The Effect of Different Pulsed Electric Field Treatments on Producing High Quality Red Wines

Abstract

The aim of this study was to apply different Pulsed Electric Field (PEF) treatments in the pre-maceration stage of the mash which derives from ‘Pinot Noir’ and ‘Merlot’ grapes that were harvested in the Crişana-Santimreu vineyard, Romania, in 2016, in order to increase the content of total phenols, flavonoids, monomeric anthocyanin pigment and colour intensity of ‘Pinot Noir’ and ‘Merlot’ wines. The electrical and mechanical parameters that represent the variables in this experiment were: the distance between the drums, different voltages (7-8 kV), and different frequencies (178-344 Hz). The wines obtained were also analyzed in terms of the antioxidant capacity using two different methods. All PEF treatments applied in the pre-maceration stage resulted in an increase in bioactive compounds content and colour intensification. Of the five PEF treatments tested, the PEF treatment using the distance between the drums of 2.5 mm, U = 8 kV, the frequency f = 344 Hz, pulse durations of 300 s resulted in a wine with a content of total phenols 2 times and 1.5 times higher than the control sample in the case of ‘Pinot Noir’ and ‘Merlot’, respectively. Also, this type of PEF treatment also resulted in an extraction of the total flavonoids as efficiently as 1.8 times and 1.4 times, respectively, in the case of ‘Pinot Noir’ and ‘Merlot’, respectively. PEF treatment is a technology suitable for extracting phenols from grapes and so this technology can be used in the food industry to obtain wines rich in bioactive compounds with antioxidant capacity.