Assessment of Some Ripening Parameters (Antioxidant and Enzymes) during Storage of Banana (Musa acuminata) after Treatment with Calcium Chloride

The valorisation of the large scale production of bananas in the producing countries depends on the safeguarding of the quality during exports throughout the world. The objective of the present study was to extend the shelf life of bananas by elucidating some physical and physiological phenomena that accompany the ripening process. To achieve this, bananas were treated by soaking in solutions of tween 20 for 10 minutes and calcium chloride at 2, 4, 6 and 8% for 30 minutes. The following parameters were evaluated generally in the peel and pulp as a function of time during ripening: green life, firmness of bananas, water content, Brix index, pigments, antioxidant compounds such as ascorbic acid and flavonoids, activity of two enzymes, chlorophyllase and pectin-methylesterase. The green life was 25 days for bananas treated with tween 20 at 4% calcium chloride and almost 15 days for controls. Firmness was lower in bananas treated with tween 20 at 6 and 8% calcium chloride as well as in control bananas. While the Brix index was higher in the latter, photosynthetic pigment contents such as chlorophylls a and b were lower over time. Lycopene, β-carotene and ascorbic acid contents increased significantly during ripening. Flavonoid content in the skin varied less during the sampling period. However, a regression of the latter was noted in the pulp. The enzymatic activity of both chlorophyllase and pectin-methylesterase was increasing during the whole experiment. The effect of the treatments on the majority of the evaluated parameters was elucidated. Although it was not always statistically significant. The treatments with tween 20 at 2 and 4% calcium chloride were the best, certainly because of an adequate integration of calcium chloride in the tissues. On the other hand, the 6 and 8% treatments showed an unexpected result, similar to the control. The integration of a high calcium content would lead to a tearing of the tissues and consequently to a disorganisation of the membrane, resulting in a faster ripening.