Widely Untargeted Metabolome Profiling Provides Insight into Browning and Nutritional Quality Changes in Short-Term Stored Fresh-Cut Potato(Solanum tuberosum L.)Shreds

Potato(Solanum tuberosum L.)is susceptible to enzymatic browning after fresh processing,resulting in color change and potential alteration in the nutritional quality.In this study,a popular potato cultivar,Feiwuruita,was used to profile the metabolites involved in color and nutritional quality changes in fresh shreds stored at 0 and 4 h at 25°C(designated CK and CK4H,respectively).The shreds turned brown within 4 h of storage.In all,723 metabolites consisting 12 classes of compounds were detected in the samples,largely lipids,phenolic acids,alkaloids,amino acids and derivatives,flavonoids,organic acids,nucleotides and derivatives.Of these,163 metabolites accumulated differentially between CK and CK4H shreds.Polyphenolic compounds(phenolic acids and flavonoids)mostly increased in the shreds after 4 h storage.Conversely,the short-term storage drastically reduced lipid compounds(25 LysoPC and 19 LysoPE),while essential alkaloids and terpenoid compounds that are beneficial to human health increased in accumulation.The findings present global metabolome and nutritional composition changes in short-term stored shreds of Feiwuruita.This study provides important foundation for future studies on browning prevention/reduction and for better utilization of Feiwuruita.

A novel mitigator of enzymatic browning--hawthorn leaf extract and its application in the preservation of fresh-cut potatoes

Objectives:The purpose of this study was to evaluate the antibrowning functions of hawthorn leaf extract on fresh-cut potato and its possible mechanism.Materials and Methods:Fresh-cut potatoes were treated with different concentrations(0.01%,0.05%,and 0.1%)of hawthorn leaf extract and preserved at 4 C for 8 days.The appears nee and colour of potato slices were evaluated,along with the content of the phenol,malondialdehyde(MDA),and hydrogen peroxide(H2O2)during cold storage.Meanwhile,the activities of polyphenol oxidase(PPO),peroxidase(POD),phenylalanine ammonia-lyase(PAL),lipoxygenase(LOX),catalase(CAT),superoxide dismutase(SOD),and the antioxidant capacity were determ in ed.Furthermore,the composition of hawthorn leaf extract was analyzed by high-performance liquid chromatographytandem mass spectrometry(HPLC-MS/MS).Results:The addition of hawthorn leaf extract effectively delayed the browning process.It not only enhanced the CAT activity and antioxidant capacity but also reduced the LOX activity and accumulation of MDA and H_(2)O_(2).Meanwhile,the activities of PPO,POD,and PAL as well as the content of phe nol were con trolled.Additionally,25 phe nols,34 flavonoids,and 5 proa nthocya nidins were identified through high-performance liquid chromatography-tandem mass spectrometry(HPLC-MS/MS),ideluding caffeic acid,quercetin and catechol.Conelusion:Hawthorn leaf extract significantly alleviated the browning of fresh-cut potato.It could serve as a n atural an tibrowning alter native by stabilizing the membra ne and modulating reactive oxygen species and redox reactions.

Accurate pH decrease induced inactivation of myrosinase and polyphenol oxidase in salted radish for color improvement

Yellowing even browning of radish commonly occurred during the traditional pickling.This research aimed to determine the reason of yellowing of pickled radish,and propose the method for yellowing inhibition.The activity of endogenous enzymes in radish were analyzed,and the relationship between the activity and the browning was investigated.Myrosinase and polyphenol oxidase(PPO)were found as main potential enzymes resulting in browning of radish.During traditional salting processing,the myrosinase activity decreased,particularly at a high speed in the first 14 days,while the PPO activity did not decrease observably.The a*and b*values of salted radish were significantly correlated with myrosinase and PPO activity.Acid treatment was observed to be effective for browning inhibition of radish during soaking and storage,and the low pH conditions contributed to the preservation of original green color of radish.Stronger acidification during the first 3 d played a much more important role in browning inhibition than following weaker acidification treatment for 27 d.Low pH showed an inhibition effect on PPO activity,but myrosinase reactivity was more sensitive to pH changes than PPO.The myrosinase in the radish treated in the pickling solution at pH 2 was completely inactivated during the first 3 days.Further investigation of pH effect on improvement of salted radish color concluded that pH 2.4 was the optimal pH for the inactivation of myrosinase and PPO.Accordingly,short-term accurate acidification coupled with traditional salting treatment was originally proposed for effective browning inhibition of pickled radish.