Abstract: A new edible coating was developed to improve the quality of cold-stored blueberries since they are easy to deteriorate. Rabbiteye blueberries coated with three edible coating solutions, named M1, M2 and M3, were stored at (4.0 ± 0.5) ℃ with 75% relative humidity. M1 was composed of 100 mg/mL gum arabic (GA) and 1.5 % (V/V) glycerol; M2 was composed of 100 mg/mL GA, 1.5% (V/V) glycerol and 1.5% (V/V) white roselle extract (WRE); M3 was composed of 100 mg/mL GA, 1.5% (V/V) glycerol and 2.5% (V/V) WRE. The effect of edible coatings on the quality of blueberries was evaluated by detecting the physicochemical properties, the activity of antioxidant enzymes and the contents of antioxidants. The results showed that all GA edible coatings could significantly delay water loss, reduce decay incidence and slow down the decrease in hardness of blueberries. The treated samples maintained high total polyphenol content (TPC) and total anthocyanin content (TAC) and good sensory quality (P < 0.05) and showed significantly inhibited polyphenol oxidase (PPO) activity and reduced surface browning (P < 0.05). Edible coating M3 was the most effective in inhibiting PPO activity, matintaining TPC and TAC, improving the sensory quality of cold-stored blueberries. Based on all quality parameters, edible coating M3 was the most effective in preserving the quality of cold-stored blueberries.

Key words: rabbiteye blueberry, edible composite coating, preservative effect, cold storage