(35) The Influence of 1-MCP on Firmness, Soluble Sugar Levels, Chlorogenic Acid, and Total Phenolic Compounds in Ripening Banana Fruit

Abstract

In previous studies, 1-methylcyclopropene (1-MCP) was shown to significantly suppress peel degreening and appearance of senescent spotting of banana fruit (Stanley and Huber, 2004). In the present study, the effect of the ethylene antagonist on banana pulp soluble sugar levels and on peel soluble and total phenolics was measured. One hundred and sixty hands (10 boxes) of banana fruit (Musaacuminata cv. Cavendish) were treated with ethylene (300 μL·L-1, 24 h, 15 °C, 90% RH) at a commercial ripening facility in Bradenton, Fla., and transported by truck (15 °C) to the University of Florida. Fruit were sorted and placed in 174-L ripening chambers, where 80 hands received 500 nL·L-1 1-MCP for two 12-h periods at 18 °C, while the other 80 hands (controls) were maintained in identical containers without 1-MCP for equal time periods at 18 °C. Mean whole fruit firmness in both treatment groups was 140 N and decreased to 15 N (controls) and 30 N (1-MCP) by day 12. Soluble sugars in the pulp of control fruit achieved levels between 160–180 mg·g-1 fresh weight by day 8, while 1-MCP treated fruit required about 12 days to achieve similar soluble sugar levels. Total phenolic compounds present in peel tissue of control and 1-MCP treated fruit required 10 and 14 days, respectively, to achieve levels of about 4000 μg·g-1 fresh weight. Chlorogenic acid levels, a subset of total peel phenolic compounds, peaked above 500 μg·g-1 by day 10 in control fruit and by day 12 in 1-MCP treated fruit. Maintenance of fruit firmness along with the achievement of acceptable sugar levels of 1-MCP treated fruit demonstrate possible benefits of suppression of ethylene action for retail and processing markets for banana fruit.