Department of Food Science and Technology, Faculty of Veterinary Science, University of Murcia, Campus de Espinardo, 30100 Murcia, Spain.
Department of Viticulture and Oenology, Faculty of AgriSciences, South African Grape and Wine Research Institute, Stellenbosch University, Matieland 7602, South Africa.
Molecules. 2021 Feb 2;26(3):770. doi: 10.3390/molecules26030770.
This study evaluates the capacity of four hydrolytic enzymes to limit the interactions between grape cell-walls and tannins and/or to favor tannin desorption. Adsorption and desorption tests were conducted by mixing a commercial seed tannin with purified skin cell-walls from Syrah grapes, in the presence or absence of hydrolytic enzymes, in a model-wine solution. The effects of the enzymes were evaluated by measuring the tannins in solution by High Performance Liquid Chromatography (HPLC) and the changes in the cell wall polysaccharide network by Comprehensive Microarray Polymer Profiling (COMPP) while the polysaccharides liberated from cell walls were analyzed by Size Exclusion Chromatography (SEC). The results showed that the enzymes limited the interaction between tannins and cell walls, especially cellulase, pectinase and xylanase, an effect associated with the cell wall structural modifications caused by the enzymes, which reduced their capacity to bind tannins. With regards to the tannin desorption process, enzymes did not play a significant role in liberating bound tannins. Those enzymes that showed the highest effect in limiting the adsorption of tannins and in disorganizing the cell wall structure, cellulase and pectinase, did not lead to a desorption of bound tannins, although they still showed a capacity of affecting cell wall structure. The results indicate that enzymes are not able to access those polysaccharides where tannins are bound, thus, they are not a useful tool for desorbing tannins from cell walls. The practical importance implications of these findings are discussed in the manuscript.
本研究评估了四种水解酶限制葡萄细胞壁与单宁相互作用和/或促进单宁解吸的能力。通过在模型酒溶液中混合商业种子单宁和来自西拉葡萄的纯化果皮细胞壁，在存在或不存在水解酶的情况下进行吸附和解吸测试。通过高效液相色谱法（HPLC）测量溶液中的单宁和综合微阵列聚合物分析（COMPP）测量细胞壁多糖网络的变化来评估酶的效果，同时通过尺寸排阻色谱法（SEC）分析从细胞壁中释放的多糖。结果表明，酶限制了单宁与细胞壁之间的相互作用，特别是纤维素酶、果胶酶和木聚糖酶，这种作用与酶引起的细胞壁结构修饰有关，降低了它们结合单宁的能力。关于单宁解吸过程，酶在释放结合的单宁方面没有起到显著作用。那些在限制单宁吸附和扰乱细胞壁结构方面表现出最高效果的酶，如纤维素酶和果胶酶，并没有导致结合的单宁解吸，尽管它们仍然表现出影响细胞壁结构的能力。结果表明，酶无法进入单宁结合的多糖，因此，它们不是从细胞壁中解吸单宁的有用工具。本文讨论了这些发现的实际重要性。
