total polyphenol and flavonoid contents were highest in 1646-44 (35.08 mg gallic acid equivalent (GAE)/g and 25.57 mg catechin equivalent (CE)/g), while 1665-97 had the highest anthocyanin content (4.45 mg cyanidin-3-O-glucoside equivalent (CGE)/g). Transition metal ion reducing capacities (Phosphomolybdenum complex assay (PMA) and Ferric reducing antioxidant power (FRAP)) were also highest in 1646- 44 (49.76 mg ascorbic acid equivalent (AAE)/g and 1127.17 mM trolox equivalent (TE)/g). Free radical scavenging activities (1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2'-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS)) peaked in 1611-105 and 1646-44, while oxygen radical absorbance capacity (ORAC) was highest in 1643-27 (598.12 mM TE/g). Total flavonoid content correlated strongly with ABTS (r=0.924, 95% CI: 0.68-0.99, p<0.01). These new cultivars demonstrated enhanced antioxidant potential compared to 'Seol-hyang'.