S. H. Ziaolhagh - Department of Agricultural Engineering Research, Agricultural and Natural Resources Research Center of Semnan Province (Shahrood), AREEO, Shahrood, Islamic Republic of Iran.
S. Kanani - Department of Food Science and Technology, Damghan Branch, Islamic Azad University, Damghan, Islamic Republic of Iran.

Formulation of an edible coating based on gum tragacanth and chitosan was optimized for fresh apricots by Response Surface Methodology (RSM). The effects of the concentration of gum tragacanth and chitosan (independent variables) on soluble solids content, weight loss, titratable acidity, pH, reducing sugar, moisture content, and firmness (response variables) were studied. The results showed that the obtained RSM models were fitted for all response variables, except for soluble solids content and titratable acidity. Gum tragacanth and chitosan treatments significantly decreased the weight loss of the apricots during storage. The firmness of apricots was increased at higher concentrations of gum tragacanth. The pH of the apricots was lower at lower concentrations of gum tragacanth and chitosan. This work showed that the coating could improve apricot firmness and stability in terms of weight loss, pH, and moisture content during storage, and increase the commercial value of the product. To meet the desirable properties, the ideal concentrations of gum tragacanth and chitosan in the coating were ۱.۰۲ and ۰.۳۳% (w/v), respectively.

Prunus armeniaca L., Fruit postharvest, Fruit storage, Response surface methodology.