Lukić Igor, Horvat Ivana
Institute of Agriculture and Tourism, Karla Huguesa 8, HR-52440 Poreč, Croatia.
Centre of Excellence for Biodiversity and Molecular Plant Breeding, Svetošimunska 25, HR-10000 Zagreb, Croatia.
Foods. 2020 Oct 25;9(11):1534. doi: 10.3390/foods9111534.
To test the effect of the moment of bentonite addition, co-addition of tannins, and bentonite type on the differential affinity of pathogenesis-related (PR) proteins towards bentonite during grape must fermentation, three separate experiments were set up. PR proteins in the obtained wines were analyzed by reverse phase and size exclusion high-performance liquid chromatography (HPLC). The most significant reduction of bentonite dose and PR protein concentration was achieved by applying bentonite in the last third of fermentation. Particular thaumatin-like proteins (TLP) and proteins with lower molecular mass in general were more affected than others, while TLPs were more affected than chitinases. Exogenous enological tannins interacted with particular PR proteins, mostly TLPs, and lowered the total bentonite dose required. The combined application of tannins and bentonite in fermentation removed more PR proteins than bentonite alone, but did not achieve a synergistic effect in reducing the bentonite dose. Various bentonite types, including two Na-activated bentonites, an activated Na bentonite with specifically adsorbed silica, and an active Na-Ca bentonite, exhibited differential affinity towards different PR proteins. The results obtained could be used in developing wine fining protocols which combine treatments with complementary affinity for adsorption and removal of PR proteins, and in this way achieve greater efficiency of bentonite fining by reducing its total dose, which is of significant interest to the wine industry.
为了测试膨润土添加时间、单宁共添加以及膨润土类型对葡萄汁发酵过程中病程相关（PR）蛋白与膨润土的差异亲和力的影响，开展了三个独立实验。通过反相和尺寸排阻高效液相色谱（HPLC）分析所获葡萄酒中的PR蛋白。在发酵的最后三分之一阶段添加膨润土，可使膨润土用量和PR蛋白浓度显著降低。一般来说，特定的类thaumatin蛋白（TLP）和分子量较低的蛋白比其他蛋白受影响更大，而TLP比几丁质酶受影响更大。外源酿酒单宁与特定的PR蛋白（主要是TLP）相互作用，降低了所需的膨润土总用量。单宁和膨润土在发酵过程中的联合应用比单独使用膨润土去除了更多的PR蛋白，但在降低膨润土用量方面未达到协同效应。包括两种钠活化膨润土、一种吸附有特定二氧化硅的活化钠膨润土和一种活性钠钙膨润土在内的各种膨润土类型，对不同的PR蛋白表现出不同的亲和力。所得结果可用于制定葡萄酒澄清方案，该方案结合了对PR蛋白具有互补吸附亲和力的处理方法，从而通过减少膨润土总用量提高膨润土澄清效率，这对葡萄酒行业具有重要意义。
