Carboxyl methylcellulose (CMC) containing moringa plant extracts as new postharvest organic edible coating for Avocado (Persea americana Mill.) fruit

This study investigated the potential of edible carboxyl methylcellulose (CMC) containing moringa leaf and seed extracts as a novel postharvest treatment for maintaining storage quality and controlling diseases in 'Hass' and 'Gem' avocado fruit. The study also investigated the antifungal activity of methanolic and ethanolic moringa plant extracts. Briefly, 1% CMC was blended with 2% of moringa leaf (MLE) or seed extract (MSE). After the fruit was dipped in either CMC + MLE or CMC + MSE, it was stored at 5.5 degrees C (95% RH) for 21 days. After cold storage, fruit were stored at ambient conditions (21 +/- 1 degrees C) and 60% RH to simulate retail conditions. Postharvest quality attributes such as ethylene production, respiration rate and fruit firmness were measured. Both coatings were also tested against postharvest fungi in reference to potato dextrose agarose (PDA). Coated fruit had lower mass loss, ethylene production and respiration rate compared to the uncoated fruit. Ethanolic leaf extract had an inhibition of 43.6% and 42.9% against C. gloeosporioides and A. alternata, respectively. Scanning electron microscopy analysis revealed damaged hyphal structures for all pathogens exposed to coatings while such structures remained intact in uncoated fruit. Ethanolic moringa leaf extracts proved to have higher antimicrobial activity compared to methanolic extracts. The findings reported in this study demonstrated that CMC containing moringa extract suppresses diseases, prolongs the shelf-life and maintain the overall quality avocados during postharvest supply chain. The CMC blended with moringa extracts could potentially be commercialized as a new organic edible coating for avocado fruit industry.