Postharvest conservation of ‘Prata’ bananas with a starch-based coating derived from straw potato processing

In the production process of straw potatoes, a large amount of residual starch from the washing stage can be used to formulate biodegradable materials. The present study evaluated the use of a coating made from this residual starch in the postharvest conservation of ‘Prata’ bananas during storage (23.5±0.5ºC and 73.3±2.4% RH). The following postharvest treatments were performed: 1) control; 2) immersion in a solution (82% residual starch, 13% glycerol, and 5% acetic acid at 4.5% w/v). Samples were characterized every two days for mass loss, L* value, hue angle, chroma, firmness, soluble solids, titratable acidity, and pH. The coated fruits showed greater mass loss compared to the control from the fourth day onwards, without changes in the appearance and quality of the banana. A lower hue angle and higher L* value and chroma were observed in the control fruits compared to the coated ones. A more pronounced linear reduction in firmness was observed in the control fruits compared to the coated bananas. The coating was effective in reducing the soluble solids content of the fruits. Therefore, the starch, acetic acid, and glycerol coating applied to the banana peel proved to be effective in delaying the ripening of the fruits for 8 days.