Influence of the use of acids and films in post-harvest lychee conservation

lychee (litchi chinensis sonn.) has a high commercial value; however, it has a short shelf-life because of its rapid pericarp browning. the objective of this study was to evaluate the shelf-life of 'bengal' lychee fruits stored after treatment with hydrochloric acid and citric acid, associated with cassava starch and plastic packaging. uniformly red pericarp fruits were submitted to treatments: 1-(immersion in citric acid 100 mm for 5 minutes + cassava starch 30 g l-1 for 5 minutes), 2-(immersion in hydrochloric acid 1 m for 2 minutes + starch cassava 30 g l-1 for 5 minutes), 3-(immersion in citric acid 100 mm for 5 minutes + polyvinyl chloride film (pvc, 14 μm thick)) and 4-(immersion in hydrochloric acid 1 m for 2 minutes + pvc film). during 20 days, the fruits were evaluated for mass loss, pericarp color, ph, soluble solids and titratable acidity, vitamin c of the pulp and pericarp and activities of polyphenol oxidase and peroxidase of the pericarp. the treatment with hydrochloric acid associated with pvc was the most effective in maintaining the red color of the pericarp for a period of 20 days and best preservation of the fruit. the cassava starch associated with citric acid, and hydrochloric acid did not reduce the mass loss and did not prevent the browning of lychee fruit pericarp.