Pulsed Electric Fields vs. Pectolytic Enzymes in Arinto Vinification: Effects on Yield and Oenological Parameters

Abstract

The increase in awareness of consumers and producers regarding the sustainable production and consumption of food commodities is motivating the emergence of new technologies to improve the efficiency of pre-established methods and reduce or supplant the usage of production factors. Thus, innovative technologies, such as the nonthermal application of pulsed electric fields (PEFs), may play a crucial role in the optimization of processes, both economically and environmentally (shrinkage of wastage, energy efficiency and decrease in the use of food additives), without compromising the quality of the final product. Thus, a comparison was made between the application of commercial-grade enzymes and PEF treatment to assess the impact on cuvée white grape must and on wine yield and quality. Oenological parameters were evaluated during alcoholic fermentation and after 3 months, with tartaric stability measured after 6 months. For this, assays resorting to 1.5 tons of Arinto grapes were separated into nine similar batches: three control, three treated with enzymes (1.5 g/100 kg) and three subjected to PEFs (1 kV/cm; 2 kJ/kg) at a rate of 4 ton/h. PEFs presented the highest increase in cuvée wine yield of 5.47%; a reduction of 19% of wine lees production was also determined. The effect of PEFs on pH, total acidity, turbidity, total phenols, color intensity, %Ye, total dry extract, volatile acidity and tartaric stability was studied and compared with control and enzymatic treatment. PEF and enzyme usage direct costs were determined; the employment of PEFs represented a direct cost of 0.12 EUR/ton, while enzyme usage was 1.80 EUR/ton.