Aroma Recombination Experiments 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.

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.

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.

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.

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.

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.

Difference comparison of characteristic aroma compounds between braised pork cooked by traditional open-fire and induction cooker and the potential formation cause under electromagnetic cooking

The characteristic aroma compounds of braised pork were identified through molecular sensory science and PLSR analysis, and the difference between two cooking methods, traditional open-fire (BPF) and induction cooker (BPC), was compared. Seventeen aroma compounds with odor activity values (OAVs) > 1 were identified in both samples. BPF revealed higher OAVs for most of the aroma compounds compared to BPC, and the higher aroma quality. Aroma recombination and omission experiments confirmed that twelve aroma compounds significantly contributed to the characteristic aroma of braised pork, and eight compounds such as hexanal, (E)-2-octenal, and methanethiol were further confirmed as important contributors by PLSR analysis. Furthermore, PLSR analysis clarified the role of aldehydes such as hexanal, (E)-2-octenal, and (E,E)-2,4-decadienal in contributing to fatty attribute, whereas methanethiol was responsible for the meaty aroma. These characteristic aroma compounds mainly derived from lean meat due to its high content of phospholipids, and the exogenous seasonings contributed to the balanced characteristic aroma profile of braised pork by altering the distribution of these characteristic aroma compounds. Variations in heating parameters affected the formation of lipid oxidation and Strecker degradation products, which might explain aroma discrepancy between braised pork cooked by two methods with different heat transfer efficiencies.

Identification of key aroma‐active compounds in long shelf‐life yoghurt and milk produced by different pre‐sterilisation processes of raw milk using SBSE‐GC × GC–O–MS

SummaryAroma is a vital attribute of dairy products. This study employed a combination of human sensory evaluation and instrumental analysis to study the effect of two different pre‐sterilisation processes (A and B) on the odour characteristics of milk and long shelf‐life yoghurt. The results from the sensory evaluation and electronic nose analysis indicated that the pre‐sterilisation process significantly influences the aroma profile and compounds of the samples. Stir bar sorptive extraction coupled with comprehensive two‐dimensional gas chromatography−olfactometry−mass spectrometry (SBSE‐GC × GC−O−MS) was applied to identify the aroma‐active compounds present. Aldehydes and ketones emerged as the most abundant aroma‐active compounds. Quantitative analysis showed variations in the concentrations of aroma‐active compounds. For example, higher concentrations of hexanal, butanoic acid and hexanoic acid were observed in long shelf‐life yoghurt and milk produced by process B than process A, while higher concentrations of nonanal, 2,3‐butanedione and 3‐hydroxy‐2‐butanone were detected in products from process A than process B. Initial odour activity values provided insight into the contribution of aroma‐active compounds to the overall odour perception. Based on the results of aroma recombination, omission and spiking experiments, 13 and 11 key aroma‐active compounds were identified in long shelf‐life yoghurt and milk, respectively. These compounds, including 2,3‐butanedione, 2,3‐pentanedione, 2‐heptanone, 2‐undecanone, hexanal, octanal, nonanal, decanal, furfural, butanoic acid, hexanoic acid, 3‐hydroxy‐2‐butanone and styrene, can serve as potential indicators for determining odour differences between long shelf‐life yoghurt (milk) samples. Consequently, they offer a chemical basis for manufacturers to make informed decisions regarding production processes.

Variations in Key Aroma Compounds and Aroma Profiles in Yellow and White Cultivars of Flammulina filiformis Based on Gas Chromatography-Mass Spectrometry-Olfactometry, Aroma Recombination, and Omission Experiments Coupled with Odor Threshold Concentrations.

Flammulina filiformis (F. filiformis) is called the 'benefiting intelligence' mushroom. There is a notable difference between a yellow cultivar (with a robust aroma) and a white mutant cultivar (with a high yield) of F. filiformis. A thorough analysis of aroma differences is essential to improve the aroma of high-yield strains. This study employed a combination of gas chromatography-mass spectrometry-olfactometry (GC-MS-O) and aroma extract dilution analysis (AEDA) to analyze the variations in aroma compounds. Then, the contribution of the odorants was determined using flavor dilution (FD) factors and odor activity values (OAVs). Aroma omission and recombination experiments were used to identify the key odorants. A total of 16 key aroma compounds were characterized in F. filiformis, along with four eight-carbon volatiles (3-octanone, 3-octanol, octanal, and 1-octen-3-ol). Finally, the dominant aroma characteristic was "sweet" for the yellow strain, while it was "green" for the white strain. More research is required to investigate the enzymes and corresponding genes that regulate the synthesis of aroma compounds in F. filiformis for future breeding programs.

Comparison of Aroma Compounds and Sensory Characteristics between Two Different Types of Rice-Based Baijiu.

Rice-based Baijiu has gained popularity in the Chinese market. Qingya-flavored Baijiu, a variant of Xiaoqu-fermented Baijiu, employs rice as its primary raw material, with an improved production process compared to traditional rice-flavored Baijiu. We comprehensively characterized and compared the aroma profiles of these two rice-based Baijiu types using static sensory experiments (QDA, quantitative descriptive analysis) and dynamic sensory experiments (TDS, temporal dominance of sensations). Qingya-flavored Baijiu exhibited pronounced plant, oily, and roasted aromas, while traditional rice-flavored Baijiu displayed more prominent fruity, floral, and sour notes. Utilizing GC-O-MS (gas chromatography-olfactometry-mass spectrometry) and multi-method quantification, we qualitatively and quantitatively analyzed 61 key aroma compounds, identifying 22 compounds with significant aroma contributions based on odor activity values (OAVs). Statistical analyses, combining sensory and chemical results, were conducted to predict important aroma compounds responsible for the aroma differences between the two Baijiu types. Aroma Recombination and Omission experiments showed that seven compounds play key roles in the aroma of Qingya-flavored Baijiu, including (2E,4E)-Deca-2,4-dienal, linalool, apricolin, ethyl acetate, ethyl isobutyrate, ethyl caprylate, and ethyl isovalerate.

Identification of the key aroma compounds in flaxseed milk using stir bar sorptive extraction, aroma recombination, and omission tests

Flaxseed milk is a plant-based dairy alternative that is rich in nutrients. Due to the low concentration of odor compounds in flaxseed milk, it cannot be completely extracted. This poses significant challenges for analysis. Therefore, this study developed a method suitable for extracting volatile compounds from flaxseed milk and compared it with three other extraction methods. It was found that Stir Bar Sorptive Extraction had the best extraction performance, identifying 39 odorants. Flavor dilution factors ranged from 1 to 512, with higher values observed for esters. 13 key odor compounds were identified (odor activity value > 1) using the external standard method for quantification; these included four aldehydes, three pyrazines, two alcohols, two esters, and two other compounds. Pyrazine compounds exhibited the highest concentrations. Aroma recombination and omission experiments showed that nine key odorants contributed significantly to the flavor profile of flaxseed milk, imparting aroma of cucumber, green, mushroom, fruity, sweet, and coconut.

Characterization of key aroma compounds in soy sauce flavor baijiu by molecular sensory science combined with aroma active compounds reverse verification method

The distinctive flavor profile of soy sauce flavor baijiu (SAB) is shaped by its unique aroma compounds. The characteristic aroma compounds in Langjiu soy sauce flavor baijiu (LSAB) were explored based on molecular sensory science. A total of 66 aroma active compounds were identified by gas chromatography–olfactometry (GC–O) combined with aroma extract dilution analysis (AEDA), and 6 important unknown sulfur compounds were identified using the aroma active compounds reverse verification method (ACRVW). A total of 39 key aroma compounds were determined to have odor activity values (OAVs) ≥ 1. The aroma contribution of aroma components was verified by aroma recombination and aroma omission experiments. 15 characteristic aroma compounds were identified in LSAB. Meanwhile, a simple and easy-to-understand sensory expression language was described to fully understand the style characteristics of LSAB. Overall, the present paper offers insights into research uncovering the key “sauce flavor” of soy sauce flavor baijiu.

Revealing the characteristic aroma and boundary compositions of five pig breeds based on HS-SPME/GC-O-MS, aroma recombination and omission experiments

To clarify the characteristic aroma compounds and flavor discrepancies of five Chinese typical pig species, headspace-solid phase microextraction gas chromatography–olfactometry-mass spectrometry (HS-SPME/GC-O-MS), electronic nose (E-nose), aroma recombination and omission experiments were used to analyze the characteristic aroma and boundary of five boiled pork. A total of 38 volatile compounds were identified, of which 14 were identified as important odorants with odor-activity values (OAVs) greater than 1. Aroma recombination and omission experiments revealed 8 key characteristic aroma compounds, which significantly contributed to the overall aroma. Sensory evaluation of the recombination model with the 8 aroma compounds scored 3.0 to 4.0 out of 5 points. 12 potential markers were identified to distinguish by principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA), including (E)-2-octenal, 3-ethyl-2-methyl-1,3-hexadiene, (E)-2-heptenal, 2-pentylfuran, cyclooctanol, 1-heptanol, sec-butylamine, D-limonene, N-vinylformamide, 2,3-octanedione, 2-ethylfuran and 3-pentanamine. Alongside benzaldehyde and pentanal, the combinations and fluctuations of these 14 aroma markers were proposed to constitute the aroma boundaries of different pork breeds. The aroma-active substances were able to effectively differentiate different breeds.

Sensomics-assisted key aroma molecules decoding of ginger-infused stewed beef

The utilization of ginger (Zingiber officinale Rosc.) is prevalent in beef cuisine for the purpose of flavor modification in China. The key aroma molecules in ginger-infused stewed beef were identified by sensomics methods. GC-MS (gas chromatography-mass spectrometry) identified 54 compounds. Nonanal, citral, β-bisabolene, α-terpineol, geraniol and endo-borneol were responsible for remarkable difference of stewed beef after ginger additions by orthogonal partial least squares-discriminant analysis (OPLS-DA). Seven aroma attributes were chosen for sensory analysis by check-all-that-apply (CATA) and free choice profiling method (FCP). Then, 23 compounds were perceived by gas chromatography-olfactometry (GC-O), and further quantified. Of these, 20 aroma-active compounds presented odor activity values (OAV) ≥ 1. Combined with aroma recombination and omission experiments, 19 compounds, including hexanal, β-myrcene, 2-acetylthiazole et al. were identified to be key contributors to characteristic aroma.