Phenolics are an important group of wine compounds which have been linked with key sensory attributes, including the color and astringency of wines. For winemakers, accurate determination of ...phenolics is an increasingly important component of the quality monitoring process. One promising approach for the quantification of phenolics is through the use of ultraviolet-visible (UV-Vis) spectroscopy, which is inexpensive and requires minimal sample preparation. Previous research has explored some parts of the UV–vis spectrum for various types of red wines, though none have extensively explored Pinot noir wines, which have a lower average phenolic content than other common varieties such as Cabernet Sauvignon and Merlot. UV-Vis spectra were obtained alongside reference determinations of phenolic compounds using high-performance liquid chromatography, for a set of 155 Pinot noir wines from New Zealand. Partial least squares (PLS) regression models, using the UV-Vis spectra and the reference HPLC measurements, were constructed. Overall, the PLS regression models indicated that phenolic compounds with high concentrations and groups of compounds could be determined with a high degree of accuracy, while for phenolic compounds with lower concentrations the prediction performance was generally less accurate.
•UV-Vis combined with chemometric tools to predict phenolic content of Pinot noir wines.•HPLC reference method for determination of 18 phenolic compounds.•PLS regression models showed robust performance for major phenolic compounds.
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.
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•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.
•Elemental composition characterized in 14 wines made from an identical clone of Pinot noir.•Concentrations of 47 elements were determined in the wines by ICP–MS.•Several elements, including Mo, Er, ...Na, Li, Cs and Pb, varied by 10-fold the 14 wines.•Wine composition differences are mediated by the soil and microclimate conditions.
Elemental composition was used to characterize and differentiate 14 wines made from the identical clone of Vitis vinifera cv. Pinot noir (clone 667). The vineyards span distances which range from several hundred meters to 1540 km and their elevations vary from near sea level to nearly 500 m. Twenty-seven elements were observed above the limit of quantitation by using inductively coupled plasma mass spectrometry (ICP–MS) in the wines from at least half of the 14 sites. Concentrations of several elements, including Mo, Er, Na, Li, Cs and Pb, varied by 10-fold across the 14 wines. Multiple factor analysis (MFA) of elemental composition with juice chemistry and site characterization show associations consistent with expectations, such as high Ca with high clay content. These results demonstrate that even when grapevine clone and winemaking protocol are controlled, composition differences in wines produced from sites are mediated by diverse soil and microclimate conditions.
The increase of temperature due to climate change at different phenological stages of grapevine has already been demonstrated to affect accumulation of primary and secondary metabolites in grape ...berries. This has a significant implication for Pinot noir especially in New Zealand context as these compounds can have direct and indirect effects on wine quality.
This study investigates how varying bunch microclimate through changes in temperature applied at veraison stage can affect: fresh weight, total soluble solids, the accumulation of anthocyanins, total phenolics and amino acids of the grape berries. This was studied over two growing seasons (2018/19 and 2019/20) with Pinot noir vines being grown at two different temperatures in controlled environment (CE) chambers. The vines were exposed to 800 µmol/m2/s irradiance with diurnal changes in day (22°C or 30°C) and night (15°C) temperatures. This experimental set up enabled us to determine the accumulation of these metabolite at harvest (both seasons) and throughout berry development (second season).
The results showed that berry weight was not influenced by temperature increase. The total soluble solids (TSS) were significantly increased at 30°C, however, this was not at the expense of berry weight (i.e., water loss). Anthocyanin content was reduced at higher temperature in the first season but there was no change in phenolic content in response to temperature treatments in either season. The concentrations of total amino acids at harvest increased in response to the higher temperature in the second season only. In addition, in the time course analysis of the second season, the accumulation of amino acids was increased at mid-ripening and ripening stage with the increased temperature. Significant qualitative changes in amino acid composition specifically the α-ketoglutarate family (i.e., glutamine, arginine, and proline) were found between the two temperatures.
This study is the first to provide detailed analysis and quantification of individual amino acids and phenolics in Pinot noir in response to changes in temperature applied at veraison which could aid to develop adaptation strategies for viticulture in the future.
Wine flavor and quality are determined by the assessment of multiple sensory stimuli, including aroma, taste, and mouthfeel. It is therefore important to consider the contribution of as many ...metabolites as possible when attempting to relate wine composition to quality. In this study, partial least squares regression of the volatile (untargeted headspace solid-phase microextraction coupled with gas chromatography time-of-flight mass spectrometry), non-volatile (untargeted reverse-phase ultra-high-performance liquid chromatography mass spectrometry), and combined metabolite profiles were used to predict Pinot Noir wine quality ratings as assessed by experts. Non-volatile metabolite profiles predicted wine quality ratings better than volatile metabolite profiles, suggesting that the non-volatile composition of Pinot Noir wines contributes to quality perception to a greater extent than the volatile composition. This was underscored by descriptive sensory analysis, which found that taste and mouthfeel attributes were better correlated with wine quality ratings than aroma attributes. Important predictors of Pinot Noir wine quality were also characterized. Some new relationships between wine metabolites and quality ratings were found: dipeptides and unsaturated fatty acids were positively related to Pinot Noir wine quality, while N-(3-methylbutyl)acetamide and xanthine were negatively associated.
In South Brazil, grapevines (Vitis vinifera L.) have been grown in acid sandy soils, increasing phosphorus (P) need for fertilization. However, current fertilizer guidelines for growers are based on ...Vitis labrusca grown in clay soils. Therefore, there is a clear need to provide new recommendations on fertilization in vineyards. This study aimed to: (i) establish critical levels (CL) for P in the soil and grape leaves at flowering and veraison growth stages; and (ii) propose P maximum technical efficiency (MTE) rates for white and red grapevines grown in sandy soils based on a Bayesian approach. The study was carried out in sandy soil in South Brazil, with six P fertilization rates (0, 10, 20, 40, 60, and 100 kg P2O5 ha−1) applied annually from 2011 to 2015. Grape yield, P concentration in both soil and leaves (at flowering and veraison), and grape composition were measured during three growing seasons (2016, 2017, and 2018). The CL of P in the soil was 37 mg dm−3. This study is the first to propose CL for grapevine leaves at flowering (1.63 g kg−1) and at veraison for white (1.12 g kg−1) and red (1.38 g kg−1) grapevine cultivars in Brazil. Lastly, we proposed MTE rates for ‘Chardonnay’ (42 kg P2O5 ha−1) and ‘Pinot Noir’ (66 kg P2O5 ha−1). This new information provides foundational knowledge to reduce the rate of P fertilization up to 60 % for ‘Chardonnay’ vineyards. The utilization of this Bayesian approach has relevant implications for defining the optimal P management to be applied to vineyards around the globe.
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•The critical level of P in vineyard soils is 37 mg dm−3.•The critical level of P in grapevine leaves is 1.63 g Kg−1 at flowering.•At veraison, the critical level of P in ‘Pinot Noir’ leaves is 25 % higher than ‘Chardonnay’.•The P maximum technical efficiency rate is up to 60 % lower than the current guideline.
Two contrasting cap management regimes were applied during the winemaking of two clones of Pinot noir (UCD 23 and 828). Control wines received regular punch-downs throughout alcoholic fermentation ...(AF), whereas minimal intervention (MI) wines did not receive punch-downs during active AF but only after completion of AF. The basic chemical composition of the wines, including alcohol and acetic acid, flavonol and polymeric pigment formation and chromatic characteristics were not affected by the cap management protocol. Differences that were small in magnitude were observed only for anthocyanins (favoring Control wines) and tannins (favoring MI wines) throughout winemaking but not after bottle aging. Although current results may be confined to fermentors of moderate size (1.5 tons) and appropriate geometry, MI protocols seem to result in comparable phenolic and chromatic composition than wines produced with traditional cap management protocols.
•Two cap management regimes applied to two clones of Pinot noir (UCD 23 and 828).•Control and Minimal Intervention (MI) wines received 23 and 13 punch-downs, respectively.•Anthocyanins slightly higher in Control wines and tannins higher in MI wines.•MI wines had comparable polymeric pigment and color to control wines.•Gentle cap management may benefit Pinot noir wines.
Anthocyanins are flavonoid compounds responsible for red/purple colors in the leaves, fruit, and flowers of many plant species. They are produced through a multistep pathway that is controlled by MYB ...transcription factors. VvMYBA1 and VvMYBA2 activate anthocyanin biosynthesis in grapevine (Vitis vinifera) and are nonfunctional in white grapevine cultivars. In this study, transgenic grapevines with alteredVvMYBAgene expression were developed, and transcript analysis was carried out on berries using a microarray technique. The results showed that VvMYBA is a positive regulator of the later stages of anthocyanin synthesis, modification, and transport in cv Shiraz. One up-regulated gene,ANTHOCYANIN 3-O-GLUCOSIDE-6ʹʹ-O-ACYLTRANSFERASE(Vv3AT), encodes a BAHD acyltransferase protein (named after the first letter of the first four characterized proteins: BEAT for acetyl CoA:benzylalcohol acetyltransferase, AHCT for anthocyaninO-hydroxycinnamoyltransferase, HCBT for anthranilateN-hydroxycinnamoyl/benzoyltransferase, and DAT for deacetylvindoline 4-O-acetyltransferase), belonging to a clade separate from most anthocyanin acyltransferases. Functional studies (in planta and in vitro) show that Vv3AT has a broad anthocyanin substrate specificity and can also utilize both aliphatic and aromatic acyl donors, a novel activity for this enzyme family found in nature. In cv Pinot Noir, a red-berried grapevine mutant lacking acylated anthocyanins,Vv3ATcontains a nonsense mutation encoding a truncated protein that lacks two motifs required for BAHD protein activity. Promoter activation assays confirm thatVv3ATtranscription is activated by VvMYBA1, which adds to the current understanding of the regulation of the BAHD gene family. The flexibility of Vv3AT to use both classes of acyl donors will be useful in the engineering of anthocyanins in planta or in vitro.
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