Laboratory of Food Chemistry, Wageningen University, P.O. Box 8129, 6700EV Wageningen, The Netherlands.
J Agric Food Chem. 2011 Sep 28;59(18):10247-55. doi: 10.1021/jf202624q. Epub 2011 Sep 6.
The effect of sodium hydrogen sulfite (S), used as antibrowning agent, on the phenolic profile of potato extracts was investigated. This extract was compared to one obtained in the presence of ascorbic acid (A). In the presence of A, two major compounds were obtained, 5-O-caffeoylquinic acid (5-CQA) and 4-O-caffeoyl quinic acid. With S, their 2'-sulfo-adducts were found instead, the structures of which were confirmed by nuclear magnetic resonance spectroscopy and mass spectrometry. Also, for minor caffeoyl derivatives and quercetin glycosides, the corresponding sulfo-adducts were observed. Feruloyl and sinapoyl derivatives were not chemically affected by the presence of S. Polyphenol oxidase (PPO) was thought to be responsible for the formation of the sulfo-adducts. This was confirmed by preparing 2'-sulfo-5-O-caffeoyl quinic acid in a model system using 5-CQA, sodium hydrogen sulfite, and PPO. This sulfo-adduct exhibited a small bathochromic shift (λmax 329 nm) as compared to 5-CQA (λmax 325 nm) and a strong hypochromic shift with an extinction coefficient of 9357±395 M(-1) cm(-1) as compared to 18494±196 M(-1) cm(-1), respectively. The results suggest that whenever S is used as an antibrowning agent, the O-quinone formed with PPO reacts with S to produce sulfo-O-diphenol, which does not participate in browning reactions.
研究了亚硫酸氢钠（S）作为抗褐变剂对马铃薯提取物酚类成分的影响。将该提取物与含有抗坏血酸（A）的提取物进行了比较。在 A 的存在下，得到了两种主要化合物，5-O-咖啡酰奎宁酸（5-CQA）和 4-O-咖啡酰奎宁酸。而在 S 的存在下，发现了它们的 2'-磺酸加合物，其结构通过核磁共振波谱和质谱得到了确认。此外，对于次要的咖啡酰衍生物和槲皮苷，也观察到了相应的磺酸加合物。阿魏酰和芥子酰衍生物没有受到 S 的化学影响。多酚氧化酶（PPO）被认为是磺酸加合物形成的原因。通过在含有 5-CQA、亚硫酸氢钠和 PPO 的模型系统中制备 2'-磺酸-5-O-咖啡酰奎宁酸，证实了这一点。与 5-CQA（λmax 325nm）相比，该磺酸加合物的最大吸收波长（λmax 329nm）发生了微小的红移，与 18494±196 M（-1）cm（-1）相比，消光系数为 9357±395 M（-1）cm（-1），发生了强烈的蓝移。结果表明，只要将 S 用作抗褐变剂，与 PPO 形成的 O-醌就会与 S 反应生成磺酸-O-二酚，它不会参与褐变反应。
