Physico-Chemical, Sensory and Nutritional Quality of Oranges Cv. Valencia Coated with Chitosan
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AutorContreras-Oliva,Adriana; Bernardita Perez-Gago,M.; Salvador,Alejandra; Bermejo,Almudena; Rojas-Argudo,Cristina
Applying waxes and natural coatings, such as chitosan, to citrus fruits lengthens their post-harvest shelf life. Although coating induces changes in the internal atmosphere, there is no information regarding the effects on their nutritional compounds. The objective of this study was to evaluate the effect of chitosan on the physiology and quality of 'Valencia' oranges (Citrus sinensis). Chitosan was applied in three proportions of solid content (CS) (0.6, 1.2 or 1.8 %). The results with chitosan were compared with those obtained with a commercial wax (CC) made of 10 % CS polyethylene/shellac and a control without coating. After 5, 9 and 16 weeks of refrigeration at 5 degrees C followed by one week at 20 degrees C, physico-chemical, sensorial and nutritional quality of the oranges was assessed. After five weeks under refrigeration, CC and 0.6 % chitosan reduced weight loss by 10 % with respect to the control. When storage was prolonged, 0.6 % chitosan was less effective than CC in reducing weight loss, but maintained internal CO2 and O-2 levels close to those of uncoated oranges, unlike CC, which restricted gaseous exchange, increased internal CO2 and decreased internal O-2 significantly with respect to uncoated fruits. Chitosan at 1.2 and 1.8 % CS modified the internal atmosphere with levels of CO2 and O-2 similar to those of oranges coated with CC. Nevertheless, the coating that most restricted gaseous exchange did not deteriorate the flavor of the fruits. Application of the coatings did not affect nutritional quality of the fruits, and flavonoids increased during storage.