Does u.v. light affect the total phenolic compound, anthocyanin, antioxidant capacity, and sensory profiles in wines?

Abstract

In the study, by applying ultraviolet (u.v.) lights (254 nm) for 45 min to red wines from fermented Cabernet Franc, Cabernet Sauvignon, Merlot, and Petit Verdot (Vitis vinifera L.) grapes, we examined the total phenolic compound, total anthocyanin, and antioxidant capacity by four different methods, trans-resveratrol, (+)-catechin, gallic acid content, and the change in tasting profiles of the wines after application. According to the results of the research, the u.v.-C application has caused an increase in all parameters examined. If we talk about averages without distinguishing between varieties, after the application the total phenolic compound content of 3206 increased to 3356 mg gallic acid equivalent (GAE) per L and after u.v.-C application, the total anthocyanin content increased from 411 to 780 mg L-1, the ABTS [2,2 '-azinobis(3-ethyl-benzothiazoline-6-sulphonic acid)] value increased from 30 to 33 mu mol trolox mL(-1), the DPPH ((2,2-diphenyl-1-picrylhydrazyl) level increased from 13 to 16 mu mol trolox mL(-1), the FRAP (ferric reducing antioxidant power) level increased from 15 to 16 mu mol trolox mL(-1), and the CUPRAC (cupric reducing antioxidant capacity) level increased from 40 to 45 mu mol trolox mL(-1). The u.v. application affected trans-resveratrol the most among the phenolic compounds and an average increase of 12.99% was obtained. The rate of increase after u.v. application was 3.33% in (+)-catechin and 5.57% in gallic acid. The highest correlation between antioxidant activity measurement methods was measured to be 0.998 between FRAP and DPPH. In addition, u.v.-C application has had a positive effect on taste-based sensory profiles. In recent years, the search for a diet with a high antioxidant content has become even more important.