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Chinese traditional liquor, a major type of global distilled spirits, offers a unique flavor system acquired across thousands of years of development. Owing to the various raw brewing materials, types of koji, fermentation vessels, and processes used during liquor production, significant differences can occur in the content of flavor chemical components, such as esters, alcohols, aromatics, ketones, nitrogen compounds, acids, and aldehydes in the resulting liquor. Therefore, the liquor can be characterized on the basis of four basic flavors: sauce‐, strong‐, light‐, and rice‐aroma, and eight derivative flavors: feng‐, sesame‐, chi‐, te‐, mixed‐, laobaigan‐, herbal‐, and fuyu‐aroma. In this review, we describe the production and development process of Chinese traditional liquor in detail; summarize the flavor types, flavor chemical composition characteristics, and research progress related to this liquor; and discuss the influence of trace chemical components on liquor flavor, with the aim of laying a theoretical foundation for stabilizing the quality and increasing the yield of traditional liquor. [ABSTRACT FROM AUTHOR]

Triggered by the development of lactic acid bacteria (LAB) during the production of Scotch whisky, this study examined the influence of yeast and LAB inoculation on whisky flavor. Four new spirits were produced using the same process. LAB were added as a form of a Greek yogurt's live culture. In each category (barley and rye), one sample was fermented with Greek yogurt while the other was fermented without it. The spirits were matured and analyzed at five different points. Results from gas chromatography‐mass spectrometry (GC‐MS) analysis showed basic volatile compounds, along with some important extra compounds with yogurt culture. The most obvious differences were observed in the concentration of butanoic acid, a characteristic acid in spirits undergoing lactic acid fermentation: to identify esters such as ethyl butanoate, ethyl isobutanoate, isoamyl butanoate, and 2‐phenylethyl butanoate, they are not typical compounds in whisky. [ABSTRACT FROM AUTHOR]

An HS-SPME/GC-MS procedure was optimised in order to characterize the aromatic fingerprint of 82 spirit drinks, belonging to Grappa GI samples and other distillates. "Grappa" is a geographical indication (GI) allowed by EC Regulation No 110/2008 only for Italian-made grape marc spirit. Multivariate chemometric techniques were applied to the collected chromatographic profiles in order to classify the samples on the basis of chemical information provided by their volatile composition data. Partial Least Squares-Discriminant Analysis (PLS-DA) showed natural grouping of samples highlighting good classification results, providing a good separation between the two distillate categories with high prediction accuracy (the total classification rate on the external test set was 95%). In addition, VIP scores of PLS-DA models were calculated, allowing to identify a reduced number of volatile compounds which are relevant for discrimination of the different categories. Also Soft Independent Modelling by Class Analogies (SIMCA) was tested to build class models for predictive classification purposes. The proposed approach may represent a powerful tool suitable to assess the authenticity of Grappa GI samples and, hence, it may help to protect this product from possible frauds by verifying whether samples comply with the product specification. • HS-SPME/GC-MS with chemometric modelling was developed for the characterization of Grappa GI. • 82 spirit drinks, including Grappa GI and distillates of fruits and cereals, were studied. • PLS-DA and SIMCA were tested to discriminate grappa spirits from other distillates. • PLS-DA model provided 100% correct classification rate (in external validation) for samples belonging to class Grappa. • VIP analysis was used to characterize the flavour fingerprint of GI Grappa. [ABSTRACT FROM AUTHOR]

As an alternative technology for the production of cachaça, fermented sugar cane must was clarified by ceramic α‐alumina membranes, followed by water removal by pervaporation using a silk sericin/polyvinylalcohol (PVA) non‐porous membrane. The high solute content in the fermented must resulted in fouling and concentration polarisation in both microfiltration and pervaporation. The hydrophilicity of the sericin/PVA blends was exploited in ethanol and aroma concentration, at an optimal temperature of 20°C, resulting in a separation factor and permeation flux of 3.7 and 958.3 g/m2 h. An aroma profile was performed using GC SPME/headspace and GC‐MS, analysing the content of ethanol, 3‐methyl‐1‐butanol, 2‐methyl‐1‐butanol, ethyl lactate, isoamyl acetate, ethyl octanoate and ethyl laurate. The results show that the volatiles present in the fermented sugar cane must were concentrated, with recoveries of 93.9 and 94.3% of the principal aromatic compounds. © 2019 The Institute of Brewing & Distilling [ABSTRACT FROM AUTHOR]

Lactic acid is the main acid produced during the Maotai liquor brewing process, influencing the quality of the base liquor and fermentation process. However, the microorganisms responsible for lactic acid production have not been identified. In this work, the dynamic changes in bacterial community structure in the Zaosha round (second sorghum feeding and fermentation) of the brewing process were analysed by 16S rRNA high‐throughput sequencing. Results show that lactic acid bacteria (LAB) and Bacillus spp. are the dominant bacteria in the brewing process, where Bacillus spp. are found in the early stage, whilst LAB are found throughout the brewing process. Furthermore, 10 types of LAB and five Bacillus spp. were isolated from Zaopei (a mixture of fermented grains including sorghum and wheat) by a culture‐dependent method. Lactobacillus panis accounts for 68% of the LAB, and Bacillus amyloliquefaciens for 54% of Bacillus spp. Solid‐state fermentation experiments were performed with L. panis and B. amyloliquefaciens and lactic acid production was consistent with the accumulation of lactic acid in Zaosha. The results showed that L. panis was the main producer of lactic acid in pits, while B. amyloliquefaciens plays an important role in the production of lactic acid in the early stages of fermentation. The approach used in this study may facilitate the identification of key microorganisms with specific functionality involved in other food and beverage fermentation processes. © 2018 The Institute of Brewing & Distilling [ABSTRACT FROM AUTHOR]

Maotai‐flavor liquor is one of the three basic traditional Chinese baijiu and is also the most famous baijiu in the world. Guizhou Maotai baijiu is the representative of Maotai‐flavor liquor, which has a long history of culture and is prepared using unique brewing methods. However, the main flavor of Maotai‐flavor liquor as well as the mechanism by which its aroma is produced is unclear. In this review, the Da‐qu production and fermentation processes for Maotai‐flavor liquor are briefly described along with the flavoring constituents of Maotai‐flavor liquor that have been recently reported. In addition, the volatile compounds and the aroma derived from Maotai‐flavor liquor are discussed. Finally, the microorganisms for the high‐temperature Daqu and fermentation processes of Maotai‐flavor liquor are discussed. Practical Application: Maotai is one of the most famous baijiu in China and the most valuable in the market. However, it is unclear what is the key flavor of Maotai and what microbial metabolism is produced. So, if we can figure out the key flavor substances of Maotai baijiu, we can use the various technology to explore the microbes that produce this flavor to understand the mechanism of the production of Maotai. This will not only achieve breakthroughs in academic value, but also bring higher value to Maotai. On this basis, we can brew Maotai baijiu with better quality according to the fermentation mechanism of Maotai. [ABSTRACT FROM AUTHOR]

Fig fruits (Ficus carica L.) are used in several Mediterranean countries to produce alcoholic spirits, with either plurivarietal dried figs or, monovarietal fresh figs as the raw material. To determine the influence of different varietal attributes and production methods on the quality of fig spirits, we analyzed the volatile compounds that contribute to the aroma and organoleptic characteristics of spirits derived from eight Portuguese varieties of fresh figs, as well as mixtures of dried figs processed in the laboratory and plurivarietal fig spirits already in the market. The quantification of major and minor volatiles by GC-FID revealed that the plurivarietal dried fig spirits contained greater quantities of short-chain fatty acid esters and higher alcohols (associated with poor-quality spirits) and compounds with a negative influence on aroma and flavor (such as ethyl lactate, ethyl acetate and diethyl succinate) than the fresh fig spirits. HS-SPME/GC-MS analysis detected 130 volatile compounds, among which the esters ethyl decanoate, ethyl octanoate and ethyl dodecanoate, the aldehydes benzaldehyde and furfural, the monoterpene limonene and the norisoprenoide β-damascenone were common constituents in most of the spirits. The volatile profile of all dried fig distillates was similar and diverse, reflecting the plurivarietal origin, whereas the monovarietal fresh fig spirits produced distinct profiles (sufficient for varietal chemical differentiation), with Burjassote branco distillates containing the greatest number of volatile compounds. This volatile analysis provides a way to determine the quality of fig spirits objectively and to develop spirits with novel characteristics for the market. [ABSTRACT FROM AUTHOR]

Abstract Although esters were important odorants in light aroma-type liquor, it was still puzzling that sensory interaction between esters made the odor quality of light aroma-type liquor outstanding. The aim of the paper was to investigate perceptual interaction among esters. The odor thresholds of eighteen esters and 35 binary mixture were determined by a three-alternative forced-choice procedure. The relationship between odor threshold and carbon chain length of homologous ethyl esters was investigated. Moreover, 31 binary mixtures present either a synergistic effect or additive action. Furthermore, odor quality and odor intensity were determined by p/τ plot and σ/τ plot, respectively. From the p/τ plot, an ideal sigmoidal function for odor quality was obtained. From the σ/τ plot, for all 120 binary mixtures, just 9 mixtures were in the hyper-additivity area (σ > 1.05), and two were in the so-called perfect additivity area (0.95 < σ < 1.05). Almost one half (48%) showed compromise level. Finally, a significantly difference was observed by flash gas chromatography electronic nose (p <.05). Sensory analysis revealed that a mask effect of fruity note was occurred by adding ethyl phenylacetate at various levels (100, 2500, 58,000 ppb) to the fruit recombination and an enhancement effect of floral note was reported by adding phenylethyl acetate at low (1400 ppb) or high level (11,500 ppb). It was noticed that sweet note was significantly enhanced by adding phenylethyl acetate at peri-threshold (3200 ppb). Graphical abstract Unlabelled Image Highlights • The relationship between odor threshold and carbon chain length of homologous ethyl esters was investigated. • The perceptual interaction was related with the structure or aroma of compounds. • An ideal function of odor quality was obtained from experimental data. • Four principle basic rules were verified by five odor pairs. • Sub-threshold level compounds had a significantly impact on the overall aroma of the FR solution. [ABSTRACT FROM AUTHOR]

Developing new distillation strategies can help the spirits industry to improve quality, safety and process efficiency. Batch stills equipped with a packed column and an internal partial condenser are an innovative experimental system, allowing a fast and flexible management of the rectification. In this study, the impact of four factors (heart-cut volume, head-cut volume, pH and cooling flow rate of the internal partial condenser during the head-cut fraction) on 18 major volatile compounds of Muscat spirits was optimized using response surface methodology and desirability function approaches. Results have shown that high rectification at the beginning of the heart-cut enhances the overall positive aroma compounds of the product, reducing off-flavor compounds. In contrast, optimum levels of heart-cut volume, head-cut volume and pH factors varied depending on the process goal. Finally, three optimal operational conditions (head off-flavors reduction, flowery terpenic enhancement and fruity ester enhancement) were evaluated by chemical and sensory analysis. [ABSTRACT FROM AUTHOR]

Monoterpene alcohols (MTAs) are characteristic flavour-imparting compounds in sweet potato shochu (Japanese distilled spirit) that are liberated following hydrolysis by specific enzymes during fermentation. In the present study, we evaluated the effect of an exogenously added diglycoside-specific β-glycosidase (β-primeverosidase) on aroma formation during shochu brewing using various sweet potato species to address whether MTAs are predominantly present as diglycosidic precursors in raw materials. The results showed that the amount of MTAs produced from enzyme-treated mash was dramatically increased by 2- to 9-fold compared with untreated controls, and the increase varied with sweet potato species. In addition, levels of methyl salicylate, 1-octene-3-ol and ethyl benzoate were also elevated by enzyme treatment. These results indicate that a large amount of MTAs and other volatile aroma compounds are stored in the form of disaccharide β-glycosides such as β-primeverosides in sweet potato. This enzyme may therefore be useful for controlling aroma formation during shochu manufacturing, and may ultimately contribute to diversifying shochu quality. [ABSTRACT FROM AUTHOR]

Abstract: One of the major objectives of food industry is predicting the sensory profile of a product by chemical analysis. In the case of spirit drinks, their volatile compounds can exhibit odour interactive effects. This study investigated the odour perception of linalool, ethyl hexanoate, ethyl acetate and acetaldehyde with model solutions (in 40% v/v ethanol) on flowery, fruity and glue‐like attributes. Design of experiments for sensory analysis and response surface methodology were used to evaluate the aroma interactions of these compounds by sniffing or orthonasal olfaction. Results showed that ethyl hexanoate masks flowery and glue‐like descriptors. Acetaldehyde provides a low‐intensity fruity odour, which is confused with ethyl hexanoate odour. High levels of ethyl acetate suppress and enhance the fruity descriptor at high and low levels of ethyl hexanoate, respectively. In summary, this sensory technique enables the rapid but consistent assessment of the interaction of aroma compounds in an alcoholic spirit. It is suggested that this approach may be a useful tool in the optimization and development of alcoholic products. Copyright © 2017 The Institute of Brewing & Distilling [ABSTRACT FROM AUTHOR]

Odor-active compounds of Wuliangye liquors with markedly different aging years were identified by aroma extract dilution analysis (AEDA) and gas chromatography-olfactometry (GC-O). A total of 62 aroma compounds were identified in three Wuliangye liquors and 45 odorants were further screened out and quantified as the important odorants according to Flavor Dilution (FD) values. They were selected as specific compounds correlated to sensory attributes by the Pearson coefficient. The correlation results showed that ethyl hexanoate, ethyl 3-methylbutyrate, ethyl octanoate, ethyl 2-methylbutyrate, pentanoic acid, ethyl octanoate, furfural, 4-methylphenol, hexanoic acid, isovaleric acid, and 1,1-diethoxyethane were related to the characteristic aroma of Wuliangye liquors. It will be helpful for the improvement of characteristic aroma of Wuliangye liquors through adjusting fermentation parameters or compensating typical aroma compounds after alcoholic fermentation. [ABSTRACT FROM AUTHOR]

[Objective] This study was conducted to extract the scarce natural liquor flavorings desired by many liquor factories from yellow water. [Method] Strong water absorbent resin was used to absorb moisture from the yellow water in order to concentrate it into dense yellow water at first, followed by azeotropic distillation of the previously concentrated yellow water, and then, catalytic esterification was performed to the remaining liquid after the distillation. [ Results ] The 7. 066 7 fractions of concentrated yellow water with 56. 7% ethanol could be obtained after the treatment of 100 fractions of yellow water with strong water absorbent resin. Azeotrope of 0. 432 8 fraction of natural acetaldehyde, 0. 269 4 fraction of ethyl formate and methyl alcohol, 0. 975 0 fraction of ethyl acetate and methyl alcohol could be obtained after the azeotropic distillation per 100 fractions of concentrated yellow water. After the addition of CaCl2, 0. 2207 fraction of ethyl formate and 0. 514 2 fraction of ethyl acetate could be obtained after distillation of the azeotrope. Finally, 92. 094 8 fractions of esterification liquid with 38 kinds of flavoring compound could be obtained after catalytic esterification of 100 fractions of concentrated yellow water, and the content of ethyl acetate, ethyl propionate, ethyl-butyrate, ethyl valerate, ethyl lactate ad ethyl hexanoate were a much a 142. 9, 22.2, 54.2, 3.3, 75.4 ad 158. 9 g/L, respectively. [ Conclusion] Top-grade Luzhou-favor liquor could be made by mixing 6. 5 fractions of common liquor with acetaldehyde, ethyl formate, ethyl acetate and esterification liquid which were obtained from 1 fraction of yellow water. Therefore, the yellow water has a great recycling value, and it tells us that the technique of extracting liquor flavorings from yellow water has tremendous market value. [ABSTRACT FROM AUTHOR]

The aroma profiles of five Chinese light aroma-type liquors were investigated in this study. Gas chromatography-olfactometry (GC-O) and GC-flame photometric detection (FPD) were employed to investigate aroma-active compounds. A total of 80 odorants were identified, including ten sulfur compounds. In addition, aroma-active compounds (FD ≥ 16) were determined, according to quantitative study and odor activity values (OAVs). Finally 27 key aroma compounds, mainly possessing fruity and floral notes, were successfully used to simulate the aromas of Chinese light aroma-type liquors by dissolving them in 53% (v/v) hydroalcoholic solution in their natural concentrations. Moreover, the correlation between the key aroma compounds, seven sensory attributes and liquor samples was evaluated through partial least-squares regression analysis. [ABSTRACT FROM AUTHOR]

At present, artificial pit mud (APM) is widely used in Chinese liquor-making industry and plays a particular role in the production of Chinese strong flavor liquor (CSFL). However, APM frequently ages during fermentation, thus becoming unsuitable for sustainable use due to its low-quality. The reasons behind, and results of, APM aging during the production of CSFL are not yet understood. Sequencing the V4 region of the 16S rRNA gene shows that prokaryotic diversity is significantly decreased (Shannon's diversity index, P < 0.01) and community composition is distinctly changed (from 1197 to 865 OTUs) in aging APM. On the phylum level, the increase of Firmicutes and decrease of Proteobacteria are the main consequences of APM aging during the production of CSFL. The counting of cultivatable bacteria confirmed that there was a large increase in Lactobacilli and aerobic spore-forming bacteria in aging low-quality APM (more than twofold). Unexpectedly, the total number of caproic acid-producing bacteria, mainly Clostridia, did not change significantly between the two kinds of APM. Furthermore, biochemical analysis indicates that the pH and the levels of NH and K are decreased in aging low-quality APM ( P < 0.01). The results obtained in this study support the possibility that environmental factors (pH, nutrients) induce the decrease of prokaryotic diversity, and the changed community composition influences the environmental properties. Therefore, through interfering with the cycle, APM aging can be controlled potentially by adjustment of environmental factors and/or supplementation of diminished or missed microorganisms. [ABSTRACT FROM AUTHOR]

The differentiation of aromas of Chinese liquor is important for their unique flavors. In this work, aromas of Chinese liquor were characterized by gas chromatography and chemometrics. Ten representative aroma compounds, including three alcohols, four esters, two organic acids, and acetal in 16 Chinese liquor were determined by gas chromatography with flame ionization detection. The relationship between these compounds and six classic aromas was investigated using principal component analysis andk-means clustering. The cumulative contribution of the first three principal components reached up to 84.607%, which effectively differentiated the liquors. The variables with the highest loading absolute value were acetal and ethyl acetate for principal component 1, ethyl butanoate and ethyl hexanoate for principal component 2, and the hexanoic acid and ethyl butanoate for principal component 3. The aromas of the liquors were characterized byk-means clustering with the first three principal component scores, indicating that the acetal, ethyl acetate, ethyl butanoate, ethyl hexanoate, and hexanoic acid are important for the aroma of Chinese liquors. This work demonstrated that the gas chromatography with chemometrics is effective for the characterization of aromatic liquor. [ABSTRACT FROM PUBLISHER]

Roasted-sesame-like aroma and flavour type liquor is extensively welcomed by consumers owing to its typical aroma, particularly in the north of China. To our knowledge, age markers which can distinguish between fresh and aged raw liquor have not been investigated. 1,1-Diethoxymethane and methanethiol were identified and quantified by headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry. The results showed that 1,1-diethoxymethane was not detected in all fresh raw liquors, and the contents increased with raw liquor age, contrary to the great decrease of methanethiol. Both of them showed good correlations with raw liquor age ( R = 0.955 and R = 0.695, respectively). Furthermore, the reduction in the concentrations of methanethiol and derivatives (rotten cabbage aroma) might be responsible for the mild aromas of aged raw liquors. Therefore, our research suggested that 1,1-diethoxymethane and methanethiol could be used as effective age markers of roasted-sesame-like aroma and flavour type raw liquor. [ABSTRACT FROM AUTHOR]

A novel bioinspired neural network is proposed as a replacement for traditional data processing methods in the electronic nose (e-nose) that we designed. This neural network mimics the main structures of the mammalian olfactory system. It contains olfactory sensing neurons, mitral cells, and granule cells. The proposed method can directly use the raw data collected from sensors in the e-nose without any signal preprocessing, feature selection, or reduction. The output neurons of the network can change the sensors’ responses into two new time series, of which we only use the variances to perform classification. This significantly simplifies the data processing procedure in e-noses. In order to test the performance of the proposed bioinspired neural network in the e-nose, two sampling methods, three classification methods, and seven kinds of Chinese liquors were employed. The highest classification rates of the proposed method and traditional method are 100% and 93%, respectively. [ABSTRACT FROM PUBLISHER]

Chinese liquors can be classified according to their flavor types. Accurate identification of Chinese liquor flavors is not always possible through professional sommeliers' subjective assessment. A novel polymer piezoelectric sensor electric nose (e-nose) can be applied to distinguish Chinese liquors because of its excellent ability in imitating human senses by using sensor arrays and pattern recognition systems. The sensor, based on the quartz crystal microbalance (QCM) principle is comprised of a quartz piezoelectric crystal plate sandwiched between two specific gas-sensitive polymer coatings. Chinese liquors are identified by obtaining the resonance frequency value changes of each sensor using the e-nose. However, the QCM principle failed to completely account for a particular phenomenon: we found that the resonance frequency values fluctuated in the stable state. For better understanding the phenomenon, a 3D Computational Fluid Dynamics (CFD) simulation using the finite volume method is employed to study the influence of the flow-induced forces to the resonance frequency fluctuation of each sensor in the sensor box. A dedicated procedure was developed for modeling the flow of volatile gas from Chinese liquors in a realistic scenario to give reasonably good results with fair accuracy. The flow-induced forces on the sensors are displayed from the perspective of their spatial-temporal and probability density distributions. To evaluate the influence of the fluctuation of the flow-induced forces on each sensor and ensure the serviceability of the e-nose, the standard deviation of resonance frequency value (SDF) and the standard deviation of resultant forces (SDFy) in y-direction (Fy) are compared. Results show that the fluctuations of Fy are bound up with the resonance frequency values fluctuations. To ensure that the sensor's resonance frequency values are steady and only fluctuate slightly, in order to improve the identification accuracy of Chinese liquors using the e-nose, the sensors in the sensor box should be in the proper place, i.e., where the fluctuations of the flow-induced forces is relatively small. This plays a significant reference role in determining the optimum design of the e-nose for accurately identifying Chinese liquors. [ABSTRACT FROM AUTHOR]

Shochu, a traditional Japanese distilled liquor, makes use of rice koji, which is koji mould grown on rice grain. Rice koji is an essential ingredient of Japanese liquors such as shochu, and it plays a role as a source of the enzyme to degrade starch. However, there has been no research on the effect of rice koji on the flavour of shochu. Therefore, in this study, the volatile compounds in shochu derived from rice koji were investigated. Two shochu samples were prepared to assess the contribution of rice koji to the flavour. One shochu sample was prepared from rice koji, yeast and water (rice koji- shochu). The other shochu sample was obtained from steamed rice and various enzymes instead of rice koji (enzyme- shochu), along with yeast and water. The volatile compounds were analysed by gas chromatography-mass spectrometry (GC-MS) and GC-MS/olfactometry with aroma extract dilution analysis. The results showed that enzyme- shochu had a higher flavour dilution value of dimethyl trisulphide and hexanal, whereas rice koji- shochu had a higher flavour dilution value of some ester compounds that imparted aromatic odours such as fruity. Some unknown peaks representing compounds that impart characteristic odours such as soda, potato, lavender, and tea-like were specifically detected in rice koji- shochu. The concentrations and calculated odour active values of 14 compounds were measured. These results showed that isovaleraldehyde, ethyl caprylate, ethyl caproate and ethyl 2-methylbutyrate played an important role in imparting the specific odour of rice koji- shochu. Copyright © 2016 The Institute of Brewing & Distilling [ABSTRACT FROM AUTHOR]

Samples of non-mature and añejo (matured) tequila of the same brand/provenance were analysed using GC-MS and gas chromatography olfactometry (GC-O)/aroma extract dilution analysis (AEDA) to provide quantitative data on the most odour active compounds that contribute to the aroma of these spirits. Extracts of non-mature tequila were characterized by 26 odour-active regions, which included ethyl hexanoate, ethyl octanoate, 2-phenylethyl acetate, β-damascenone, isoamyl alcohol and octanoic acid as the most odour-active compounds (flavour dilution, FD, factor ≥ 6561). In contrast, extracts of the mature spirit showed 36 odour-active zones, where the compounds with the highest FD factors (6561) were ethyl hexanoate, ethyl octanoate, 2-phenylethyl acetate, isoamyl alcohol, phenethyl alcohol, guaiacol, 4-ethyl guaiacol, vanillin, cis/ trans whisky lactones, β-damascenone and octanoic acid. The aromagram of mature tequila was thus differentiated from that of the non-mature spirit owing to the presence of cask-extractive compounds and the increased FD factors of certain terpenes, higher alcohols and acetals. This study provides a comprehensive and quantitative understanding of changes in key odourants of tequila as a result of the maturation process and also reveals a further characterization of the likely impact of each compound on overall spirit flavour, in terms of odour activity values. Copyright © 2016 The Institute of Brewing & Distilling [ABSTRACT FROM AUTHOR]

The solid-state fermentation state of Chinese Maotai liquor involves the interaction of several complex microbial communities leading to the generation of the most complex liquor fermentation system in the world and contributes to the unique flavor and aroma of the liquor. In this study, total DNA was extracted from 3 fermented grain samples (FG1, FG2, and FG3) and 12 environmental samples, including Daqu (DA1, DA2, DA3, and DA4), cellar mud (CS1, CS2, and CS3), soil (SL1 and SL2), air (A1 and A2), and sorghum (SH), and the 16S and 18S rRNA genes were amplified. The distribution of typical microorganisms in the samples was analyzed using nested PCR-denaturing gradient gel electrophoresis, while quantitative PCR amplification of 16S rRNA and internal transcribed spacer genes was performed to estimate the microbial abundance present in each sample. The results indicated that Daqu was the primary source of bacteria, followed by the air, soil, and sorghum samples, while the majority of the fungi responsible for Maotai liquor fermentation were from Daqu and sorghum. Highest bacterial concentrations were found in fermented grains, followed by Daqu and sorghum, while the highest fungal concentrations were found in Daqu, followed by sorghum and an air sample from outside the liquor production area. The findings of this study may provide information regarding the mechanisms responsible for flavor development in Maotai liquor, and may be used to further optimize the traditional art of making liquor. [ABSTRACT FROM AUTHOR]

Microbial interactions could impact the metabolic behavior of microbes involved in food fermentation, and therefore they are important for improving food quality. This study investigated the effect of Bacillus licheniformis, the dominant bacteria in the fermentation process of Chinese Maotai-flavor liquor, on the metabolic activity of Saccharomyces cerevisiae. Results indicated that S. cerevisiae inhibited the growth of B. licheniformis in all mixed culture systems and final viable cell count was lower than 20 cfu/mL. Although growth of S. cerevisiae was barely influenced by B. licheniformis, its metabolism was changed as initial inoculation ratio varied. The maximum ethanol productions were observed in S. cerevisiae and B. licheniformis at 10:10 and 10:10 ratios and have increased by 16.8 % compared with single culture of S. cerevisiae. According to flavor compounds, the culture ratio 10:10 showed the highest level of total concentrations of all different kinds of flavor compounds. Correlation analyses showed that 12 flavor compounds, including 4 fatty acids and their 2 corresponding esters, 1 terpene, and 5 aromatic compounds, that could only be produced by S. cerevisiae were significantly correlated with the initial inoculation amount of B. licheniformis. These metabolic changes in S. cerevisiae were not only a benefit for liquor aroma, but may also be related to its inhibition effect in mixed culture. This study could help to reveal the microbial interactions in Chinese liquor fermentation and provide guidance for optimal arrangement of mixed culture fermentation systems. [ABSTRACT FROM AUTHOR]

Luzhou-flavor liquor is fermented based on the metabolism of special microbial communities in pit. In this study, total proteins and DNAs of microbes from 30- and 300-year pit muds were firstly extracted. Meanwhile, an efficient approach for protein extraction with increased protein content was optimized. iTRAQ-based proteomic was then applied to investigate the aroma-forming functional protein expression of microbes from the samples. Furthermore, high-throughput sequencing of 16S rDNA was employed to reveal microbial diversity. We comparatively identified 63 proteins of aroma-forming functional microbes in these samples, and found that 59 of these proteins were highly expressed in the 300-year pit mud. Those aroma-forming functional proteins were found to be involved in methanogenesis, as well as the formation of caproic acid and butyric acid during the liquor fermentation. High-throughput sequencing revealed that the microbes most commonly found in both samples were members of phylum Firmicutes (by 97% sequence similarity), both of which, along with another common Methanobacterium , were important components of aroma-forming functional colonies in the pit muds for the brewing of Chinese liquor. The findings in this study afford us new insight into the different protein expression levels and microbial communities in two pit muds. [ABSTRACT FROM AUTHOR]

Changes in enological variables, metal ions, and aromas of Fenjiu were examined after 3 years of ageing in ceramic and glass bottles. Container type and ageing time showed significant effects on six enological variables, all metal ions, and most of the aromas. A principal component analysis was performed for aromas exhibiting simultaneous dependence on the container type and ageing time at thep < 0.001 level. The first two components accounted for 81.50% of the overall variance. Sensory analysis indicated that ceramic-aged Fenjiu was of higher quality than glass bottle-aged Fenjiu given the same ageing time. The ceramic container was more suitable for the ageing of Fenjiu. [ABSTRACT FROM PUBLISHER]

Maotai -flavor liquor is produced by simultaneous saccharification and fermentation (SSF), in which filamentous fungi produce hydrolases to degrade the starch into fermentable sugar. Saccharomyces cerevisiae simultaneously transforms the sugars to ethanol and flavor compounds. The saccharification rate plays an important role in regulating the liquor yield and flavor profile. This work investigated the effect of saccharification rate on fermentation by regulating the inoculation ratio (1:0.1, 1:0.5, 1:1, 1:5, 1:10) of S. cerevisiae and Aspergillus oryzae , the main saccharification agent. We found no significant difference in reducing sugar content among the mixed cultures with different ratios. This indicated a balance of the saccharification rate and the sugar consumption rate, in which the former was controlled by the interaction between A. oryzae and S. cerevisiae , and the latter controlled the metabolism of the two species. The ethanol yield was the highest in ratios of 1:0.5, 1:1, and 1:5, while the total production of flavor compounds was the highest for the ratio of 1:0.5, which was mainly attributed to the vigorous metabolism of S. cerevisiae . The inoculum ratio of 1:10 produced the second highest content of flavor compounds in which a large number of alcohols and esters were derived from the vigorous metabolism of A. oryzae . This indicated that the saccharification rate significantly influenced the flavor metabolism. This study improves understanding of the interaction and cooperation between A. oryzae and S. cerevisiae in co-culture fermentation for Chinese liquor making. [ABSTRACT FROM AUTHOR]

Fruit spirits and liqueurs are among the most popular spirit-based beverages made from fruits such as plums, cherries, melon, apple, citrus and pear. The types of fruits and production methods have a great significance for the quality of the final product. The production process of spirits consists of the following stages: fermentation, distillation and maturation. For this reason scientists started to investigate the composition of fruit spirits and liqueurs in order to monitor the changes occurring in the production process and to control the content of selected compounds negatively affecting human health as well as compounds influencing the flavour and aroma of spirits. Furthermore, studies investigating the authenticity of the products and the identification of their botanical and geographical origin were performed. This article is a summarized description of fruit liqueurs and spirits produced from the above-mentioned fruits and the characteristics of commonly used techniques for quality assessment of both types of product. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Aroma compositions of Chinese Daohuaxiang liquors, including five kinds of commercial liquors and three kinds of base liquors, were extracted by solid phase microextraction using a sol–gel divinylbenzene/hydroxy-terminated silicone oil fibre. The effectiveness of the fibre was evaluated in comparison with commercial fibres and liquid–liquid extraction. After identification by GC–MS and GC–O, the compounds were accurately quantified by GC–FID using internal standards. Wide linear ranges, low limits of detection, satisfactory precision and recoveries were achieved. A total of 57 volatile compounds were detected and 28 of them were quantified. Most of them were common in these liquors but differed in terms of their relative amounts. Thirteen out of the 28 compounds had odour activity values greater than 1 in all of the liquors, and are suggested to be the key aroma-contributing substances of Daohuaxiang liquors. Besides, the differences among different aroma types and kinds of Daohuaxiang liquors were also discussed. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the evolution of some physicochemical properties of fermented Zaopei throughout the fermentation. For each layer of Zaopei, the temperature gradually increased to a maximum after about 2 weeks, and then remained stable for about 15 days before it began to decrease; acidity tended to increase during the entire fermentation, while the starch content decreased throughout the fermentation. The reducing sugar content for all layers reached a maximum after one week and decreased afterwards. Ethanol accumulated with time and reached a peak after 5 weeks for each layer, then tended to decrease but rose again slightly after 7 weeks. The moisture content in the top and middle layers increased gradually and reached saturation after 5 weeks, then remained almost unchanged, while the moisture of the bottom layer increased throughout the fermentation. The ethyl caproate, ethyl acetate and ethyl butyrate content of all layers remained almost constant for the first 2 weeks, then increased gradually and reached a maximum after 6 weeks, and subsequently declined slightly. The ethyl lactate of each layer increased throughout the fermentation. The caproic acid, acetic acid, butyric acid and lactic acid in all of the layers reached the highest level on the sixth week, followed by a continuous decrease until week 8, thereafter followed by a slight increase in trend. Additionally, the qualities of the raw liquor distilled from the different layers of Zaopei were investigated and the results demonstrated that the bottom layer possessed the best quality. Copyright © 2015 The Institute of Brewing & Distilling [ABSTRACT FROM AUTHOR]

The present study investigated the variations in main flavor compounds of a Chinese brandy during the second distillation process using headspace-solid-phase microextraction coupled with gas chromatography-mass spectrometry. A total of 97 volatile compounds involving esters, alcohols, aldehydes, ketones, furans, benzene derivatives and terpenes were quantified, and 28 components were identified as key ingredients. By monitoring the second distillation process, it was found that most ethyl esters (ethyl hexanoate, ethyl octanoate, etc.), alcohols (3-methylbutanol, etc.), terpenes (linalool, etc.), acetaldehyde and ionone all had higher values at the beginning of the distillation, but declined gradually or sharply along with the distillation process. However, two esters (ethyl lactate and diethyl succinate), acids (acetic acid, hexanoic acid), benzene derivatives (2-phenylethanol, etc.) and furan (furfural) showed lower levels when the distillation was just started, and gradually increased, accumulating as a large quantity at the end of the distillation. [ABSTRACT FROM AUTHOR]

Grain fermenting with separate layers in a fermentation pit is the typical and experiential brewing technology for Chinese Luzhou-flavor liquor. However, it is still unclear to what extent the bacterial communities in the different layers of fermented grains (FG) effects the liquor's quality. In this study, the spatial distributions of bacterial communities in Luzhou-flavor liquor FG (top, middle, and bottom layers) from 2 distinctive factories (Jiannanchun and Fenggu) were investigated using culture-independent approaches (phospholipid fatty acid [PLFA] and polymerase chain reaction-denaturing gel electrophoresis [DGGE]). The relationship between bacterial community and biochemical properties was also assessed by Canonical correspondence analysis (CCA). No significant variation in moisture was observed in spatial samples, and the highest content of acidity and total ester was detected in the bottom layer ( P < 0.05). A high level of ethanol was observed in the top and middle layers of Fenggu and Jiannanchun, respectively. Significant spatial distribution of the total PLFA was only shown in the 50-y-old pits ( P < 0.05), and Gram negative bacteria was the prominent community. Bacterial 16S rDNA DGGE analysis revealed that the most abundant bacterial community was in the top layers of the FG both from Fenggu and Jiannanchun, with Lactobacillaceae accounting for 30% of the total DGGE bands and Lactobacillus acetotolerans was the dominant species. FG samples from the same pit had a highly similar bacterial community structure according to the hierarchal cluster tree. CCA suggested that the moisture, acidity, ethanol, and reducing sugar were the main factors affecting the distribution of L. acetotolerans. Our results will facilitate the knowledge about the spatial distribution of bacterial communities and the relationship with their living environment. [ABSTRACT FROM AUTHOR]

Ethyl carbamate (EC) is a potential human carcinogen widely existing in fermented foods and alcoholic beverages. The solid-phase extraction (SPE) coupled to gas chromatography mass spectrometry is a widely-used method to determine EC levels, but the accuracy varies with sample matrix and the effects of operation parameters are rarely examined. In this study, the influence factors involved in EC determination were investigated using Chinese liquor as sample matrix, and the improved method was further applied. Three types of SPE columns, including diatomite, Florisil, and primary-secondary amine, were compared in extraction efficiency, and the diatomite column exhibited the highest extraction efficiency. The optimal volumes of elution solvents with diatomite column were 15 mL for 3-mL samples solution loaded. In addition, the alcoholic strength for EC determination should be diluted below 20% (v/v) to avoid the enhancement of matrix-induced chromatographic response. Moreover, the pH neutralization could help improve EC recovery and peak resolution, reducing interfering effects. Based on these results, the improved method showed that the limit of detection, the limit of quantification, and average recoveries were 1.10 μg/L, 3.65 μg/L, and 93.06%, respectively. To further elucidate the underlying factors related to EC accumulation, partial least square regression analysis was conducted, and the results suggested that EC levels had the closest relationship with alcoholic strength among the remaining precursors. [ABSTRACT FROM AUTHOR]

Highlights: [•] The volatile compounds of different brands of Chinese spirits differ with respect to their composition and concentration. [•] The results of the first study on Chinese spirits volatiles analysis using gas-phase infrared spectroscopy were reported. [•] This study demonstrated that different brands of Chinese spirits with the same flavour from the same origin can be differentiated. [Copyright &y& Elsevier]

The aim of this study was to investigate and compare the microbial community structures of eubacteria and archaea in the pit mud of Chinese Luzhou- flavor liquor from the wall (C) and bottom (C) of cellar through nested PCR-denaturing gradient gel electrophoresis (DGGE). The Shannon-Wiener index (H) calculated from the DGGE profiles showed that the community diversities of eubacteria and archaea in samples from C were almost higher than that from C. In addition, cluster analysis of the DGGE profiles revealed that some differences were found in the microbial community structure in samples from different locations. The closely relative microorganisms of all eubacterial 16S rRNA gene sequences fell into four phyla ( Firmicutes, Proteobacteria, Bacteroidetes and Actinobacteria), including 12 genera and 2 uncultured eubacteria. Moreover, 37.1 % eubacteria were affiliated with Clostridium. Particularly, genus Acinetobacter was absent in all samples from C but present in all samples from C. The closely relative microorganisms of all archaeal 16S rRNA gene sequences fell into four genera, which included Methanobrevibacter, Methanoculleus, Methanobacterium and Methanosaeta, while the dominant archaea in samples from C and C were similar. Results presented in this study provide further understanding of the spatial differences in microbial community structure in the pit mud, and is of great importance for the production and quality improvement of Luzhou- flavor liquor. [ABSTRACT FROM AUTHOR]

Abstract: Food quality control and grade identification have an importance for protecting consumer benefits. In this paper, taking Yanghe Daqu for instance, we studied quality grade discrimination of Chinese liquor with strong aroma type. 108 samples were divided into calibration set (81 samples) and validation set (27 samples), whose mass spectra were obtained by head space-solid phase microextraction-mass spectrometry (HS-SPME-MS) technology in the range of m/z 55–191. And then, the partial least squares (PLS) regression and principal component regression (PCR) models were constructed by calibration set and predicted the quality grade of validation set. Discrimination accuracy of the PLS model was >96.3% for both calibration set and validation set, which was obviously superior to PCR model. The support vector machine (SVM) models were built by different ion selection methods, PLS regression coefficients, PLS X-loading, PCR regression coefficients, and PCR X-loading. Of these, the optimal SVM model was achieved with ions (m/z 112, 134, 140, 162, 167, 168, 175, 187, and 191) selected by PLS regression coefficients, whose prediction accuracy for the validation set was up to 92.6%. The overall results indicated that the PLS regression coefficients was a powerful way for selecting effective ion variables and mass spectrometry combined with SVM could well discriminate the quality grade of liquor. [Copyright &y& Elsevier]

Abstract: The pit mud (PM), a specific fermented soil, is an essential material for the fermentation of strong aromatic liquor. The microbial diversities of PM from different ages of strong aromatic liquor fermentation pits (20-, 50-, 100-, 200- and 300-year old) were investigated using combined phospholipid fatty acids (PLFAs) and polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) methods. The total PLFA content of 20-year-PM (477.32nmol/g) was significantly higher than that of other PMs (P <0.05), and G+ bacteria biomarkers' biomass dominated in PMs. Results of bacterial 16S rDNA gene fragment analysis suggested that a total of 31 bands belong to 8 families Clostridiaceae, Lactobacillaceae, Synergistaceae, Sphingomonadaceae, Ruminococcaceae, Clostridiales_Incertae Sedis XI, Lanchnospiraceae and Plannococcaceae) were identified, and Clostridiales (11 bands), Lacotobacillales (5 bands) and Bacillales (3 bands) were main microorganisms in PM. Fungal 18S rDNA gene fragment identification demonstrated that a total of 6 bands identified, and only 3 genus, Wickerhamomyces, Kluyveromyces and Pichia, were sequenced and Pichia anomala was the main yeast in PM. This is the first report about the microbial community structure and diversity in PMs of different ages by combined PLFA and PCR-DGGE analyses. [Copyright &y& Elsevier]

The potential of Bacillus licheniformis as a starter culture for aroma concentration improvement in the fermentation of Chinese Moutai-flavour liquor was elucidated. The volatile compounds produced by B. licheniformis were identified by GC- MS, in which C4 compounds, pyrazines, volatile acids, aromatic and phenolic compounds were the main ingredients. The strains B. licheniformis ( MT-6 and MT-15) produced more volatile compound concentrations, mainly C4 compounds, than the type strain of B. licheniformis ( ATCC 14580) at the fermentation temperature of 55°C. Meanwhile, more volatile compound concentrations were produced by B. licheniformis in solid-state fermentation than in submerged state fermentation. Thus, the strains MT-6 and MT-15 were used as the Bacillus starter culture for investigating Moutai-flavour liquor production. The distilled liquor inoculated with Bacillus starter culture was significantly different from the liquor without inoculum. This was particularly evident in the fore-run part of the distilled sample which was inoculated with Bacillus starter culture, where volatile compounds greatly increased compared to the control. Furthermore, the distilled liquor with Bacillus starter culture showed improved results in sensory appraisals. These results indicated that B. licheniformis was one of the main species influencing the aroma characteristics of Moutai-flavour liquor. Significance and Impact of the Study This is the first report of an investigation into the effect of Bacillus starter cultures on the flavour features of Moutai-flavour liquor, which verified that Bacillus licheniformis can enhance aroma concentration in Moutai-flavour liquor. Bacillus starter culture brought C4 compounds, pyrazines, volatile acids, aromatic and phenolic compounds to the liquor, which gave a better result in sensory appraisals. [ABSTRACT FROM AUTHOR]

Pits are necessary solid bioreactors for the production of Chinese strong aromatic liquor, and the microbial community in these pits significantly affects the quality and yield of the liquor. In this study, the microbial community structures of different aged pit muds were evaluated by phospholipid fatty acid analysis. The results indicated that the microbial community was composed of bacteria, actinomycetes and fungi, with Gram-positive (G+) bacteria and anaerobic bacteria being dominant. The biomass of the pit mud increased and the microbial community shifted to G+ bacteria as the pit age increased. Principal component analysis showed that PC1 consisted mainly of fatty acids of saturated (15:0, 16:0 and 18:0), methyl-branched ( a15:0, i16:0, a16:0, i17:0 and 8Me18:0), polyunsaturated (16:1 ω7c, 16:1 ω9) and cyclopropane ( cy17:0 and cy19:0), and PC2 mainly of 18:1 ω9, 18:1 ω10 and a14:0, The characteristics of the microbial community structure in the pit mud resulted from the stress effects of low oxygen concentration, low pH and a high alcohol concentration. Copyright © 2013 The Institute of Brewing & Distilling [ABSTRACT FROM AUTHOR]

The volatile flavour compounds of different Chinese traditional rice wines and the corresponding representative fungi in the wheat Qu (comparable to the koji used in sake brewing) samples were investigated. Results showed that alcohols, acids and esters were abundantly present in the three Chinese rice wines, but the types and concentrations of the volatile flavour compounds by fermentation from different wheat Qu samples were quite distinctive. Cladosporium cladosporioides, Penicillium chrysogenum, Aspergillus oryzae and Saccharomyces cerevisiae were the major components of the fungal flora in the three kinds of wheat Qu samples. Less prevalent genera and species represented in the fungal communities of the three kinds of wheat Qu samples, however, varied greatly, and the richer the flavour substances in the rice wines were, the more abundant the microbe species in the corresponding wheat Qu samples. The results indicate that the types and concentrations of volatile compounds were significantly influenced by the species of microorganisms (moulds and yeasts) in the wheat Qu, which brings a unique flavour to Chinese rice wine. Copyright © 2012 The Institute of Brewing & Distilling [ABSTRACT FROM AUTHOR]

Ginger (Zingiber officinalis, Roscoe) is a common ingredient in various foods and beverages. It contains potent anti-inflammatory agents and oleoresin, in which 6-gingerol and 6-shogaol are major active compounds. Studies show that 6-shogaol has stronger anti-inflammatory effects. The objectives of this study were to investigate the yield of ginger oils obtained by freeze drying at −80°C, solar drying at atmospheric conditions, and hot air drying at temperatures ranging from 40–80°C and to study the effect of temperature on the transformation of 6-gingerol into 6-shogaol. Dehydrated ginger samples obtained using the drying methods mentioned above were subjected to grinding and the powder was then subjected to supercritical fluid extraction (SFE) to extract ginger oils. The results showed that drying temperatures lower than 70°C resulted in a higher yield of ginger oil (2.4–2.6%, p < 0.05). Scanning electron microscope (SEM) images showed that high drying temperatures caused starch gelatinization during the drying process and thus reduced the yields of extracted ginger oil. However, drying temperatures lower than 70°C did not promote the transformation of 6-gingerol (113.31 mg/mL, with a peak at 12.01 min) to 6-shogaol (6.05 mg/mL, with a peak at 29.85 min). High-performance liquid chromatography (HPLC) showed that drying temperatures higher than 80°C could induce the transformation, and the amount of 6-gingerol was as high as 12.73% compared to 3.5–5.5% using other methods with temperatures lower than 80°C (p < 0.05). In addition, this study revealed that solar drying had no effect on the transformation process, probably because of the low temperatures in solar drying. [ABSTRACT FROM AUTHOR]

Abstract: When the information given by a panel of judges on wine sensory characteristics is resumed in a three-way table, Y , and the objective is to extract knowledge from a chemical data-set, X, which has a predictive power for wine sensorial variables, the study of the relationships between chemical–physical variables and sensorial data sets is really complex. In this paper after resuming the information in Y , we propose to consider multivariate additive partial least squares via splines, recently presented in literature, to predict Y by X. [Copyright &y& Elsevier]

Acetaldehyde is relevant for wine aroma, wine color, and microbiological stability. Yeast are known to play a crucial role in production and utilization of acetaldehyde during fermentations but comparative quantitative data are scarce. This research evaluated the acetaldehyde metabolism of 26 yeast strains, including commercial Saccharomyces and non- Saccharomyces, in a reproducible resting cell model system. Acetaldehyde kinetics and peak values were highly genus, species, and strain dependent. Peak acetaldehyde values varied from 2.2 to 189.4 mg l and correlated well ( r = 0.92) with the acetaldehyde production yield coefficients that ranged from 0.4 to 42 mg acetaldehyde per g of glucose in absence of SO. S. pombe showed the highest acetaldehyde production yield coefficients and peak values. All other non- Saccharomyces species produced significantly less acetaldehyde than the S. cerevisiae strains and were less affected by SO additions. All yeast strains could degrade acetaldehyde as sole substrate, but the acetaldehyde degradation rates did not correlate with acetaldehyde peak values or acetaldehyde production yield coefficients in incubations with glucose as sole substrate. [ABSTRACT FROM AUTHOR]

The perception of wine flavor and aroma is the result of a multitude of interactions between a large number of chemical compounds and sensory receptors. Compounds interact and combine and show synergistic (i.e., the presence of one compound enhances the perception of another) and antagonistic (a compound suppresses the perception of another) interactions. The chemical profile of a wine is derived from the grape, the fermentation microflora (in particular the yeast Saccharomyces cerevisiae), secondary microbial fermentations that may occur, and the aging and storage conditions. Grape composition depends on the varietal and clonal genotype of the vine and on the interaction of the genotype and its phenotype with many environmental factors which, in wine terms, are usually grouped under the concept of 'terroir' (macro, meso and microclimate, soil, topography). The microflora, and in particular the yeast responsible for fermentation, contributes to wine aroma by several mechanisms: firstly by utilizing grape juice constituents and biotransforming them into aroma- or flavor-impacting components, secondly by producing enzymes that transform neutral grape compounds into flavor-active compounds, and lastly by the de novo synthesis of many flavor-active primary (e.g., ethanol, glycerol, acetic acid, and acetaldehyde) and secondary metabolites (e.g., esters, higher alcohols, fatty acids). This review aims to present an overview of the formation of wine flavor and aroma-active components, including the varietal precursor molecules present in grapes and the chemical compounds produced during alcoholic fermentation by yeast, including compounds directly related to ethanol production or secondary metabolites. The contribution of malolactic fermentation, ageing, and maturation on the aroma and flavor of wine is also discussed. [ABSTRACT FROM AUTHOR]

There have been numerous developments in ethanol fermentation technology since the beginning of the new millennium as ethanol has become an immediate viable alternative to fast-depleting crude reserves as well as increasing concerns over environmental pollution. Nowadays, although most research efforts are focused on the conversion of cheap cellulosic substrates to ethanol, methods that are cost-competitive with gasoline production are still lacking. At the same time, the ethanol industry has engaged in implementing potential energy-saving, productivity and efficiency-maximizing technologies in existing production methods to become more viable. Very high gravity (VHG) fermentation is an emerging, versatile one among such technologies offering great savings in process water and energy requirements through fermentation of higher concentrations of sugar substrate and, therefore, increased final ethanol concentration in the medium. The technology also allows increased fermentation efficiency, without major alterations to existing facilities, by efficient utilization of fermentor space and elimination of known losses. This comprehensive research update on VHG technology is presented in two main sections, namely VHG brewing, wherein the effects of nutrients supplementation, yeast pitching rate, flavour compound synthesis and foam stability under increased wort gravities are discussed; and VHG bioethanol fermentation studies. In the latter section, aspects related to the role of osmoprotectants and nutrients in yeast stress reduction, substrates utilized/tested so far, including saccharide (glucose, sucrose, molasses, etc.) and starchy materials (wheat, corn, barley, oats, etc.), and mash viscosity issues in VHG bioethanol production are detailed. Thereafter, topics common to both areas such as process optimization studies, mutants and gene level studies, immobilized yeast applications, temperature effect, reserve carbohydrates profile in yeast, and economic aspects are discussed and future prospects are summarized. [ABSTRACT FROM AUTHOR]

Abstract: Moderate consumption of wine, beer, whisky or liqueur is known to be beneficial for improving health because of the radical scavenging action of antioxidants present in them. Thus, antioxidant and aroma properties of anthograin liqueur made from purple wheat grain were evaluated for the added-value processing purpose of that grain. Anthograin liqueur showed the highest 2,2-diphenyl-1-picryhydrazyl (DPPH) free radical scavenging activity, total phenolic content (TPC) and oxygen radical absorbance capacity (ORAC) in comparison with three control samples Canadian iceberg vodka (CIV), Hiram walker special old rye whisky (HWSORW) and Wiser’s De Luxe Canadian whisky (WDLCW). Only anthograin liqueur contained anthocyanins and its total anthocyanin content (TAC) was 81mg/l. In lipid-soluble phase, TPC and ORAC were 241.1 and 998.6mg/l for anthograin liqueur, 40.0 and 93.6mg/ld for WDLCW, 23.1 and 63.6mg/l for HWSORW, and 1.1 and 12.4mg/l for CIV, respectively. In water-soluble phase, TPC and ORAC were 685.5 and 1467.7mg/l for anthograin liqueur, 29.0 and 96.0mg/l for WDLCW, 36.4 and 99.2mg/l for HWSORW, and 2.0 and 42.8mg/l for CIV, respectively. Eight types of phenolic acids in anthograin liqueur, four types of phenolic acids in WDLCW and three types of phenolic acids in HWSORW were found and no phenolic acid was detectable in CIV. Total phenolic acids in anthograin liqueur, WDLCW and HWSORW were 28.8, 10.3 and 5.7mg/l, respectively. Similarity in aroma quality was found between anthograin liqueur and CIV by using the electronic nose. Purple wheat grain may have potential as a novel material for liqueur brewing. [Copyright &y& Elsevier]

Abstract: To characterize the aroma of cherry wine, five samples were analyzed by quantitative descriptive sensory analysis, gas chromatography–mass spectrometry (GC–MS) and gas chromatography–olfactometry (GC–O). The aroma of cherry wines was described by 6 sensory terms as fruity, sour, woody, fermentation, cameral and floral. Fifty-one odor-active (OA) compounds were detected by GC–O and quantified by GC–MS, and 45 of them were identified. Twenty-nine OA compounds having more than 50% detection frequency were selected as specific compounds correlated to sensory attributes by partial least squares regression (PLSR). The correlation result showed ethyl 2-methyl propionate, 2,3-butanedione, ethyl butyrate, ethyl pentanoate, 3-methyl-1-butanol, ethyl hexanoate, 3-hydroxy-2-butanone, ethyl lactate, 1-hexanol, (Z)-3-hexen-1-ol, ethyl hydroxyacetate, acetic acid, furfural, 2-ethyl-1-hexanol, benzaldehyde, propanoic acid, butanoic acid, guaiacol, beta-citronellol, hexanoic acid, 2-methoxy-4-methylphenol, 2-ethyl-3-hydroxy-4H-pyran-4-one, ethyl cinnamate, 2-methoxy-4-vinylphenol were typical OA compounds, which covaried with characteristic aroma of cherry wines. [Copyright &y& Elsevier]

In Scotch malt whisky production, the use of copper for the construction of the pot stills for distillation is regarded as having an important effect on whisky aroma. During distillation in copper pot stills, the copper acts to reduce sulphury aromas in the resultant spirit by reducing the levels of sulphur compounds such as dimethyl trisulphide (DMTS). This work has shown that the copper is more effective in this role in some parts of the pot stills than others. This information can be used to help distillers maintain or, indeed, to alter new make spirit aroma. It was also noted that in addition to DMTS, other, as yet unidentified, compounds make a significant contribution to sulphury aromas, so future research efforts should focus on identifying such compounds. [ABSTRACT FROM AUTHOR]

Abstract: This paper presents the application of comprehensive two-dimensional gas chromatography and time-of-flight mass spectrometry (GC×GC/TOFMS) using the longitudinal modulated cryogenic system (LMCS) device, to the aroma analysis of spirit samples. The volatile organic compounds present in samples of a Brazilian cane sugar spirit were collected by using a solid-phase microextraction (SPME) method. Other samples studied included gin, vodka, whiskey, tequila and flavoured liqueurs. In this study GC×GC/TOFMS with a bi-dimensional non-polar – polar phase column set comprising of a first dimension BPX5 primary column and a second dimension BP20 second column enabled the tentative identification of 95 compounds in cachaça. In excess of 200 compounds were found amongst group of samples that were analysed. The results, presented as peak apex plots, showed that groups of compounds were present in well-defined regions of the 2D separation space in each beverage, making it possible to recognise the differences and similarities among the spirit samples. [Copyright &y& Elsevier]