Department of Chemical Engineering, University of California, One Shields Avenue, Davis, CA 95616, USA.
Department of Viticulture and Enology, University of California, One Shields Avenue, Davis, CA 95616, USA.
Molecules. 2019 Apr 2;24(7):1275. doi: 10.3390/molecules24071275.
Phenolic extraction is a critical part of red wine making. Though empirical models of phenolic extraction kinetics exist, the current level of mechanistic understanding does not allow for accurate predictions. In this work, we propose a mechanistic model for the extraction of phenolics from grape skins and seeds as a function of temperature and ethanol. This model examines the release of phenolics, the adsorption of phenolics onto grape material, and the disappearance of anthocyanins from solution. Additionally, we performed epifluorescence microscopy to explore our finding that seed tannins' release rate appears independent of concentration, and found that the grape seed appears to ablate over fermentation. We also determined the activation energy of anthocyanin disappearance, in good agreement with similar systems. The proposed model results in an excellent fit, and increases the understanding of phenolic extraction and the ability to predict and optimize product outcome in red wine making.
酚类提取是红酒酿造的关键环节。虽然存在经验模型来描述酚类提取动力学，但目前的机械理解水平还无法进行准确的预测。在这项工作中，我们提出了一个机械模型，用于研究温度和乙醇对从葡萄皮和籽中提取酚类物质的影响。该模型考察了酚类物质的释放、酚类物质在葡萄材料上的吸附以及花青素从溶液中的消失。此外，我们还进行了荧光显微镜观察，以探讨我们发现的种子单宁释放速度似乎与其浓度无关的现象，并发现葡萄籽在发酵过程中似乎会消融。我们还确定了花青素消失的活化能，与类似体系吻合良好。所提出的模型拟合效果极佳，提高了对酚类提取的理解，并增强了在红酒酿造中预测和优化产品结果的能力。
