The effect of active coating and refrigerated storage on the quality of avocado cultivar, Quintal

Abstract

Postharvest technologies, such as the application of coatings, could contribute to the extension of the shelf life of avocado fruit. The objective of the present research was to evaluate the effects of coating, based on agro-industrial co-products (citrus pectin, broken rice grain flour, and cellulosic rice skin nanofiber), sorbitol and potassium sorbate, on the quality of avocado (cultivar 'Quintal') stored under refrigeration. The coating contributed to a longer conservation of the green color of avocado, both peel and pulp, and significantly reducing the respiration rate of the coated fruit, which was 35% lower than that of the control fruit. The coated fruit was firmer and, possibly, the addition of cellulosic nanofiber contributed to the maintenance of this firmness. Regarding the bioactive compounds, there was no difference (p > 0.05) among the coated and control fruit. During refrigerated storage, total phenolic compounds content increased (p < 0.05) from 311.44 ± 25.89 to 800.25 ± 160.74 mg kg^-1 gallic acid equivalents (GAE) in the control fruit, and from 242.86 ± 52.33 to 584.75 ± 125.57 mg kg^-1 GAE in the coated fruit. It was concluded that the shelf life of avocado (cultivar 'Quintal') could be extended and ripening delayed by a minimum of 8 days, by applying a coating formulated with rice flour, pectin, sorbitol, potassium sorbate, and cellulosic rice skin nanofiber.

Keywords: Antioxidant activity; Firmness; Persea americana Mill.; Phenolic compounds; Respiration rate.

Fig. 1

The effect of a coating based on agro-industrial coproducts (citrus pectin, broken rice grain flour and cellulosic nanofibers from the rice skin), sorbitol and potassium sorbate on ‘Quintal’ cultivar avocados, and of the refrigerated storage time (10 ± 2 °C and 65–85% RH) on respiratory rate (a) and mass loss (b). Diamond: control fruit; square: coated fruit

Fig. 2

Storage trial with avocado (Persea americana Mill.) ‘Quintal’ cultivar; control avocado (no coating) (a); coated avocado (b), both after 20 days of refrigerated storage

Fig. 3

The effect of the coating and refrigerated storage time (10 ± 2 °C and 65–85% RH) on hue angle peel (a), hue angle pulp (b), A chlorophyll (c) total chlorophyll (d) and B chlorophyll content (e). Diamond: control fruit; square: coated fruit; triangle: tendency of control and coated fruit

Fig. 4

The effect of the coating and refrigerated storage time (10 ± 2 °C and 65–85% RH) on firmness (a), soluble pectin content (b), total sugar content (c), ascorbic acid (d), total phenolic compounds (e) and % protection of the β-carotene/linoleic acid system (f). Diamond: control fruit; square: coated fruit