Effect of microoxygenation on acetaldehyde, yeast and colour before and after malolactic fermentation on Pinot Noir wine

Abstract

Background and Aims Microoxygenation (MOX) is widely used in winemaking. Its impact, however, on Pinot Noir wines has not been well documented. We investigated the influence of MOX on colour parameters and on the anthocyanin and polymeric pigment concentration of a young Pinot Noir wine. The relationship between MOX, yeast growth and acetaldehyde production was also explored. Methods and Results Microoxygenation was applied before or after malolactic fermentation (MLF), and at two oxygen doses [10.8 and 52.4 mg/(L ·month)], for 30 days. The end result was reported after dissolved oxygen was depleted and 90 mg/L SO2 was added. Microoxygenation induced a higher yeast growth and acetaldehyde production, where the latter was associated with both yeast metabolism and chemical oxidation. A larger loss in total anthocyanins and malvidin‐3‐glucoside occurred under MOX but absorbance at 520 nm and colour intensity were higher. With the higher oxygen dose, MOX promoted the formation of large polymeric pigments. Conclusions Acetaldehyde formation was strongly induced by MOX, contributing to reactions between anthocyanins and acetaldehyde forming pigments in the red spectrum. Between MOX treatments, only slight variation was found for each parameter, indicating a less important effect of the timing and dosage of MOX on the young Pinot Noir wine than anticipated from prior work. Significance of the Study Microoxygenation caused a significant impact on the colour development of light‐coloured Pinot Noir wine, increasing the colour intensity.

Impact of microoxygenation on Pinot noir wines with different initial phenolic content

“…Recently, we have demonstrated that MOX applied to a young Pinot noir wine led to an increase in colour intensity (with a higher absorbance at 520 nm) and tannin concentration, and a higher oxygen dosage favoured the formation of polymeric pigments (Yang et al, 2021a;Yang et al, 2021b). At the same time, a higher percentage of galloylated tannins but fewer trihydroxylated tannins were found after MOX, indicating a negative impact on astringency perceptions (Yang et al, 2021a;Yang et al, 2021b).…”

“…Recently, we have demonstrated that MOX applied to a young Pinot noir wine led to an increase in colour intensity (with a higher absorbance at 520 nm) and tannin concentration, and a higher oxygen dosage favoured the formation of polymeric pigments (Yang et al, 2021a;Yang et al, 2021b). At the same time, a higher percentage of galloylated tannins but fewer trihydroxylated tannins were found after MOX, indicating a negative impact on astringency perceptions (Yang et al, 2021a;Yang et al, 2021b). However, Yang et al (2021b), attributed the decrease in trihydroxylated tannins to Saccharomyces cerevisiae activity, as MOX had also induced yeast growth (Yang et al, 2021a), where the proliferation and autolysis of this yeast species have been shown to affect tannin composition through adsorption to the cell walls (Mazauric and Salmon, 2005;Mekoue Nguela et al, 2015).…”

“…The set-up for MOX and control treatments were the same as outlined by Yang et al (2021a). The control treatment received no oxygenation and was sealed in the 2 L Fisherbrand TM glass bottles.…”

“…Several factors affecting the influence of MOX on red table wines have been demonstrated, such as the timing and duration of MOX, the addition of preservatives, oxygen dosage, and microbial influence (Anli and Cavuldak, 2012;Ji et al, 2020). However, very limited information is available for wines made from Pinot noir (Durner et al, 2010;Durner et al, 2015;Yang et al, 2021a;Yang et al, 2021b). Pinot noir wines tend to be lighter in colour than Cabernet-Sauvignon, Malbec and Syrah wines (Burns and Osborne, 2013;Casassa et al, 2015) and are associated with poor colour development, low pigment stability, and limited ageing potential (Sacchi et al, 2005;Sparrow et al, 2016).…”

“…At the same time, a higher percentage of galloylated tannins but fewer trihydroxylated tannins were found after MOX, indicating a negative impact on astringency perceptions (Yang et al, 2021a;Yang et al, 2021b). However, Yang et al (2021b), attributed the decrease in trihydroxylated tannins to Saccharomyces cerevisiae activity, as MOX had also induced yeast growth (Yang et al, 2021a), where the proliferation and autolysis of this yeast species have been shown to affect tannin composition through adsorption to the cell walls (Mazauric and Salmon, 2005;Mekoue Nguela et al, 2015). Therefore, the changes in tannin composition observed in previous work (Yang et al, 2021b) might not be solely caused by oxygenation.…”