Abstract Enzymatic browning is a crucial factor affecting the quality of fresh-cut potatoes. In this study, the effects of aspartic acid (Asp) on browning, polyphenol oxidase (PPO) activity, and phenolic substrates were investigated. The results showed that all the Asp solution treatments significantly reduced the browning of fresh-cut potato chips. At 2–4 °C, control chips had lost saleability on day 1, while 1.0 % Asp treated chips were still acceptable on the day 7 evaluation. Asp can prevent the discoloration of potato pulp completely and also partly decolorize the brown color. Addition of Asp decreased the PPO activity of potato pulp. At the same pH, the PPO activities of potato pulps treated with Asp were lower than those treated with phosphoric acid (H3PO4). With the recovery of pH to the control level, the activity of the Asp-treated pulp did not improve completely like those treated with H3PO4. Moreover, the addition of copper acetate solution to the Asp-treated pulp significantly increased PPO activity. As browning progressed, tyrosine and chlorogenic acid content in the Asp-treated potato pulp was higher than that of the control, but caffeic acid, gallic acid, and protocatechuic acid content did not increase. In vitro simulation experiments demonstrated that Asp prevented the discoloration of tyrosine and chlorogenic acid solution, and also caused the fading of the discoloration to a certain degree. These results indicated that Asp is a promising anti-browning agent for fresh-cut potato and the mechanism involves the reduction of PPO activity via a decrease in pH and chelating Cu2+ by Asp, inhibiting the formation of brown color from tyrosine and chlorogenic acid solution and enhancing the fading of the brown color.

中文翻译：

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天冬氨酸通过调控褐变产物的生成和转化有效防止马铃薯酶促褐变

摘要 酶促褐变是影响鲜切马铃薯品质的重要因素。在这项研究中，研究了天冬氨酸 (Asp) 对褐变、多酚氧化酶 (PPO) 活性和酚类底物的影响。结果表明，所有的Asp溶液处理都显着降低了鲜切薯片的褐变。在 2–4 °C 下，对照薯片在第 1 天失去了可销售性，而在第 7 天的评估中，经过 1.0% Asp 处理的薯片仍然可以接受。Asp可以完全防止马铃薯果肉变色，也可以部分地使褐色脱色。Asp的添加降低了马铃薯果肉的PPO活性。在相同的 pH 值下，用 Asp 处理的马铃薯果肉的 PPO 活性低于用磷酸 (H3PO4) 处理的那些。随着 pH 值恢复到控制水平，Asp 处理的纸浆的活性没有像用 H3PO4 处理的那样完全提高。此外，将醋酸铜溶液添加到经 Asp 处理的纸浆中显着提高了 PPO 的活性。随着褐变的进行，Asp处理的马铃薯果肉中酪氨酸和绿原酸含量高于对照，但咖啡酸、没食子酸和原儿茶酸含量没有增加。体外模拟实验表明，Asp 阻止了酪氨酸和绿原酸溶液的变色，同时也在一定程度上引起了变色的消退。这些结果表明，Asp 是一种很有前途的鲜切马铃薯抗褐变剂，其机制涉及通过降低 pH 值和 Asp 螯合 Cu2+ 来降低 PPO 活性，