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

Food Res Int. 2017 Dec:102:738-747. doi: 10.1016/j.foodres.2017.09.053. Epub 2017 Sep 23.

Abstract

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.

Keywords: Abiotic stress; Anthocyanin; HPLC; Hormesis; Isabel grapes; Polyphenol.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anthocyanins / analysis
  • Antioxidants / analysis*
  • Dose-Response Relationship, Radiation
  • Food Irradiation / methods*
  • Fruit / chemistry
  • Fruit / enzymology
  • Hybridization, Genetic
  • Phenols / analysis
  • Phytochemicals / analysis
  • Sulfhydryl Compounds / analysis
  • Ultraviolet Rays
  • Vitis*

Substances

  • Anthocyanins
  • Antioxidants
  • Phenols
  • Phytochemicals
  • Sulfhydryl Compounds