Pulsed Electric Fields as a Green Pretreatment to Enhance Mass Transfer from Grapes of Bioactive Molecules: Aromatic, Phenolic, and Nitrogen Compounds

Abstract

The objective of this chapter was to summarize the effects of four pulsed electric field (PEF) treatments on the chemical composition of three grape varieties. To this end, Graciano, Tempranillo, and Grenache grapes were destemmed and crushed and then were treated using a PEF continuous system. Phenolic and nitrogen compounds were analyzed by HPLC and volatile compounds by GC-MS. The results showed that the influence of PEF treatments on these bioactive molecules was different depending on the grape variety and PEF treatment applied. This non-thermal technology improved Grenache aromatic composition, but Tempranillo and Graciano volatile composition was not affected by PEF. The treatment with the highest time and energy was the most effective on the total stilbene extraction, greatly increasing the content of these compounds in all grape varieties. Moreover, all PEF treatments enhanced yeast assimilable nitrogen (YAN) and total amino acids of Grenache grape variety, while for Graciano and Tempranillo, the PEF treatments hardly affected its nitrogen compounds content. In conclusion, from the point of view of the chemical composition and taking into account the treatments used in this study, it can be concluded that PEF is an appropriate technology to improve the quality of Grenache variety.