Chemical and sensory changes in white wines fermented in the presence of oak chips

Summary Three samples of French oak and one sample of American oak were analyzed by different gas chromatographic-mass spectrometric (GC/MS) methods. Two methods of quantifying the main volatile compounds in oak wood were compared, namely, Direct Thermal Desorption coupled with GC/MS and analysis of mixtures of water-ethanol and wines that had been in contact with oak chips by extraction using an organic solvent followed by GC/MS analysis of the extract. The ratio of the two oak lactones released into the wine by the oak chips was the same as the ratio observed in original, untreated wood. These substances are of particular sensory importance in wines aged in oak wood barrels. Thus, the use of oak chips in white wines may be advantageous. The wines steeped with the oak chips improved their acceptability rating 2 points on a scale of 9.     

Volatile aroma and sensory analysis of black raspberry wines fermented by different yeast strains

Robus coreanus Miquel is a small berry fruit used for Korean black raspberry (KBR) wine‐making. Twelve different yeast strains were investigated by laboratory‐scale fermentation to develop a wine with a high flavour quality. Volatile aroma compounds from the wines were analysed using headspace–solid phase microextraction–gas chromatography–mass spectrometry and sensory evaluation was performed to evaluate the flavour characteristics. The volatile aroma compounds that mostly contributed to the flavour of KBR wines were those related to fruity (esters) and floral (terpenes) aromas. Fifteen out of the 67 identified volatile compounds showed higher odour activity values than other compounds in the wines, and these compounds were considered as important contributors to the final aromas of the wine. Additionally, the KBR wine fermented by the M1 yeast strain had the highest sensory preference because of higher fruity and floral aroma characters compared with other wines. In addition to the M1 strain, the other yeast strains that produced favourable sensory characteristics included Enoferm CSM, Uvaferm VRB, Lalvin ICV GRE, Lalvin ICV Opale and LevureSeche Active. Of these strains, the M1 strain produced a particularly excellent black raspberry wine, and thus could be applied for further large‐scale production of black raspberry wines. It is also expected that this work will expedite research on the production of high‐quality black raspberry wines with beneficial physicochemical properties, functionality and good sensory characteristics. Copyright © 2015 The Institute of Brewing & Distilling     

Chemical and sensory evaluation of Bordeaux wines (Cabernet-Sauvignon and Merlot) and correlation with wine age

Wine quality study was carried out with 24 vintages of Cabernet-Sauvignon (CS) and 7 vintages of Merlot (M) produced by two different Bordeaux wine-growing areas. Proanthocyanidin monomers and oligomers were identified and quantified by HPLC-UV-Fluo. Percentage of galloylation (%G), of prodelphinidins (%P) as well as mean degree of polymerisation (mDP) were also determined. Total phenolic compounds, total anthocyanins, total tannins, hue, CI (colour intensity), titratable acidity, ethanol level and pH were evaluated. Sensory analysis concerning astringency and bitterness intensity was also performed. Total phenolic compounds, total anthocyanins, total tannins, tannin monomers, hue, CI, % G, % P, mDP and astringency intensity differentiate both wines (M and CS) according to vintage. Correlations between wine age and: mDP, hue, astringency and tannin monomers (C + EC) are obtained. Qualitative tannin characterisation is established by correlation between astringency and mDP (R² = 0.509, p = 0.051, CS; R² = 0.780, p = 0.000 M). In addition, mDP decreases significantly during ageing (R² = 0.796, p = 0.000; CS and R² = 0.946, p = 0.000; M). Scale patterns between wine mDP and tannin perception (astringency) are proposed.     

不同酿酒酵母发酵的干红樱桃酒酒体成分及感官质量分析

为选择适宜樱桃酒酿造的专用酵母,测试和对比了7株市售商业化酿酒酵母对樱桃酒的发酵过程、酒体成分以及感官质量的影响。研究发现,菌株D254发酵效率高,能够高效萃取樱桃果浆中的生物活性物质(如多酚、花色苷等),且赋予樱桃酒较佳的感官品质,使其香气馥郁协调、酒体圆润,因而是适宜樱桃酒酿造的优良酿酒酵母菌株。     

不同酿酒酵母菌发酵树莓果酒的理化特性

该研究以秋福树莓为原料,采用五种商业酿酒酵母菌（71B、CECA、VP5、BV818、Montrachet）酿制树莓果酒。实验测定分析了各树莓果酒样品的发酵曲线、理化指标、有机酸及非花色苷单体酚类物质含量,并进行了感官评价。结果表明,菌株VP5启动最为缓慢,菌株71B无明显降酸效果,菌株CECA和BV818感官评分略低,而酿酒酵母Montrachet发酵启动快速,发酵速率平缓,发酵彻底,酒样酒精度高,为9.77%vol;甘油生成能力强,为8.22 g/L;具有较强的降低柠檬酸和苹果酸的能力,且酿酒酵母Montrachet酒样感官评分最高,为43分。单体酚检测结果表明,其总酚含量最高,为21.39 mg/L,其中鞣花酸、没食子酸含量高,黄烷醇类含量居中,这有助于形成树莓果酒鲜艳的色泽,且避免强烈的苦涩感。故酿酒酵母Montrachet适合树莓果酒酿造的优良菌株。     

The effect of ascorbic acid on oxidative browning of white wines and model wines

The effects of ascorbic acid addition to white wines and model wines were either anti-oxidative or pro-oxidative, and depended, inter alia , on the duration of storage. Soon after its addition, ascorbic acid decreased the redox potential and brown colour of model wines and white wines. However, with time, these effects were reversed, and redox potential, SO₂ consumption and browning were greater in samples with added ascorbic acid. The point at which the net effect of ascorbic acid addition was to increase browning occurred earlier at higher SO₂ levels. Under a variety of accelerated (45®), or prolonged (ranging from three months to five years) storage conditions, the browning of model wines and white wines was invariably enhanced by ascorbic acid addition, and this enhancement took place whether or not SO₂ was present. The addition of SO₂ alone, rather than ascorbic acid alone or SO₂ plus ascorbic acid, appears to be the most effective and least expensive way of protecting white wine from browning during bottle conservation.     

Cabernet Sauvignon wines from two different clones, characterization and evolution during bottle ageing

Phenolic compounds constitute important quality parameters of wines. Wines produced from different clones of the same grape variety show differences in relation to their chemical composition. The aim of this study was to characterize and differentiate Cabernet Sauvignon wines from two clones in relation to their chemical composition and to examine changes in the phenolic composition and antioxidant activity during wine ageing in the bottle. All wines were produced with Cabernet Sauvignon grapes, clones 685 and 169, from two vineyards, under the same microvinification conditions. The wines were characterized in relation to phenolic composition and antioxidant activity, as well as monitored over 11 months of bottle ageing. A significant difference was observed between the chemical compositions of the wines produced from clones 169 and 685, clone 169 showing the highest phenolic content while clone 685 had better color characteristics. The wines showed high antioxidant activity. Principal components and cluster analyses demonstrated separation of the wine according to the clone. In relation to wine bottle ageing, for both clones evaluated was observed a decrease in all phenolic compound, except of quercetin, and the antioxidant activity of these wines increased during storage.     

The role of corks in oxidative spoilage of white wines

The permeability of corks to oxygen was examined by comparing the level of browning and the concentration of the antioxidants, free and total sulfur dioxide and ascorbic and erythorbic acids in wines bottled and sealed with two cork types and stored in an atmosphere of either nitrogen, oxygen or air. Three different batches of corks that had been treated with peroxide during processing, representing one cork type, and a batch of corks that had been treated with chlorine during processing representing the second cork type, were taken for the study. In bottled wines stoppered with one of the peroxide-treated corks (Cork A), there was a higher level of browning and a greater loss of the antioxidants in those wines in bottles stored under oxygen and air than that in the wines in bottles stored under nitrogen, indicating that corks of this batch were permeable to oxygen. There was no significant difference in the loss of ascorbic and erythorbic acid or the level of browning from bottled wines stored under the three gases and sealed with the chlorine-treated corks (Cork C). For the other two peroxide-treated corks (Corks B and D), there was no significant difference in the level of browning or loss of the antioxidants from bottled wines stored under the three gases and sealed with Cork B, nor was there a significant difference in the level of browning or loss of free or total sulfur dioxide from bottled wines stored under the three gases and sealed with Cork D. From comparative data, it was evident that oxidation of the wines sealed with Corks B and D was due to compounds in the corks rather than oxygen permeation through the corks, or oxygen ingress at bottling. Because the bottles of wine selected for this study were from batches that had already exhibited sporadic oxidation, the results found are indicative, but not necessarily representative, of the properties of all peroxide- and chlorine-treated cork types used in the wine industry.     

The sensory evaluation of 2,4,6‐trichloroanisole in wines

This work proposes a sensory method to verify the ‘cork taint’ defect in food and beverages. This off‐flavour has considerable economic impact in wine but occasionally can occur in other food and beverages. In wine, 2,4,6‐trichloroanisole (TCA) is generally considered to be the main compound responsible for this taint. It is an easily recognized compound because of its low sensorial threshold, and it is described as a mouldy and damp cardboard odour. This sensory method, developed in wine, consists of specific panel training to recognize TCA in a series of olfactory tests. The effectiveness of the panel was tested with contaminated wines in which the TCA content had been previously determined by Solid Phase Microextraction‐Gas Chromatography Mass Spectrometry (SPME‐GC/MS) analysis. This sensory method is useful to train a panel able to recognize the ‘cork taint’ defect in different situations (legal appraisals or quality assurance systems). The use of a reliable sensory assay can reduce the number of chemical analyses and the proposed method can be applied to other beverages such as beer. Copyright © 2015 The Institute of Brewing & Distilling     

Differences in the phenolic composition and sensory profile between red wines aged in oak barrels and wines aged with oak chips

The aim of this study was to evaluate the similarities or differences in the phenolic composition and the sensory characteristics between wines traditionally aged in new French and American barrels for different periods of time, and wines aged for 30 days with different kinds (different geographical origin al toasting degree) of oak chips. This study was carried out with two grape varieties, Mencía and Tinta del País, and in two consecutive vintages. The results obtained indicated that it was not possible to obtain wines aged with chips with sensory characteristics similar to those aged for a long time in new barrels, independently. However, the results showed that the use of oak chips could be a good alternative for elaborating young wines with slight olfactory and gustative wood notes quite similar to wines aged in new barrels for short periods of time (about three months).     

Chemical, physical and sensory attributes for the characterization of an Italian dry-cured sausage

This work was designed to characterize Felino salami, an Italian dry-cured sausage. For this purpose, a wide range of chemical, physical and sensory parameters were studied in 29 samples. Seven chemical and physical variables were selected by using principal components analysis: namely, pH, NaCl/moisture, moisture/protein, soluble N/protein, lactic acid, elasticity index and sample luminosity (L(?)). The first two principal components were significant according to double-cross validation and accounted for 79% of variance. The seven-variable chemometric model shows that variability in the first principal component is determined by variables expressing the acidity and the extent of lactic fermentation, while the second component is determined by variables expressing the degree of ripening and is related to the sensory scores maturation and hardness, and to salami age (p < 0.001). Sensory scores were evaluated by a multivariate method to verify the consonance among assessors as to the different attributes. The semi-trained panel was consonant and reliable for five of the nine sensory attributes evaluated. The predictive ability of the chemometric model for the sensory attributes was assessed with cross-validation.     

Changes in volatile composition and sensory attributes of wines during alcohol content reduction

A desirable sensory profile is a major consumer driver for wine acceptability and should be considered during the production of reduced‐alcohol wines. Although various viticultural practices and microbiological approaches show promising results, separation technologies such as membrane filtration, in particular reverse osmosis and evaporative perstraction, in addition to vacuum distillation, represent the most common commercial methods used to produce reduced‐alcohol wine. However, ethanol removal from wine can result in a significant loss of volatile compounds such as esters (ethyl octanoate, ethyl acetate, isoamyl acetate) that contribute positively to the overall perceived aroma. These losses can potentially reduce the acceptability of the wine to consumers and decrease their willingness to purchase wines that have had their alcohol level reduced. The change in aroma as a result of the ethanol removal processes is influenced by a number of factors: the type of alcohol reduction process; the chemical‐physical properties (volatility, hydrophobicity, steric hindrance) of the aroma compounds; the retention properties of the wine non‐volatile matrix; and the ethanol level. This review identifies and summarises possible deleterious influences of the dealcoholisation process and describes best practice strategies to maintain the original wine composition. © 2016 Society of Chemical Industry     

Analysis,occurrence and potential sensory significance of aliphatic aldehydes in white wines

An analytical method was developed for C8–C11 aliphatic aldehydes in wine consisting of solid phase extraction (SPE) followed by multidimensional gas chromatography/mass spectrometry (MDGC/MS). The method achieves low detection limits (<30 ng L⁻¹), minimises problems of blank contamination and shows high repeatability (RSD% < 5%), but strong matrix effects were noticed during validation. These matrix effects were attributed to strong interactions between aliphatic aldehydes and other matrix elements. Three fractions were differentiated: free extractable aldehydes, aldehydes bound in hydrophilic complexes (extractable in the presence of acetaldehyde) and aldehydes bound in hydrophobic complexes (extractable in the presence of heptanal). The distribution of the three aldehyde species in wine samples was estimated using a surrogate (3,5,5-trimethylhexanal) and an internal standard (methyl phenylacetate) in double determinations (directly and after incubation with 1000 mg L⁻¹ acetaldehyde). These components had a clear additive sensory effect in mixtures and odour thresholds in wine were very low. This caused that although they were present at very low levels, in 2 out of 24 white wine samples were clearly above threshold, and in six more were at levels close to threshold. These results suggest that these components are active contributors to the citrus fruit notes of some white wines.     

Chemical and microbiological parameters and sensory attributes of a typical Sicilian salami ripened in different conditions

A study was carried out on a typical Sicilian salami prepared from meat of the local Nero Siciliano pig in order to characterize this typical product. One formulation of salami was divided in two batches and ripened in two different environments, a traditional sicilian room (TR) and a controlled industrial ripening room (RR). Microbiological and physico-chemical analysis were performed on raw mixture and after 7 and 90 days of ripening. Sensory analysis was carried out on salami at the end of ripening, and flavour compounds were extracted by simultaneous distillation–extraction and analysed by gas chromatography/mass spectrometry. Commercial salami prepared from meat from white pig were purchased locally and used as comparative samples. The experimental salami at the end of ripening was characterized by a high level of fat and low level of moisture. Fatty acid analysis showed that experimental salami contained a higher percentage of oleic acid, vaccenic acid and palmitic acid and a lower percentage of stearic acid and linoleic acid, when compared to commercial salami (P<0.05). No significant differences were found in fatty acid composition of the experimental salami between the two types of ripening. Instrumental analysis of flavour volatile compounds in the experimental salami demonstrated that traditionally ripened salami contained the most volatiles, especially aldehydes (8217 vs. 3104 ng g⁻¹, P<0.05). Sensory analysis showed no significant differences as a consequence of different ripening conditions for firmness, saltiness, acidity, cohesiveness and elasticity. In contrast, there were significant differences for hardness and rancidity, which were higher in TR salami compared with RR and commercial salami. Lactic acid bacteria and Micrococcaceae counts were higher in controlled ripened salami although the hygienic quality of both products was satisfactory. The use of a controlled room for the ripening of this typical salami seems to be a potential technological improvement to maintain an all year around production of this salami, that otherwise cannot be produced in the summer period due to the higher environmental temperatures. However, the non traditionally ripened product showed some chemical differences that were not evidenced by sensory analysis.     

Influence of co-winemaking technique in sensory characteristics of new Spanish red wines

The influence of co-winemaking technique on the sensory profile of wines made from minority red grape varieties cultivated in La Mancha region (Spain) was researched by sensory characterization. Sensory analysis was carried out by a panel of 15 experienced wine-testers, all with a previous training. The sensory profiles of monovarietal red wines—Cencibel, Bobal and Moravia Agria—were studied and also the effects of co-winemaking technique on sensory characteristics were evaluated. Co-winemaking red wines were obtained by blending (a) Cencibel (50%) + Bobal (50%); (b) Cencibel (50%) + Moravía Agria (50%) and (c) the three grape varieties Cencibel (33%) + Bobal (33%) + Moravía Agria (33%). The co-winemaking technique intensified the principal sensory properties of monovarietal wines and the wines proved to be more complex than the monovarietal wines.     

Fractionation and partial characterization of protein fractions present at different stages of the production of sparkling wines

Soluble proteins from sparkling wines (var. Chardonnay) manufactured industrially following the Champenoise method were analysed by analytical anion-exchange FPLC (fast protein liquid chromatography). Samples of the must, the unfined wine, the fined wine and the sparkling wines after 3, 6, 9, 12, 15 and 18 months of ageing with yeast lees were taken. Eight main must protein fractions were collected and characterized by isoelectric focusing and capillary electrophoresis. Six fractions consisted of proteins with isoelectric points (pIs) from 4.27 to 3.04. Two fractions, according to their UV spectra, seemed to contain phenolic compounds. A comparison of FPLC profiles of the must, the unfined wine and the fined wine indicated that both fermentation and stabilization processes decrease the concentration of those proteins with less affinity for the anion-exchange column and with a higher pI. No changes in the protein profiles of sparkling wines were observed during the first 18 months of ageing with yeast..     

Chemical and sensory changes of different dairy products during storage in packages containing nanocrystallised TiO2

The chemical changes of three types of cheese, yoghurt and kefir were evaluated during storage in packages containing TiO₂ with two different compositions of the mixed anatase–rutile phase. The influence of TiO₂ packaging during storage on titratable acidity and fat content and on the external aspect was investigated. Fourier Transformed Infrared Spectroscopy (FTIR) analyses were performed to establish whether the TiO₂ penetrated the food during storage. The results showed that the TiO₂ nanoparticles deposited on polyethylene surface significantly decreased acidity and fat content of the investigated cheese and yoghurt types. During storage in TiO₂ nanopackages, the change in chemical parameters is accentuated as the content of rutile grows from 2.8% to 6.9%. The sensory evaluation revealed that the dairy products stored for 11 days in TiO₂ nanopackages present similar colour, texture and flavour with that of the references; the samples stored in polyethylene film were found to be unacceptable.