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Postharvest UV-C irradiation stimulates the non-enzymatic and enzymatic antioxidant system of ‘Isabel’ hybrid grapes (Vitis labrusca×Vitis vinifera L.)

Maurer, Luana Haselein, Bersch, Andriely Moreira, Santos, Roberta Oliveira, Trindade, Simone Cezar, Costa, Eduarda Lasch, Peres, Marcelle Moreira, Malmann, Carlos Augusto, Schneider, Mauricio, Bochi, Vivian Caetano, Sautter, Claudia Kaehler, Emanuelli, Tatiana
Food research international 2017 v.102 pp. 738-747
Vitis, anthocyanins, antioxidant activity, antioxidants, elicitors, enzymes, grapes, hybrids, irradiation, thiols, ultraviolet radiation
Ultraviolet light type C (UV-C) was studied as a tool to increase enzymatic and non-enzymatic antioxidant defenses and phytochemical levels in ‘Isabel’ grapes (Vitis labrusca×Vitis vinifera L.). Grapes were exposed to 0, 0.5, 1.0, 2.0, or 4.0kJm−2 UV-C and stored for 1, 3, or 5days post-treatment. One day after UV-C irradiation, the activities of grape antioxidant enzymes and thiols were increased, especially at 1.0 and 2.0kJm−2. These doses increased total phenolic content by almost 20%, while 0.5 and 4.0kJm−2 had no effects. Total monomeric anthocyanin content was increased by >35% by UV-C at 1.0kJm−2; however, anthocyanin profile was unchanged. Grape skin antioxidant capacity was also improved by UV-C irradiation. The 1.0kJm−2 UV-C was considered the hormetic dose. Postharvest UV-C had an elicitor effect on ‘Isabel’ grapes, positively impacting the antioxidant capacity and phytochemical content.