Effect of ethanol on ripening and amylase activity of banana.

Abstract

Effect of ethanol on rate of ripening of bananas (Cavendish) and of the alpha- and beta-amylase activities in the fruits was examined. Mature green bananas were sprayed with 5 ml of 20, 40 or 60% ethanol, stored at 20 degree C for 1-3 days and analysed for starch, total and reducing sugars and alpha- and beta-amylases. Application of 40% ethanol advanced ripening by 3 days (from the normal 12 days at this temp.), 60% ethanol similarly hastened ripening by 1-3 days while 20% concn. delayed ripening. On the 9th day of storage control fruits still had 9.4% starch compared with 0.7% and 1.8% in fruits treated with 40 and 60% ethanol, resp. Total sugar during this period increased from initial level of 1.3% in the green stage to approx. 15% for the 40 and 60% ethanol-treated bananas. Increase in sucrose was delayed in the control and 20% ethanol-treated fruits by 3 days in comparison to the other 2 treatments. In green fruits sucrose formed 69.5% of total sugar. Reducing sugar increased more rapidly in the 40 and 60% ethanol-treatments than in the 20% or control treatment. alpha-Amylase activity was slightly higher in 40 and 60% ethanol treatments than in control 20% treatment on 3rd and 6th days though activity was similar by the 9th day. beta-Amylase activity increased 16-49x on the 12th day, it was lower in 40 and 60% treatments than in control and 20% treatments during this period. The increase in activity of these enzymes occurred later than the commencement of starch hydrolysis indicating that they were not the principal enzymes involved in starch degradation.