Endogenous compound chenodeoxycholic acid in potatoes can delay enzymatic browning by inducing antioxidant capacity

Abstract

Enzymatic browning is a primary factor affecting the quality of fresh-cut potatoes. Our previous research demonstrated that warming the tubers after cold storage can alleviate the enzymatic browning of fresh-cut potatoes. In this research, we explored if some new endogenous compounds play roles in browning inhibitory effects. Utilizing a non-targeted metabolomics approach on tubers subjected to pre-cutting different temperature treatments, thirteen differential metabolites in potatoes were revealed, and five compounds with anti-browning effects were screened out. Among these five compounds, chenodeoxycholic acid (CDCA) exhibited the best inhibitory effect on browning and has not been reported in plants till now. The changes in CDCA content in tubers of pre-cutting different temperature treatments were further confirmed by LC-MS/MS. Subsequent experiments showed that the anti-browning effect of pre-cutting CDCA treatment was much better than post-cutting. Pre-cutting CDCA treatment only at a low concentration of 5 mg L−1 for a 10 min soaking and then standing for 6 h extended the shelf life of fresh potato slices to 5 d from less than 1 d of control. Not a big difference in polyphenol oxidase (PPO) activity and tyrosine contents were caused by pre-cutting CDCA treatment compared with control. However, pre-cutting CDCA treatment caused a notable reduction in the contents of malondialdehyde (MDA), superoxide anion (O2-), H2O2, and lipoxygenase (LOX) activity, and elevated the activities of superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX). Meanwhile, CDCA suppressed phenylalanine ammonia-lyase (PAL) activity and reduced the contents of both individual and total phenolic compounds. These results suggest that CDCA, an endogenous compound in potato tuber, can improve the anti-browning ability of fresh-cut potatoes mainly by inducing the enhancement of antioxidant capacity.