Inhibition of Apple Polyphenol Oxidase Activity by Sodium Chlorite

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• 作者：Shengmin Lu ; Yaguang Luo ; and Hao Feng
• 刊名：Journal of Agricultural and Food Chemistry
• 出版年：2006
• 出版时间：May 17, 2006
• 年：2006
• 卷：54
• 期：10
• 页码：3693 - 3696
• 全文大小：94K
• 年卷期：v.54,no.10(May 17, 2006)
• ISSN：1520-5118

文摘

Sodium chlorite (SC) was shown to have strong efficacy both as a sanitizer to reduce microbial growthon produce and as a browning inhibitor on fresh-cut apples in previous experiments. This study wasundertaken to investigate the inhibitory effect of SC on polyphenol oxidase (PPO) and the associatedmechanisms. The experiment showed that SC had a strong inhibition of apple PPO. The extent ofinhibition was influenced by SC concentration and pH. Inhibition was most prominent at pH 4.5, atwhich ~30% of enzyme activity was lost in the presence of 10 mM SC, followed closely by that at pH4.0 with a 26% reduction in PPO activity. The inhibition mode was determined using Dixon andLineweaver-Burk plots, which established SC to be a mixed inhibitor of apple PPO for the oxidationof catechol. Preincubation of PPO with 8 mM SC for 8 min caused a maximum of 46% activity reductioncompared to noninhibited control. However, preincubation of SC with catechol for 8 min resulted inno additional loss of PPO activity. These findings provide further evidence that the inhibition of PPOactivity by SC is due to the inhibition of the enzyme itself rather than removal of the substrate.Keywords: Inhibition mode; sodium chlorite; polyphenol oxidase; apple; fresh-cut