Effect of edible coating on ascorbic acid, betalains, organic acid, sugar, polyphenol content and antioxidant activity in minimally processed cactus pear (Opuntia ficus-indica).

The quality and nutraceutical traits of minimally processed cactus pear fruits were investigated after application of the following edible coatings: "Food coat" (composed of fatty acids derivatives and polysaccharides in alcohol solution) and "Pomfresh" (composed of a mixture of organic acids and antioxidant compounds). Fruit were manually peeled, dipped for 3 s in in water emulsions containing each coating alone or in combination and placed on a sterile adsorbent material, in number of three, inside easy-to-open polylactic acid (a biodegradable polymer) tray. Fruits were stored at 4°C and inspected after 4, 8 or 12 days. Concentration of ascorbic acid, polyphenol, indicaxanthin and antioxidant activity were positively affected by "Pomfresh", in contrast "Food coat" both applied alone or in combination with "Pomfresh" increased fruit degradation rate. Both coatings did not significantly affect in-package gas composition with respect to untreated control fruit: in-package CO2 partial pressure amongst treatments ranged between 4.8 and 5.7 kPa, while in-package O2 partial pressure never dropped below 14 kPa. Taste and firmness were little affected by treatments and showed that control fruit and those treated with Pomfresh coating alone were better than the other treatments. Results indicate that "Pomfresh" could be applied as edible coating to preserve the nutraceutical traits and prolong the shelf life of minimally processed cactus pear fruit.