Effects of wax treatment on quality and postharvest physiology of pineapple fruit in cold storage

Pineapple (Ananas comosus (L.) Merr.) is an important fruit crop grown in tropical and subtropical areas. Cold storage is one of methods for prolonging postharvest storage life for pineapple fruit. A major problem of this method is that low temperature causes chilling injury symptoms in fruits and deterioration of their quality and nutritional values. This study aimed to find a new way to effectively alleviate chilling injury and maintain fruit quality during cold storage. Thus, the effects of two types of waxing treatment (Sta-Fresh 2952 wax and Sta-Fresh 7055 wax) of pineapple fruits of cultivar'Paris' (a major cultivar for pineapple production) on alleviating chilling injury and their physiological responses during cold storage were examined. Sta-Fresh 2952 wax (60 g/l) was more effective in: (1) alleviating chilling injury, which delayed the changes in firmness, flesh color, weight loss and soluble protein content; (2) decreasing titratable acidity, total soluble solids, cell membrane permeability and malondialdehyde content when compared with those in control. This waxing also improved total sugars and the contents of ascorbic acid in pineapple fruits. These results suggested that this treatment might be a useful technique to alleviate chilling injury and maintain fruit quality during cold storage.