The role of hydrogen-rich water in delaying the pulp breakdown of litchi fruit during postharvest storage

Previous studies have indicated that hydrogen-rich water (HW) treatment can delay fruit ripening and senescence. However, little is known about the HW-delaying pulp breakdown. In this study, eight physiological characteristics revealed that HW treatment delayed both pericarp browning and pulp breakdown of litchi fruit. To gain a comprehensive understanding of the changes in litchi pulp, a combination of multiple metabolomics and gene expression analyses was conducted, assessing 67 primary metabolites, 103 volatiles, 31 amino acids, and 13 crucial metabolite-related genes. Results showed that HW treatment promoted starch degradation, decelerated cell wall degradation and glycolysis, and maintained the flavor and quality of litchi fruit. Furthermore, HW treatment stimulated the production of volatile alcohols, aldehydes, ketones, olefins, and amino acids, which might play a vital role in HW-delaying pulp breakdown. This study sheds light on the mechanism by which HW delayed pulp breakdown by investigating small molecule metabolites and metabolic pathways. •Hydrogen-rich water (HW) treatment delayed pulp breakdown of litchi fruit.•HW accelerated starch degradation, TCA cycle, lipid synthesis, ester synthesis and amino acids synthesis.•HW slowed down cell wall degradation, glycolysis, and sesquiterpene synthesis.•HW treatment induced volatile alcohols and olefins at early stage of storage.•Aldehydes, ketones and amino acids play vital role in HW-delaying pulp breakdown.