Effect of Ethylene on the Ripening of Bananas

Abstract

1. Bananas ripening in an atmosphere containing 1:1000 parts of ethylene turn yellow at a somewhat more rapid rate than do controls, but the difference is only slight. 2. Such bananas show also a slightly greater increase in sugars and decrease in starch from day to day than do the controls, but the difference is even slighter. 3. Concentrations of ethylene ranging from 1:100 to 1:10,000 all seem equally effective in bringing about the small differences observed. 4. Ripe bananas have 17-20 per cent of total sugars, 10-14 per cent of sucrose, and less than 1 per cent of starch, in both the Gros Michel and the Cavendish varieties. 5. Respiratory activity of bananas treated with ethylene differs little or not at all from that of untreated ones, when 12-hour periods are considered, regardless of the concentration of ethylene used. 6. Rarely there is found a bunch of bananas which is in a quasidormant condition, and in this case ethylene stimulates an immediate commencement of ripening, while the controls are delayed several days in starting. 7. The "coefficient of ripeness" is unreliable, as well as insensitive. 8. Comparable results in investigations of the effect of various factors on the ripening of bananas cannot be obtained with bananas from different bunches, no matter how closely similar in aspect, but can be obtained only with bananas properly selected from the same bunch.