Blood oranges maintain bioactive compounds and nutritional quality by postharvest treatments with γ-aminobutyric acid, methyl jasmonate or methyl salicylate during cold storage

The effects of postharvest treatments with gamma-aminobutyric acid (GABA), methyl jasmonate (MeJA) or methyl salicylate (MeSA) on antioxidant systems and sensory quality of blood oranges during cold storage were evaluated (150 days at 3 degrees C plus 2 days at 20 degrees C, shelf life). Fruit firmness, titratable acidity (TA), total antioxidant activity (TAA) and ascorbic acid (AA) decreased during cold storage, all these changes being delayed in treated fruit, with the greatest differences observed with the 50 mu mol. L-1 MeJA and 100 mu mol L-1 MeSA treatments. Total phenolic content (TPC), total anthocyanin content (TAC) and the major individual anthocyanins, cyanidin 3-glucoside and cyanidin 3-(6 ''-malonylglucoside), were found at higher concentration in treated fruit than in control during the whole cold storage period. Overall, 100 mu mol L-1 MeSA was the most effective for maintaining fruit quality and maintained higher anthocyanin concentration due to higher phenylalanine ammonialyase (PAL) and lower polyphenol oxidase (PPO) activities.