Background and Aims Although most proteins and a significant proportion of phenolic substances are extracted from grape pulp, the extraction of grape skin components may contribute to and modulate the final concentration of these components in juice. This study investigated the influence of skin contact time and various extractants on the extraction of Sauvignon Blanc grape skin components. Methods and Results Two trials were conducted. The first evaluated the impact of skin contact time on the extraction of phenolic substances and proteins from grapes (fresh vs chilled) into juice. The juice with 24 h skin contact showed a significantly higher concentration of phenolic substances and chitinases, but not of thaumatin‐like proteins. No difference was observed between fresh and chilled berries. The second trial evaluated the extractability of phenolic substances and proteins from grape skin (ground vs peeled) using different extractants. More phenolic substances and tannin were extracted using ground skin powder as greater mechanical damage assisted in the extraction of skin components. Compared to mechanically crushed and pressed grape juice, hand squeezed juice showed a lower protein concentration and the presence of tannin. It is suggested that hand squeezing was more effective in extracting components (mainly phenolic substances) from grape skin, but mechanically crushing and pressing was more effective in extracting components (mainly proteins) from grape pulp. Extractants containing bovine serum albumin or protein resulted in a lower concentration of phenolic substances and tannin in the extracts, and the concentration of bovine serum albumin and protein was dramatically decreased after extraction. Conclusion This study confirmed that longer skin contact increased the extraction of skin phenolic substances. Longer skin contact also increased the protein concentration in juice, particularly the pathogenesis‐related proteins, but it can be modulated by the co‐extraction of phenolic substances. Significance of the Study This study improves our current understanding of interactions between phenolics and proteins during grape processing, which can be used as a tool for winemakers to manage the extraction of these compounds into juice.

中文翻译：

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表皮接触及不同提取剂对长相思葡萄皮中蛋白质和酚类物质提取的影响

背景和目的 虽然大多数蛋白质和大部分酚类物质是从葡萄果肉中提取的，但葡萄皮成分的提取可能有助于并调节这些成分在果汁中的最终浓度。本研究调查了皮肤接触时间和各种提取剂对长相思葡萄皮成分提取的影响。方法和结果 进行了两项试验。第一个评估了皮肤接触时间对将葡萄（新鲜与冷藏）中的酚类物质和蛋白质提取到果汁中的影响。与皮肤接触 24 小时的果汁显示出显着更高浓度的酚类物质和几丁质酶，但未显示类奇异果甜蛋白。在新鲜和冷藏的浆果之间没有观察到差异。第二项试验评估了使用不同提取剂从葡萄皮（磨碎与去皮）中提取酚类物质和蛋白质的能力。使用磨碎的皮粉提取更多酚类物质和单宁，因为更大的机械损伤有助于提取皮肤成分。与机械压碎和压榨的葡萄汁相比，手压葡萄汁显示出较低的蛋白质浓度和单宁的存在。表明手压对葡萄皮中成分（主要是酚类物质）的提取效果较好，而机械压榨对葡萄果肉中成分（主要是蛋白质）的提取效果较好。含有牛血清白蛋白或蛋白质的提取剂导致提取物中酚类物质和单宁的浓度较低，提取后牛血清白蛋白和蛋白质浓度显着降低。结论 本研究证实，皮肤接触时间越长，皮肤酚类物质的提取就越多。长时间的皮肤接触也增加了果汁中的蛋白质浓度，特别是与发病机制相关的蛋白质，但它可以通过酚类物质的共同提取来调节。研究的意义 这项研究提高了我们目前对葡萄加工过程中酚类物质和蛋白质之间相互作用的理解，这可以用作酿酒师管理将这些化合物提取到果汁中的工具。长时间的皮肤接触也增加了果汁中的蛋白质浓度，特别是与发病机制相关的蛋白质，但它可以通过酚类物质的共同提取来调节。研究的意义 这项研究提高了我们目前对葡萄加工过程中酚类物质和蛋白质之间相互作用的理解，这可以用作酿酒师管理将这些化合物提取到果汁中的工具。长时间的皮肤接触也增加了果汁中的蛋白质浓度，特别是与发病机制相关的蛋白质，但它可以通过酚类物质的共同提取来调节。研究的意义 这项研究提高了我们目前对葡萄加工过程中酚类物质和蛋白质之间相互作用的理解，这可以用作酿酒师管理将这些化合物提取到果汁中的工具。