227 Effect of Edible Coatings on Quality of Mango Fruit (Mangifera indica) ‘Chok-Anan’ during Storage A. Phaiphan and N. Rattanapanone Department of Food Science and Technology Faculty of Agro-Industry Chiang Mai University Chiang Mai, 50100 Thailand Keywords: physico-chemical change, pectin methylesterase, acid phosphatase Abstract Four coatings were used for treatment mango fruit, ‘Chok-Anan’. These were 0.5% chitosan, 1% carboxymethyl-cellulose (CMC) with 2% propyleneglycol, butter emulsion (butter:water = 4:1) and non-coated control. During storage at 13±0.5°C, 93±2% relative humidity for 21 days, the fruit were analyzed to determine quality every 3 days. All three coatings reduced weight loss and respiration rate, delayed softening and peel and pulp color. Total soluble solids (TSS) content, reducing sugar, total sugar, and titratable acidity (TA) were slightly lower in coated fruits. The respiratory patterns of fruit coated with 0.5% chitosan and 1% CMC showed climacteric rise. Fermentation was induced in fruit coated with the butter emulsion. The pectin methylesterase activity increased at the beginning of storage and then decreased, while acid phosphatase activity decreased during the storage, but was not significantly different among treatments. INTRODUCTION Mango (Mangifera indica L.) is economically very important for Thailand. The postharvest problem for exporting mangos to other country is that the fruit ripen during transportation, especially when transportation is by sea. Use of edible coatings can extend fruit shelf-life (Baldwin, 1994). Coating mango fruit after the harvest can delay quality changes and extend the storage or transport period (Baldwin et al., 1999). Butter emulsion has been reported to delay the ripening of banana and mango fruits (Boonyakiat and Rattanapanone, 2003). However, there is no information on the effect of edible coatings on quality and shelf-life of most Thai varieties of mango. The objective of this work is to study the effect of selected edible coatings on the quality of mango fruit cv. Chok-Anan during storage at low temperature. MATERIALS AND METHODS Sample Preparation Mango fruits (cv. Chok-Anan) were obtained from a commercial orchard, in Chiang Mai Province. The fruits were selected for uniform maturity by specific gravity where fruit sink in 1% (specific gravity is 1.007) and float in 3% saline solutions (specific gravity is 1.022) (Subramanyam et al., 1976). The fruits were washed thoroughly twice with tap water, air-dried, labeled and weighed. Coating Materials The fruit were coated with 3 different coatings; 0.5% chitosan (Fluka, Japan) in 0.5% lactic acid (Sigma-Aldrich, USA); 1% carboxymethyl cellulose (CMC) in aqueous solution containing 2% (v/v) propylene glycol (Sigma-Aldrich, USA); butter emulsion (unsalted butter:water = 4:1) and non-coated as control. After coating by gloved hands and air dried, the fruits were kept in plastic baskets (w×l×h = 31.5×36×11.6 cm) and stored at 13±0.5°C, 93±2% relative humidity for 21 days. Three replicates of 6 fruits per treatment were analyzed for quality every 3 days. Proc. XXVII IHC-S16 Citrus and Other Trop. & Subtrop. Fruit Crops Ed.-in-Chief: Dae-Geun Oh Acta Hort. 773, ISHS 2008