Different approaches to supplement polysaccharide-degrading enzymes in vinification: effects on color extraction, phenolic composition, antioxidant activity and sensory profiles of Malbec wines

LONGHI, SARA JAQUELINA; MARTÍN, MARÍA CAROLINA; FONTANA, ARIEL R.; MORATA DE AMBROSINI, VILMA INÉS

FOOD RESEARCH INTERNATIONAL

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2022

0963-9969

Enzymes play an essential role in the winemaking process. Besides an improvement in the color of the wine they also enhance the quality, which makes it well worth to develop new dosage/application strategies. The present study examined two approaches to apply microbial enzymes during different winemaking techniques using Malbec grapes from the San Rafael wine region, Mendoza, Argentina. i) Torulaspora delbrueckii was used in sequential inoculation with an autochthonous Saccharomyces cerevisiae strain. First T. delbrueckkii was inoculated for four days to produce in situ an enzyme complex during winemaking, and then the winemaking yeast/Saccharomyces yeast was added. The process was carried out under traditional winemaking conditions at 22°C (Td-Sc). ii) A second approach used a multi-enzyme extract produced by Aureobasidium pullulans m11-2 during pre-fermentative cold maceration (PCM) for four days at 8°C (PCM-E), and S. cerevisiae was inoculated at the end of the PCM. Controls were carried out without enzymatic treatments (Sc and PMC, respectively). T. delbrueckii started the fermentation and remained viable throughout the process. The fermentation kinetics in the mixed culture were not affected compared with a pure culture of S. cerevisiae. Monitoring of the pectinolytic activity of Td-Sc showed maximum activity (14.2 U mg-1) on day one of the inoculation, while in PCM-E the must activity increased during the PCM until day one of the fermentation, reaching a maximum of 16.85 U mg-1. Both enzyme-treated wines maintained their red hue, regardless of the duration of the macerations, while the control wines were characterized by a faster rate of color loss and more yellow tones. During the sensory evaluation, enzymatically treated wines presented greater color intensity, enhanced red and violet tones and floral and fruit aromas, which are distinctive features of the Malbec variety. Anthocyanin values obtained in PCM and in PCM-E were higher than in vinifications without cold maceration (Td-Sc and Sc), which could be attributed to the effectiveness of the maceration technique. Similarly, the composition of stilbenes, especially trans-resveratrol, showed an increase in PCM techniques with or without enzymatic treatment, and both techniques were comparable and statistically superior to traditional winemaking.