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Cigar tobacco leaves exhibited distinct regional characteristics, and aroma compounds were the key substances determining the different style features of cigars. However, the differences in aroma characteristics and the mechanisms of key aroma compound synthesis have not been fully elucidated. This study collected filler tobacco leaves (FTLs) from 5 representative domestic and international production regions. Gas chromatography-mass spectrometry (GC-MS) identified aroma compounds, an aroma wheel was established based on odor activity values (OAV), and principal component analysis (PCA) and orthogonal partial least squares discriminant analysis (OPLS-DA) revealed major differences. Synthesis pathways of key differential components were further explored using the Kyoto Encyclopedia of Genes and Genomes (KEGG). In this study, 56 aroma compounds were identified in FTLs. Imported-FTLs (IMP-FTLs) contained higher levels of ketones and esters, along with moderate nicotine content, and exhibited a more noticeable sour and woody aroma. In contrast, Domestic-FTLs (DOM-FTLs) had a greater distribution of aldehydes, phenols, and neophytadiene, presenting a more prominent bean, burnt-sweet, and floral aroma. Nine compounds, including sclareol, 5-methylfurfural, and (E)-5-isopropyl-8-methylnona-6,8-dien-2-one, were identified as key differential components, and their synthesis primarily involves pathways such as phenylalanine metabolism and carotenoid biosynthesis. These findings provided a novel perspective on the targeted enhancement of key aroma compounds, which was significant for improving the aroma quality of filler tobacco leaves. [ABSTRACT FROM AUTHOR]

The effect of frozen storage (−18°C for 2 months) and thawing (4°C for 16 h) on the taste-related compounds and volatile organic compounds (VOCs) in chicken breast meat was studied. After freeze–thawing, inosine monophosphate levels in chicken meat decreased and inosine levels increased. Free amino acid content increased significantly, regardless of bitter, sweet, or umami amino acids. Increase in arachidonic, eicosapentaenoic, adrenic, and docosahexaenoic acids after freeze–thaw cycle was observed suggesting the impact of lipid oxidation during freezing and thawing. Total 95 VOCs were detected, and multivariate analysis discriminated the differences in aroma- and taste-related compounds. The variable importance in the projection score indicated that the total amounts of sweet and bitter amino acids, inosine monophosphate, ketones, oxetane, and 3,3-dimethyl-2-butanone were important in discriminating between fresh and frozen–thawed chicken meat. The freeze–thawing altered the flavor of fresh chicken meat, and these important compounds could be utilized as markers for characterizing fresh or frozen-thawed meat.

Flat black tea (FBT) has been innovatively developed to alleviate homogenisation competition, but the dynamic changes in aroma components during the process remain unclear. This study employed HS-SPME-GC-MS to analyse the aroma components of tea samples from various processing stages of FBT, and to make a comparative assessment with conventional strip-like Congou black tea (SBT). Additionally, a proteomic analysis was conducted on fresh leaves, withered leaves, and frozen–thawed leaves. Significant changes were observed in the aroma components and proteins during the processing. The results of the multivariate and odour activity value analysis demonstrated that the principal aroma components present during the processing of FBT were linalool, (E)-2-hexen-1-al, methyl salicylate, geraniol, hexanal, benzeneacetaldehyde, (Z)-3-hexenyl butyrate, dimethyl sulphide, 2-methylbutanal, 2-ethylfuran, nonanal, nonanol, 3-methylbutanal, (Z)-3-hexen-1-ol, 2-pentylfuran, linalool oxide I, and β-myrcene. Freezing–thawing and final roasting are the key processing steps for forming the aroma quality of FBT. The final roasting yielded a considerable quantity of pyrazines and pyrroles, resulting in a high-fried aroma, but caused a significant reduction in linalool, geraniol, β-myrcene, and esters, which led to a loss of floral and fruity aromas. The freezing–thawing treatment resulted in an accelerated loss of aroma substances, accompanied by a decrease in the expression level of lipoxygenase and 2-C-methyl-D-erythritol 2,4-cyclodiphosphate synthase. The formation of aroma substances in the linoleic acid metabolic pathway and terpenoid metabolic process was hindered, which had a negative impact on tea aroma. This study elucidates the causes of unsatisfactory aroma quality in tea products made from frozen tea leaves, providing theoretical support for the utilisation of frostbitten tea leaves, and helps us to understand the mechanism of aroma formation in black tea. [ABSTRACT FROM AUTHOR]

Cigar tobacco leaves exhibited distinct regional characteristics, and aroma compounds were the key substances determining the different style features of cigars. However, the differences in aroma characteristics and the mechanisms of key aroma compound synthesis have not been fully elucidated. This study collected filler tobacco leaves (FTLs) from 5 representative domestic and international production regions. Gas chromatography-mass spectrometry (GC-MS) identified aroma compounds, an aroma wheel was established based on odor activity values (OAV), and principal component analysis (PCA) and orthogonal partial least squares discriminant analysis (OPLS-DA) revealed major differences. Synthesis pathways of key differential components were further explored using the Kyoto Encyclopedia of Genes and Genomes (KEGG). In this study, 56 aroma compounds were identified in FTLs. Imported-FTLs (IMP-FTLs) contained higher levels of ketones and esters, along with moderate nicotine content, and exhibited a more noticeable sour and woody aroma. In contrast, Domestic-FTLs (DOM-FTLs) had a greater distribution of aldehydes, phenols, and neophytadiene, presenting a more prominent bean, burnt-sweet, and floral aroma. Nine compounds, including sclareol, 5-methylfurfural, and (E)-5-isopropyl-8-methylnona-6,8-dien-2-one, were identified as key differential components, and their synthesis primarily involves pathways such as phenylalanine metabolism and carotenoid biosynthesis. These findings provided a novel perspective on the targeted enhancement of key aroma compounds, which was significant for improving the aroma quality of filler tobacco leaves.

Diguo (Ficus tikoua Bur.), an ancient wild fruit, is widely spread in southwest China. However, there is little information on the phenotypic traits, quality characteristics, and aroma compounds available to diguo fruit. The present study is an investigation into the effects of geographical origin on the phenotypic traits and quality characteristics of wild diguo fruit collected from southwest China. The volatile compounds in the mixed fruit samples were also investigated using gas chromatography–mass spectrometry. Our results indicated that significant variation existed among the sampling materials in all the phenotypic parameters. Fruit fresh weight ranged between 2.06 and 4.59 g. Moreover, significant variation existed among the selected materials in all macronutrients (dry matter, total soluble solids, crude protein, crude fat, and ash) and some nutritional parameters (glutamate, arginine, total soluble solids, maltose, and mannose, etc.). Regardless of their geographical origin, diguo fruit is relatively low in fat and fructose and high in fiber and glutamate. A total of 95 volatile constituents were identified in the frozen diguo fruit. In conclusion, diguo fruit with rich nutritional attributes has a promising future for commercial‐scale production. The variability of the observed morphological and nutritional features of diguo fruit provides important characteristics for improving the breeding of diguo as a modern fruit crop. [ABSTRACT FROM AUTHOR]

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Cigar tobacco residues are a special air-cured tobacco material with increasing production in domestic. In this present study, the effect of glycerol addition on the pyrolysis characteristic, kinetic behavior, and release of pyrolytic products was investigated by using thermogravimetry coupled with online FTIR and self-built infrared tubular furnace. The thermal weight loss process of cigar tobacco could be divided into four stages, and the glycerol exhibited significant impact on the pyrolysis process. The stage II corresponding the decomposition of volatile components and hemicellulose shifted to the lower temperature accompanied with an increase of DTGmax and weight loss at this stage. The Ti, Tf, and residues were decreased, while the CPI was increased as for the CT-G sample, indicating an increased reactivity and comprehensive pyrolysis performance. Gauss peak fitting was used to separate the pyrolysis process of different pseudocomponents in the tobacco biomass. Pyrolysis kinetic analysis based on Coats-Redfern method showed that the activation energy for the decomposition of each pseudocomponents decreased after the addition of glycerol. The online FTIR and MS analysis also reflected the interaction between glycerol and biomass through the release of pyrolytic gaseous products. GC–MS was further used to analyze the compositions of pyrolytic products in the trapped particulate matter under different heating rates. High heating rate was beneficial for the sufficient release of pyrolysis products and aroma compounds. The glycerol addition inhibited the generation of alkaloids, phenols, esters, ketones, acids, and heterocyclic compounds, indicating some effect may exist between cigar tobacco and glycerol. [ABSTRACT FROM AUTHOR]

Copyright of China Brewing is the property of China Brewing Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This study was investigated the effect of adding fat to pork sausage on taste and aroma persistence. Sensory evaluation indicated that increasing fat content intensified umami and saltiness perception, enhancing the mouthfulness and flavor persistence, leading to Koku enhancing effect. Gas chromatography/mass spectrometry (GC/MS) analysis identified aroma compounds such as β-pinene, 3-carene, D-limonene, octanal, nonanal, caryophyllene, and methyl eugenol, which were consistently present regardless of fat content. These aroma compounds were less likely to be released as the fat content increased. Furthermore, the release of these aroma compounds from the sausage with addition of fat was larger than that without addition of fat in the presence of saline, indicating that the added fat retained these aroma compounds and released them in the presence of saline. This suggests that sausages with added fat release more aroma compounds during consumption, resulting in a more intense flavor and flavor persistence of Koku perception. These seven compounds detected in pork sausage were found to be easily retained by cholesterol and lecithin, likely due to differences in their log P values (octanol/water partition coefficients), which were greater than 3. [ABSTRACT FROM AUTHOR]

Copyright of China Brewing is the property of China Brewing Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This study investigated the effect of polyols erythritol, d-mannitol, and maltitol on the volatility of aroma compounds γ-butyrolactone, 3-methyl-1-butanol, and 2-phenylethanol in aqueous solution. Headspace solid-phase microextraction/gas chromatography and diffusion-ordered nuclear magnetic resonance techniques were used to obtain information on aroma–food matrix interaction. Results demonstrated that adding polyols at final low concentrations of 5% or 10% (w/w) to an aqueous solution of 2-phenylethanol reduced the release of vapor-phase aromas, except in the case of 3-methyl-1-butanol, which was not affected by the presence of polyols in the liquid matrix. Polyols also reduced the diffusion coefficients of all three aroma compounds, probably due to friction between the molecules. At low polyol concentrations, aroma compound volatility and diffusion coefficient values were altered compared to those of aromas released from pure water. This observation is related to the physicochemical properties of the aroma compounds. These insights may help guide the use of the combination of aroma compounds and polyols in the formulation of sugar-free and reduced-sugar beverages. Chemical compounds: γ-butyrolactone (PubChem CID: 7302), 3-methyl-1-butanol (PubChem CID: 31260), 2-phenylethanol (PubChem CID: 6054), erythritol (PubChem CID: 222285), d-mannitol (PubChem CID: 6251), maltitol (PubChem CID: 493591).

Flat black tea (FBT) has been innovatively developed to alleviate homogenisation competition, but the dynamic changes in aroma components during the process remain unclear. This study employed HS-SPME-GC-MS to analyse the aroma components of tea samples from various processing stages of FBT, and to make a comparative assessment with conventional strip-like Congou black tea (SBT). Additionally, a proteomic analysis was conducted on fresh leaves, withered leaves, and frozen–thawed leaves. Significant changes were observed in the aroma components and proteins during the processing. The results of the multivariate and odour activity value analysis demonstrated that the principal aroma components present during the processing of FBT were linalool, (E)-2-hexen-1-al, methyl salicylate, geraniol, hexanal, benzeneacetaldehyde, (Z)-3-hexenyl butyrate, dimethyl sulphide, 2-methylbutanal, 2-ethylfuran, nonanal, nonanol, 3-methylbutanal, (Z)-3-hexen-1-ol, 2-pentylfuran, linalool oxide I, and β-myrcene. Freezing–thawing and final roasting are the key processing steps for forming the aroma quality of FBT. The final roasting yielded a considerable quantity of pyrazines and pyrroles, resulting in a high-fried aroma, but caused a significant reduction in linalool, geraniol, β-myrcene, and esters, which led to a loss of floral and fruity aromas. The freezing–thawing treatment resulted in an accelerated loss of aroma substances, accompanied by a decrease in the expression level of lipoxygenase and 2-C-methyl-D-erythritol 2,4-cyclodiphosphate synthase. The formation of aroma substances in the linoleic acid metabolic pathway and terpenoid metabolic process was hindered, which had a negative impact on tea aroma. This study elucidates the causes of unsatisfactory aroma quality in tea products made from frozen tea leaves, providing theoretical support for the utilisation of frostbitten tea leaves, and helps us to understand the mechanism of aroma formation in black tea.

In order to investigate the differences of aroma components and aroma profiles in segmented smoke of cigars, gas chromatography-mass spectrometry (GC-MS) was used to detect the aroma compounds of Great Wall No. 2 and Montecristo No. 4 cigars, supplemented by sensory evaluation and odor contribution weight to investigate the aroma characteristics of cigars, and the key aroma components in cigars were screened based on partial least squares discriminant analysis (PLS-DA). The results showed that the cigar was shorter, the interception effect was weakened, and the quantity and release of aroma components in cigar smoke were increased during smoking. In the odor contribution weight of segmented smoke of cigars, the bean and woody aromas of Great Wall No. 2 weakened and the coffee aroma increased as smoking proceeded, while the bean aroma of Montecristo No. 4 weakened and the spicy aroma increased. These changes in odor contribution weight were consistent with the results of the sensory evaluation. 12 key differential aroma components such as γ-hexalactone, 2-furoic acid, acetophenone, phenylacetic acid, 2,6-dimethylpyrazine were obtained during the smoking process of Great Wall No. 2, and 11 key differential aroma components such as cedrol, 2-methylbutyraldehyde, 2-methoxy-4-vinylphenol, guaiacol, γ-nonanolactone were obtained during the smoking process of Montecristo No. 4. The results of this study reflected the change rules of smoke composition in the smoking process of cigar and explained the reasons for the flavor changes in the smoking process of cigar. [ABSTRACT FROM AUTHOR]

Summary: This study aimed to investigate aroma compound transformation and precursor relation in dry‐shredded beef using gas chromatography–ion mobility spectrometry, gas chromatography–mass spectrometry, high‐performance liquid chromatography, and electronic nose technologies. Forty‐eight aroma compounds were identified, of which twelve (pentanal, hexanal, heptanal, 3‐methylbutanal, nonanal, phenylacetaldehyde, trans‐2‐decenal, acetoin, 3‐octenol, 3‐octanol, ethyl hexanoate, and 2‐acetylthiazol) exhibited odour activity values (OAVs) >1. The concentration of fatty acids (FAs) decreased progressively, while that of 19 free amino acids (FAAs) increased with prolonged cooking. Pearson's correlation analysis revealed correlations between aroma components (OAV >1), FAAs, and FAs. Specifically, 2‐acetylthiazol, acetoin, heptanal, 3‐methylbutanal, and hexanal exhibited positive correlations, while phenylacetaldehyde and trans‐2‐decenal showed inverse correlations with most FAAs. Notably, phenylacetaldehyde positively correlated with C16:0, C18:1, n9c, and C18:2, n6c. This research presents a practical framework for the application of analytical and computational techniques in the commercial production of cooked beef and meat products. [ABSTRACT FROM AUTHOR]

The study examined the functional properties of lactic yeast-fermented Tartary buckwheat sprout with passion and pineapple juice (Tatary buckwheat sprout juice). Pineapple and passion fruit were included during fermentation to improve the sensory and nutritional quality of the juice. We initially created a juice with Tartary buckwheat sprouts, and then fermented it with Lactobacillus plantarum and yeast (Saccharomyces cerevisiae) to produce a novel fermented sprout juice. Our results indicated that the best organoleptic quality was achieved when the inoculum of Lactobacillus plantarum was 2%, the inoculum of yeast was 1%, and the fermentation time was 30 hours. The results showed that fermentation resulted in a 1.55-fold increase in the total amino acid content, with fresh sweet amino acids increasing by 1.75-fold and sour-bitter amino acids increasing by 1.33-fold. Additionally, the levels of acetic acid, lactic acid, citric acid, and tartaric acid in the buckwheat sprout juice increased by 12.31%, 11.45%, 4.22%, and 3.88%, respectively. GC-MS analysis revealed a significant increase of volatile flavoring substances, such as alcohols and esters, by more than 24.7% in the fermentation products. From the results, yeast-Lactobacillus fermentation process may effectively improve the nutritional values of Tartary buckwheat sprout juice. [ABSTRACT FROM AUTHOR]

The aroma extract dilution analysis (AEDA) applied to the volatile fraction of fresh perilla leaves (Oba) revealed 11 odor-active peaks with high flavor dilution (FD)-factors (≥4). Among the perceived odorants, trans-1,2-dihydroperillaldehyde (DHP), which has a unique note, such as curry-like spicy, was a newly identified compound in the fresh perilla leaf. Although DHP does not necessarily have a high FD-factor, it was difficult to determine the perilla aroma; thus we were interested in its role in the fresh perilla aroma. Therefore, the role of DHP in perilla aroma was demonstrated by the causal model based on sensory evaluation and PLS regression analysis. Consequently, it was clarified that DHP is an aroma component that enhances the "refreshing feeling of perilla" and, also plays an important role in improving its palatability. [ABSTRACT FROM AUTHOR]

The retention ability of polycaprolactone (PCL) films and their potential use for applications that require controlled release, were evaluated using eugenol, an aroma compound as a model active substance. The PCL‐eugenol samples were prepared by means of a low‐temperature extrusion process that resulted in minimum losses of eugenol and a final proportion close to nominal content. The release kinetics of eugenol were monitored for different conditions of temperature and relative humidity, both by an usual gas chromatography analysis but also by spectroscopy method that revealed sufficient. The release kinetics were compared to the numerical results obtained by the resolution of Fickian and a power‐law models. Results showed that the temperature had an influence on the release rate, and that the release kinetics were mostly Fickian. Moreover, the determination of the Arrhenius parameters will allow the use of the Fickian model to dimension PCL samples for other applications requiring controlled release. [ABSTRACT FROM AUTHOR]

Using gas chromatography-mass spectrometry (GC-MS), a metabolomic analysis of volatile metabolites of "19 Xiang" milk-ripe stage endosperm grains grown in Longchuan City and Lianshan City, Guangdong Province was conducted. The effect of origin on the formation of aroma compounds in aromatic rice was also explored by identifying the genes related to the formation of aroma compounds using transcriptome technology. Multivariate statistical analysis was performed on the original data using principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA). The results showed that the content of volatile substances in "19 Xiang" varied among grains planted in different places, exhibiting significant differences in the relative contents of 14 aroma substances. KEGG enrichment analysis revealed that the biosynthetic pathways of secondary metabolites significantly affected on the content of aroma substances. At the transcriptional level, taking the Lianshan group as the control, the samples of the Longchuan group had 56 significantly upregulated genes and 89 downregulated genes, which were mainly associated with biological processes such as catabolism of organic matter and polysaccharide metabolism. In conclusion, different planting environments greatly influence the content of aroma substances in aromatic rice, and carbohydrate metabolism activities and stress response-related mechanisms at the milking stage may be crucial factors regulating the content of aroma substances in the planting environment. [ABSTRACT FROM AUTHOR]

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【Objective】Aroma is one of the important evaluation indicators to measure the quality of food. Nine-process Dried Tangerine Peel is famous for its unique aroma. The study was carried out to compare the effects of different drying methods in the aroma of tangerine peel.【Method】Gas chromatography-ion mobility spectroscopy (GC-IMS) was used to compare and analyze the volatile flavor compounds of dried tangerine peel made by two drying methods (baking and sun-drying). According to the characteristics of volatile compounds, flavor fingerprints and sensory analysis and Partial Least-Squares Regression (PLSR) analysis, the differences between different products were explored.【Result】The two samples shared 46 kinds of monomers and dimers and trimers of some substances, mainly including aldehydes, alcohols, esters, ketones, olefins, acids and furans. According to the fingerprints, there are differences in the types and contents of the volatile aroma components contained in the two samples. Among them, six characteristic substances such as ethyl phenylacetate, ethyl acetate and 3-methylbutyraldehyde were the main characteristic volatile flavor components of the sun-dried samples, while 13 components such as 2-methyl-1-butanol, (E)-2-hexen-1-ol, (Z)-3-hexen-1-ol, cyclohexanone, γ-caprolactone were the main characteristic volatile flavor components of the baked samples, which had a richer aroma. PLSR analysis of baked samples had a higher correlation with the citrus aroma, hay aroma, fruity and sweetness attribute intensity, which were better than those of sun-dried samples, further verifying the accuracy of GC-IMS analysis results and sensory analysis results of Nine-process Dried Tangerine Peel.【Conclusion】GC-IMS can quickly identify and distinguish the volatile flavor compounds of the Nine-process Dried Tangerine Peel prepared by baking and sun-drying, and the Nine-Process Dried tangerine peel prepared by baking has a richer aroma.

Background and Aims: Water deficit modifies the concentration of the aroma compounds of grape berries, but little information is available on the effect of deficits applied at different phenological stages. We evaluated the effect of deficit irrigation on glycosylated volatile organic compounds (VOCs) responsible for the aroma of berries of Sangiovese and Merlot cultivars grafted on 1103P or SO4 rootstocks. Methods and Results: Vines were subjected to either pre‐ or post‐veraison water stress, and berry composition compared against that of fruit of fully irrigated vines. At harvest, a higher concentration of glycosylated VOCs was measured in berries from vines stressed pre‐veraison, but while it increased as water deficit increased in Sangiovese, this occurred only at a low or moderate level of stress in Merlot. Post‐veraison water stress had a negative or negligible effect on the concentration of glycosylated VOCs in berries at harvest. The rootstock affected the concentration of glycosylated VOCs, particularly in vines stressed pre‐veraison, with higher glycosylated VOCs observed for SO4 grafted vines than for 1103P grafted vines. Conclusions: Pre‐veraison water deficit enhanced the concentration of berry glycosylated VOCs, while post‐veraison deficit did not. The rootstock–scion interaction might amplify the irrigation effect on berry glycosylated VOCs. Significance of the Study: Modifying the timing and volume of irrigation might allow management of berry flavour for improved fruit and wine composition. Irrigation protocols should be tailored for specific cultivar–rootstock combinations. [ABSTRACT FROM AUTHOR]

Kam Sweet Rice (KSR) is a unique fragrant rice variety with excellent taste quality in Guizhou Province in China. However, overprocessing leads to the loss of flavor and nutrients. Herein, the effects of different degrees of milling (DOMs) (0%–15.0%) on the texture, nutritional quality, and aroma properties of KSR were investigated. As DOMs increased, the brightness (L∗) values of rice raised, while the red/green (a∗) and yellow/blue (b∗) values decreased. Twenty-one volatile compounds were identified in KSR using gas chromatography–mass spectrometry. The unique flavor compounds 2-acetyl-1-pyrroline, hexanal, nonanal, octanal and 2-pentylfuran were found in brown rice. With an increase in DOM, the types and contents of most fragrant volatiles decreased. Textural analysis showed that the hardness and chewiness of the cooked KSR decreased but cohesiveness and springiness increased with an increase in DOMs. The peak pasting viscosity increased by 20.76% when the DOM was changed from 0% to 15.0%. With the removal of protein, lipid, and dietary fiber, the in vitro digestibility increased by 9.98% after 180 min compared with brown rice. These findings could provide accurate estimation of DOMs and could promote moderate processing of fragrant rice. [Display omitted] • Effect of different milling degrees on the qualities of fragrant rice were studied. • Type and content of fragrant volatiles decreased with the increase of milling degree. • Hardness and chewiness decreased while the cohesiveness and springiness increased. • Peak pasting viscosity increased by 20.76% when milling degree increased to 15.0%. • Milled rice was easily hydrolysed and in vitro digestibility increased by 9.98%. [ABSTRACT FROM AUTHOR]

[Display omitted] • Principal mannoprotein composition of MP2 benefited the modulation of aroma release. • Transitionary interacting preferences drove mannoproteins to modulate aroma release. • Mannoproteins preferred to protect quercetin prior to malvidin-3- O -glucoside. • Mannoprotein A0A6C1DV26 might be the critical malvidin-3- O -glucoside protector. • Mannoproteins B3LQU1/B5VL26 might assist quercetin to enhance copigmentation. In this research, accelerated aroma release experiments and malvidin-3- O -glucoside copigmentation experiments in model red wine solutions were designed to investigate the abilities and molecular mechanisms of mannoproteins in modulating olfactory/chromatic properties of red wines. Results indicate that under orthonasal condition, mannoprotein MP2 was promising aroma modulator due to its predictable behaviors in expelling and retaining the aroma compounds during different periods. Low field nuclear magnetic resonance and molecular dynamic simulation proved that the modulation ability of MP2 should be explained by its transitionary interacting preferences with water/aroma compound molecules. Retronasal results show that the release of aroma compounds and olfactory perceptions were irregular and difficult to predict, probably due to the complexity of the retronasal condition. All mannoproteins protected malvidin-3- O -glucoside and quercetin via the formation of binary/ternary complexes, and quercetin was found prior to be protected than malvidin-3- O -glucoside. Principal mannoprotein A0A6C1DV26 might be the critical malvidin-3- O -glucoside protector. With the presence of quercetin, principal mannoproteins B3LQU1/B5VL26 in mannoprotein MP1 might exhibit intramolecular and/or intermolecular mechanisms that strengthened the hyperchromic effect, thus enhanced the copigmentation. [ABSTRACT FROM AUTHOR]

Copyright of China Brewing is the property of China Brewing Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Using high hydrostatic pressure (HHP) to treat liquid foods can improve their aroma; however, no information about the effects of HHP on soy sauce aroma has yet been reported. The effects of HHP on the aroma of soy sauce fermented for 30 d were investigated using quantitative descriptive analysis (QDA), SPME–GC–olfactometry/MS, hierarchical cluster analysis (HCA) and principal component analysis (PCA). Results showed that the pressure used during HHP treatment had a greater influence on soy sauce aroma than the duration of HHP. Compared to the control, soy sauce that was treated with HHP at 400 MPa for 30 min (HHP400–30) obtained the highest sensory score (33% higher) by increasing its sour (7%), malty (9%), floral (27%) and caramel-like (47%) aromas, while decreasing its alcoholic (6%), fruity (6%) and smoky (12%) aromas; moreover, the aroma of HHP400–30 soy sauce was comparable with that of soy sauce fermented for 180 d. Further investigation demonstrated that HHP (400 MPa/30 min) enhanced the OAVs of compounds with sour (19%), malty (37%), floral (37%), caramel-like (49%) and other aromas (118%), and lowered the OAVs of compounds with alcoholic (5%), fruity (12%) and smoky (17%) aromas. These results were consistent with the results of the QDA. HHP treatment positively regulated the Maillard, oxidation and hydrolysis reactions in raw soy sauce, which resulted in the improvement and accelerated formation of raw soy sauce aroma. HHP was capable of simultaneously improving raw soy sauce aroma while accelerating its aroma formation, and this could treatment become a new alternative process involved in the production of high-quality soy sauce. [ABSTRACT FROM AUTHOR]

BACKGROUND: Vine nutrition affects the composition of grapes, but how it impacts the aroma of grapes is largely unknown. OBJECTIVE: This work aimed to investigate the effect of different fertilizers: chemical fertilizer (CF), sheep manure-based organic fertilizer (OF), 50% organic fertilizer + 50% chemical fertilizer (O + C), 25% organic fertilizer + 25% chemical fertilizer [1/2(O + C)], and soil conditioner (SC) on the aroma accumulation of Cabernet Sauvignon grapes. METHODS: The treatments were applied and samples were collected in 2019 at weekly intervals from August 7 to September 22. The grapes' chemical characteristics and volatile compounds were analyzed. RESULTS: The chemical results showed that the treatments had a positive effect on grapes, with a strong preference for the 1/2(O + C) treatment. Grape aroma results showed that the concentrations of grape aromas in O + C-treated samples were lower than the other treatments. The OF treated samples had comparatively high (24.8%) volatile concentrations during maturity compared to other treatments, including the control (15.9%). Throughout development, samples treated with OF (17.4%) and CF (15.7%) had higher volatile concentrations than samples treated with SC (14.4%), 1/2(O + C) (12.8%), and O + C (12.4%). However, compared to SC-treated samples, samples treated with 1/2(O + C) increased the accumulation of terpenes and esters. The principal component analysis (PCA) results showed that samples treated with OF were strongly correlated to carbonyls, terpenes, and esters during maturity. CONCLUSION: The type and ratio of fertilizer used had a significant impact on the aroma profile of Cabernet Sauvignon grapes. [ABSTRACT FROM AUTHOR]

Background and Aims: Yeast autolysis is understood to be primarily responsible for giving traditional method sparkling wines complex and developed aromas. The contribution from ageing the wine itself, however, is less well‐established. This study aimed to determine the contribution of autolysis products and compounds associated with wine oxidation and ageing in Vitis vinifera L. Chardonnay and Pinot Noir wines over 24 months. Methods and Results: Chardonnay and Pinot Noir base wines were tiraged, or aged with and without primary lees. Volatile composition analyses (HS‐SPME/GC/MS and GC/MS/MS) were conducted at 6, 12, and 24 months post‐bottling and sensory appraisals at 12 and 24 months. The duration of ageing significantly influenced compositional changes in fermentation‐derived and oxidative‐flavour‐associated compounds. Ageing base wines off or on lees produced similar maturation‐associated aroma profiles to sparkling wines irrespective of cultivar. Conclusions: The contribution of autolysis products did not feature as strongly as anticipated over 24 months, indicating that compounds associated with wine ageing primarily influenced the aroma of mature sparkling wines. This finding suggests winemakers ageing their wines on lees for 24 months or less should place more emphasis on base wine composition to manipulate the aroma profiles of sparkling wines. Significance of the Study: First comparative chemical compositional study of base wines concurrently with sparkling wines. [ABSTRACT FROM AUTHOR]

Specialty malts comprise a promising field for innovative approaches concerning their potential in terms of color, aroma, and taste influence on the composition of beer and other beverages. Nevertheless, poor reproducibility of aroma and taste is a recurrent struggle between maltsters, leaving color as a practical parameter for quality control. However, malts with similar coloration can present distinct aroma profiles, leaving open questions concerning key aroma compounds, their dynamic responses to malting process variations and to what extent they may vary in a certain color range. Key aroma volatiles have been identified in the matrix of barley malt, comprising a variety of products of non‐enzymatic browning reactions (e.g., caramelization, pyrolysis, and Maillard reactions). Here, water plays a crucial role together with the intensity of the temperature regimes. Nevertheless, the final aroma profile of a malt product is the result of a balance between aroma formation and losses. Therefore, the correlation between color and aroma is of big complexity. That being the case, the present article questions if key aroma compounds responsible for the peculiar flavors of specialties have been defined by scientific literature and whether their production dynamics is unveiled. In this manner, this work proposes an overview of the aroma compounds present in specialty malt products studied up to the current date. More specifically, the process production of specialty malts and its potential impact on the formation of aroma and taste is studied alongside the key aroma‐active compounds, their correlation to color, and trending analytical techniques for aroma and color assessment. [ABSTRACT FROM AUTHOR]

Self-fermented oyster homogenates were prepared to investigate core microbes and their correlations with flavor formation mechanisms. Five bacterial and four fungal genera were identified. Correlation analysis showed that Saccharomyces cerevisiae , Kazachstania , and L. pentosus were core species for the flavor of fermented products. Four core microbes were selected for inoculation into homogenates. Twelve key aroma compounds with odor activity values >1 were identified by gas chromatography–mass spectrometry. L. plantarum and S. cerevisiae were beneficial for producing key aroma compounds such as 1-octen-3-ol, (E , Z)-2,6-nonadienal, and heptanal. Fermentation with four microbes resulted in significant increases in contents of Asp, Glu, Lys, inosine monophosphate, and guanosine monophosphate, which provided freshness and sweetness. Fermentation with four microbes resulted in high digestibility, antioxidant abilities, and zinc contents. This study has elucidated the mechanism of flavor formation by microbial action and provides a reference for targeted flavor control in fermented oyster products. [Display omitted] • Key aroma compounds in fermented oyster homogenates were identified. • Microbial diversity in fermented oyster homogenates were determined. • The correlation between microbial community and fermentation flavor was analyzed • Comprehensive analysis of flavor by core microbes fermentation from odor and taste. • Digestive characteristics and quality of fermentation with core microbes. [ABSTRACT FROM AUTHOR]

[Display omitted] • CSBs from three kinds of wheat flour presented different sensory profiles based on CATA. • Fifteen aroma compounds were identified which caused aroma differences between CSBs obtained from different varieties of wheat flour. • Fatty acids, organic acids, amino acids, and glucose were the main metabolites correlated with sensory properties. • The formation pathways of volatile aroma compounds were clarified in terms of metabolism. Chinese steamed bread (CSB) is an important staple of the Chinese people, and its flavor profile is mostly affected by wheat varieties among others. This study selected wheat flour made from three different wheat varieties and investigated their contribution to the CSB flavor profile in terms of metabolism. Thirteen aroma-active compounds identified by GC-O were determined as the main contributors to the different aroma profiles of three CSBs. 350 sensory trait-related metabolites were obtained from five key modules via weighted gene co-expression network analysis. It was found that the sensory characteristics of CSBs made of different wheat flour were significantly different. The higher abundance of lipids in Yongliang No.4 (YL04) wheat flour was converted to large number of fatty acids in fermented dough, which led to the bitterness of CSB. Besides, the abundance in organic acids and fatty acids contributed to the sour, milky, wetness and roughness attributes of YL04-CSB. More fatty amides and flavonoids in Jiangsu Red Durum wheat flour contributed to the fermented and winey attributes of CSB. Carbohydrates with higher abundance in Canadian wheat flour was involved in sugar-amine reaction and glucose conversion, which enhanced the sweetness of CSB. In addition, fatty acids, organic acids, amino acids, and glucose were crucial metabolites which can further formed into various characteristic compounds such as hexanal, hexanol, 2,3-butanediol, acetoin, and 2,3-butanedione and thus contributed to the winey, fresh sweet, and green aroma properties. This study is conductive to better understand the evolution of the compounds that affect the quality and aroma of CSBs. [ABSTRACT FROM AUTHOR]

• mmol L−1 of MeSA improved the storage quality of cherry at low temperature. • MeSA could reduce the loss of alcohols, aldehydes, ketones and terpenoids of cherry. • MeSA could increase the content of esters of cherry during cold storage. Cherries are easy to soften and rot during the period of storage. This work was performed to assess the impact of different concentrations of methyl salicylate (MeSA, 0.1 mmol·L−1, 1.0 mmol·L−1, 2.0 mmol·L−1) on fruit quality and aroma compounds of cherries ('Meizao' and 'Labins') during cold storage (0 °C). Results showed that 1.0 mmol·L−1 of MeSA had the greatest effect on decreasing the respiration rate, improving the firmness and maintaining the soluble solids content (SSC) of cherry fruits. The main volatile aroma compounds in 'Meizao' and 'Labins' cherries were benzyl alcohol, hexanal, trans-2-hexenal, benzaldehyde and 2-hexenal. Additional observations revealed that MeSA could increase the ester aroma compounds and delay the loss of alcohol, aldehyde, ketone and terpenoid aroma compounds in postharvest cherries. Therefore, MeSA could effectively improve the quality and inhibit aroma loss of cherry fruits during cold storage. [Display omitted] [ABSTRACT FROM AUTHOR]

Ten types of ingredients, including pressed barley, sprouted brown rice, red sorghum, amaranth, glutinous millet, upland rice, rice bran, chickpeas, rapeseed pomace, and perilla pomace, were utilized to develop a soy sauce-like seasoning. Free amino acid, aroma compound, and sensory evaluation values were measured in comparison to regular soy sauce (fermented with soybean and wheat). The content of free amino acids was highly correlated with the total nitrogen content, with regular soy sauce showing the highest value. The taste attribute amino acids levels were also high in regular soy sauce, rapeseed pomace, and perilla pomace, which attributed to a rich flavor. Except for sprouted brown rice and pressed barley, the remaining nine seasonings exhibited distinctive or elevated content of aroma compounds. Sensory evaluation separated eleven seasonings into sprouted brown rice, together with upland rice, and the rest. PLSR analysis identified sixteen free amino acids as flavor key contributors and twenty-four key aroma contributors. Among the eleven types of seasoning, regular soy sauce was characterized by a sweet and umami taste, while rapeseed pomace was predominantly bitter. The aroma of regular soy sauce was mainly derived from grains and tea, whereas rapeseed imparted distinctive flavors of broth smell and a fragrant aroma. • The main flavor-attributing and aroma-active compounds of soy sauce-like seasonings varied depending on raw ingredients. • Rapeseed pomace and rice bran seasonings had a stronger taste of sourness and bitterness. • Rapeseed pomace and rice bran seasonings had a stronger aroma in broth, mushroom, animal, medicinal, green, grainy, astringent, refreshing, pungent smell. • Regular soy sauce was characterized by a sweet taste and umami; grains and tea smell, while, soy sauce-like seasoning fermented by rapeseed pomace was predominantly bitter; broth, and fragrant smell. [ABSTRACT FROM AUTHOR]

Using high hydrostatic pressure (HHP) to treat liquid foods can improve their aroma; however, no information about the effects of HHP on soy sauce aroma has yet been reported. The effects of HHP on the aroma of soy sauce fermented for 30 d were investigated using quantitative descriptive analysis (QDA), SPME–GC–olfactometry/MS, hierarchical cluster analysis (HCA) and principal component analysis (PCA). Results showed that the pressure used during HHP treatment had a greater influence on soy sauce aroma than the duration of HHP. Compared to the control, soy sauce that was treated with HHP at 400 MPa for 30 min (HHP400–30) obtained the highest sensory score (33% higher) by increasing its sour (7%), malty (9%), floral (27%) and caramel-like (47%) aromas, while decreasing its alcoholic (6%), fruity (6%) and smoky (12%) aromas; moreover, the aroma of HHP400–30 soy sauce was comparable with that of soy sauce fermented for 180 d. Further investigation demonstrated that HHP (400 MPa/30 min) enhanced the OAVs of compounds with sour (19%), malty (37%), floral (37%), caramel-like (49%) and other aromas (118%), and lowered the OAVs of compounds with alcoholic (5%), fruity (12%) and smoky (17%) aromas. These results were consistent with the results of the QDA. HHP treatment positively regulated the Maillard, oxidation and hydrolysis reactions in raw soy sauce, which resulted in the improvement and accelerated formation of raw soy sauce aroma. HHP was capable of simultaneously improving raw soy sauce aroma while accelerating its aroma formation, and this could treatment become a new alternative process involved in the production of high-quality soy sauce.

The extract from Debaryomyces hansenii L1‐1‐fermented Flos Sophorae has a unique aroma and could be used as a natural spice. The influence of yeast growth and culture medium pH on organoleptic properties of fermented substrates, as well as on the content of volatile aromatic compounds, total sugars, polysaccharides, reducing sugars, total proteins, and amino acids, were analyzed. Metabolic pathways were annotated to compare and contrast key aromatic compounds and metabolic profiles of water and ethanol extracts of D. hansenii L1‐1‐fermented Flos Sophorae. We found that cells grew most rapidly, pH values changed significantly, and the largest consumption of sugars and amino acids occurred within 48 hr, producing bouquet‐like, fruity, and sweet odors, as well as the highest content of volatile aromatic compounds in the extracts. The main aroma metabolites were 2‐phenylethanol, linalool, and α‐terpineol. The sensory quality of the ethanol extracts was superior to that of the water extracts. Five aromatic compounds, isoamyl alcohol, 2‐methylbutan‐1‐ol, isobutyric acid, 2,3‐hexanedione, and 1‐hexanol, were positively correlated with the water extract group and negatively correlated with the ethanol extract group, whereas 13 aromatic compounds, styrene, acetophenone, 2‐octen‐1‐ol, linalool, naphthalene, α‐terpineol, dihydrocarveol, (−)‐myrtenol, methyl anthranilate, eugenol, γ‐nonanolactone, jasmone, and β‐ionone, showed the converse trend. Although 2‐phenylethanol displayed the highest concentration in the extracts, it did not significantly contribute to the separation of ethanol and water extracts. In Flos Sophorae medium, D. hansenii mainly produces 2‐phenylethanol from phenylalanine by the Ehrlich reaction, whereas it produces linalool and α‐terpineol by the terpenoid backbone and monoterpenoid biosynthetic pathways; the variable contents of proline, arginine, and glutamate could respond to the arginine and proline metabolic pathways. Practical applications: Flos Sophorae, a collection of buds of Sophora japonica L., is a traditional Chinese medicinal and edible plant for its good aroma, taste, and nutritional value. Debaryomyces hansenii is a common, aroma‐producing yeast. D. hansenii L1‐1‐fermented Flos Sophorae had a unique, bouquet‐like aroma, slightly softer than the typical Flos Sophorae‐like aroma. This study enriches our understanding of predominant aroma components and determines their contribution to the profiles of Flos Sophorae ferments obtained using D. hansenii L1‐1. Researchers and manufacturers specializing in spices making can use these data to improve the aromatic profiles of natural spices produced by microorganisms, thereby obtaining unique aromas. [ABSTRACT FROM AUTHOR]

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Berries of six Vitis davidii Foex (spine grape) cultivars ('Baiputao', 'Gaoshan 1', 'Gaoshan 2', 'Seputao', 'Miputao', and 'Tianputao') were harvested from a commercial vineyard in Hunan Province in China. Free and bound volatile compounds and fatty acids were analyzed by GC–MS, and amino acids were analyzed by HPLC. 'Tianputao' and 'Miputao' were characterized by relatively higher concentrations of aromatic amino acids and lower concentrations of branched-chain amino acids. The major free volatile compounds of spine grapes were hexanal, (E)-2-hexenal, 1-hexanol, (E)-2-hexenol, (E)-β-damascenone, and benzeneacetaldehyde. The major glycosidically bound volatile compounds identified were 1-hexanol, menthol, nerol, 1-butanol, 3-methyl-3-butenol, benzenemethanol, β-phenylethanol, eugenol, and guaiacol. (E)-β-damascenone, benzeneacetaldehyde, guaiacol, and eugenol had odor activity values (OAVs) > 1 in all cultivar grapes. Partial least squares discriminant analysis (PLS-DA) revealed 'Tianputao' to be distinct from the other cultivars due to its relatively higher concentrations of major terpenoids, norisoprenoids, higher alcohols, and aromatic amino acids. [ABSTRACT FROM AUTHOR]

In this study, the effect of milk freezing was studied, focusing on the changes in 1% and 3% fat UHT hydrolyzed-lactose milk after slow- (−20°C) and fast-rate freezing (−80°C) for 72 h. Changes on the sensory properties were first assessed by discriminant analysis (triangle test), and then by volatile organic compounds and color analysis. The milk emulsion stability was characterized by optical centrifugation, particle size analysis, and confocal microscopy. The sensory panel was not able to distinguish the milk subjected to freezing from the control (72 h at 20°C). The volatile organic compounds and color analysis demonstrated that both freezing rates did not cause any significant changes in the milk aroma or color characteristics. The results of physical properties confirmed that short-time freezing did not lead to a distinct destabilization, except for a slight increase in the mean particle diameter at −80°C. Taking all the results together, UHT hydrolyzed-lactose milk was not significantly altered during the operation of freezing and thawing and, therefore, short-time freezing at both −20°C and −80°C can be used for milk storage without altering the product. [ABSTRACT FROM AUTHOR]

The heat treatment has significant effect on the sensory and flavor quality of Boletus edulis product. We evaluated the sensory properties and volatile flavor compounds (VFCs) of six dried Boletus edulis products subjected to different heat treatment temperatures, as well as the correlation of VFCs with Maillard reaction products. The color of the dried samples turned brown as the drying temperature increased, and the content of seventeen free amino acids (FAAs) and five monosaccharides decreased simultaneously. When compared to vacuum drying methods, the content of Arg and Glu reduced significantly, reaching its lowest point at 100 °C. Sixty VFCs were identified by HS-SPME/GC-MS, and the contents of aldehydes, ketones, sulfur-containing compounds, nitrogen-containing compounds increased with heat treatments. Furthermore, the content changes of 17 FAAs, 5 monosaccharides and VFCs related to Maillard reaction were further analyzed, which allowed us to speculate on the formation mechanism of VFCs through the Maillard reaction at high drying temperatures. These findings not only provide valuable insights into understanding the sensory and flavor characteristics of Boletus edulis products, but also offer theoretical support for the dehydration of Boletus edulis and other similar heat sensitive edible mushroom products. [Display omitted] • The higher the drying temperature, the darker the color of Boletus edulis. • Maillard reactions products in Boletus edulis at different dryness were different. • Arginine was the main amino acid involved in Maillard reaction of Boletus adults. • The flavor of Boletus edulis was enhanced by Maillard reaction. [ABSTRACT FROM AUTHOR]

Aroma compounds are mainly produced during brewing, which is involved various yeast flavor enzymes. The potential application of yeast flavoring enzyme in brewing was evaluated through the study on the aroma enhancement of dry white wine treated by extracellular enzymes from two non-saccharomyces strains. Ecolly grape is a kind of white wine with weak flavor. It was used as wine making material in experiment, and the grape juice was fermented by commercial Saccharomyces cerevisiae strain. After 12 hours, the extracellular enzymes from selected Pichia fermentans (PF) and Rhodotorula mucilaginosa (RM) strains were added (10 mU/mL), as well as the commercial almond β-glucosidase (AG). The pure fermentation of Saccharomyces cerevisiae without enzyme treatment was used as the control. During the fermentation, the juice was sampled every 24 h to detect sugar content and aroma compounds. Volatile compounds were extracted by headspace solid-phase microextraction (HS-SPME), and then were desorbed and detected by gas chromatography coupled with mass spectrometry (GC-MS). Grape juice alcohol fermentation was completed when the residue sugar was less than 2 g/L, and the clear wine was racked to a clean bottle and stored at low temperature. In April of the next year,, wine aroma compounds of wine were identified and quantified by HS-SPME-GC-MS, and aroma characteristics were analyzed and quantified by well-trained panelists. Results showed that six flavor enzyme activities were detected in both PF and RM extracellular enzymes. The activities of β-D-glucosidase, α-L-rhamosidase, and β-D-xylosidase in RM enzymes were significantly higher than those in PF enzymes (P < 0.05), while the activities of α-L-arabinosidase and esterases in PF enzymes were significantly higher than those in RM enzymes (P < 0.05). In general, both the treatments of PF and RM extracellular enzymes improved the contents of varietal and fermentative volatiles during fermentation significantly (P < 0.05). Compared with AG treatment, the concentration of terpenes and phenylethyls increased by 41.7% and 31.8%, respectively. Furthermore, the production of most fermentative volatiles was promoted by PF enzymes, particularly fatty acid ethyl esters. The content of fatty acids ethyl esters in PF treatment was almost twice as much as that in the control. It is worth to be noted that the effect of aroma enhancement for dry white wine was different between PF and RM enzymes treatments according to sensory analysis results. Two kinds of extracellular enzymes of non-Saccharomyces showed their respective advantages in aroma improvement. RM enzymes enhanced temperate sour fruits aroma type, while citrus attribute was strengthened by PF enzymes. In summary, the treatment of two sample non-Sacchromyces extracellular enzymes had the clear aroma enhancement effect for dry white wine. The selected PF and RM extracellular enzymes had different flavor enzymes profiles, then their enzymes treatments during wine alcohol fermentation would bring out different improvements of varietal and fermentative aroma compounds. This results led to the different effects of aroma enhancement for dry white wine. This work would give the theoretical and practical guidance to the wine making for aroma enhancement by yeast flavor enzymes. [ABSTRACT FROM AUTHOR]

Enterococcus faecium is frequently isolated from fermented food; in particular, they positively contribute to the aroma compound generation in traditional cheese. Citrate fermentation is a desirable property in these bacteria, but this feature is not uniformly distributed among E. faecium strains. In the present study, three selected E. faecium strains, IQ110 (cit−), GM70 (cit+ type I), and Com12 (cit+ type II), were analyzed in their production of aroma compounds in milk. End products and volatile organic compounds (VOCs) were determined by solid-phase micro-extraction combined with gas chromatography mass spectrometry (SPME-GC-MS). Principal component analysis (PCA) of aroma compound profiles revealed a different VOC composition for the three strains. In addition, resting cell experiments of E. faecium performed in the presence of leucine, citrate, or pyruvate as aroma compound precursors allowed us to determine metabolic differences between the studied strains. GM70 (cit+ type I) showed an active citrate metabolism, with increased levels of diacetyl and acetoin generation relative to Com12 or to citrate defective IQ110 strains. In addition, in the experimental conditions tested, a defective citrate-fermenting phenotype for the Com12 strain was found, while its leucine degradation and pyruvate metabolism were conserved. In conclusion, rational selection of E. faecium strains could be performed based on genotypic and phenotypic analyses. This would result in a performing strain, such as GM70, that could positively contribute to flavor, with typical notes of diacetyl, acetoin, 3-methyl butanal, and 3-methyl butanol in an adjuvant culture. [ABSTRACT FROM AUTHOR]

Honkaku shochu and Awamori are traditional Japanese spirits. The detection and thresholds of 16 compounds in these spirits were determined so as to understand the compounds contributing to the aroma characteristics of Honkaku shochu and Awamori. The odour activity values calculated using detection thresholds suggested that 14 compounds affect the quality of Honkaku shochu and Awamori. The odour activity values of β‐damascenone and rose oxide were much higher in sweet potato shochu and these two compounds are considered to contribute to the characteristics of sweet potato shochu. Similarly, the odour activity value of 1‐octen‐3‐ol was higher in Awamori than in the other categories, suggesting that 1‐octen‐3‐ol produces the characteristic aroma of Awamori. In addition, the sensory attribute terms of 16 compounds are summarised. © 2019 The Institute of Brewing & Distilling [ABSTRACT FROM AUTHOR]

Lactococcus lactis is the lactic acid bacteria most frequently used for the production of cheese starter cultures, mainly because of their efficient production of aroma compounds. However, commercial cultures do not always produce the typical aroma notes of artisanal raw-milk cheeses. Thus, the objective of this study was to characterize the volatile compounds generated by wild L. lactis strains in Mexican Fresco cheese made with pasteurized milk. Four strains of wild L. lactis were evaluated for their aroma production in Mexican Fresco cheese using sensory and instrumental analysis. The aroma profiles were evaluated by descriptive sensory analysis. Volatiles were determined by solid-phase microextraction and gas chromatography-mass spectrometry. Principal component analysis was applied to interpret analytical and sensory data. Mexican Fresco cheese aroma was described as milkfat, yogurt, yeasty, barny, dirty socks, and Fresco cheese. Cheese with L. lactis strains R7 or B7 were most similar to commercial raw milk Fresco cheese in all aroma descriptors. Volatiles identified in all cheeses were esters, acids, alcohols, ketones, and aldehydes, but the main differences were found for total volatile relative abundance. Also, volatile concentrations (µg/g) in commercial raw milk Fresco cheese and cheeses made with L. lactis R7 or B7 were 4 methyl esters [C4 (4.15 vs. 5.47–13.74), C6 (0.12 vs. 1.53–15.34), C8 (1.06 vs. 0.32–6.65), and C10 (0.62 vs. 0.41–3.74)], 7 acids [C4 (1.92 vs. 0.30–9.29), C6–C10 (0.05–4.48 vs. 0.11–30.45), and C12 (0.13 vs. 0.28–0.30)], 2 alcohols [(3-methyl-1-butanol (3.48 vs. 3.4–13.13) and phenylethyl alcohol (0.10 vs. 0.63–2.04)], and 1 ketone (acetoin; 1.22 vs. 0.28–0.99). The first 3 principal components explained 78.2% of the total variation and clearly distinguished 3 main groups. Cheese made with L. lactis R7 was classified in the same group as key compounds associated with Fresco cheese aroma and show potential as a starter in Mexican Fresco cheese manufacture. [ABSTRACT FROM AUTHOR]