Effect of enzymatic debittering on antioxidant capacity and protective role against oxidative stress of grapefruit juice in comparison with adsorption on exchange resin

Antioxidant capacity, radical scavenging activity, as well as protective effect on lipoperoxidation, glutathione oxidation and DNA damage, were evaluated in grapefruit juice subjected to bitterness removal by naringinase or by physical adsorption with Amberlite®IRA-400. The results showed a reduction in naringin content for the naringinase-treated juice (N-PJ) and those processed with the exchange resin (R-PJ), which made both juices acceptable to consumers. Total antioxidant capacity, measured by ABTS and FRAP assays, was lower in R-PJ samples. The highest superoxide and hydroxyl radical scavenger activity was observed in N-PJ. With regard to inhibitory effect of juice samples on lipoperoxidation, N-PJ also provided the greatest effectiveness. In addition, R-PJ showed the lowest levels of GSH. The results showed a protective effect on DNA oxidative damage for all juice samples tested. In summary, enzymatic technology was more effective than physical adsorption in preserving the antioxidant and biomolecule protection capacity of fresh grapefruit juice.