Pre-veraison treatment of salicylic acid to enhance anthocyanin content of grape (Vitis vinifera L.) berries

BACKGROUND Grape berries produce significant amounts of phenolic compounds. These are an essential qualitative factor due to their nutritional value and effect on berry color and texture. Salicylic acid (SA) and its derivatives usually lead to enhancement of phenolic content in plant tissues. The present study was conducted to evaluate the effect of different levels of SA (0.0, 50.0, 100.0, and 200.0 mM) on the production of phenolic compounds and the derivatives (anthocyanin and flavonoid) in the grape berries, with emphasis on malvidin-3-O-beta glucoside as a regular anthocyanin in red grapes. RESULT The results showed that total phenolics content were significantly enhanced in SA-treated (100.0 and 200.0 mM) berries compared to untreated ones. Salicylic acid treatment at all concentrations considerably improved the anthocyanin content in the berries and, compared with untreated berries, the accumulation of malvidin-3-O-beta glucoside was higher in SA-treated fruits. In particular, the 200.0 mM concentration caused approximately two times more malvidin-3-O-beta glucoside than the control. The 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging capacity of the fruits treated with SA were significantly higher than those of the untreated berries. The activity of phenylalanine ammonia-lyase (PAL) in SA treated fruits significantly increased as compared with the untreated clusters. CONCLUSION A general evaluation of the current results leads us to the conclusion that SA is a suitable and recommendable treatment for improving and increasing the phenolic and antioxidant capacity of grape berries. Spraying grape berries at pre-veraison stage with SA could therefore be a convenient strategy to increase quality and nutritional value of grape berries considerably. (c) 2019 Society of Chemical Industry