Evaluating the efficacy of moringa leaf extract, chitosan and carboxymethyl cellulose as edible coatings for enhancing quality and extending postharvest life of avocado (Persea americana Mill.) fruit

This experiment was conducted to investigate a novel moringa leaf extract, together with commercially available edible coatings, namely, chitosan and carboxymethyl cellulose (CMC), as postharvest treatments to enhance shelf-life and improve the quality of 'Fuerte' and 'Hass' avocado fruit. Postharvest treatment included a 2% moringa extract with an emulsifier, two levels of chitosan (0.5, 1%), and CMC (0.5, 1%). Moringa extract with emulsifier and moringa containing chitosan and CMC significantly improved fruit quality of both cultivars. 'Fuerte' fruit treated with the combination of CMC (1%) and 2% moringa had significantly lower mass loss (1.78 +/- 0.08%), electrical conductivity (192.0 +/- 3.0 mu/m) and respiration rate (167.4 +/- 40.8 mg/kg/h) compared to the untreated control with respective values of 4.7 +/- 0.7%, 290.0 +/- 5.0 mu/m and 290.0 +/- 62.0 mg/kg/h. The same treatment had higher values for firmness (50.0 +/- 4.25 N) and phytochemical characteristics, mainly mannoheptulose (5.7 +/- 0.6 g/kg), and lower polyphenol oxidase (0.6 +/- 0.06 *1000 U/kg) and lipid peroxidation (0.89 +/- 0.06 nmol/g) in 'Fuerte' fruit. For 'Hass', similar results were also observed, where a combination of 2% moringa leaf extract with 1% of CMC reduced mass loss almost by 50%, while mannoheptulose was maintained by 8-folds. The results observed in this study showed that investigated edible coatings containing moringa leaf extract improve fruit quality and shelf-life. It could therefore potentially be commercialized as a new edible coating for future industry application. (C) 2016 Elsevier Ltd. All rights reserved.