This research aimed to screen out safe and effective inhibitors of enzymatic browning from food-derived sulfur-containing compounds. Among eighteen candidate compounds, three were found to reduce the browning of fresh potato mashes. One of these compounds, S-furfuryl thioacetate (S-Ft) at only 0.04 and 0.07 mM inhibited the browning of fresh potato sticks, for over 10 d at 4 °C with an efficacy close to sodium bisulfite at 2.40 mM. S-Ft also reduced the browning of eggplant and asparagus lettuce slices. S-Ft retarded the browning occurrence of potato mashes and tyrosine solutions, but it did not cause the brown pigments colorless. Both the decrease in tyrosine contents and the increase in quinone contents were slowed by S-Ft in potato mashes. Compared with control, S-Ft at 0.04 and 0.07 mM reduced polyphenol oxidase (PPO) activity by 91.22 % and 91.77 %, and addition of copper acetate recovered the PPO activities to 55.62 % and 59.45 % of control, respectively. Kinetics results showed S-Ft inhibited PPO activity in a reversible mixed-type manner. The data of circular dichroism analysis and fluorescence emission spectra indicated S-Ft treatment caused the decrease in α-helix content, the increase in β-sheet content and the change in secondary structure of PPO. Molecular docking results illustrated S-Ft could act with Cu²⁺ and amino acid residues of PPO. By comparison with other anti-browning inhibitors, S-Ft has the characteristics of low dosage and long shelf-life extension. These results demonstrated that S-Ft could be a novel and promising enzymatic browning inhibitor by chelating Cu²⁺ and changing the conformation of enzyme to reduce PPO activity.

本研究旨在从食品衍生的含硫化合物中筛选出安全有效的酶促褐变抑制剂。在 18 种候选化合物中，有 3 种被发现可以减少新鲜马铃薯泥的褐变。其中一种化合物，仅 0.04 和 0.07 mM 的 S-糠基硫代乙酸酯 (S-Ft) 在 4 °C 下抑制新鲜马铃薯条的褐变超过 10 天，其功效接近于 2.40 mM 的亚硫酸氢钠。S-Ft 还减少了茄子和芦笋生菜片的褐变。S-Ft延缓了马铃薯泥和酪氨酸溶液的褐变发生，但没有使棕色色素变为无色。马铃薯泥中的 S-Ft 减缓了酪氨酸含量的降低和醌含量的增加。与对照相比，0.04 和 0.07 mM 的 S-Ft 使多酚氧化酶 (PPO) 活性降低了 91。22 % 和 91.77 %，添加醋酸铜后，PPO 活性分别恢复到对照的 55.62 % 和 59.45 %。动力学结果显示S-Ft以可逆混合型方式抑制PPO活性。圆二色性分析和荧光发射光谱数据表明，S-Ft处理导致α-螺旋含量降低，β-折叠含量增加，PPO二级结构发生变化。分子对接结果表明 S-Ft 可以与 Cu 作用 β-折叠含量的增加和 PPO 二级结构的变化。分子对接结果表明 S-Ft 可以与 Cu 作用 β-折叠含量的增加和 PPO 二级结构的变化。分子对接结果表明 S-Ft 可以与 Cu 作用^PPO的2+和氨基酸残基。与其他抗褐变抑制剂相比，S-Ft具有用量少、保质期长的特点。这些结果表明，S-Ft通过螯合Cu ²⁺并改变酶的构象以降低PPO活性，可以成为一种新型且有前景的酶促褐变抑制剂。