Carvalho Elisabete, Mateus Nuno, Plet Benoit, Pianet Isabelle, Dufourc Erick, De Freitas Victor
Centro de Investigação em Química, Universidade do Porto, Faculdade de Ciências, Departamento de Química, Rua do Campo Alegre 687, 4169-007 Porto, Portugal.
J Agric Food Chem. 2006 Nov 15;54(23):8936-44. doi: 10.1021/jf061835h.
Alpha-amylase, a major human salivary protein, and IB8c, a representative of the proline-rich proteins, were obtained by isolation from saliva and by solid-phase synthesis, respectively. The interactions between these proteins and condensed tannins isolated from grape seeds were studied at different protein and tannin concentrations by measuring their aggregation. Pectic polysaccharides were isolated from wine, and their effect on protein tannin aggregation was assessed. The results presented in this study showed that the most acidic fractions of arabinogalactan proteins have the ability to inhibit the formation of aggregates between the grape seed tannins and the two different salivary proteins. Rhamnogalacturonan II has the same ability toward alpha-amylase but not IB8c under the conditions of the present study. Polysaccharides show effects at concentrations at which they are present in wine, which could mean an influence in wine astringency. The interaction between condensed tannins and alpha-amylase is differently affected by ionic strength when compared with IB8c.
α-淀粉酶是一种主要的人类唾液蛋白，富含脯氨酸的蛋白质的代表IB8c则分别通过从唾液中分离和固相合成获得。通过测量这些蛋白质与从葡萄籽中分离出的缩合单宁之间的聚集情况，研究了它们在不同蛋白质和单宁浓度下的相互作用。从葡萄酒中分离出果胶多糖，并评估了它们对蛋白质-单宁聚集的影响。本研究结果表明，阿拉伯半乳聚糖蛋白的最酸性部分具有抑制葡萄籽单宁与两种不同唾液蛋白之间聚集体形成的能力。在本研究条件下，鼠李糖半乳糖醛酸聚糖II对α-淀粉酶具有相同的能力，但对IB8c则没有。多糖在葡萄酒中存在的浓度下表现出作用，这可能意味着对葡萄酒涩味有影响。与IB8c相比，缩合单宁与α-淀粉酶之间的相互作用受离子强度的影响不同。
