Effects of chitosan–glucose complex coating on postharvest quality and shelf life of table grapes

Surface coatings and films are prospective alternatives for extending the postharvest life of fresh fruits and vegetables. In this study, freshly harvested grapes were treated with chitosan, glucose, chitosan–glucose complex (CGC), or water (control) for up to 60 days at 0 °C in 95% relative humidity followed by 3 days in the air at 20 °C. The results showed that coated samples were effective in terms of senescence inhibition and postharvest diseases prevention. Chitosan–glucose complex showed better effects on delaying the declines of total soluble solids, ascorbic acid and titratable acidity, decreasing decay and weight loss, suppressing respiration rate, inducing POD and SOD activities, in comparison with pure chitosan or glucose. In addition, CGC coating treatment ensured better berry texture and higher sensory scores, compared with those treated with chitosan or glucose alone. The results indicated that CGC may be a promising strategy for improving the postharvest quality and extending the shelf life of table grapes.