Oxalic acid alleviates surface discoloration in fresh-cut yam by regulating enzymatic browning and bisdemethoxycurcumin synthesis

Surface discoloration reduces the commercial value of fresh-cut yams. To investigate the effects of oxalic acid (OA) on color change, fresh-cut yam slices were treated with varying concentrations of OA. The results showed that 0.6% OA significantly decreased the browning and yellowing in fresh-cut yam. At the end of storage, the total phenolic content of the OA group was 5.7 times higher than that of the control group, while bisbisdemethoxycurcumin content was 0.24 times lower. 0.6% OA inhibited the accumulation of products in phenylpropaniod pathway and the consumption of phenolics in fresh-cut yams by regulating gene expression levels of PAL, C4H, 4CL, PPO and POD. Besides, the inhibition of OA on gene expressions of DCS, CURS3 and CURS led to the decreased bisbisdemethoxycurcumin content in OA treated-yam, which contributed to delay the yellowing of fresh-cut yam during storage. Taken together, we attributed the alleviation of OA on color changes of fresh-cut yam to its suppression on the enzymatic browning and the synthesis of bisdemethoxycurcumin. •Oxalic acid alleviated enzymatic browning and yellowing of fresh-cut yam.•Oxalic acid delayed polyphenols consume of fresh-cut yam.•Oxalic acid inhibited phenylalanine accumulation of fresh-cut yam.•Oxalic acid regulated phenylpropane pathway of fresh-cut yam.•Oxalic acid decreased bisdemethoxycurcumin biosynthesis in fresh-cut yam.