Saldaña Guillermo, Cebrián Guillermo, Abenoza María, Sánchez-Gimeno Cristina, Álvarez Ignacio, Raso Javier
Tecnología de los Alimentos, Facultad de Veterinaria, Universidad de Zaragoza, Instituto Agroalimentario de Aragón - IA2, C/ Miguel Servet, 177, 50013, Spain.
Innov Food Sci Emerg Technol. 2017 Feb;39:179-187. doi: 10.1016/j.ifset.2016.12.008.
The influence of the electric field intensity and pulse width on the improvement of total polyphenol index (TPI) and colour intensity (CI) during extraction in an ethanolic solution (30%) and during fermentation-maceration has been investigated in different grape varieties: Grenache from two harvesting times, Syrah and Tempranillo. The aim of this study was to develop a procedure to establish the PEF treatment conditions that cause enough permeabilization in the skin cells of different grape varieties to obtain a significant improvement in the vinification process in terms of increment on the polyphenol content or reduction of maceration time. Results obtained in this investigation indicate that extraction of polyphenols in a solution of ethanol (30%) for 2 h could be a suitable procedure to know if the PEF technology is effective for improving extraction of polyphenols from the grapes during vinification and to determine the most suitable PEF treatment conditions to obtain this objective. Improvement in the extraction during vinification only was observed with those grapes and under treatment conditions in which the improvement of the polyphenol extraction was higher than 40%. Other interesting observation from this research is the highest efficacy of PEF when treatments of the same duration are applied using longer pulses. Therefore, in a continuous process, where the flow processed is determined by the frequency applied by the PEF generator, it is possible to increase the processing capacity of the PEF installation.
Benefits from PEF treatment of the grapes before the maceration step in the vinification process have been demonstrated. Nevertheless, the characteristics of the grapes may change in different vintages and grape varieties. Therefore, it is of high importance to be able to determine the optimum PEF conditions in order to obtain the desired benefit during the vinification. The rapid method developed permits to determine PEF process parameters before the application of the PEF treatment with the objective of facilitating the phenolic extraction and therefore, reducing the maceration time. In these cases, it would be possible to remove the skins from the rest of the wine earlier, and therefore, increase the processing capacity of the winery.
研究了电场强度和脉冲宽度对不同葡萄品种（两个采收期的歌海娜、西拉和丹魄）在乙醇溶液（30%）萃取过程以及发酵浸渍过程中总多酚指数（TPI）和颜色强度（CI）改善情况的影响。本研究的目的是开发一种程序，以确定能使不同葡萄品种的果皮细胞产生足够通透性的脉冲电场处理条件，从而在多酚含量增加或浸渍时间缩短方面显著改善酿酒过程。本研究获得的结果表明，在30%乙醇溶液中萃取2小时多酚可能是一种合适的程序，以了解脉冲电场技术是否有效地改善酿酒过程中葡萄多酚的萃取，并确定实现这一目标的最合适的脉冲电场处理条件。仅在那些葡萄以及多酚萃取改善率高于40%的处理条件下，才观察到酿酒过程中萃取的改善。本研究的另一个有趣发现是，当使用较长脉冲进行相同持续时间的处理时，脉冲电场的效率最高。因此，在连续过程中，其中处理的流量由脉冲电场发生器施加的频率决定，有可能提高脉冲电场装置处理能力。
已证明在酿酒过程浸渍步骤之前对葡萄进行脉冲电场处理的益处。然而，不同年份和葡萄品种的葡萄特性可能会发生变化。因此，能够确定最佳脉冲电场条件对于在酿酒过程中获得期望的益处非常重要。所开发的快速方法允许在应用脉冲电场处理之前确定脉冲电场工艺参数，目的是促进酚类物质的萃取，从而缩短浸渍时间。在这些情况下，有可能更早地将葡萄皮与葡萄酒的其他部分分离，从而提高酿酒厂的处理能力。
