Volatile composition of Bobal red wines subjected to alcoholic/malolactic fermentation with oak chips

The effect of wood, in the form of oak chips, on the volatile composition of Bobal red wines caused by adding oak chips at different stages of the fermentation process has been studied. Aroma compounds were isolated by solid phase extraction (SPE) for subsequent analysis by gas chromatography–mass spectrometry (GC/MS). Bobal control wine was produced according to traditional winemaking processes, without oak chips. Oak chips were added to the rest of the wines at two dose levels (3 and 6 g/L) at different stages of the winemaking process: at one week during alcoholic fermentation (AF), during malolactic fermentation (MLF) and in young, red Bobal wine. Wines fermented with oak chips during AF showed higher concentrations of the ethyl esters of straight-chain fatty acids and ethyl, hexyl and isoamyl acetates than the control wine. A similar, trend was observed for higher alcohols. Higher concentrations of benzene compounds, oak lactones and furanic compounds were found in wines in contact with oak chips during MLF followed by young Bobal oak wines. These results reveal that the point of addition during the winemaking process and the dose level of oak chips used have a significant effect on the volatile composition of Bobal red wines.     

Effect of micro-oxygenation on the evolution of aromatic compounds in wines: Malolactic fermentation and ageing in wood

The effect of micro-oxygenation on the aromas of two varietal wines (Tempranillo and Cabernet Sauvignon) when alcoholic fermentation is complete was examined. Several factors, such as whether malolactic fermentation (MLF) took place in barrels or stainless steel vats and ageing time in oak barrels, were taken into account. Major aroma components were studied using GC-FID and minor compounds were studied by GC-MS analysis before and after MLF and after 4 and 8 months of maturation in oak barrels. Sensorial analysis was performed to describe and quantify the different wine notes. Micro-oxygenation affects different compounds but the effect depends to a great extent on the grape varietal used; the effect of micro-oxygenation was more marked on the aroma of Cabernet Sauvignon wine than Tempranillo wines. The concentration of extractable compounds of wood was higher in wines after MLF in barrels than in wines after MLF in steel vats; wines with steel vat MLF had fewer toast and wood notes. The compounds that showed significant differences in concentration after 8 months of maturation were present in higher concentrations in wines fermented in barrels than in stainless steel vats. Barrel-fermented wines were sweeter, with wood and toast notes, fewer alcohol notes and fewer reductive notes.     

Influence of pH and ethanol on malolactic fermentation and volatile aroma compound composition in white wines

The present study investigated the influences of pH and ethanol on malolactic fermentation (MLF) and the volatile aroma profile of the subsequent white wines from Riesling and Chardonnay inoculated with two different Oenococcus oeni strains. In all cases MLF was induced after completion of alcoholic fermentation (AF). Partial MLF occurred under low pH 3.2 and high alcohol (118.3 g/L) conditions. In the cases with complete MLF, the time required for each strain varied from 13 to 61 days and was dependent on bacterial culture, cultivar and wine parameter. Chemical properties of each wine were determined after AF, complete and partial MLF. The wines showed significant differences in total higher alcohols, esters and acids that are important for the sensory profile and quality of wine. This work demonstrated that the wine matrix as well as the pH and alcohol concentration affects MLF and the final volatile aroma profile. Results indicate that changes in volatile aroma composition are not necessarily related to complete MLF and that partial MLF already has distinct influences on the wine aroma profile of white wines.     

Effect of cofermentation of grape varieties on aroma profiles of la mancha red wines

The effect of winemaking using blends of red grape varieties cultivated in La Mancha region (Spain) on the aroma profile of wines was researched by chemical characterization. Free and glycosidically bound aroma compounds were isolated by solid phase extraction using dichloromethane and ethyl acetate, respectively, as solvents in elution and then analyzed by gas chromatography-mass spectrometry. Free and bound volatile compounds were analyzed in Cencibel, Bobal, and Moravia Agria monovarietal wines, and in 3 wines obtained with the blending of grapes: Cencibel (50%) + Bobal (50%); Cencibel (50%) + Moravía Agria (50%); Cencibel (33%) + Bobal (33%) + Moravía Agria (33%). Aroma compounds were studied in terms of odor activity values (OAVs). Ninety free aroma compounds and sixty-five bound aroma compounds were identified and quantified. The odor activity values for the different compounds were classified into 7 odorant series. The fruity and sweet series contributed most strongly to the aroma profile of all wines, independently of the winemaking technique used. In general, co-winemaking wines present a more complex chemical profile than monovarietal wines. Practical Application: Some grape varieties could benefit from this process with the presence of other varieties that might have an excess of aroma compounds. In this study, the wines were elaborated by blending different grape varieties together; this process implies co-maceration and co-fermentation steps. The co-winemaking technique could benefit from additional molecules provided by the other varieties, which results in a more complex formation than in the case of monovarietal wines. This technique provides a viable alternative to traditional winemaking methods for improving and enhancing the sensory profile of elaborated wines.     

Effect of co-winemaking in phenolic composition, color and antioxidant capacity of young red wines from La Mancha region

The influence of co-winemaking technique on the phenolic profiles, color and antioxidant capacity of wines made from red grape varieties cultivated in La Mancha region (Spain) was investigated. Co-winemaking red wines were obtained by pre-fermentative blend of grapes (1:1, w/w) from the predominant Cencibel (Tempranillo) variety in this region and the minor varieties Bobal, Moravia Agria, Moravia Dulce, Tortosí and Rojal, together with a three varieties blend (1:1:1, w/w/w) of Cencibel, Bobal and Moravia Agria grapes. The phenolic profiles obtained in co-winemaking wines showed more quantity of different compounds than single-variety wine of Cencibel used as reference. The best results were obtained using Bobal, Moravia Agria and Moravia Dulce varieties for co-winemaking, especially an improvement of color characteristics. All co-winemaking wines significantly increased the total resveratrol content as compared to the Cencibel reference wine, although cis-isomers largely predominated in all wines. Moravia Agria and Rojal varieties produced co-winemaking wines with decreased antioxidant capacity, whereas Bobal and Moravia Dulce varieties increased it, even when the co-winemaking wine from Moravia Dulce contained less total polyphenols than Cencibel reference wine. Co-winemaking technique can be suggested as a way to widen the offer of wines to consumers, incorporating characteristic properties of minor grape varieties. In addition, this enological technique has the benefit of avoiding the disappearance of native species, thus improving the biodiversity of La Mancha region.     

The use of oak chips during the ageing of a red wine in stainless steel tanks or used barrels: effect of the contact time and size of the oak chips on aroma compounds

Background and Aims:  This paper reports the influence of adding oak chips to a wine being aged either in stainless steel tanks or in used barrels on aroma compounds, comparing these wines with those aged in new barrels. Both the size of the oak chips and the length of contact time were considered.
Methods and Results:  Aroma compounds were analysed by gas chromatography–mass spectrometry to determine the differences in these compounds between the samples. The results showed that chips release aroma compounds into wine very rapidly, an effect that was clearly seen when they were added to the wines stored in tanks. The wines aged in new barrels continued to extract aroma compounds for a longer time, and higher concentrations were reached in these wines for most aroma compounds. Wines in used barrels with added oak chips behaved in an intermediate manner.
Conclusions:  Although overall quality is better in wines matured in new barrels, the use of oak chips could be considered a good choice for producing short-aged wines and for reusing used barrels under good sanitary conditions.
Significance of the Study:  The rapid spread of technique alternatives to oak ageing justifies studies to assess the influence of oak chips on the chemical characteristics of wines and to evaluate any differences from traditional oak ageing systems.     

Chemometric Analysis for the Detection of Biogenic Amines in Chilean Cabernet Sauvignon Wines: A Comparative Study between Organic and Nonorganic Production

In this work, the presence of biogenic amines (BAs) was correlated with the type of wine grape culture (traditional or organic) and their concentration in the different stages of winemaking (must, alcoholic fermentation [AF] and malolactic fermentation [MLF]). The formation of BA occurred mainly during MLF in which the percentages for putrescine, cadaverine, phenylethylamine, histamine, and tyramine were 100%, 70%, 13%, 61%, and 44% for the wines produced with traditional grapes and 100%, 94%, 25%, 88%, and 13% for the wines produced with organic grapes, respectively. In general, these latter wines exhibited a lower concentration of total amines. The principal component analysis and partial least-square discriminate analysis indicated that the generation of BA has a certain behavioral pattern in the wines analyzed, which is associated with the different stages of wine production and with the type of culture (traditional or organic) used in the wine grapes. Practical Application: Chemometrics tools can be useful as a method of characterization and classification in a global overview of the process variables involved in the development of toxic chemicals in foods, such as the production of BA in wine.     

Kinetics of sugars, organic acids and acetaldehyde during simultaneous yeast-bacterial fermentations of white wine at different pH values

Successfully inducing malolactic fermentation in the production of grape wines can be challenging, especially in wines with multiple inhibitors such as low pH values and high ethanol concentrations. In the present study, the kinetics of several chemicals of enological relevance was studied in Chardonnay vinified by traditional, consecutive alcoholic (AF) and malolactic fermentations (MLF), and simultaneous AF/MLF, where bacteria were co-inoculated with yeast. The Chardonnay must was adjusted to four pH values (3.2, 3.35, 3.5 or 3.65), and the concentrations of sugars, organic acids as well as acetaldehyde were followed throughout the fermentations. The degradation of glucose and fructose was slower at the lowest must pH value (3.2) but independent from the time point of bacterial inoculation. In all cases, malolactic conversion was faster after yeast-bacterial co-inoculation and was completed in simultaneous treatments at pH values of 3.35-3.65, and consecutive treatments at pH 3.5 and 3.65. No statistically significant difference was observed among the final acetic acid concentrations among all inoculation and pH treatments, but there was a trend towards higher acetic acid residues in wines produced by co-inoculation, especially at high pH values. Overall, simultaneous AF/MLF allowed for greatly reduced fermentation times, but the must pH remained a strong factor for fermentation success and determined the final concentration of various wine components. The time point of inoculation influenced formation and degradation kinetics of organic acids and acetaldehyde considerably, and these are of relevance for vinification decisions.     

浸渍酶对蛇龙珠葡萄酒酿造过程中类黄酮化合物变化的影响

研究了浸渍酶Lallzyme Ex-V对蛇龙珠葡萄酒酿造过程中(从酒精发酵到橡木桶贮藏12个月)类黄酮动态变化的影响。结果显示,经浸渍酶处理加快了儿茶素、表儿茶素、杨梅素、山奈酚和槲皮素等5种类黄酮化合物在葡萄酒酒精发酵期间的浸提速度,但不影响杨梅素和槲皮素在后续酿造过程中的含量,杨梅素在葡萄酒酒精发酵结束后含量逐步下降,槲皮素在橡木桶陈酿期间含量逐渐增加;酶处理对儿茶素和表儿茶素的影响一直持续到苹-乳发酵的第2周,酶处理酒中儿茶素和表儿茶素的含量高于对照;浸渍酶对山奈酚含量的影响一直持续到橡木桶陈酿3个月,处理酒中的含量高于对照。     

Evaluating the Influence of Malolactic Fermentation Inoculation Practices and Ageing on Lees on Biogenic Amine Production in Wine

Biogenic amines are compounds, produced primarily by lactic acid bacteria (LAB) that negatively affect the wholesomeness of wine. Standard winemaking practices can greatly influence the levels of biogenic amines in wine. The aim of this study was to determine the relative contribution of different malolactic fermentation (MLF) practices and ageing of wines on fermentation lees to the final levels of biogenic amines. Wines were made on small scale over two harvest seasons with two red grape cultivars. Treatments included spontaneous MLF, co-inoculated MLF, MLF inoculated after alcoholic fermentation (conventional inoculation) and 4 months of ageing in the presence and absence of fermentation lees of all MLF treatments. Biogenic amine concentrations were measured by high-performance liquid chromatography at key winemaking stages and statistically analysed for the effects of MLF treatment and winemaking stage. Results indicate that the presence of indigenous LAB increased the risk of biogenic amine formation. Inoculation proved to reduce biogenic amine production over time compared to spontaneous MLF and co-inoculation even more than conventional inoculation. The presence of yeast lees during ageing generally led to higher final concentrations of biogenic amines in wines than the absence of lees. This study confirms other works that conclude that spontaneous MLF and uncontrolled ageing on yeast lees are generally unpredictable and pose a risk of biogenic amine contamination in finished wines.     

Indigenous lactic acid bacteria communities in alcoholic and malolactic fermentations of Tempranillo wines elaborated in ten wineries of La Rioja (Spain)

Indigenous lactic acid bacteria (LAB) communities have been analyzed for three years (2006, 2007 and 2008) during alcoholic (AF) and malolactic (MLF) fermentations of Tempranillo wines in ten wineries of La Rioja. The results showed that analytical composition of wines and physical–chemical conditions of elaboration influenced the LAB populations, the MLF duration and the percentage of each isolated species and strains. The highest diversity of LAB species was observed during AF in all the wineries. Oenococcus oeni was present in all studied stages of the fermentation process, being the predominant species at final AF stage. The study of 925 isolates of O. oeni by Pulsed Field Gel Electrophoresis (PFGE) allowed the detection of a total of 112 distinct genotypes. Most fermentation stages of both AF and MLF showed mixed O. oeni strain populations, so that there were different genotypes able to share their ecological niche or tank in spontaneous MLF. The frequency of participation of each genotype varied either from year to year or from winery to winery. Otherwise, seven genotypes were detected in the three studied years and in at least three out of the ten studied wineries, being four of them also present in the three studied subzones of this region. These results suggest the existence of an endemic microbiota in this region, the adaptation of indigenous O. oeni strains to the winery conditions every year and the interest of selecting predominant genotypes in order to preserve the biodiversity and peculiarity of these wines.     

Biogenic amines and ethyl carbamate in primitivo wine: survey of their concentrations in commercial products and relationship with the use of malolactic starter

This research was conducted to determine the biogenic amine (BA) and ethyl carbamate (EC) concentrations in commercial Primitivo wine samples and the influence of the use of malolactic starter culture on concentrations of these potentially hazardous compounds in this wine. One hundred sixty bottles of wine from eight producers in the Apulia region of southern Italy were purchased at retail and analyzed. The most common BAs were histamine, 2-phenylethylamine, tyramine, cadaverine, putrescine, spermine, and spermidine. Putrescine (derived from ornithine) was the most abundant BA in all commercial Primitivo wines (5.41 to 9.51 mg/liter), 2-phenylethylamine was detected in only two commercial wines (at less than 2.12 mg/liter), and histamine was found at concentrations of 1.49 to 16.34 mg/liter. The concentration of EC in commercial Primitivo wine was 6.81 to 15.62 ppb, which is not considered dangerous for human health. Malolactic fermentation (MLF) affected the concentrations of BAs and EC differently. For EC, no significant differences were detected between samples of wine produced by spontaneous fermentation and wine that was inoculated malolactic starter. Mean EC concentrations were 12 and 14 ppb in two batches tested (always 18 ppb or less), regardless of whether the malolactic starter was added. Although present at trace levels in wine before the MLF, histamine accumulated during the MLF process, regardless of whether the malolactic starter was added. However, the increase in histamine was higher in wines without the malolactic starter. The concentrations of putrescine and cadaverine increased after MLF, especially in the wine that spontaneously fermented. The use of a selected malolactic starter resulted in reductions in BA concentrations in wine produced by this guided MLF compared with wine produced by spontaneous MLF.     

Malolactic Fermentation and Secondary Metabolite Production by Oenoccocus oeni Strains in Low pH Wines

Abstract: Different wine varieties, including some with low pH, were studied to determine the ability to grow and produce secondary metabolites of a previously selected autochthonous Oenococcus oeni strain (C22L9), compared with a commercial strain. Monitoring of malolactic fermentation (MLF) was carried out by microbiological and chemical analysis of wines. The concentration of some major volatile compounds and biogenic amines in wines before and after malolactic fermentation was also determined. The results showed major differences in MLF duration both between wines and strains, although the differences between strains were slight for most of the analyzed compounds. Statistically significant differences in citric acid degradation were found in all wine varieties and it was confirmed that O. oeni C22L9 is a poor degrader of citric acid; this means that MLF can be prolonged without the risk of producing high concentrations of diacetyl and acetoin. Sensory analysis of wines after MLF showed similar characteristics in wines from both strains. This study thus shows that O. oeni C22L9 possesses even better sensory and fermentation properties than the commercial strain and can be used in wines with different characteristics, which makes it highly valuable for industrial use. Practical Application: The increasingly use of grape varieties of low pH in winemaking and the higher alcohol content of wines, as a consequence of the climatic change, make interesting the study of the behavior during MLF of O. oeni strains in order to determine their ability to grow, when growth conditions are not optimal, and to produce secondary metabolites. A comparative study was conducted using an autochthonous O. oeni strain (C22L9) and a commercial O. oeni strain and 4 wine varieties.     

Volatile composition and sensory characteristics of Chardonnay wines treated with American and Hungarian oak chips

Toasted or non-toasted chips of oak woods of different geographical provenances were macerated in Chardonnay wines (4 g/l) during a period of 25 days. Oak lactones were detected in significant quantities in wines treated with American oak. Only trace amounts of oak lactones were detected in the wines treated with Hungarian oak. Toasting of the oaks increased the quantities of the compounds derived from the thermal degradation of lignin: vanillin, eugenol, guaiacol and its derivatives and the pyrolysis of cellulose and hemicellulose: furfural and 5-methyl furfural, and decreased the concentrations of the two isomers of oak lactones. The concentrations of the majority of the volatile compounds did not present statistically significant differences between 15 and 25 days. However, the wines preferred by the tasters and with maximum intensity of the sensory attributes acquired were those treated with oak chips for 25 days. Chemical and sensorial analyses of wines revealed that the effect of the toasting of oak chips on wine characteristics was greater than the type of oak used. All wines studied were positively evaluated by the panellists.     

橡木片对霞多丽葡萄酒发酵的影响

该文研究在发酵过程中添加法国中度烘烤橡木制品对霞多丽干白葡萄酒的影响,增加霞多丽干白葡萄酒酿造工艺的选择性.接种酵母菌进行酒精发酵的同时在葡萄汁中添加法国中度烘烤橡木制品,未添加橡木制品发酵的样品为对照样,分别在发酵降糖50％和酒精发酵结束时测定理化指标、有机酸与挥发性化合物的含量.结果表明:添加橡木制品发酵对霞多丽葡萄酒化学物质有一定影响,其总高级醇、总橡木挥发性化合物含量较高.而对照样的葡萄酒中总酸和总酯含量较高,总高级醇含量是添加橡木制品发酵的葡萄酒中总高级醇含量的70％～85％,而酸类物质含量是添加橡木制品发酵葡萄酒的2倍.     

Malolactic fermentation of Tempranillo wine: contribution of the lactic acid bacteria inoculation to sensory quality and chemical composition

Malolactic fermentation (MLF) of Tempranillo Rioja wines (Spain) inoculated with two lactic acid bacteria (LAB) strains were studied and compared with spontaneous MLF. Inoculation with selected Oenococcus oeni lyophila shortened MLF duration up to 19 days and lead to wines with more fresh and fruity characters, especially when implantation was 100%. We demonstrated modifications in the concentration of volatile and nitrogenous compounds and a good correlation between analytical and sensory attributes was also noted. In addition, the low initial amino acid concentration and the consumption of these compounds by the inoculated yeast strain during alcoholic fermentation resulted in wines with very low biogenic amines levels (under 3.75 mg L^?1) after MLF and 3 month storage period in all cases. The results showed the significance of choose the most suitable starter to elaborate quality wines and suggest the control of amino acid content in must and wine to prevent the formation of biogenic amines.     

Impact of malolactic fermentation on the volatile composition of Turkish Kalecik karası red wines

The effects of spontaneous malolactic fermentation (MLF) and a malolactic starter culture (Oenococcus oeni) on the volatile compounds of Kalecik karas? red wines were investigated. The volatile compounds were extracted using liquid–liquid extraction and quantified by GC–MS–flame ionisation detection. Starter cultures of O. oeni had a positive effect in shortening MLF and producing lower volatile acidity. After MLF, the total volatile compounds increased in both the inoculated wines and the spontaneously fermented wine. Ethyl lactate, diethyl succinate and γ‐butyrolactone increased upon inoculation with cultures of O. oeni strains PN4 and VP41. MLF increased the diacetyl concentration in all Kalecik karas? wines. Strain dependent differences were found in the level of diacetyl, with O. oeni PN4 producing more diacetyl than O. oeni VP41. After MLF, the concentrations of acetoin, 4‐ethylguaicol and 4‐ethylphenol increased in spontaneously fermented wine compared with wines inoculated with O. oeni. Accordingly, the use O. oeni PN4 is recommended for a controlled MLF to produce better quality Kalecik karas? wines. © 2018 The Institute of Brewing & Distilling