POSTHARVEST USE OF ORGANIC COATING FOR MAINTAINING BIO-ORGANIC AVOCADO AND MANGO QUALITY

Abstract

Two organic coatings for post-harvest application on fruits have recently been developed in Israel and the USA. One coating is a colloidal solution based on beeswax (BeeCoat); the other is based on carnauba wax. Both organic waxes are in the product list of the Organic Materials Review Institute (OMRI, 2003) as regulated processing products. The main distinguishing feature between the two wax coatings is that beeswax coated fruits had a lusterless look, whereas the carnauba wax coated ones were shiny. Coating organic avocado and mango effectively reduced the water loss, shrinkage, chlorophyll breakdown, chilling injury symptoms and decay development in the fruits, thereby extending their shelf life. In mango cv. 'Tommy Atkins', coating with the beeswax-based organic wax, 'BeeCoat' decreased the rates of weight loss, fruit softening, color development and acid breakdown, thus ensuring a longer shelf life. Moreover, after 3 wks at 12°C following 10 days at 20°C, 'Tommy Atkins' coated with BeeCoat showed only a low level of the red spots which are symptomatic of chilling injury. In addition, the coated fruits did not develop anaerobic metabolites or off-flavors, and were preferred by the taste panelists. Coating bio-organic avocado cv. 'Ettinger' prior to cold storage for 3 weeks at 5°C followed by 8 d at 20°C, retained the green peel color and reduced the chilling injury symptoms expressed as internal and external distal end browning. Ripe uncoated 'Ettinger' fruits produced significant amounts of acetaldehyde (AA) and ethanol, whereas these volatiles were not detected in coated fruits. The higher level of anaerobic volatiles was correlated with greater mesocarp discoloration.