The increase in colour and solubilisation of extract, polyphenols and ellagitannins were studied in wine spirit in new oak casks over a period of 23 years. Ellagitannins and oak colour were solubilised during the early years of maturation. After five years, the concentration of ellagitannins decreased markedly, while colour increased, although at a lower rate. Ellagitannins were oxidised into coloured polymers and hydrolysed into ellagic acid. The dry extract, containing polysaccharides, polyphenols and lignin, increased throughout maturation, growing quickly during the early years and slowly thereafter. In a model solution, ethanol exhibits a strong solvent effect. For higher concentrations (50% v/v and more), the extraction of colour was faster, and was typically dark yellow/brown with a red tone, attributable in part to the solubilisation of lignin and lignin by‐products. © 2020 The Institute of Brewing & Distilling

中文翻译：

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酒精成熟过程中从新橡木桶中提取酚类：对酒精颜色的影响

在新橡木桶中的酒中研究了提取物，多酚和鞣花单宁的颜色增加和增溶，历时23年。Ellagitannins和橡木色在成熟的早期就被溶解了。五年后，鞣花单宁的浓度显着下降，而色泽增加，尽管速率较低。鞣花单宁被氧化成有色聚合物，然后水解成鞣花酸。含有多糖，多酚和木质素的干燥提取物在整个成熟过程中均增加，在早年迅速生长，然后缓慢生长。在标准溶液中，乙醇表现出很强的溶剂作用。对于更高的浓度（50％v / v和更高），颜色的提取速度更快，通常为深黄色/棕色和红色调，部分归因于木质素和木质素副产物的增溶。©2020酿酒与蒸馏研究所