Improved storage and eat-ripe quality of avocados using a plant protein-based coating formulation

Abstract

Coating comprising the plant protein, kafirin, propylene glycol (PG) and glucono-delta-lactone (GDL) have been shown to extend the quality of ‘Packham’s Triumph’ pears. In this study, both of these coating treatments considerably extended the shelf-life and the time that the eat-ripe quality of ‘Hass’ avocados was maintained when compared to uncoated fruit. To determine the roles of the additives, PG and GDL in the functionality of kafirin edible coatings, different kafirin coatings were applied to ‘Hass’ avocados prior to storage under ripening conditions of 18 °C for up to 21 days. All the kafirin coatings were effective at extending and maintaining the shelf-life quality of avocados compared to uncoated fruit due to reduced respiration rate, 102 ml CO2/kg/h for kafirin-PG+GDL compared to 115 ml CO2/kg/h uncoated avocados on day 14 and consequently reduced ethylene production of the coated fruit. Kafirin-PG+GDL coated avocados lost less weight and remained firmer than uncoated fruit. Descriptive sensory analysis showed kafirin-PG+GDL coatings were most effective, extending the quality of the avocados 7 days beyond the untreated control due to improved kafirin solvation facilitated by the GDL. Thus kafirin-PG+GDL coatings are an effective method of increasing shelf-life and extending the eat-ripe quality of climacteric fruit.