Effect of UV Irradiation on the Nutritional Quality and Cytotoxicity of Apple Juice.

UV-C irradiation operating at 254 nm wavelength on the polyphenolic and vitamin contents of apple juice including cytotoxicity analysis was studied. UV doses ranging from 0 to 150 mJ·cm-2 were selected for the treatments. Polyphenols (catechin, epicatechin, chlorogenic acid, and phloridzin) and vitamins (riboflavin, thiamine hydrochloride, pyridoxal hydrochloride, pyridoxine, pyridoxamine dihydrochloride, cyanocobalamin, choline chloride, biotin, niacin, and niacinamide) were chemically profiled. It was observed that UV treatment of apple juice at disinfection doses caused minor reductions (p < 0.05) in the concentrations of two main polyphenols (i.e., chlorogenic acid and epicatechin). In contrast, significant (p < 0.05) decreases in vitamin concentrations were observed (p < 0.05). The irradiated juice was evaluated for cytotoxic effects. The irradiated apple juice showed no cytotoxic effects on normal intestinal cells, and both irradiated and nonirradiated samples are significantly comparable in inhibiting the growth of human colon cancer cells. Overall, these results indicated that UV-C treatment of apple juice neither significantly degraded polyphenols nor generated cytotoxic compounds.