Laboratory of Food Chemistry, Wageningen University, Wageningen, The Netherlands.
J Agric Food Chem. 2012 Apr 25;60(16):4136-43. doi: 10.1021/jf205292r. Epub 2012 Apr 17.
Enrichment of flavonoids in food is often limited by their off-tastes, which might be counteracted by the use of food proteins as carriers of flavonoids. Various milk proteins, egg proteins, and gelatin hydrolysates were compared for their binding characteristics to two flavan-3-ols. Among the proteins tested for their affinities toward epigallocatechin gallate (EGCG), β-casein and gelatin hydrolysates, in particular fish gelatin, were found to be the most promising carriers with an affinity on the order of 10(4) M(-1). A flexible open structure of proteins, as present in random coil proteins, was found to be important. The saturation of binding observed at high flavonoid/protein ratios was used to estimate the maximal binding capacity of each protein. To reach a daily intake of EGCG that has been associated with positive health effects, only 519 mg of gelatin B and 787 mg of β-casein were required to complex EGCG on the basis of their maximal binding capacity. When the absence of turbidity is taken into account, β-casein prevails as carrier. Three selected proteins were further investigated for their binding potential of representative flavonoids differing in their C-ring structure. An increase in hydrophobicity of flavonoids was related to a higher affinity for proteins, and the presence of a gallic acid ester on the C-ring showed an overall higher affinity.
食品中类黄酮的富集常常受到其不良口感的限制，而使用食物蛋白作为类黄酮的载体可以克服这一问题。研究人员比较了各种乳蛋白、卵蛋白和明胶水解物对两种黄烷-3-醇的结合特性。在测试的几种对表没食子儿茶素没食子酸酯（EGCG）具有亲和力的蛋白中，β-酪蛋白和明胶水解物，尤其是鱼明胶，被发现是最有前途的载体，其亲和力约为 10(4) M(-1)。研究发现，蛋白具有灵活的开放结构，如无规卷曲蛋白，这一点很重要。在高类黄酮/蛋白比例下观察到的结合饱和可用于估计每种蛋白的最大结合容量。根据最大结合容量，要达到与健康益处相关的每日 EGCG 摄入量，只需 519 毫克 B 型明胶和 787 毫克β-酪蛋白就可以与 EGCG 结合。当考虑到无浊度时，β-酪蛋白是首选载体。进一步研究了三种选定的蛋白质对其结合代表性黄烷类化合物的潜力，这些化合物在 C 环结构上存在差异。黄烷类化合物疏水性的增加与其对蛋白质的亲和力增加有关，C 环上存在没食子酸酯基显示出更高的整体亲和力。
