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Fu Brick Tea (FBT) is characterized by Fungus Aroma (FA), which determines the quality of FBT products. However, the aroma constituents and their interactive mechanism for FA remain unclear. In this study, the FBT sample with the optimal FA characteristics was selected from 29 FBTs. Then, 19 components with OAV ≥ 1 were identified as the odorants involved in the FA formation. The aroma recombination test suggested that the FA was potentially produced by the synergistic interplay among the 15 key odorants, including (E,E)-2,4-heptadienal, (E,E)-2,4-nonadienal, (E)-2-nonenal, (E,Z)-2,6-nonadienal, (E)-2-octenal, (E)-ß-ionone, 4-ketoisophorone, dihydroactinidiolide, (E)-ß-damascenone, 1-octen-3-ol, linalool, geraniol, heptanal, hexanal, and phenylacetaldehyde. And, the synergistic effects between them were preliminarily studied by aroma omissions, such as modulatory effects, masking effects, compensatory effects, and novelty effects, ultimately contributing to the FA. In all, this work helps us better understand the formation of the FA and provides a basis for the improvement of FBT production technology.

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The effect of adding bamboo shoots to stewing on the quality and flavor of chicken soup has never been reported. Therefore, this study investigated the effects of 4 kinds of bamboo shoots on the edible quality, volatile and water-soluble flavor components of Chahua chicken soup. The results showed that adding bamboo shoots changed the sensory and nutritional quality of chicken soup. A total of 62 volatile flavor components were identified by HS-SPME-GC-MS, of which 12 were identified as characteristic volatile flavor components, and 9 were the main reasons for the flavor differences between bamboo shoot chicken soup with blank chicken soup. LC-MS found that after adding bamboo shoots, the differential water-soluble components in chicken soup significantly increased, and most of the increased components have been proven to have physiological functional activity. In conclusion, adding bamboo shoots improved the nutritional and sensory quality, and changed the flavor components of chicken soup.

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To investigate the differences of volatile and non-volatile metabolites between oyster enzymatic hydrolysates and boiling concentrates, molecular sensory analysis and untargeted metabolomics were employed. "Grassy," "fruity," "oily/fatty," "fishy," and "metallic" were identified as sensory attributes used to evaluate different processed oyster homogenates. Sixty-nine and 42 volatiles were identified by gas chromatography-ion mobility spectrometry and gas chromatography-mass spectrometry, respectively. Pentanal, 1-penten-3-ol, hexanal, (E)-2-pentenal, heptanal, (E)-2-hexenal, 4-octanone, (E)-4-heptenal, 3-octanone, octanal, nonanal, 1-octen-3-ol, benzaldehyde, (E)-2-nonenal, and (E, Z)-2,6-nonadienal were detected as the key odorants (OAV > 1) after enzymatic hydrolysis. Hexanal, (E)-4-heptenal, and (E)-2-pentenal were significantly associated with off-odor, and 177 differential metabolites were classified. Aspartate, glutamine, alanine, and arginine were the key precursors affecting the flavor profile. Linking sensory descriptors to volatile and nonvolatile components of different processed oyster homogenates will provide information for the process and quality improvement of oyster products.

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Soy products are rejected by Western consumers because of their green and beany off-aroma. The off-aroma profiles of typical soy products (soy drink and soy protein isolate) were analyzed and forty-five regions imparting green and beany odor impressions were perceived after application of direct immersion-stir bar sorptive extraction coupled with gas chromatography-mass spectrometry-olfactometry. After a fermentation of 28 h with Lycoperdon pyriforme the intensity of the off-aroma was reduced. Accordingly, thirteen and fourteen of the thirty-five quantified compounds were significantly decreased after fermentation of soy drink and soy protein isolate, respectively. The major off-aroma contributors, aldehydes, were reduced during fermentation and their degradation products were analyzed. The following bio-pathways were suggested (i) saturated aldehydes were reduced to the corresponding alcohols with increased odor threshold, leading to less intense sensorial perception, and (ii) di-unsaturated aldehydes did not form any odor-active substance in the volatile spectrum. Both of the phenomena explained the decreased sensorial perception of the off-aroma.

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The yeast Saccharomyces cerevisiae is effective in reducing the fishy malodor of sea products. However, the biotransformation pathways are still unclear. The seaweed B. fusco-purpurea was taken as an example to investigate the chemical transformation pathways for the deodorization process with S. cerevisiae fermentation. Sensory evaluation, GC-MS, GC-MS-O and odor activity value (OAV) analyses showed the fishy odorants were 1-octen-3-ol, (E)-2-nonenal, 2,4-decadienal, 2-pentylfuran, 2-octen-1-ol and nonanal. The removal of fishy malodor was related to the reactions of reduction, dehydrogenation, deformylation-oxygenation and ester syntheses via catalysis of aldehyde dehydrogenase, alcohol dehydrogenases, epoxide hydrolase, aldehyde deformylating-oxygenase, enone reductase, oxidases, dehydrogenases, aldo-keto reductases, ester synthase and acyltransferase. Interestingly, for the first time, it was found that 3,5-octadien-2-one transformed to 6-octen-2-one; and 2-pentylfuran transformed to o-cymene and hexyl acetate. Our findings enrich the knowledge for the removal of fishy malodor from sea products such as seaweeds.

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Wine models with or without a dearomatised and lyophilized red wine extract containing a young red aroma base (control) plus one vector with one or several aroma compounds (unsaturated-aldehydes, saturated-aldehydes, benzaldehyde, isoamyl-alcohol, methoxypyrazines and (Z)-1,5-octadien-3-one) were prepared. Models were spiked with increasing amounts of acetaldehyde whose headspace concentrations were controlled. Odour and nasal chemesthesic properties were assessed by a trained sensory panel. Results confirm the contribution of the different players, notably isoamyl-alcohol, (Z)-1,5-octadien-3-one, benzaldehyde and methoxypyrazines, to wine aroma and tactile nasal characteristics and demonstrate that acetaldehyde levels play an outstanding role in their modulation. At low levels, it can play positive roles in some specific aromatic contexts, while at higher levels, enhance the negative effects associated to the generic presence of other aldehydes (saturated, unsaturated and Strecker aldehydes) by enhancing "green vegetable" notes and "itching" character and the "burning" effects linked to high levels of isoamyl alcohol.

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Volatile compounds of raw and cooked adzuki beans under three cooking methods namely frying, roasting, and boiling were extracted and identified. The odorants in raw beans changed from "green" and "grassy" to "roasted" and "nutty" in fried and roasted beans. Roasted adzuki beans had the greatest number of volatile compounds and best flavor properties. Because volatiles improve biscuit flavor profiles, biscuits were prepared in which wheat flour was substituted with adzuki bean flour and/or millet flour. The effects of grain flours on the sensory acceptability and aroma of biscuits were evaluated. Descriptive sensory analysis showed that the adzuki bean-millet biscuit had the best sensory quality. Correlation of volatile compounds, biscuit sensory attributes, and biscuit samples showed that maltol contributed to the "caramel-like" aroma of adzuki bean-millet biscuits. Adzuki bean and millet flours have potential in the development of biscuits that meet flavor and nutritional requirements.

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The consumption of soy drink in Western countries is limited due to its green off-flavor. Hence, fermentation of soy drink with Lycoperdon pyriforme to tailor the aroma has been investigated. After 28 h the green off-flavor was not perceived by 60% of the sensory panel (n = 23). Molecular sensory changes of soy drink during fermentation were decoded by means of direct immersion-stir bar sorptive extraction coupled with gas chromatography-mass spectrometry-olfactometry and aroma dilution analysis. The semi-quantification of key odorants revealed a significant decrease of the representative green odorants (i.e., hexanal, (E)-2-nonenal, (E,E)-2,4-decadienal) of soy drink, among of which hexanal even turned below its odor threshold. The quantitative reduction of these odorants correlated with the organoleptic difference. Besides that, nutritionally relevant parameters of soy drink including protein, fat, and polyphenol content kept consistent during the short fermentation process.

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The contents of volatile aroma compounds in orange juice vary after high hydrostatic pressure (HHP) processing and pasteurization, and hence gas chromatography-mass spectrometry has potential for discriminating between orange juice samples according to the processing method. Effects of HHP processing and pasteurization on orange juice were investigated immediately after processing and after storage for 28 days at 4 °C. Processing decreased the contents of most terpenes and esters and increased those of alcohols and aldehydes. Volatile compounds that could serve as discriminant indicators of HHP processing and pasteurization were heptanal, (E)-2-heptenal, (E)-2-nonenal, and d-carvone and ß-terpineol, p-mentha-1,5-dien-8-ol, carveol, and ß-copaene, respectively. The discrimination abilities of pH, ascorbic acid, total soluble solids, and color were compared with those of volatile compounds, which were found to be lower. The compounds d-carvone and ß-terpineol could be used as discriminant indicators of HHP-treated and pasteurized orange juice, respectively, throughout the storage period.

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Volatile compounds of Lentinula edodes grown in different culture substrate (CS) formulations were analyzed to reveal (i) the relationship between volatile compound production and CS formulations, (ii) the contribution of volatile compounds to L. edodes flavor, (iii) the activities of LOX and γ-GGT enzymes, (iv) γ-GGT gene expression, and (v) the correlation between enzyme activity and volatile compound production. Our results showed that 82 kinds of volatile compounds were analyzed; 25 volatile compounds were considered key flavor components, and sulfur containing compounds, eight-carbon compounds, and aldehyde compounds also had great contributions to mushroom flavor. Bagasse could be used as a partial substitute for sawdust as a carbon source. LOX and γ-GGT activities showed a weak correlation with the volatile end products. The results indicated that the mechanisms by which CS formulations influence volatile compounds production were complex.

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The efficacy of two sodium reduction strategies in preserving sensory profile and consumer liking of yeasted wheat bread was tested, by combining sensory data, aroma compounds and consumer investigations. The use of (i) a reduced-sodium salt substitute, Pansalt® (NaCl 57%, other salts and minor ingredients) at 1.5%, and (ii) the heterogeneous NaCl distribution (average level of 1%) leading to enhanced saltiness by taste contrast, were compared with standard (1.5%) and reduced (1.0%) addition of NaCl. The heterogeneous NaCl distribution was effective in preserving saltiness. Salt substitution with Pansalt® was less effective but preserved the overall flavour. Higher amount of Maillard reaction volatile products, associated with more intense toasted odour of the crust, was found in breads with higher NaCl content. The consumer survey highlighted satisfactory results of Pansalt® use for 58% of the respondents (equal or higher liking and purchase intention). Heterogeneous salt distribution was effective for 31% of consumers.

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Lipid oxidation is a major contributor to the deterioration of the sensory quality of fat-containing dairy powders. Hydroperoxides are the primary oxidation products from unsaturated fatty-acids that readily yield a complex mixture of volatile organic compounds that can adversely impact product quality and shelf life. Headspace solid-phase microextraction gas-chromatography mass-spectrometry was chosen to quantify thirteen lipid oxidation compounds in whole milk powder encompassing a range of volatilities and chemical classes. A central composite rotatable design (CCD, α = 1.1) based on a 23 factorial table was used with response surface methodology to optimize the HS-SPME parameters; determined at; 45 min extraction time and 43 °C extraction temperature. The significant model terms were found to be extraction temperature (p < 0.05) and the interaction between time and temperature (p < 0.05). Precision, accuracy, LOD and LOQ were determined and the method was validated for whole milk powder.

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A wild plant (Sanguisorba albanica) from Kosovo exhibits an appealing aroma, which was perceived as intensely fresh, green, and slightly sweetish with hints of cucumber, melon, and green tea. The characteristic aroma of S. albanica was analyzed for the first time by employing advanced molecular sensory techniques coupled with multiple headspace solid phase microextraction (MHS-SPME). Thirty-six different odor impressions were perceived, and 34 corresponding compounds were identified by a gas chromatography system equipped with a mass spectrometric detector and an olfactory detection port. By aroma dilution analysis, sixteen key odorants with flavor dilution factors higher than 16 were identified. Their respective concentrations were quantified by means of MHS-SPME according to the determined ß values (0.43-0.83), and odor activity values (OAVs) were calculated. (E,Z)-2,6-Nonadienal (green, melon-like, and sweetish odor; OAV 20,046), followed by linalool (floral and citrus-like odor; OAV 10,563), (Z)-6-nonenal (cucumber-like, green, and melon-like odor; OAV 4200), ethyl isobutyrate (floral and fruity odor; OAV 1315), and (E)-2-nonenal (green and fatty odor; OAV 1062) were representative odorants contributing to the overall aroma of S. albanica. Differences between stems, leaves, and flowers of S. albanica with regard to the key odorants were also presented. Intensely green and floral aromas of the leaves and flowers were greatly attributed to (E,Z)-2,6-nonadienal and linalool, respectively. Apart from these compounds, (Z)-6-nonenal contributed to the overall aroma of the stems as well.

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To provide precision management of cucumber under protected cultivation, the relationships between environmental factors and daily increment of aroma in two lines were analyzed during development, using Pearson correlation and stepwise regression. Irrespective of the line tested, the daily increment of volatile compounds and C6 aldehydes were positively correlated with average daily light intensity (X1), while the daily increment of C9 aldehydes was negatively correlated with average daily relative humidity (X4) and average daytime relative humidity (X7). X1 was considered as the most significant environmental factor which affected the daily increment of volatile compounds in both lines, X7 was the environmental factor which affected the daily increment of C9 aldehydes most in No.14-1, and X1 and X4 were the factors which affected the daily increment of C6 aldehydes and C9 aldehydes most in No.26. A range of environmental factors was forecast for the maximal daily increment of volatile compounds.

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Biopolymers used for food contact materials must be evaluated in order to ensure food safety and quality. In this work, the aroma profile of starch-based packaging materials, presented as pellets and films has been characterized. Headspace solid phase microextraction (HS-SPME) technique and gas chromatography coupled to both mass spectrometry and a sniffing port (GC-MS-O) were used for identification. In total, 35 odorant compounds were detected. The results showed that aldehydes were the odorants with the highest aromatic impact in starch-based films. Eight odorant compounds, such as trimethylamine, 1-octen-3-one, sotolon, (Z) and (E)-2-nonenal, p-vinylguaiacol, eugenol and 1-undecanol, defined as aroma-impact compounds, obtained modified frequency values (MF%) above 60% in at least 3 out of 4 films. A sensory panel evaluated the toasted, sweet/fruity, green, flower, distasteful, fat and spices notes in the films and it was observed that the quality of all samples decreased when the toasted and spices notes increased.

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Volatile profiles of jujube fruits at different ripening stages were characterized by GC-MS and E-nose. Changes in the possible precursors of volatile components were also investigated. Four ripening stages were established: GM, green maturity; YM, yellow maturity; HRM, half-red maturity; RM, red maturity. Fruit maturity showed significant effect on the volatile components and their precursors. (E)-2-hexenal was the most abundant component which showed rising trend from 169.2 µg/kg (GM) to 733.4 µg/kg (RM). Glucose and fructose showed a decreasing tendency during ripening. As the important precursors of jujube flavor, seven fatty acids were identified, the predominant ones were C16:0, C16:1n7, C18:1n9c and C18:2n6c; twenty-six free amino acids were quantified, in which l-AspNH2 and l-Pro were the abundant components. Owing to the highest content of total aldehydes (59.33%) and the strongest responses of E-nose, jujubes at HRM stage showed superior overall flavor quality among all the samples.

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Volatile profile of ten different varieties of fresh jujubes was characterized by HS-SPME/GC-MS (headspace solid phase micro-extraction combined with gas chromatography-mass spectrometry) and E-nose (electronic nose). GC-MS results showed that a total of 51 aroma compounds were identified in jujubes, hexanoic acid, hexanal, (E)-2-hexenal, (Z)-2-heptenal, benzaldehyde and (E)-2-nonenal were the main aroma components with contributions that over 70%. Differentiation of jujube varieties was conducted by cluster analysis of GC-MS data and principal component analysis & linear discriminant analysis of E-nose data. Both results showed that jujubes could be mainly divided into two groups: group A (JZ, PDDZ, JSXZ and LWZZ) and group B (BZ, YZ, MZ, XZ and DZ). There were significant differences in contents of alcohols, acids and aromatic compounds between group A and B. GC-MS coupled with E-nose could be a fast and accurate method to identify the general flavor difference in different varieties of jujubes.

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The impact of sodium chloride (NaCl) concentration on the yeast activity in bread dough and its influence on the aroma profile of the baked bread was investigated. Key aroma compounds in the bread samples were analysed by two-dimensional high-resolution gas chromatography-mass spectrometry in combination with solvent-assisted flavour evaporation distillation. High-sensitivity proton-transfer-reaction mass spectrometry was used to detect and quantify 2-phenylethanol in the headspace of the bread dough during fermentation. The analyses revealed significant (p < 0.05) changes in the aroma compounds 2-phenylethanol, (E)-2-nonenal, and 2,4-(E,E)-decadienal. Descriptive sensory analysis and discriminating triangle tests revealed that significant differences were only determinable in samples with different yeast levels but not samples with different NaCl concentrations. This indicates that a reduction in NaCl does not significantly influence the aroma profile of yeasted bread at levels above the odour thresholds of the relevant compounds, thus consumers in general cannot detect an altered odour profile of low­salt bread crumb.