Pinot Noir Grape Research Articles

Impact of climate change on grape cluster structure, grape constituents, and processability

Over the last 20 years in the Pfalz region of Germany, GDD were highest in the vintages 2018-2020. To visualize the effect of climate change for the Pfalz region of Germany, the development of TSS and TAwere documented during Pinot noir grape ripening for the vintages 1998-2021. It was observed that climate change causes sooner and accelerated ripening, however, sooner or accelerated ripening were not connected with each other. The presented study investigated the impact of vintages on berry physiology development, ripening heterogeneity in grape clusters, changes in grape constituent concentrations and their extractability with progressing grape maturity. Pinot noir and Cabernet Sauvignon, both cultivated in the Pfalz region, were compared during three consecutive vintages. Different maturities were considered in the range of 17-25 Brix and berry size distribution was documented. The changes in grape constituent concentrations and their extractability with progressing grape maturity were analyzed using HPLC-DAD/FD, LC-QToF-MS and protein precipitation assay. It was revealed that tannin extractability differs for grape varieties and vintages and progressing maturity seemed to have only a small influence on the extractability of anthocyanins.

Impact of functional spray coatings on smoke volatile phenol compounds and Pinot noir grape growth.

The frequency and intensity of wildfires have been increasing over the last 50 years and negatively impacted the wine industry. Previous methods of smoke mitigation during grape processing have shown little impact in reducing smoke taint in wines. Therefore, a novel method of using edible spray coatings for vineyard application was developed to help prevent volatile smoke phenol uptake in wine grapes. Four cellulose nanofiber-based coating suspensions incorporated with chitosan and/or β-cyclodextrin were evaluated. Films derived from the coating suspensions were exposed to volatile phenols found in wildfire smoke (guaiacol, 4-methyl guaiacol, m-cresol, o-cresol, p-cresol, syringol, and 4-methyl syringol) and evaluated with ultraviolet-visible spectroscopy where the results indicated that the coatings could uptake smoke phenols in varying degrees. The coatings were also applied in a vineyard at three different application times during grape growth: pea-sized, pre-bunch closure, and both at pea-sized and pre-bunch closure. The results showed that the application time did not have a significant (p < 0.05) effect on berry size, weight, °Brix, pH, or titratable acidity. The type of coating, time of application and washing were found to impact the number of volatile phenols in the grapes after a smoke event. Results from this study indicated that edible coatings could help mitigate smoke uptake in wine grapes without sacrificing the growth and key composition parameters of wine grapes. PRACTICAL APPLICATION: This research provides a novel spray coating that can be applied to wine grapes in the vineyard to potentially mitigate volatile smoke compounds in wine grapes without impacting fruit growth and key compositional parameters of wine grapes, thus maintaining high quality of wines for consumers. Results from this study can also be potentially applied to other agricultural commodities to solve the issues caused by the wildfire smoke.

Exploring the Potential of Grape Pomace Extract to Inhibit Thermo-Oxidative Degradation of Sunflower Oil: From Routine Tests to ATR-FTIR Spectroscopy.

Exploring new sources of natural antioxidants is of great interest to edible oil producers, in line with the toxicological problems generated by the use of synthetic antioxidants. This study assesses the potential of lyophilized Pinot Noir grape pomace extract (GPE) to enhance the sunflower oil stability against thermo-oxidative damage compared to BHT during a prolonged exposure to convective heat at 185 °C. Oil thermo-oxidation was monitored based on specific indices such as peroxide value (PV), para-anisidine value (p-AV), inhibition of oil oxidation (IO), total oxidation (TOTOX) value, conjugated dienes and trienes (CDs, CTs), but also by attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), where absorbance ratios A 3009 cm-1/A 2922 cm-1 (RI), A 3009 cm-1/A 2853 cm-1 (RII), A 3009 cm-1/A 1744 cm-1 (RIII) and RIV = A 1744 cm-1/A 2922 cm-1 (RIV) were investigated. GPE showed a significant inhibitory effect on oil thermo-oxidation and this response was concentration-dependent. Substantial decreases in the investigated indices, compared to the control without added antioxidants, were obtained after 4 h and 8 h of heat exposure of the 800 ppm GPE sample: PV (47%; 42%), p-AV (38%; 33%), IO (54%; 46%), TOTOX (41%; 37%), CDs (46%; 39%), CTs (44%; 29%). Oil exposure to heat resulted in changes in RI-RIV attributed to the reduction in the degree of unsaturation, in response to primary and secondary lipid oxidation. FTIR spectroscopy can be used to differentiate untreated and heat-treated oils based on the absorbance ratios. An inhibitory effect close to that of BHT was achieved by 500 ppm GPE, while a dose of 800 ppm provided greater protection against thermo-oxidation. Our results promote GPE as a natural additive to limit the thermo-oxidative damage of plant oils.

Terroir Influence on the Antioxidant Activity of Grape Wines

The article analyzes the global wines production and consumption in the period from 2000 to 2020. The authors studied the total antioxidant activity of 19 samples of red wine from the Old and New World. They found that in the studied red wine samples, the total antioxidant activity value was in the range from 8,408 to 19,249 mmol-eq/dm3 . In red Old-World wines samples, the total antioxidant activity values were in the range from 10.056 to 19.249 mmol-eq/dm3 , while the highest were in red wines produced in Italy from the grape varieties Nero di Troia, Corvina and Rondinella, as well as in French wines from the varieties Merlot and Cabernet Franc; the smallest antioxidant activity values were in Italian wines produced from varieties Cabernet Sauvignon and Spanish wines from the varieties Tinta Roriz, Turiga Nacional, Turiga Franca. In the studied samples of red New-World wines, the total antioxidant activity values accounted for the range from 8.408 to 16.456 mmol-eq/dm3 , while the highest values were for Australian wines produced from the Shiraz grape variety and American wines from the Merlot variety; the lowest indexes were for American wine produced from the grape variety Pinot Noir. In the red Russian wines samples, the total antioxidant activity values were in the range from 5.903 to 15.566 mmol-eq/dm3 , while the highest indicators were in the wine from the varieties Merlot and Cabernet Sauvignon produced by the manufacturer “Usadba Divnomorskoe”; the lowest figures were for the wine produced from the “Pinot Noir” variety of the same producer. The antioxidant activity of wines varied from 26.3 to 60.1 % of the recommended daily intake in terms of ascorbic acid (ascorbic acid AOA – (32.024 ± 0.350) mmol-eq/dm3 ). The researchers revealed that the antioxidant activity as an identification marker for French wines must be at least (15.0 ± 0.5) mg-eq/dm3 , for Italian wines – at least 16.5 mg-eq/dm3 , for wines from Cabernet Sauvignon grapes, possible deviation was 5 mg-eq/dm3 . For New-World wines and Russian wines, the antioxidant activity must be at least (10.0 ± 0.5) mg-eq/dm3 , for wines from Pinot Noir grapes, possible deviation was 2 mg-eq/dm3 .

Influence of Grape Cell Wall Polysaccharides on the Extraction of Polyphenols during Fermentation in Microvinifications.

Grape cell wall polysaccharides influence the extraction of phenolic compounds during winemaking and consequently polyphenol concentrations in the final wine. During ripening, both compound groups undergo pronounced structural and compositional changes, resulting in a dynamic change of extractability. Grape cell wall polysaccharides from different ripe grapes were added to fermentations of Cabernet Sauvignon and Pinot noir grapes. Polyphenol-polysaccharide interactions affected the concentrations of tannins and monomeric flavanols in the wines depending on the maturity of the added polysaccharides. With higher polysaccharide maturity, the effects became more pronounced. Polysaccharides protected monomeric flavanols and tannin in Pinot noir, thereby increasing the concentrations, but they precipitated or masked these compounds in Cabernet Sauvignon. The added polysaccharides affected the concentrations in anthocyanins and polymeric pigments much less compared to the ripening status of the grapes. It was concluded that structural changes of polysaccharides during ripening affect the extraction of tannins and monomeric flavanols the most.

Interactions of Vitis vinifera L. cv. Pinot Noir grape anthocyanins with seed proanthocyanidins and their effect on wine color and phenolic composition

The initial concentration of anthocyanin and proanthocyanidin in wine affects the development of SO2-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 SO2-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.

Effects of Yeast Product Addition and Fermentation Temperature on Lipid Composition, Taste and Mouthfeel Characteristics of Pinot Noir Wine

Lipids have important impacts on wine sensory. By targeting the lipid sources in wine, mainly from grape tissues and yeast cell walls, it was possible to alter the wine lipid profile thus potentially changing the final product quality. This research examined the changes of wine total lipids, lipid composition and sensory characteristics of Pinot noir wines in response to the winemaking factors, fermentation temperature and yeast product addition. Pinot noir grapes were fermented at 16 °C and 27 °C. After fermentation, Oenolees® yeast product was added to the wines at three levels (0 g/L, 0.5 g/L and 1.0 g/L). The six wine treatments were subjected to chemical analyses measuring total lipids and an untargeted lipidomic approach analyzing lipid composition. High temperature fermentation wines had significantly higher total lipid content. Random forest analysis distinguished the wine groups based on the 25 main lipids, including free fatty acids, acylcarnitines, diglycerides, triglycerides and phospholipids. Taste and mouthfeel characteristics of each treatment were assessed using descriptive analysis and check-all-that-apply (CATA) techniques. Multivariate analyses showed that changing fermentation temperature significantly impacted sweetness and drying perception in Pinot noir wines. Yeast product addition had nuanced effects on wine lipid profiles and sensory perception.

The effects of cell-cell contact between Pichia kluyveri and Saccharomyces cerevisiae on amino acids and volatiles in mixed culture alcoholic fermentations

This study used a double-compartment fermenter to assess yeast growth, fermentation activity, and aroma production in response to cell-cell contact during mixed culture fermentation of Pinot noir grape must with Pichia kluyveri and Saccharomyces cerevisiae. Furthermore, amino acids were analyzed in order to study yeast interactions and possible reasons for aroma modulation as a response to cell-cell contact. Our results show that cell-cell contact between the two yeasts decreased cell viability of each yeast during mixed culture fermentation, and that it increased acetate and ethyl ester production and decreased varietal volatile levels. Moreover, it increased the consumption of glutamic acid and the biosynthesis of some specific amino acids related to cell growth, mainly histidine, glycine and proline, while suppressing the production of higher alcohols through the Ehrlich pathway. These results may contribute to an improved understanding, and thus control, of aroma production in mixed culture wine fermentations.

Prevention of Campylobacter jejuni K49/4 adhesion to porcine small intestine cell line PSI cl1 using different plant extracts

Purpose: The aim of this study was to investigate the in vitro anti–adhesive properties of chemically characterized ethanolic extracts from waste Pinot noir grape (GSS) skins and seeds, olive tree leaves (OE), thyme (Thymus vulgaris) prior to (TE) and its residue after (TE–R) hydrodistillation of the essential oil, as well as Alpinia katsumadai ethanolic seed extracts (SEE) and its hydrodistillation residue (hd- SEE–R) against the pig small intestine epithelial cell line, PSI cl1.&#x0D; Methods: Using PSI cl1, the anti– adhesion activities of these extracts, which normally represent "waste material" and by–products from the agro– food industry, were determined. Initially, the anti–Campylobacter jejuni and cytotoxic activities of GSS, TE, TE–R, SEE and hdSEE–R were determined to avoid any interference in the anti– adhesion assay being used.&#x0D; Results: The A. katsumadai extracts showed the strongest anti–adhesive activities against C. jejuni K49/4. When using TE and TE–R, C. jejuni adhesion to PSI cl1 cells was inhibited by almost 30% over a large concentration range of extracts. GSS extracts had the lowest impact on the adhesion rate of C. jejuni to PSI cl1 cells.&#x0D; Conclusion: Our findings suggest that agro–food waste material and many by–products from the agro–food industry represent sources of bioactive phytochemicals that are effective at low concentrations and could be used as therapeutic agents to prevent bacterial adhesion. This represents a step towards the application of new innovative strategies to control Campylobacter contamination and infection in the food chain. We suggest that not only plant extracts, but also waste material and agro–food industry by–products can be used as promising novel therapeutic agents with possible medical and industrial applications.

Direct analysis of wines from the province of Lower Silesia (Poland) by microplasma source optical emission spectrometry

New microplasma source optical emission spectrometry (OES) for the determination of Na, K, Mg, Ca, and Zn in wine was developed. As the microplasma source, a solution anode glow discharge (SAGD) or a solution cathode glow discharge (SCGD) were employed. The diluted samples solutions (0.5–2%) were directly analyzed (no acid digestion required) and the detection limits of Na, K, Mg, Ca, and Zn were 0.015, 0.03, 3, 12, and 0.1 µg L−1, respectively. The developed method was used for the analysis of wine samples from the province of Lower Silesia (Poland). It was found that 1) red wines were characterized by a higher content of K and Mg, 2) it was possible to discriminate between Regent and Pinot Noir grape varieties (both red) by the concentrations of K and Ca, 3) the concentration of Na in the analyzed wines was lower than that found in wines from other European countries.

Chemical and chromatic effects of saignée combined with extended maceration and microwaved stem addition on three Pinot Noir clones from the Central Coast of California

Background and Aims Pinot Noir grapes show variations within clones, and winemaking techniques aimed at increasing phenolic substances and colour may or may not affect them similarly. Methods and Results Three Pinot Noir clones, 2A, 115 and 777, were vinified including a Control wine, a saignée treatment followed by extended maceration for 30 days (S + EM), and a stem addition treatment in which microwaved stems (52°C, 5 min) (MW stems) were added. Generally, wines of clones 777 and 2A were higher in phenolic substances than those of clone 115. Relative to Control wines, MW stems wines exhibited an eightfold, 19-fold and 13-fold increase in wine tannins for clones 2A, 115 and 777, respectively, which was attributed to the extraction of stem-derived tannins, whereas S + EM wines of clones 2A, 115 and 777 displayed a threefold, eightfold and sevenfold increase in the tannin concentration, respectively. Also relative to Control wines, the concentration of large polymeric pigments was more than doubled in MW stems and S + EM wines. Conclusions The only clear effects across the three clones this study observed were for tannins and large polymeric pigments in MW stems and S + EM wines, and for small polymeric pigments in Control wines. Significance of the Study Techniques such as saignée, extended maceration and addition of microwaved stems can be used to build chemical complexity by utilising the resulting wines as blending options, or to increase wine ageing potential and commercial lifespan by enhancing tannins and polymeric pigments.

Large-Scale Reassessment of In-Vineyard Smoke-Taint Grapevine Protection Strategies and the Development of Predictive Off-Vine Models.

Smoke taint in wine is thought to be caused by smoke-derived volatile phenols (VPs) that are absorbed into grape tissues, trapped as conjugates that are imperceptible by smell, and subsequently released into wines as their free odor-active forms via metabolism by yeasts during fermentation. Blocking VP uptake into grapes would, therefore, be an effective way for vineyards to protect ripening grape crops exposed to smoke. Here, we re-evaluated a biofilm that had previously shown promise in pilot studies in reducing levels of smoke-derived VPs. A suite of nine free and acid-labile VPs were quantitated in Pinot Noir grapes that had been exposed to smoke after being coated with the biofilm one, seven or 14 days earlier. In contrast with earlier studies, our results demonstrated that in all cases, the biofilm treatments led to increased concentrations of both free and total VPs in smoke-exposed grapes, with earlier applications elevating concentrations of some VPs more than the later time points. Tracking VP concentrations through the grape ripening process demonstrated that some (phenol, p/m-cresol, and guaiacol) were not entirely sequestered in grapes as acid-labile conjugates, suggesting the presence of VP storage forms beyond simple glycosides. Free VPs in grapes, though a minor portion of the total, most clearly correlated with concentrations present in the resulting wines. Finally, red table grapes, available year round, were observed to replicate the effects of the biofilm treatments and were capable of transforming most VPs into acid-labile conjugates in under 24 h, indicating that they might be an effective model for rapidly assessing smoke-taint prophylactic products in the laboratory.

Correlations between Total Antioxidant Capacity, Polyphenol and Fatty Acid Content of Native Grape Seed and Pomace of Four Different Grape Varieties in Hungary.

Grape pomace is a valuable source of various bioactive compounds such as plant-derived polyphenols and polyunsaturated fatty acids (PUFAs). The commercial demand of grape skin and seed powders as nutraceuticals is still growing. However, no distinction is currently made between unfermented native grape seed and grape seed pomace powders regarding their antioxidant activities. Our aim was to find the relationship between the polyphenol and fatty acid content as well as the antioxidant capacity of native and fermented grape seeds of four different grape varieties harvested in the Villány wine region. According to our results, none of the three investigated polyphenols (resveratrol, rutin, quercetin) could be detected in native grape seed samples in correlation with their significantly lower total antioxidant capacities compared to fermented seed samples. Pinot Noir (PN) grape seed pomace samples with the highest resveratrol and oil content showed significantly higher total antioxidant capacity than Cabernet Sauvignon (CS), Syrah (S) and Blue Portugal (BP) samples. Based on the statistical analysis, positive correlation was found between the fatty acid content and the resveratrol concentration in the pomace samples of different grape varieties. In contrast, rutin concentrations were negatively proportional to the fatty acid content of the fermented samples. No significant correlation was found considering the quercetin content of the samples. According to our findings, grape pomace seems a more promising source in the production of nutraceuticals, since it contains polyphenols in higher concentration and exerts significantly higher antioxidant activity than native grape seeds.

Saccharomyces cerevisiae Gene Expression during Fermentation of Pinot Noir Wines at an Industrially Relevant Scale.

Saccharomyces cerevisiae metabolism produces ethanol and other compounds during the fermentation of grape must into wine. Thousands of genes change expression over the course of a wine fermentation, allowing S. cerevisiae to adapt to and dominate the fermentation environment. Investigations into these gene expression patterns previously revealed genes that underlie cellular adaptation to the grape must and wine environments, involving metabolic specialization and ethanol tolerance. However, the majority of studies detailing gene expression patterns have occurred in controlled environments that may not recapitulate the biological and chemical complexity of fermentations performed at production scale. Here, an analysis of the S. cerevisiae RC212 gene expression program is presented, drawing from 40 pilot-scale fermentations (150 liters) using Pinot noir grapes from 10 California vineyards across two vintages. A core gene expression program was observed across all fermentations irrespective of vintage, similar to that of laboratory fermentations, in addition to novel gene expression patterns likely related to the presence of non-Saccharomyces microorganisms and oxygen availability during fermentation. These gene expression patterns, both common and diverse, provide insight into Saccharomyces cerevisiae biology critical to fermentation outcomes under industry-relevant conditions.IMPORTANCE This study characterized Saccharomyces cerevisiae RC212 gene expression during Pinot noir fermentation at pilot scale (150 liters) using industry-relevant conditions. The reported gene expression patterns of RC212 are generally similar to those observed under laboratory fermentation conditions but also contain gene expression signatures related to yeast-environment interactions found in a production setting (e.g., the presence of non-Saccharomyces microorganisms). Key genes and pathways highlighted by this work remain undercharacterized, indicating the need for further research to understand the roles of these genes and their impact on industrial wine fermentation outcomes.

Grape pomace as a promising source of biologically valuable components

Experimental data on the content of biologically valuable components in grape pomace are presented. The presence of organic acids was revealed in an amount from 33.35 g/kg (Saperavi) to 108.2 g/kg (Rebo). The main acid is tartaric. Phenolic compounds have been identified: anthocyanins, flavones, flavan-3-ols, oxycinnamic and hydroxybenzoic acids, procyanidins. The main anthocyanins found in grape pomace are the 3-O-glycosides of malvidin, petunidin, cyanidin, peonidin and delphinidin. The highest total content of hydroxybenzoic acids was in the pomace of Pinot Noir grapes – 720 mg/kg, further in descending order of concentration followed by pomace from Saperavi grapes (708 mg/kg), Cabernet Sauvignon (681 mg/kg), Merlot (575 mg/kg) and Rebo (545 mg/kg). The highest total content of vitamins was found in the pomace of Rebo grapes – 639 mg/kg, the lowest – Merlot (471 mg/kg). In all samples, vitamin B1 prevails, then in decreasing order – ascorbic acid, vitamins B2, B3, B5, B7. Moreover, their concentrations vary significantly depending on the grape variety from which the pomace is obtained. The influence of the grape variety on the content of these biologically valuable components in the pomace has been established, which must be taken into account in the production of biologically active substances that increase the nutritional status of a person.

Focus on the role of seed tannins and pectolytic enzymes in the color development of Pinot noir wine

Maceration techniques which promote the extraction of color pigments and tannin from grapes are often sought in Pinot noir winemaking to optimise color stability; alternatively, exogenous grape tannins may be included during fermentation. To examine the effect of seed-derived tannins and the use of pectolytic enzymes on color development in wines, conventional must preparations of Vitis vinifera L. cv Pinot noir grapes were compared with wines made using a supplementary addition of either a commercial seed tannin product or previously fermented seeds, while in a complementary experiment, seeds were sequentially removed during fermentation. After 6 months bottle aging, wines supplemented with either a commercial seed tannin solution (0.4 ​g/L), or fermented seeds (20% w/w seeds) had from 60% to 95% higher tannin concentration than the untreated wine, and up to 60% more monomeric anthocyanins. Conversely, when a third of the seeds were removed from the fermenting wine, the concentration of both tannin and non-bleachable pigments was 20–30% lower than in untreated wines and the wine hue had more red-purple tones. Exploration of the use of pectolytic enzymes in conjunction with seed removal was also found to have a significant impact on wine color parameters. Further insights on the timing of egress of tannin precursors from seeds was obtained from histochemical examination of the seeds that had been removed during alcoholic fermentation.

Vintage by vine interactions most strongly influence Pinot noir grape composition in New Zealand

Vine genetics, fruit maturity, region and vineyard are perceived as factors that strongly influence Pinot noir grape and wine composition. Our study aims to understand the relationship between grape (and ultimately wine) composition and the physical appearance and performance characteristics of a vine (i.e. vine ideotype). Our experimental approach controlled these variables by studying within-block differences in vine performance across multiple seasons and vineyards. Grapes were sourced at commercial harvest from 20 single vines from 12 vineyard sites in three Pinot noir growing regions (Central Otago, Martinborough and Marlborough) of New Zealand.Across three vintages yields ranged from 0.1 kg to 6.3 kg per metre, but there was no general relationship between yield and berry soluble solids. On a vine by vine basis normalised yields did not correlate among seasons. Berry extract colour measures were, on average, three-fold higher in 2019 than in 2018.Principal Component Analysis has indicated that vintage dominated berry composition effects that might otherwise be associated with yield per vine, region and vineyard. The extent of the variation in performance of the same vines between seasons largely excludes factors that are stable between seasons as primary causes. Changes in management of the same vine from year to year appeared the most likely contributors to variation. We have derived highly significant negative linear relationships between vine yield class and the frequency of vines that were within a benchmark specification established for icon vines, providing evidence of the quality risk associated with higher yield. The results also indicate that a proportion of vines meet the benchmark specification at higher yields. From results to date we can further our research confident in the knowledge that factors such as vine yield, region or vineyard are, in themselves, unlikely to be the principal drivers of major differences in Pinot noir grape and wine composition.

Anthocyanins concentration by adsorption onto chitosan and alginate beads: Isotherms, kinetics and thermodynamics parameters

The anthocyanins health benefits are diverse, but numerous factors affect the anthocyanins stability, thus, this work aimed to extract anthocyanins from Pinot Noir grape skins and, afterward, to concentrate them onto edible and safety adsorbents, chitosan and alginate beads, by adsorption operation. Chitosan was obtained from shrimp waste, and alginate was purchased. Batch adsorption experiments were carried out as pH function, and the highest adsorption capacities and removal percentages were, respectively, 216 mg g−1 and 65% for chitosan beads at pH 8, and 126.4 mg g−1 and 38% for alginate beads at pH 4. All equilibrium isotherms models were suitable for chitosan beads, while for alginate beads only Langmuir and Freundlich models showed fitting. The thermodynamic parameters demonstrated physical adsorption and endothermic behavior for the chitosan and alginate beads. The pseudo-first order model best described the kinetic behavior for both beads. It was demonstrated that is possible to concentrate the different molecular structures of anthocyanins onto chitosan and alginate beads with high yields.

The effects of leaf removal and artificial shading on the composition of Chardonnay and Pinot noir grapes

Aims: The aim of this study was to assess the effects of leaf removal and bunch shading on the analytical composition of Pinot noir and Chardonnay (Vitis vinifera L.) grapes suitable for making premium sparkling wine.Method and results: Total bunch defoliation (TD) and different treatments using shading nets (TD1L, TD2L and ND1L) were evaluated in comparison with a test with no defoliation and shading (ND) over three seasons in the southern part of Franciacorta, one of the most famous Italian sparkling wine regions. Micrometeorological variables, yield components, musts and grapes chemical composition were evaluated. Shading practices lead to a delay in ripening and they improve the acidic content of must, thus resulting in a potential improvement in the quality of juice suitable for producing sparkling wines. Furthermore, this particular type of vine canopy management leads to changes in the phenolic content of grapes.Conclusions: From the results obtained it was possible to underline the positive effect - delaying ripening, preserving acid concentration and reducing flavonol content - of shading on the composition of Pinot noir and Chardonnay grapes suitable for making premium sparkling wine.Significance of the study: This study shows the importance of shading, because it delays grape ripening and thereby preserves the acidic content of musts and, specifically, deals with the problem of early ripening related to the climate change now underway.

Characterization of Sub-Regional Variation in Saccharomyces Populations and Grape Phenolic Composition in Pinot Noir Vineyards of a Canadian Wine Region.

Wine is a product of grape juice fermentation by yeast. Terroir is a term that encompasses all environmental factors and interactions at a specific geographical site, resulting in the development of regional-specific microbial strains and grape metabolites. In this study we determine the distribution of vineyard-associated wine yeast strains and characterize the flavonoid profile of Pinot Noir grapes among 3 sub-regions in the Okanagan Valley (OV), a major wine region in British Columbia, Canada. Pinot Noir grape samples were collected from 13 vineyards among 3 sub-regions of the OV, namely Kelowna (KE), Naramata-Penticton (NP) and Oliver-Osoyoos (OO), within a week prior to the winery harvesting date in 2016 and 2017. A total of 156 spontaneous Pinot Noir fermentations were conducted and vineyard-associated Saccharomyces strains were isolated from fermentations that reached two-thirds sugar depletion. Using microsatellite genotyping, we identified 103 Saccharomyces cerevisiae strains and 9 Saccharomyces uvarum strains. We also identified Saccharomyces paradoxus in one vineyard using ITS sequencing. We developed a microsatellite database of 160 commercial S. cerevisiae strains to determine the identity of the isolated strains and we include the database herein. Commercial strains were widely distributed across the three sub-regions. Forty-two of our 103 S. cerevisiae strains were equivalent or highly similar to commercial strains whereas the remaining 61 were considered as ‘unknown’ strains. Two S. uvarum strains were previously isolated in other OV studies and none matched the S. uvarum commercial strain BMV58. S. cerevisiae population structure was driven by sub-region, although S. cerevisiae populations did not differ significantly across vintages. S. uvarum and S. paradoxus were only identified in the 2017 vintage, demonstrating dynamic wine yeast populations between vintages. We found that the flavonoid profile of Pinot Noir grapes from the same 13 vineyards was also affected by sub-regional terroir. The anthocyanin content was lower and the proportion of methoxylated anthocyanins and flavonols was higher in Pinot Noir grapes from OO, the warmer sub-region as compared to KE, the cooler sub-region. Our study demonstrates that both yeast populations and metabolites associated with the Pinot Noir variety have sub-regional variation within a viticultural area.