Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer reviewed journal
Publication Acceptance Date: 6/22/2010
Publication Date: 8/11/2010
Citation: Wang, C.Y., Chen, H., Jin, P., Gao, H. 2010. Maintaining quality of litchi fruit with acidified calcium sulfate. Journal of Agricultural and Food Chemistry. 58:8658-8666. Interpretive Summary: Two of the most serious problems affecting the postharvest quality of litchi fruit are decay and browning or loss of red color on the peel of the fruit. We found that treatment of litchi fruit with acidified calcium sulfate, a GRAS (Generally Recognized As Safe) compound, could inhibit the mold growth, prevent browning and retain red color of the peel. We also showed that this treatment did not have any adverse effect on the internal quality of the litchi fruit including soluble solids, sugar, and organic acid content. Information obtained in this study is of interest to other scientists and will be useful and beneficial to the litchi fruit industry and consumers.
Technical Abstract: The effect of acidified calcium sulfate (ACS) on quality of litchi (Litchi chinensis Sonn. cv ‘Brewster’) fruit after harvest was evaluated. ACS at 1.25% or higher concentrations significantly inhibited the activities of polyphenoloxidase and peroxidase in pericarp during storage at both 5 and 10 ºC. These treatments also effectively prevented browning and retained red color of the outer shell of the fruit. Total phenolic and total anthocyanin content in pericarp were increased by the ACS treatments at the dose dependent manner. The radical scavenging activities for ROO•, DPPH*, •OH and O2•- were also enhanced by ACS, particularly by 2.5 and 5% concentrations. The activities of several antioxidant enzymes and enzymes of ascorbate-glutathione cycle including catalase, ascorbate peroxidase, glutathione peroxidase, glutathione reductase, dehydroascorbate reductase, and monodehydroascorbate reductase gradually declined during storage. However, ACS enhanced the activities of these enzymes especially at the beginning of the storage. Samples treated with ACS generally had higher flavonoid levels then the control. The two major flavonoids, cyanidin-3-rutinoside and cyaniding-3-glucoside, were found to be significantly increased by 2.5 and 5.0% ACS at both 5 and 10 ºC. No differences were detected among various treatments in soluble solids content, sugar, and organic acid levels in the pulp of litchi fruit, indicating that the internal quality of the fruit was not affected by the ACS treatment.