Odor Activity Values Research Articles

Characterization of the flavor profile and dynamic changes in Chinese traditional fish sauce (Yu-lu) based on electronic nose, SPME-GC-MS and HS-GC-IMS

In this study, flavor characteristics and dynamic change of Chinese traditional fermented fish sauce (Yu-lu) with different fermentation time (2, 4, 6, 8, and 12 months) were analyzed. The electronic nose analyses confirmed a notable flavor change in fish sauce samples from different stages. During the 12-months fermentation, the total volatile compounds in fish sauce increased from 3.9 mg/L to 13.53 mg/L. Acids, aldehydes, esters and phenols were the main aroma substances and their contents gradually increased during the fermentation process. The PCA of GC–MS and GC-IMS showed that fish sauce samples from different fermentation periods can be well distinguished. A total of 110 volatile compounds identified by GC–MS, and 102 volatile compounds were detected by GC-IMS. Among them, 13 compounds were identified by both GC–MS and GC-IMS. The most varieties (49) of volatiles appeared after 8 months of fermentation. The odor activity value (OAV) analysis showed that 10 volatile compounds were considered as characteristic flavor in traditional fish sauce. The variable influence on projections (VIPs) in PLS-DA models constructed by GC–MS and GC-IMS identified 5 and 10 volatile compounds as biomarkers, respectively. Our results revealed the dynamic changes of characteristic flavor in fish sauce in combination of GC–MS and GC-IMS, which provides theoretical basis for the production and flavor regulation of fish sauce.

Volatile profiles of Murcott and Ponkan mandarins obtained by stir bar sorptive extraction technique and their contributions to the fruit aroma.

Citrus species have undergone immense diversification ever since their ancestral origin. Ponkan and Murcott are two mandarin varieties widely consumed in Brazil and their aroma producing active compounds have not yet been extensively investigated. The present study analyzed the volatile constituents of the Ponkan and Murcott varieties employing the stir bar sorptive extraction (SBSE) technique and gas chromatography-mass spectrometry (GC-MS) analysis for the first time. Extraction was performed using the two phases of Twister bar, polydimethyl siloxane (PDMS), and ethylene glycol (EG) silicone in immersion and headspace modes. Among the detected 62 compounds comprising alcohols, aldehydes, esters, terpenes, and others identified, 55 and 37 compounds in the Ponkan and Murcott variety were determined, respectively, from both immersion and headspace modes using the two phases of Twister bar. From the odor active values, the Ponkan was characterized with the domination of compounds such as hexanal, decanal, nonanal, (E)-2-hexanal, ethyl hexanoate, d-limonene, linalool, and geraniol. Similarly, the Murcott variety was characterized with predominant compounds, namely, nonanal, octanal, hexanal, (E)-2-hexanal, ethyl hexanoate, d-limonene, and linalool. The profile of volatile compounds was found to be unique in both the varieties studied, and SBSE technique with GC-MS analysis favored the characterization of their respective profile due to the high amount of phase in the Twister bars, when compared to similar techniques, like solid phase microextraction. The PDMS Twister bar showed better capacity of adsorption of volatile compounds, since it is a relatively low-polarity polymer, which discriminates less analytes with different structures and polarities sampled from complex matrices, such as fruits juice.

Study on Interaction of Aromatic Substances and Correlation between Electroencephalogram Correlates of Odor Perception in Light Flavor Baijiu.

Light-flavor Baijiu (LFB) is widely cherished for its flavor. This study identified the thresholds of 14 aroma compounds in a 52% ethanol-water matrix and conducted a comprehensive analysis of the interactions among key aroma compounds in LFB using the Feller additive model and odor activity values approach. Among them, the interactions of β-damascenone with ester and alcohol compounds were primarily promotive, while the interaction with acid compounds was predominantly masking. Furthermore, for the first time, the electroencephalogram (EEG) technology was used to characterize the interactions between aroma compounds. The results showed that the brain activity in the alpha frequency band demonstrated heightened olfactory sensitivity. The EEG could not only display the additive effect of odor intensity but also reflect the differences in aroma similarity between different odors. This study demonstrated that the EEG can serve as an effective tool for olfactory assessment.

Dietary vitamin E further enhances the effectiveness of Clostridium autoethanogenum protein as an alternative source of soybean meal in grass carp (Ctenopharygodon idellus) diets based on growth performance, flesh quality and antioxidant status

The effects of replacing soybean meal with Clostridium autoethanogenum protein and supplementing it with different gradients of vitamin E in grass carp diets on growth performance, flesh quality and antioxidant capacity were evaluated in a 69-day feeding trial. Five isonitrogen and isolipid diets were configured with the soybean meal-based diet (SM) served as the basal control diet, and the Clostridium autoethanogenum protein-based diet (CAP) as the treatment control diet. The CAP diet was supplemented with 80 mg/kg, 160 mg/kg and 240 mg/kg vitamin E (namely, 80VE, 160VE and 240VE), respectively. Final body weight (FBW) and specific growth rate (SGR) were significantly better in the CAP group than in the SM group (P < 0.05), and the 160 VE group was significantly better than the CAP group (P < 0.05). In terms of muscle quality, muscle fat content was significantly higher in the CAP group than in the SM group (P < 0.05), and muscle vitamin E content was significantly higher in each vitamin E-supplemented group than in the CAP group (P > 0.05). The total odor activity value in muscle in the CAP group was not significantly different from the SM group (P < 0.05), but the vitamin E-supplemented groups were significantly higher than the CAP group (P < 0.05). Muscle hardness and gumminess were significantly higher in the CAP group than the SM group and muscle shear force and gumminess were significantly higher in the 80VE group than the CAP group (P < 0.05). Muscle development-related genes in the CAP group were not significantly different from those in the SM group (P > 0.05), and Muscle Myf5 mRNA levels in the 160VE and 240VE groups were significantly higher than those in the CAP group, while the expression of MSTN genes was suppressed (P < 0.05). In terms of antioxidant properties, muscle MDA content was significantly higher in the CAP group than in the SM group (P < 0.05), and muscle MDA content was significantly lower in the 160VE and 240VE groups than in the CAP group (P < 0.05), at the same time, CAT and T-SOD activities were significantly higher (P < 0.05). In conclusion, complete replacement of soybean meal by the Clostridium autoethanogenum protein in grass carp diets promoted growth performance and muscle quality, but negatively affected antioxidant capacity, and supplementation of 160 mg/kg vitamin E in the CAP diet could further enhance growth performance and improve antioxidant capacity.

Molecular decoding a meat-like aroma generated from Laetiporus sulphureus-mediated fermentation of onion (Allium cepa L.)

The organoleptic properties of plant-based meat alternatives do not meet consumer expectations due to the lack of characteristic flavors resembling meat. To address this challenge, a fermentation system utilizing Laetiporussulphureus was developed to generate a meat-like and fatty flavor from a vegetable source, onion. By means of multiple stir bar sorptive extraction and gas chromatography-mass spectrometry-olfactometry, an unsaturated aldehyde, (E,Z)-2,4-decadienal, which imparts a tallow-like and fatty odor, and a sulfurous compound benzothiazole, with a broth-like odor were identified, which well contributed to the characteristic odor of the supernatant. (E,Z)-2,4-Decadienal as the most important odorant (odor activity value = 206) was biosynthesized by transformation of linoleic acid with L.sulphureus, as revealed by isotopic tracing experiments. For the first time in Basidiomycota, the biogenetic pathway of (E,Z)-2,4-decadienal from linoleic acid was proposed.

The perception interaction of complex fruits aroma system: Including binary, ternary, quaternary, and with different chain length, functional groups and substituent positions compounds

The perceptual interactions between key aroma compounds (binary, ternary, and quaternary) of fruits were comprehensively evaluated using thresholds, odor activity values, Feller's additive model (S-curve), σ-τ diagram, and U model. Meanwhile, support vector machine (SVM) was initially introduced to evaluate and compare the 5 methods for selecting the most appropriate approach for investigating fruits aroma interaction. Finally, the effects of aroma molecular structure characteristics (chain length, functional group and substituent site) on the interaction was investigated. The results showed that S-curve, σ-τ diagram and U model are suitable for the binary and ternary systems, and σ-τ diagram and U model are suitable for quaternary systems. Furthermore, the functional groups strongly (P < 0.05) influenced the perception interactions. Especially, the greater the difference in carbon chain length, the more significant the synergistic effect of aldehydes and alcohols with similar chains, and the substituent site had no significant effect on aroma interactions.

Evolution of Aroma Profiles in Vitis vinifera L. Marselan and Merlot from Grapes to Wines and Difference between Varieties.

The fermentation process has a significant impact on the aromatic profile of wines, particularly in relation to the difference in fermentation matrix caused by grape varieties. This study investigates the leaching and evolution patterns of aroma compounds in Vitis vinifera L. Marselan and Merlot during an industrial-scale vinification process, including the stages of cold soak, alcohol fermentation, malolactic fermentation, and one-year bottle storage. The emphasis is on the differences between the two varieties. The results indicated that most alcohols were rapidly leached during the cold soak stage. Certain C6 alcohols, terpenes, and norisoprenoids showed faster leaching rates in 'Marselan', compared to 'Merlot'. Some branched chain fatty-acid esters, such as ethyl 3-methylbutyrate, ethyl 2-methylbutyrate, and ethyl lactate, consistently increased during the fermentation and bottling stages, with faster accumulation observed in 'Marselan'. The study combines the Orthogonal Partial Least Squares-Discriminant Analysis (OPLS-DA) model based on odor activity values to elucidate the accumulation of these ethyl esters during bottle storage, compensating for the reduction in fruity aroma resulting from decreased levels of (E)-β-damascenone. The 'Marselan' wine exhibited a more pronounced floral aroma due to its higher level of linalool, compared to the 'Merlot' wine. The study unveils the distinctive variation patterns of aroma compounds from grapes to wine across grape varieties. This provides a theoretical framework for the precise regulation of wine aroma and flavor, and holds significant production value.

Insight into sensory characteristics and volatile differences of freeze-dried Citrus aurantium L. var. amara Engl. flower essential oil-casein phospholipid nanocomposites sustained-release scented tea by combining GC-E-nose and SBSE-GC-MS

Scented tea is popular for its attractive flavor and health benefits, but cumbersome processing limits its production. In this study, freeze-dried optimized casein nano-embedded Citrus aurantium L. var. amara Engl. flower essential oil combined with phospholipids (CAVAO-CPNs) sustained-release aroma was used to efficiently process high-quality scented tea. Sensory evaluation and GC-E-Nose analysis indicated that new the newly processed scented tea (NST) had higher floral quality than the traditional scented tea (TST). SBSE-GC-MS identified 76 volatile compounds. Further analysis indicated that the levels of 21 key compounds increased significantly in scented tea, accounting for 94.4% and 69.3% of the total NST and TST, respectively. The total aroma content of NST was 9.08 times higher than that of TST. Relative odor activity values revealed six aroma characteristics dominated by floral aromas such as linalool, geranyl acetate etc. Correlation analysis indicated that NST has advantages over TST in terms of sensory intensity and the odor contribution of aroma compounds.

Ultrasound-induced modifications of beef flavor characteristics during postmortem aging

To investigate the effect of ultrasound treatment on the flavor profile of beef during postmortem aging, a comprehensive analysis of beef flavor was conducted at 0, 7, and 12 d of aging using sensory evaluation and electronic nose. Furthermore, the key volatile flavor compounds were identified using gas chromatography-mass spectrometry (GC–MS), and the odor activity value (OAV) was further evaluated. In addition, the primary pathway involved in flavor formation during beef aging after ultrasound treatment was explored. The results indicated that ultrasound enhanced the flavor profile of beef during postmortem aging by modifying the OAV of hexanal, heptanal, octanal, nonanal, decanal, (Z)-2-nonenal, dodecanal, pentanal, 1-octen-3-ol, octanoic acid, and 2-pentylfuran. Lipid oxidation was a crucial pathway through which ultrasound promoted the generation of volatile flavor compounds in beef, confirmed by the improved oxidation level of fatty acids, particularly monounsaturated ones. The study indicates that ultrasound technology can be regarded as an effective method for enhancing the beef flavor profile during postmortem aging.

Influences of thioalcohols on the release of aromas in sesame-flavor baijiu

This study investigated the interactions between 2-furylmethanethiol, benzenemethanethiol, and 18 skeletal aroma-active compounds as well as four aroma notes in sesame-flavor baijiu based on the Feller Additive Model, the Odor Activity Value (OAV) Approach, and the Sigma-Tau (σ-τ) plots. In addition, a predictive model for the interactions between 2-furylmethanethiol and esters was developed, and the determinants of the interaction results in complex systems were explored. The results reveal that both thioalcohols interacted with the skeletal aroma-active compounds in a similar trend, where 2-furylmethanethiol tends to enhance the release of fruit and acid aroma. Moreover, the intensity of the thiols and their intensity ratio to the notes were the determinants of the interaction results in the multivariate blended system, with the lower the concentration of the thiols, the closer the ratio was to 1, and the more likely that additive interactions would take place. Predictive modeling showed that 2-furylmethanethiols were more likely to have additive or synergistic effects with esters when the olfactory thresholds of the esters were between 75.86 and 199.53 μg/L. Conversely, masking effects were more likely.

Characteristic volatile compounds contributed to aroma of braised pork and their precursor sources

The characteristic aroma compounds of traditional braised pork were investigated by gas chromatography–mass spectrometry−olfactometry (GC–MS–O), odor-activity values, and aroma recombination and omission experiments. A total of 56 volatile compounds were detected by GC–MS, among which hexanal, octanal, nonanal, (E)-2-octenal, 2,3-octanedione, 1-octen-3-ol, 2-pentylfuran, methanethiol, and dimethyl trisulfide were identified as the key aroma compounds by molecular sensory science. Partial least squares regression analysis indicated that some aroma compounds significantly contributed to fatty (hexanal, heptanal, 2-pentylfuran, nonanal, and (E)-2-octenal), meaty (methanethiol, dimethyl disulfide, dimethyl trisulfide, and octanal), sauce-like flavor (3-hydroxy-2-butanone and 2-furfural), and sweet, caramel (2,3-octanedione, 1-octen-3-ol). Lean meat produced more aldehydes, alcohols, ketones, and sulfur-containing compounds than subcutaneous fat. The seasonings (saccharose, cooking wine, and soy sauce) facilitated the formation of ethyl L-lactate, 2-acetylfuran, 2-furfural, 5-methyl-2-furaldehyde, 2-methyl-pyrazine, and 2-acetylpyrrole. Meanwhile they reduced the content of lipid oxidation products, thereby stimulated the characteristic aroma of the Chinese traditional braised pork.

Changes in microbial diversity and volatile metabolites during the fermentation of Bulang pickled tea

The present study aimed to determine microbial community, short-chain fatty acids (SCFAs), and volatilome of Bulang pickled tea during fermentation. Sequencing of 16S rRNA and ITS revealed that Bualng pickled tea was dominated by Lactobacillus plantarum, unclassified Enterobacteriaceae, unclassified Debaryomyces, Candida metapsilosis, Cladosporium sphaerospermum, and unclassified Aspergillus. The overall contents of SCFAs increased, with acetic acid showing the highest content. A total of 398 differential volatile metabolites were detected using differential metabolomics analysis. Out of these different volatile compounds, ten key volatile compounds including (Z)-4-heptenal, 1-(2-thienyl)-ethanone, 5-methyl-(E)-2-hepten-4-one, 2-ethoxy-3-methylpyrazine, p-cresol, 2-methoxy-phenol, ethy-4-methylvalerate, 3-ethyl-phenol, p-menthene-8-thiol, and 2-s-butyl-3-methoxypyrazinewere were screened based on odor activity value (OAV). The Spearman correlation analysis showed a high correlation of SCFAs and volatile compounds with microorganisms, especially L. plantarum and C. sphaerospermum. This study provided a theoretical basis for elucidating the flavor quality formation mechanism of Bulang pickled tea.

Changes in flavour- and taste-presenting substances in Hypsizygus marmoreus mushroom packaged in polypropylene nanofilm

Hypsizygus marmoreus mushroom is known for its pleasant flavour and delicious taste. However, its flavour quality deteriorates rapidly during postharvest storage. In the present work, we explored the dynamic changes in flavour-presenting substances and taste components in H. marmoreus packaged in polyethylene nanofilm (0.05 mm) during low temperature storage (12 days). We used headspace solid-phase microextraction combined with gas chromatography-mass spectrometry to analyse the volatile flavour components; high performance liquid chromatography and liquid chromatography-mass spectrometry to analyse the non-volatile flavour (taste-presenting) substances (e.g., soluble sugars, taste nucleotides, free amino acids, and organic acids); and the relative odour activity value (ROAV) and taste active value (TAV) methods to determine the flavour substances in fresh and stored H. marmoreus. Results revealed that n-octanal, 1-octene-3-one, and 1-octene-3-ol were the characteristic volatile flavour substances, and that trans-2-octenal was the key substance affecting the formation of volatile flavours in fresh H. marmoreus. Trans,trans-2,4-nonadienal, and 3-octanone were the key volatile substances that resulted in flavour deterioration. Among the non-volatile flavour substances, trehalose, 5'-GMP, glutamic acid, alanine, and arginine were the key taste-presenting substances. In addition, oxalic acid and lysine were the key taste substances after H. marmoreus deterioration. These results provided a theoretical basis for rapid quality detection, flavour identification, and shelf-life prediction of H. marmoreus.

Differences in the aroma quality of large-leaf yellow tea subjected to different roasting methods

Roasting is a key process in the production of large-leaf yellow tea (LYT) and substantially affects the formation of its aroma. In order to investigate the effect of roasting method on the aroma of large-leaf yellow tea and to identify the potential causes. In this study, guided by molecular sensory science, the aroma components of charcoal-roasted, electric-roasted and drum-roasted LYTs were analyzed using headspace solid phase microextraction and solvent-assisted flavor evaporation in conjunction with gas chromatography-mass spectrometry, and the data were visualized and analyzed using SMICA, SPSS and Origin. The results of quantitative descriptive analysis revealed that rice crust, burnt, corn and floral aromas were significantly different between the three samples. The results of aroma extract dilution and odor activity value analyses revealed that 2,4,5-trimethyloxazole, 1-ethylpyrrole-2-carboxaldehyde, 2-ethyl-3,5-dimethylpyrazine, 3-ethyl-2,5-dimethylpyrazine, linalool, 2,3-diethyl-5-methylpyrazine, 3,5-diethyl-2-methylpyrazine, β-damascenone, and (E)-β-ionone were the main compounds responsible for differences in the aroma of LYT subjected to different roasting methods. Aroma recombination and addition experiments verified these findings. All in all, charcoal roasting enhances the rice crust and burnt aromas of LYT, and drum roasting facilitates the presentation of floral and corn aromas. This study provides a theoretical basis for the processing of high-quality LYT.

Comparative Analysis of Texture Characteristics, Sensory Properties, and Volatile Components in Four Types of Marinated Tofu.

In this study, three different brands of commercially available marinated tofu were analyzed and compared with homemade products to explore the effect of key flavor substances on their sensory quality, sensory properties, texture characteristics, and volatile components. The texture characteristics and flavor substances of the three brands of commercially available marinated tofu were significantly different from those of homemade products. A total of 64 volatile components were identified by headspace-gas chromatography-ion mobility spectrometry (HS-GC-IMS), mainly including 11 hydrocarbons, 11 alcohols, 10 ketones, 15 aldehydes, 4 esters, 1 acid, and 12 other volatile substances. Among these, nine key flavor compounds (ROAV > 1, VIP > 1) were identified using the relative odor activity value (ROAV) combined with a partial least squares discriminant analysis (PLS-DA) and variable importance in projection, including α-Pinene, β-Myrcene, α-Phellandrene, 1-Penten-3-one, Butanal, 3-Methyl butanal, acetic acid ethyl ester, 1,8-Cineol, and 2-Pentyl furan. The correlation heatmap showed that sensory evaluation was positively correlated with hardness, gumminess, chewiness, and springiness while negatively correlated with 2-Pentyl furan, α-Pinene, resilience, α-Phellandrene, 1-Penten-3-one, acetic acid ethyl ester, and 1,8-Cineol. Overall, this study provides a theoretical reference for developing new instant marinated tofu snacks.

The aroma profiles of dried gonggans: Characterization of volatile compounds in oven-dried and freeze-dried gonggan

Dehydration is an effective method for the long-term storage and aroma retention of gonggan (Citrus sinensis Osb. ‘Deqing Gonggan’), which is a Chinese variety of citrus, with unique and characteristic floral, fruity, and citrus flavors. However, the aroma profiles of gonggans prepared using oven- and freeze-drying, the most widely-used drying methods, remain unclear. In this study, a total of 911 volatile organic compounds (VOCs) were detected in dried gonggan. These were primarily composed of alcohols (7.69%), aldehydes (7.03%), esters (15.38%), ketones (7.58%), and terpenoids (23.19%). A total of 67 odorants contributed significantly to the overall aroma of dried gonggans, with the major odor qualities being detected as green, citrus, fruity, floral, and sweet. These were mainly attributed to the presence of aldehydes, esters, and terpenoids. Freeze-drying was more effective in maintaining the unique citrus and mandarin-like aromas attributed to compounds such as limonene, citrial, β-myrcene, β-pinene, and γ-terpinene. Moreover, (E,E)-2,4-decadienal had the highest relative odor activity value (rOAV) in freeze-dried gonggans, followed by (E)-2-nonenal, furaneol, (E, E)-2, 4-nonadienal, and E-2-undecenal. Oven-drying promoted the accumulation of terpenes such as octatriene, trans-β-ocimene, cyclohexanone, copaene, and ɑ-irone, imparting a soft aroma of flowers, fruits, and sweet. Increasing the temperature led to an increase in existing VOCs or the generation of new VOCs through phenylpropanoid, terpenoid, and fatty acid metabolism. The findings of this study offer insights into an optimized procedure for producing high-quality dried gonggans. These insights can be valuable for the fruit-drying industry, particularly for enhancing the quality of dried fruits.

Metabolomic and transcriptomic analyses of monoterpene biosynthesis in Muscat and Neutral grape hybrids

Monoterpenes are typical aroma components of muscat grape (Vitis vinifera L.) cultivars. However, differences in the molecular mechanism of monoterpene biosynthesis between Muscat and non-Muscat grapes remain unclear. Here, comprehensive transcriptomic and metabolomic analyses of two F1 hybrids with different aroma profiles obtained from crosses between 'Muscat Hamburg' and 'Red Globe' grapes were performed to examine the unique monoterpene accumulation pattern and related candidate genes. The concentrations of most monoterpenes differed at various times, in the hybrid progeny, increasing from the pre-veraison stage to the veraison stage, followed by a decreasing trend from veraison to maturity. Within the F1 generation, the concentrations of accumulated monoterpenes were significantly higher in Muscat grapes than in neutral grapes. Furthermore, linalool, α-terpineol, and l-α-terpineol may be important odorants affecting the floral characteristics of Muscat grapes due to their high odor activity values. Transcriptional analysis identified three VvDXS (LOC100249323, LOC100268079, and LOC100247834), 1 VvHDS (LOC100257071), one VvMVK (LOC100251148), one VvHMGR (LOC100265082), and one VvGGPPS (LOC100257234) genes encoding proteins involved in the MEP and MVA pathways. Eleven TPS genes potentially involved in monoterpene regulation were also identified. Among them, VvTPS (LOC100853562) showed consistency with the accumulation of monoterpenes and had a high expression level; MYB (LOC100255488), GATA (LOC100262474), and ERF (LOC100255943, LOC100260401) were selected as candidate genes encoding transcription factors. The findings in this study provide new insights for further functional validation and investigation of genes related to monoterpene synthesis in Muscat aroma grapes.

The Volatile Compounds Change during Fermentation of Saccharina japonica Seedling.

It is important to eliminate the fishy odor and improve the aroma quality of seafood. In this study, the Saccharina japonica (S. japonica) seedling, which is a new food material, was investigated for the effects of fermentation with Saccharomyces cerevisiae (S. cerevisiae) through sensory evaluation, GC-MS, and odor activity value (OAV) analysis. GC-MS analysis revealed the presence of 43 volatile compounds in the unfermented S. japonica seedling, with 1-octen-3-ol, hexanal, and trans-2,4-decadienal identified as the main contributors to its fishy odor. After fermentation with S. cerevisiae, 26 volatile compounds were identified in the S. japonica seedling. Notably, the major malodorous fish compounds, including 1-octen-3-ol, hexanal and trans-2,4-decadienal, were no longer present. The results indicate that fermentation with S. cerevisiae is an effective method for removing fishy malodor compounds and enhancing the volatile components with fruity, sweet, green, and floral notes in the Saccharina japonica seedling. This process facilitates the elimination of fishy malodor and enhance the fruity, sweet, green, and floral notes of S. japonica seeding and other seaweeds.

Comparative analysis of the aromatic profile of single malt whiskies from different regions of Scotland using GC-MS, GC-O-MS and sensory evaluation

Single malt whiskies are popular around the world. The 37 esters, 10 alcohols, 10 phenols, 8 aldehydes, 8 acids, 6 alkanes, 4 ketones and 3 heterocycles were detected in the single malt whiskies extracted from different origins in Scotland by HS-SPME (headspace solid-phase microextraction) and LLE (liquid-liquid extraction) and identified by GC-MS (gas chromatography-mass spectrometry). QDA (quantitative descriptive analysis) combined with multivariate statistics were used to investigate the effects of the differential aroma-active compounds on the sensory aroma characteristics. O-cresol, ethyl 2-methylbutyrate, 5-methylfurfural and propionic acid might influence the flavor of single malt whiskies of different origins in Scotland. The 54 key whisky aroma compounds were analyzed, with isoamyl acetate having the highest OAV (odour activity value) of all whisky samples. In addition, the aromas of volatile compounds were analyzed using OSME (odor-specific magnitude estimation) and OAV. Based on these facts, the researchers developed a flavour wheel with 10 aroma profiles. This paper evaluates Scotch single malt whisky from a Chinese perspective, which helps the development of the Chinese whisky market.

Combining multivariate statistical analysis to characterize changes in amino acids and volatiles during growth of Lou onion pseudostems.

The main edible part of the Lou onion is the pseudostem, which is highly valued for its distinctive flavour. However, harvesting decisions for the pseudostem are often based on size and market price, with little consideration given to flavour. By clarifying the growth of flavour in pseudostems, farmers and consumers may benefit from evidence-based insights that help optimize harvesting time and maximize flavour quality. This study employed amino acid analysis and gas chromatography-ion migration spectroscopy (GC-IMS) to elucidate the compounds of the pseudostem across different growth phases, and 17 amino acids and 61 volatile substances. Subsequently, analysis revealed that 18 compounds, including arginine (Arg), aspartic acid (Asp), glutamic acid (Glu), valine (Val), (E)-2-nonenal, decanal, 2,4-nonadienal, 2-octenal, (Z)-4-decenal, 2,4-decadienal benzeneacetaldehyde, linalool, eugenol, (Z)-6-nonen-1-ol, methyl anthranilate, 2-acetylpyridine, 3-sec-butyl-2-methoxypyrazine, and 2,6-dichlorophenol, were the key compounds in determining the flavour characteristics of the pseudostems, as assessed by taste activity value and relative odour activity value calculations. In addition, correlation analysis, focusing on five amino acids and 38 volatile compounds with variable importance for predictive components scores of >1, identified anisaldehyde, eugenol, (Z)-6-nonen-1-ol, 2,4-decadienal, 3-sec-butyl-2-methoxypyrazine, Arg, Asp, and Val as the key differentiators and contributors to the pseudostems flavour profile. During the rapid growth of Lou onions just before the emergence of flower stems, the pseudostem exhibited the most prominent flavour, making this stage most suitable for harvesting compared to the regreening growth stage and the rapid growth period of the aerial bulbs. © 2024 Society of Chemical Industry.