The combined effect of edible coating, containing moringa and ozonated cold storage in avocado (Persea americana) fruit quality

Postharvest avocado fruit quality deterioration and uneven fruit ripening during cold storage as well as fruit shelf-life are some of the major challenges that require special attention by fruit industries. The aim of this work was to investigate the combined effect of ozone treatment with edible coating in enhancing avocado fruit quality. Fruits were treated with carboxymethyl cellulose (CMC) that contains moringa and fruit were then exposed to intermittent dosages of ozone of 0.25 ppm for 12 h during cold storage. The ozone exposure treatments were designed on weekly basis, where exposure frequency was distributed in the following manner: once, twice, or three times during the 28-day cold storage period. Data on fruit physical quality attributes and bio-chemical properties were analysed using GenStat 18 version. 'Gem' fruit treated with moringa CMC (1%) that were exposed to ozone two times at 7, 14 d; 7, 21 d; 14, 21 d and three times at 0, 7, 14 d; 0, 7, 21 d; 7, 14, 21 d had significantly lower mass loss (3.25 +/- 1.2%), electrical conductivity (3.5 +/- 0.9 mmho cm(-1)),respiration rate (160 +/- 36 mg kg(-1) h(-1)) and ethylene accumulation (3.5 +/- 1.2 mg kg(-1) h(-1)) compared to the control with respective values of (7.8 +/- 1.4%), (11.3 +/- 1.3 mmho cm(-1)), (220 +/- 29 mg kg(-1) h(-1)) and (11.8 +/- 1.8 mg kg(-1) h(-1)). The same treatment had higher values for firmness (80.0 +/- 6.25 N) and phytochemical characteristics, mainly D-mannoheptulose (5.67 +/- 0.6 g kg(-1)) against (1.2 +/- 0.6 g kg(-1)). In conclusion, intermittent ozone treatment application together with edible coating could enhance postharvest fruit quality and reduce uneven ripening in 'Gem' fruit during storage. The efficacy could only be efficient if ozone is applied at optimum dose and using adequate storage conditions: low temperature (5 degrees C) and high relative humidity (90-95%).