Vilar-Bustillo Juan, Ruiz-Rodríguez Ana, Carrera Ceferino A, Piñeiro Zulema, Palma Miguel
Department of Analytical Chemistry, Center of Agri-Food and Wine Research (IVAGRO), Faculty of Science, University of Cadiz, 11510 Puerto Real, Spain.
IFAPA Rancho de la Merced, Carretera de Trebujena, Km. 2.2, Apdo. 589, 11471 Jerez de la Frontera, Spain.
Foods. 2023 May 11;12(10):1963. doi: 10.3390/foods12101963.
In white wine production, the technique consisting of freezing whole or crushed grapes usually increases the levels of aroma-related compounds in the final wine products. However, this technique may affect phenolic compounds, among other chemical compounds. Phenolic compounds are crucial to white wines because of their susceptibility to oxidation and their role with regard to color stability. In this study, white wines made from Muscat of Alexandria grapes were subjected to two different freezing techniques: whole-bunch freezing and crushed-grape freezing. In addition, a pre-fermentative maceration was applied to each experiment in order to determine if the effects of freezing were comparable to those of maceration. The phenolic compounds studied were gallic acid, protocatechuic acid, caffeic acid, -coutaric acid, and epicatechin, which are the key compounds from the point of view of wine stability. The freezing of crushed grapes enhanced the extraction of phenolic compounds in comparison to the freezing of whole bunches of grapes without pre-fermentative maceration. On the other hand, the effect of pre-fermentative maceration was comparable to that resulting from freezing crushed grapes. This step made the must from whole frozen grapes having even larger levels of phenolic compounds. Without pre-fermentative maceration, freezing whole bunches of grapes only allowed a moderate extraction of phenolic compounds and produced wines with lower individual phenolic contents than those obtained through traditional winemaking procedures.
在白葡萄酒生产中，将整串或破碎的葡萄冷冻的技术通常会提高最终葡萄酒产品中与香气相关的化合物的含量。然而，该技术可能会影响酚类化合物以及其他化学化合物。酚类化合物对白葡萄酒至关重要，因为它们易氧化且在颜色稳定性方面发挥作用。在本研究中，用亚历山大麝香葡萄制成的白葡萄酒采用了两种不同的冷冻技术：整串冷冻和破碎葡萄冷冻。此外，对每个实验都进行了发酵前浸渍，以确定冷冻的效果是否与浸渍的效果相当。所研究的酚类化合物有没食子酸、原儿茶酸、咖啡酸、对香豆酸和表儿茶素，从葡萄酒稳定性的角度来看，它们是关键化合物。与未经发酵前浸渍的整串葡萄冷冻相比，破碎葡萄冷冻增强了酚类化合物的提取。另一方面，发酵前浸渍的效果与破碎葡萄冷冻的效果相当。这一步使得整串冷冻葡萄制成的葡萄汁中酚类化合物的含量更高。如果没有发酵前浸渍，整串葡萄冷冻只能适度提取酚类化合物，所生产的葡萄酒中单个酚类化合物的含量低于通过传统酿酒工艺获得的葡萄酒。
