Chemically modified polysaccharides from alternative sources to improve the acerola postharvest quality

Abstract The high postharvest losses have affected the profitability of growers worldwide mainly for acerola, a highly perishable fruit. To overcome this, edible coatings with polysaccharides chitosan and galactomannan have been proposed. However, raw polysaccharides are not fully adequate to be used as coatings. In this way, these polysaccharides were chemically modified to get quaternary derivative with improved action on acerola postharvest coating. The chemical modification was confirmed by spectroscopy analyses, showing Infrared peak at 1478 cm − 1 and 1 H-NMR at 3.2 ppm. Modified polysaccharide showed reduction in thermogravimetric T max (~ 22–40 °C), tensile stress (~ 6–30 MPa), and elongation (~ 6%) in comparison with the parent polymers. The water vapor permeability was similar in both cases (~ 3 g mm kPa − 1 h − 1 m − 2 ). The swelling degree (< 2% in ethanol and > 70%) confirms the hydrophilic character of the modified polymers. Analysis by Scanning Electron Microscopy showed a smoother surface for the modified material. The most affected postharvest physiological parameter for stored acerola (18 days, 12 °C, relative humidity 90%) was the respiration rate (CO 2 mol kg − 1 h − 1 ) that was lower for uncoated (1.10 10 − 2 ±1.96 10 − 4 ) compared with chitosan derivative (0.99 10 − 2 ±3.36 10 − 4 ) coated fruit. This indicates a post-climacteric peak shift and consequent delayed ripening, improving the acerola postharvest losses.