Effect of cassava-starch coatings with ascorbic acidic and N-acetylcysteine on the quality of harton plantain (<i>Musa paradisiaca</i>)

Abstract

The effect of coatings was evaluated on the quality of harton plantain fruits (Musa paradisiaca) in the postharvest stage. Solutions for three treatments were prepared from 50 g L-1 cassava starch (Manihot esculenta) with 30 g L-1 glycerol as the plasticizer and 6 g L-1 polyethylene glycol-600®; for anti-browning agents, 6 g L-1 ascorbic acid (AA) and 8 g L-1 N-Acetyl-Cysteine (NAC) were added. The fruits were coated by immersion, stored at 18 ± 4°C and 85% RH. Physicochemical properties were determined at 32 days postharvest. The applied coatings decreased the physiological weight loss (%WL) and resulted in a higher pulp firmness (PF); no significant difference was seen with a confidence level of 95% in the concentration of total soluble solids (TSS), acidity or maturity index. The skin color was measured by the CIE L*a*b* method, with an average L value of 70 for the fruits coated with the 6 g L-1 AA and 8 g L-1 NAC mixture, while the control fruits had a value of 57. Also, lower a* coordinate values and browning indices were found for the epidermis of the coated fruits. The enzymatic activity of the polyphenol oxidase decreased with the number of postharvest days for all of the treatments, being lower for the fruits with the mixture of anti-browning agents by 27%, as compared to the control. It was concluded that the coating mixture containing the anti-browning agents ascorbic acid, 6 g L-1, and N-acetyl-cysteine, 8 g L-1, showed a better effect as an alternative for storing fruits and prolonging the shelf-life of harton plantain.