Aroma Recombination Research Articles

Preparation and flavor characteristics of plant-based meat flavoring by mixed fermentation of multiple strains

In this study, plant-based meat flavoring was prepared by mixed fermentation and thermal reaction. Based on the changes of amino acid nitrogen, reducing sugar, and total acid during the fermentation process and combined with sensory evaluation, the optimal fermentation conditions were determined as 4 % total inoculation amount of Monascus purpureus, Actinomucor elegans, and Bacillus subtilis with an inoculation ratio of 1:1:1, and 36 h of fermentation time. The odor characterization of meat flavoring was identified by solid-phase microextraction–gas chromatography–mass spectrometry (SPME–GC–MS), aroma extract dilution analysis (AEDA), quantitative measurements, odor activity value (OAV) and aroma recombination and omission experiments. 64 volatile compounds and 28 odorants were identified. The compounds with FD ≥ 27 were precisely quantified by five-point standard calibration curve and OAVs were calculated, and those with OAV ≥ 1 were subjected to aroma recombination and omission experiments. Finally, furfuryl mercaptan, difurfuryl disulfide, 4-methyl-5-ethylthiazole, 1-octanal, and 2-acetylthiophene were determined to be the key aroma-active compounds. These compounds have been recognized as key aroma-active compounds or detected in other meats or meat flavorings. In this study, we prepared plant-based meat flavoring through mixed fermentation, and provide new ideas for the development of plant-based thermal reaction meat flavoring process.

Characterization and perceptual interaction of key aroma compounds in Rosa roxburghii Tratt by sensomics approach

Rosa roxburghii Tratt (RRT) is esteemed for its unique aroma and nutritional value. Analyzing RRT juice samples from four elevations using GC–MS and GC-O, 99 volatile compounds were identified with 37 exhibiting aroma activity. 29 compounds including aldehydes, alcohols, and terpenes, were key contributors to RRT's aroma, based on high OAVs. Aroma recombination and omission tests confirmed 18 key aroma compounds in RRT while 2,5-Dimethyl-4-methoxy-3(2H)-furanone, hexanal, furfuryl acetate, furaneol acetate, and benzaldehyde as critical aroma compounds. The σ-τ graph revealed additive interactions among primary aroma compounds, indicating synergistic effects on RRT's overall aroma profile. Longli produced the most fragrant RRT at the lowest elevation of the four producing areas.

Unraveling Shengmuxiang in Jiang-flavor base baijiu using a combination of metabolomics and sensomics strategy

Shengmuxiang (SMX), an important aroma in Jiang-flavor base baijiu, significantly influences the quality of the product. This study employed untargeted metabolomics combined with sensomics to explore the key compounds responsible for SMX. Results indicated that SMX samples had higher intensities of green and woody-like odors compare to control samples. A total of 87 aroma compounds were identified by headspace solid phase microextraction combined with gas chromatography–mass spectrometry technology. Based on the variable projection importance, PCA and OPLS-DA were employed to identify 22 potential marker compounds. Quantitative results combined with hierarchical cluster and OAV analysis revealed that 9 aroma compounds (OAV > 1) had high concentrations in SMX samples. Aroma recombination and omission experiments further indicated that acetaldehyde and acetal were the key compounds responsible for the characteristic aroma of SMX in Jiang-flavor base baijiu. These findings provide valuable insights into the distinct aroma profile of SMX and offer a basis for quality control of Jiang-flavor base baijiu.

Characterization and Profiling of Key Odorants in Roasted Hybrid American-European Hazelnuts.

American-European hybrid hazelnuts (Corylus americana × Corylus avellana) are an emerging crop in the Upper Midwest of the United States that have been reported to have unique sensory characteristics compared to traditionally grown European hazelnuts. In this study, key odor-active compounds in a roasted hybrid hazelnut variety (C. americana × C. avellana) were identified and profiled across different hybrid hazelnut varietals to understand sensory differences. Gas chromatography/mass spectrometry/olfactometry analysis identified 33 odorants with high flavor dilution factors (FD ≥ 16) in the roasted hybrid hazelnut, including 2-acetylpyrazine and 2-aminoacetophenone as first reported hazelnut odorants. Descriptive sensory analysis profiles of the roasted hazelnut and an aroma recombination model consisting of 27 odorants quantified above their odor detection thresholds were not significantly different for the six evaluated attributes, confirming the aroma contribution of the identified odorants. Variation in all 33 aroma-active compounds across 12 hybrid and two European hazelnut varieties was visualized through principal component analysis and related to aroma profiles previously characterized by consumers.

Revealing the differences in aroma of black tea under different drying methods based on GC–MS, GC-O

Drying greatly affects the aroma of black tea. In this study, the differences in aroma of black tea under hot-air drying (HD), sun drying (SD), and pan-fired drying (PD) were investigated through quantitative descriptive analysis. Headspace solid-phase microextraction and solvent assisted flavor evaporation combined with gas chromatography–mass spectrometry and gas chromatography-olfactory were used to analyze the overall aroma profile of black tea. Aroma extract dilution analysis and odor activity values revealed that 15 aroma-active compounds led to differences in aroma, namely linalool, geraniol, phenylethyl alcohol, phenylacetaldehyde, (Z) -linalool oxide (furanoid), β-damascenone, dimethyl sulfide, methional, 2-methylbutanal, 3-methylbutanal, methyl salicylate, β-myrcene, hexanal, 1-octen-3-ol, and heptanal. Among them, geraniol, linalool, and methional significantly enhanced the floral and roasty aroma of HD, while hexanal enhanced the green aroma of SD. Finally, our results were validated through aroma recombination and addition experiments. This study provides a theoretical basis for improving the aroma of black tea.

Chemometrics and sensomics-assisted identification of key odorants responsible for retort odor in shelf-stored green tea infusion: A case study of Biluochun

The deterioration of aroma quality in tea beverages during the shelf life is a significant issue. In this study, sensomics techniques were employed to identify the characteristic factor contributing to aroma degradation in green tea infusion. Samples A (no/faint retort odor) and B (high intensity retort odor) were selected based on their retort-like odor intensity after heat treatment simulating shelf-life conditions. The key odorants were identified through a combination of chemometrics analysis, comparative aromatic extract dilution analysis (cAEDA), detection frequency analysis (DFA), and odor-specific magnitude estimation (OSME). Subsequently, eight odorants, including linalool (892.451 μg/L), (E)-β-damascenone (5.105 μg/L), phenylacetaldehyde (27.720 μg/L), nonanal (2201.439 μg/L), α-terpineol (7.166 μg/L), geraniol (0.499 μg/L), theaspirane (0.044 μg/L), and 2-hydroxy-5-methylacetophenone (2.973 μg/L), were identified as the key substances contributing to the retort-like odor in sample B. Aroma recombination and omission test further demonstrated that elevated concentrations of nonanal, geraniol, phenylacetaldehyde, and theaspirane might be the primary reasons for the retort odor observed in samples.

Analysis of aroma compounds in different grades of Luzhou Laojiao strong-aroma Baijiu by molecular sensory science

Strong-aroma Baijiu is a beloved drink in China because of its elegant cellar aroma, sweetness and mellow taste, and its sales account for more than half of the Baijiu production. In this study, three different grades of strong-aroma Baijiu were analyzed systematically using comprehensive two-dimensional gas chromatography–time-of-flight mass spectrometry coupled with molecular sensory science. A total of 342 aroma compounds were identified in the three samples, including 152 aroma-active compounds. Principal component analysis revealed that higher-grade Baijiu contained more terpenes, acetals, and esters. In contrast, lower-grade Baijiu contained fewer esters and many compounds likely generated by the Maillard reaction, such as 5-methylfurfural, 2-propanoylfuran, 2,6-dimethylpyrazine, and 5-ethyl-2(5H)-furanone. Most of the aroma attributes of Baijiu samples could be simulated through aroma recombination experiments, but there were still some slight differences in individual aromas. Finally, the key aroma compounds of the three different grades of Baijiu were revealed through omission experiments. This study provided a scientific basis for the classification of strong-aroma Baijiu quality grades, thereby contributing to the high-quality development of the Baijiu industry.

The hotspot of consumers complaints on infant formula: Exploring the relationship among volatile components, sensory evaluation, and aroma recombination and omission experiment

Two-stage infant formula (IF) is rich in polyunsaturated fatty acids (PUFAs), However, PUFAs are susceptible to oxidation, thus affecting the flavor profile of the product. This study aimed to evaluate 4 samples with the participation of 60 consumers. Among these, three samples with the lowest consumer preference and one with the highest preference were selected as controls to explain the causes of off-flavors in two-stage infant formulas. Through qualitative and quantitative analysis of 28 flavor-active compounds in two-stage infant formulas using GC-MS, E-nose, GC-O, odor activity values (OAVs), and variable importance in projection (VIP) values, hexanal, heptanal, pentanal, octanal, and 1-penten-3-one were identified as the important compounds affecting the flavor of two-stage infant formulas. Further, recombination/deficiency experiments confirmed hexanal and heptanal as the key undesirable flavor components in two-stage infant formulas.

A comparative study to determine the key aroma components of yogurt aroma types based on Sensomics and Flavoromics

This study used Sensomics to examine four previously obtained yogurt aroma type profiles. 14 key aroma-active compounds were identified as significant contributors (p ≤ 0.05) in the four aroma types using gas chromatography–mass spectrometry-olfactometry (GC–MS/O), aroma extract dilution analysis (AEDA), odor activity values (OAV), and aroma recombination and omission experiments. The Sensomics and previous Flavoromics results were compared, showing that Flavoromics identified 10 indicator compounds for distinguishing aroma types. Eight were the same as the key aroma-active compounds identified via Sensomics, namely acetic acid, pentanoic acid, decanoic acid, 3-hydroxy-2-butanone, 2,3-pentanedione, acetaldehyde, δ-decalactone, and dimethyl sulfone. Sensomics revealed a prominent similarity between the categories of key aroma-active compounds of the four aroma types, with a higher sensory contribution. Flavoromics showed less overlapping between the indicator compounds, mainly related to the distinction between the four aroma types. Sensomics and Flavoromics serve distinct research objectives and should be selected according to the study subject.

Contribution of tea stems to large-leaf yellow tea aroma

Large-leaf yellow tea (LYT) is processed from both leaves and stems, resulting in a distinctive rice crust–like aroma. Tea stems may contribute differently to the aroma of LYT than leaves. This study aimed to clarify the specific contribution of stems to LYT. The volatile compounds in different components of LYT were extracted and analyzed using a combination of headspace solid-phase microextraction and stir bar sorptive extraction coupled with gas chromatography-olfactory-mass spectrometry. The results revealed high concentrations of compounds with roasty attributes in stems such as 2-ethyl-3,5-dimethylpyrazine (OAV 153–208) and 2-ethyl-3,6-dimethylpyrazine (OAV 111–140). Aroma recombination and addition experiments confirmed that the roasty aroma provided by stems plays a pivotal role in the formation of the distinctive flavor of LYT. This study offers novel insights into the contribution of stems to the aroma of LYT, which can be used for processing and quality enhancement of roasted tea.

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.

Effects of different fixation methods on the aroma quality of Anjibai tea

Fixation is a crucial step in the processing of Anjibai tea. In this study, gas chromatography tandem with mass spectrometry was used to analyze the aroma compositions of Anjibai tea across three types of fixation methods: roller-electrical fixation (REF), carding machine fixation (CMF), and roller-hot air fixation (RHF). Nine key volatile compounds were found responsible for Anjibai tea's aroma variations. Results from quantitative descriptive analyses, along with aroma recombination and omission tests, showed that linalool and geraniol significantly contribute to the formation of the medium flowery, fruity, and honey aromas in the REF samples; hexanal has a significant impact on the green aroma in the CMF samples; and 2-ethyl-3,6-dimethylpyrazine is an important aroma compound for the strong roasty aroma in the RHF samples. These findings provide an important theoretical foundation for improving the aroma quality of Anjibai tea and selecting the optimal fixation method.

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.

Decoding the Qu-aroma of medium-temperature Daqu starter by volatilomics, aroma recombination, omission studies and sensory analysis

Qu-aroma is of great significance for evaluation the quality of Daqu starter. This study aimed to decode the Qu-aroma of medium-temperature Daqu (MT-Daqu) via “top-down” and “bottom-up” approaches. Firstly, 52 aroma descriptors were defined to describe the MT-Daqu aroma by quantitative descriptive analysis. Secondly, 193 volatile organic compounds (VOCs) were identified from 42 MT-Daqu samples by HS-SPME-GC–MS, and 43 dominant VOCs were screened out by frequence of occurrence or abundance. By Thin Film (TF)-SPME-GC-O-MS, 27 odors and 90 VOCs were detected in MT-Daqu mixture, and 14 odor-active VOCs were screened out by odor intensity. Thirdly, a five-level MT-Daqu aroma wheel was constructed by matching 52 aroma descriptors and 37 aroma-active VOCs. Finally, Qu-aroma of MT-Daqu was reconstructed with 37 aroma-active VOCs and evaluated by omission experiments. Hereinto, 26 key aroma-active VOCs were determined by OAV value ≥1, including isovaleric acid, 1-hexanol, isovaleraldehyde, 2-octanone, trimethylpyrazine, γ-nonalactone, 4-vinylguaiacol, etc.

Sensomics-assisted analysis unravels the formation of the Fungus Aroma of Fu Brick Tea

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)-β-ionone, 4-ketoisophorone, dihydroactinidiolide, (E)-β-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.

Effect of storage time on aroma profiles of wuyi rock tea

Wuyi rock tea (WRT) is typically stored for weeks or months before consumption, and the roasted aroma changes into a floral aroma during the storage. However, little is known about the aroma change that occur during this period. The aroma in WRT during storage was extracted and identified using simultaneous distillation extraction coupled with gas chromatography mass spectrometry, in addition to calculating the odor activity value (OAV) and conducting aroma recombination experiments. The results revealed the emergence of floral aroma with increasing storage time. Alcohols, aldehydes, and aromatics were the main volatile types in WRT. According to partial least squares discriminant analysis, 20 volatiles were crucial variables contributing to the volatile differences in WRT with variations in storage time. The key volatiles causative for the overall aroma of WRT were determined based on their OAVs. In total, 25 volatiles with OAVs >1 were identified as aroma-active compounds. Notably, trans-β-ionone, 2-ethyl-3,5-dimethylpyrazine, linalool, octanal, nonanal, dehydro-β-ionone, and pentylfuran were substantial players in the overall aroma profile of WRT under storage. Based on the results of aroma combination experiments, the contribution of 18 volatiles with OAVs >2 to the overall aroma of WRT was confirmed. The findings augment our comprehension of aroma development in WRT throughout the storage.

Sensory-directed flavor analysis reveals the improvement in aroma quality of summer green tea by osmanthus scenting

Flower scenting is an effective way to enhance the aroma of green tea (GT), including those osmanthus scented green tea (OSGT). However, the mechanism of aroma enhancement by scenting is still unclear. Here, the volatiles of GT, OSGT, and osmanthus were detected by GC–MS. The total volatile content of OSGT was significantly increased compared to GT, with the flowery and coconut aromas enhanced. Furthermore, 17 of 139 volatiles were responsible for the enhancement by GC–olfactometry and their absolute odor activity values (OAVs). Aroma recombination, omission and addition experiments showed that dihydro-β-ionone, (E)-β-ionone, (E, E)-2,4-heptadienal, geraniol, linalool, α-ionone, and γ-decalactone were the key aroma volatiles with flowery or coconut aromas. Additionally, the dynamics of the key volatiles (OAVs >1) from different scenting durations were analyzed, proving that the optimal duration was 6–12 h. This study provides new insight into the mechanism of aroma formation during OSGT production.

2- Acetyl-1-pyrroline originated from Maillard reaction is the key odorant of cooked Lipu taro

Lipu taro is one of the most famous varieties of taro in China with strong aroma. In this study, vacuum simultaneous steam distillation and extraction and gas chromatography-mass spectrometry were applied to extract and analyze the volatile components, combined with gas chromatography-olfactometry, aroma extraction dilution analysis, odor activity value, aroma recombination and omission experiments to determine the key aroma-active compounds in cooked Lipu taro. Results revealed that 18 odorants, such as 2-acetyl-1-pyrroline (2-AP), (E,E)-2,4-decadienal, methional, nonanal, 1-octen-3-one, etc., were identified as the key aroma-active compounds, and they could recombine the taro aroma at detected concentration. Among these key odorants, 2-AP exhibited the most significant roles in cooked Lipu taro. 2-AP was confirmed to be originated from Maillard reaction, as the addition of Maillard reaction precursors (L-proline and D-glucose) could increase its content significantly. This result offers a practical method of enhancing the characteristic aroma of cooked taro.

Characteristic aroma compounds during the fermentation of Chinese steamed bread fermented with different starters

The characteristic aroma compounds of Chinese steamed bread (CSB) fermented with different starters were studied using HS-SPME-GC/MS, aroma recombination and omission experiments. The dynamic changes of the microbiota and their function and metabolites during fermentation were analyzed using metagenomics and non-targeted metabolomics. Forty-nine volatile flavor compounds were identified, while 5 characteristic aroma-active compounds were investigated in CSB fermented with commercial dry yeast (AQ-CSB), and 10 were investigated in CSB fermented with traditional starter (NY-CSB). Microbial structure and function analysis showed that Saccharomyces cerevisiae dominated during AQ-CSB fermentation and contributed >95% to its KEGG pathways, while Pediococcus pentosaceus, unclassified Pediococcus, Lactobacillus plantarum, Lactobacillus brevis and unclassified Lactobacillus were predominant in NY-CSB and together had an ~96% contribution to these pathways. NY-CSB showed higher metabolic activity during fermentation, and the characteristic metabolites were mainly involved in carbohydrate, amino acid and lipid metabolism. The characteristic aroma compounds were identified and increased the understanding of the contributions of the microbiota. This may be useful for designing starter cultures that produce CSB with desirable aroma properties.

Characterization of key aroma-active compounds in fresh and vacuum freeze-drying mulberry by molecular sensory science methods

Mulberry is prone to rapid deterioration, but its quality can be maintained through vacuum freeze-drying. In this study, the aroma compositions of fresh mulberry (FM) and vacuum freeze-dried mulberry (VFDM) were analyzed through headspace solid-phase microextraction (HS-SPME) and solvent-assisted flavor evaporation (SAFE) coupled with GC×GC–O–TOF-MS. A total of 232 volatiles were detected in FM and VFDM, and the content of volatile compounds in VFDM decreased by at least 21.37 % after drying compared to FM. Additionally, 51 and 50 aroma-active compounds were detected in FM and VFDM, respectively, with 13 aroma-active compounds being identified in FM initially. Based on the aroma extraction dilution analysis (AEDA) results, 14 compounds with high flavor dilution (FD) factors were accurately quantified by GC–MS. The calculated odor activity value (OAV) showed that a total of 12 compounds significantly contributed to the aroma of mulberry. Finally, aroma recombination and omission experimental results showed that (E,Z)-2,6-nonadienal, β-ionone, hexanal, and (E)-2-nonenal were the key aroma-active compounds in FM, whereas (E,Z)-2,6-nonadienal, β-ionone, (E)-2-nonenal, eugenol and ethyl isovalerate were the key aroma-active compounds in VFDM.