Numerical Expression for Estimating the Minimum Ethylene Exposure Time Necessary to Induce Ripening in Banana Fruit

Abstract

A numerical expression for the minimum treatment time (MTT) for ethylene necessary to induce ripening in banana [Musa (AAA group, Cavendish subgroup) ‘Giant Cavendish’] fruit was determined using the concentration of applied ethylene, fruit temperature, and a number of fruit variables. The content of sugars, organic acids and ACC, and the activity of the ethylene-forming enzyme (EFE) in the fruit just prior to ethylene treatment were measured as fruit variables. In a linear regression analysis between MTT determined at 30°C with 1000 μl·liter −1 ethylene and each fruit variable, significant correlations were found with ACC ( r = −0.84) and individual sugar content. MTT (y hours) in banana fruit treated with a selected ethylene concentration (x μl·liter −1 ) at a given temperature (t °C) could be estimated from their initial ACC content (k nmol·g −1 ) by the following equation: y = (0.202 − 0.238k)t 2 − (11.92 − 13.1k)t + 185.8 − 190.7k − (0.02t 2 − 1.3t + 22)log 10 x. When the calculated values for MTT were compared with the observed values, this equation adequately represented the MTT for Japanese commercial bananas. Chemical name used: 1-aminocydopropane-1-carboxylic acid (ACC).