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The initial concentration of anthocyanin and proanthocyanidin in wine affects the development of SO 2 -resistant pigments, as well as color and non-color contributing polymeric fractions. However, the effect of extracted monomeric Pinot Noir (Vitis vinifera L. cv.) grape anthocyanins with seed proanthocyanidins are poorly studied. In model ferments, the reaction of purified Vitis vinifera L. cv. Pinot noir monomeric anthocyanins with seed proanthocyanidins extract were investigated at high and low concentrations of each reactant. During wine aging, monomeric anthocyanins decreased whereas SO 2 -resistant pigments increased. Higher anthocyanin concentrations retained more soluble tannins in model ferments during aging, while those with higher anthocyanin and lower proanthocyanidin concentrations had the highest MCP-tannin concentration in model ferments. HPLC analysis showed that the color contributing polymeric fractions are dependent upon the initial concentration of anthocyanin/proanthocyanidin ratios and more inclined towards high anthocyanin/low proanthocyanidin concentrations. Wine color parameters were measured in the form of L*, a*, b*, C (chroma) and H (hue) values and showed a decrease in hue and chroma in model wines after aging. The color data supported the HPLC findings that the initial anthocyanin/proanthocyanidin ratio was critical for the establishment of a color contributing polymeric fractions and stable deep red color in wines. [Display omitted] • Monomeric anthocyanin disappeared faster in the presence of high proanthocyanidin concentrations. • High anthocyanin/low proanthocyanidin retained more tannins in contrast to high anthocyanin/high proanthocyanidin. • High anthocyanin/low proanthocyanidin ratio resulted in more color contributing polymeric fractions. [ABSTRACT FROM AUTHOR]

To assess the possible impact of climatic variation on microbial community composition in organic winemaking, we employed a metabarcoding approach to scrutinize the microbiome in a commercial, organic, Pinot noir wine production system that utilizes autochthonous fermentation. We assessed microbial composition across two vintages (2018 and 2021) using biological replicates co-located at the same winery. Microbial dynamics were monitored over four important fermentation time points and correlated with contemporaneous climate data. Bacterial (RANOSIM = 0.4743, p = 0.0001) and fungal (RANOSIM = 0.4738, p = 0.0001) compositions were different in both vintages. For bacteria, Lactococcus dominated the diversity associated with the 2018 vintage, while Tatumella dominated the 2021 vintage. For fungal populations, while Saccharomyces were abundant in both vintages, key differences included Starmerella, copious in the 2018 vintage; and Metschnikowia, substantive in the 2021 vintage. Ordination plots correlated the climatic variables with microbial population differences, indicating temperature as a particularly important influence; humidity values also differed significantly between these vintages. Our data illustrates how climatic conditions may influence microbial diversity during winemaking, and further highlights the effect climate change could have on wine production. [ABSTRACT FROM AUTHOR]

Summary: Polymeric phenolic material (PPM) was separated from monomeric anthocyanins by removing the latter using isoamyl alcohol in 22 Pinot Noir wines of different vintages and grades. The colour and tannin concentrations of PPM were determined using a modified Somers assay and methylcellulose precipitation (MCP) tannin assay, respectively. With wine age increasing, the ratio of absorbance at 520 nm at pH 1.0 to that at 3.4 decreased from 2.6 to 1.1. This decreasing trend with wine age is reported for the first time in Pinot Noir wines. The presence of bleachable polymeric pigments was also observed in PPM, and the degree of ionisation of these bleachable pigments increased along with wine age. Statistical analysis demonstrated the dominant effect of age on colour properties of PPM, regardless of vintage and grade. In contrast, total phenolics and tannin concentration mainly related to vintage, rather than age. [ABSTRACT FROM AUTHOR]

Summary: Pinot noir wines were made with inclusion of different amount of whole bunches or grape stems: destemmed grapes only (DS), 30% whole bunch (WB30), 60% whole bunch (WB60), 100% whole bunch (WB100), and destemmed grapes with 100% stems added back (DS100). Wines were analysed using modified Somers assay and CIELab method at the end of fermentation and after a 2 years bottle ageing. CIELab analysis showed that DS100 was significantly different from all other treatments at both sampling points, and whole bunch addition treatments (except of WB30) only showed significant colour difference compared to DS treatment after bottle ageing. Total anthocyanins were significantly reduced in stem inclusion treatments at the end of alcoholic fermentation, but after the 2 years bottle ageing, only DS100 treatment showed significantly lower anthocyanins than DS treatment. Stem inclusion treatments significantly increased tannin concentration. Total anthocyanins and tannins in wines reduced by 69%–71% and 24%–31% respectively after bottle ageing. [ABSTRACT FROM AUTHOR]

This study examined the impact of leaf removal timing, rootstock, and clone selection on Pinot noir grape composition and subsequent impact on tannin extractability. Results showed that leaf removal increased anthocyanin levels in berries and tannins in stems and seeds, while also raising the mean degree of polymerisation (mDP) of skin tannins. Schwarzman rootstock had lower seed tannins but higher mDP in skin and seed tannins compared to own roots. UCD5 clone exhibited higher mDP in skin tannins than AM10/5 clones in acetone extraction. Tannin extractability was determined by the ratio of model wine-extracted tannins and acetone-extracted tannins. For the first time, this study reported that stems had the highest tannin extractability (64%-78%) compared to skins (37–52%) and seeds (26–34%). Compositional differences in grape tissues from different treatments had no impact on tannin extractability except for grape skins from two treatments. This suggests that tannin extractability is mainly influenced by grape ripeness which largely determines the composition of cell wall materials that can interact with tannins and thus influence tannin extractability. The differences in grape skin tannin extractability observed in this study between treatments were likely due to the significantly different galloylation (G%) levels in the extracted tannins. [Display omitted] • Leaf removal increased anthocyanin and tannin content, and mDP of skin tannin. • Schwarzman rootstock showed higher mDP in skin and seed tannins than own roots. • UCD5 clone showed higher mDP in skin tannins than AM10/5 clone. • Grape stems showed the highest tannin extractability than skins and seeds. • Grape skin tannin extractability seems correlating with the galloylation level. [ABSTRACT FROM AUTHOR]

[Display omitted] • Early and late leaf removal enhance berry anthocyanins and reduce stem methoxypyrazines. • Early leaf removal (7 or 30 days after flowering) was more effective in increasing wine colour, polymeric pigments, and tannins. • Leaf removal at 7 days after flowering enhances skin-derived tannin in wine. • Higher skin tannins and anthocyanins, along with lower seed tannins, result in increased wine tannins. • Leaf removal timing affects wine aroma composition without a significant impact on descriptive sensory evaluation. This study aimed to investigate the impact of leaf removal on concentrations of anthocyanin, tannin, and methoxypyrazines (MPs) in Pinot noir grapes and wines. Leaf removal after 7 days (LR7), 30 days (LR30), and 60 days (LR60) of flowering were compared with no leaf removal control (LRC). Grapes and resultant wines were analysed for tannin and aroma composition using liquid chromatography and two-dimensional gas chromatography–mass spectrometry. All leaf removal treatments increased anthocyanin concentration in grapes and reduced MP levels in grape stems compared to LRC, indicating the effectiveness of both early and late leaf removal. Leaf removal after 7 days and 30 days were more effective in enhancing colour density, polymeric pigments, and tannin concentration in wines. Higher grape skin tannin and anthocyanin concentrations, along with lower seed tannin concentration in berries, correlated with higher tannin concentrations in wines. LR7 showed significantly higher skin-originated tannin proportion than LRC, suggesting a useful tool to manage tannin extraction. Aroma composition of resultant wines was influenced by leaf removal, although these differences were not evident in the sensory evaluation. [ABSTRACT FROM AUTHOR]

Rapid yeast identification is of particular importance in monitoring wine fermentation and assessing strain application in winemaking. We used MALDI-TOF MS analysis supported by 26 S rRNA gene sequence analysis and Saccharomyces- specific PCR testing to differentiate reference and field strains recovered from organic wine production facilities in Waipara, New Zealand, in which Pinot Noir wine was produced by spontaneous fermentations in the vineyard and in the winery. Strains were isolated from each of four key stages of each ferment to evaluate changes in taxonomic diversity. MALDI-TOF MS analysis was confirmed as an excellent yeast identification method, with even closely related Saccharomyces species readily distinguished. A total of 13 indigenous species belonging to eight genera were identified from Pinot Noir ferments, with taxonomic diversity generally reducing as fermentation progressed. However, differences between the taxa recovered were observed between the vineyard and winery ferments, despite the grapes used being from the same batch. Furthermore, some consistent proteomic differences between strains of S. cerevisiae, Hanseniasporum uvarum , Candida californica , Pichia membranifaciens and Starmerella bacillaris correlated with the different fermentation systems used. The high speed, low cost, taxonomic resolution and ability to characterise subtle changes in phenotype that may result from variations in environmental conditions makes MALDI-TOF analysis an attractive tool for further and wider applications in the wine industry. Such applications may include monitoring wine fermentation to actively support the consistency of high-quality wine products, and potentially for the development of such products too. • First known examination of yeast diversity in wine produced in Waipara, New Zealand. • MALDI-TOF utility for identification of winemaking yeast confirmed. • Production systems influence yeast diversity of wild ferments. • Yeast MALDI-TOF profiles may reflect responses to different fermentation conditions. [ABSTRACT FROM AUTHOR]

Previous studies have shown MALDI-TOF MS to be a powerful tool in wine yeast identification and potential prediction of application. However, it is also established that substrate composition influences protein expression, but the degree to which this may affect MALDI-TOF spectra (and analytical results thereof) has not been fully explored. To further inform assay optimisation, the influence on MALDI-TOF spectra was determined using eight Saccharomyces strains of diverse origins cultivated on grape juices from Pinot Noir and Chardonnay varieties, synthetic grape juice, and laboratory-grade artificial culture media (YPD broth and agar). Our results demonstrated significant influences of culture media on strain MALDI-TOF spectra. Yeast culture on YPD agar is recommended for taxonomic studies, with YPD broth culture of S. cerevisiae offering improved intra-subspecific differentiation Furthermore, our data supported a correlation between MALDI spectra and the potential industrial application of individual yeast strains. • Effect of growth media on MALDI-TOF profiles of winemaking yeast examined for the first time. • Natural and synthetic juices generally unsuited for yielding good quality spectra for analysis. • Culture on YPD agar recommended for MALDI-TOF characterisation of strains to species level. • Culture in YPD broth may yield improved differentiation of S. cerevisiae at strain level. [ABSTRACT FROM AUTHOR]