Impact of lipase treatment on cuticle wax structure and anthocyanin metabolism in postharvest blueberries

Abstract

In this paper, we explored the influence of lipase on cuticle wax and anthocyanin metabolism in blueberries. The results demonstrated a progressive alteration in wax crystal structure, transitions from rod-like to short rod-like and flaky, and even disappearance of the cuticle wax. Gas chromatography–mass spectrometry analysis revealed a reduction in esters, aldehydes, long-chain alkanes, and total wax content following lipase treatment of blueberry fruits. Additionally, ultra high performance liquid chromatography–mass spectrometry analysis showed significant decreases in peonidin, petunidin, cyanidin, and delphinidin, accompanied by an increase in malvidin content due to lipase treatment. Subsequent investigations uncovered that lipase treatment inhibited the activities of key anthocyanin synthetic enzymes, namely phenylalanine ammonia-lyase (PAL), chalcone isomerase (CHI), and dihydroflavonol reductase (DFR). Moreover, lipase treatment downregulated the expression of synthesis-related genes, including PAL, 4-coumarate: CoA ligase, chalcone synthase (CHS), CHI, and DFR. In summary, our findings indicate that lipase disrupts the integrity of cuticle wax structure, inhibits anthocyanin synthesis, and reduces anthocyanin content. Accordingly, our studies suggest that inhibiting lipase could offer a novel approach to preserving the freshness and anthocyanin concentration of blueberries.