Gas Chromatography-mass Spectrometry-olfactometry Research Articles

Characterization of the key aroma compounds of wild bitter melon lujiu based on LLE coupled with GC–O–MS and the aroma influence of polysaccharide addition using VASE–GC–MS

Wild bitter melon (Momordica charantia L. Var. Abbreviata Ser; WBM) is widely cultivated in East and Southeast Asia. It is made into lujiu with high-quality strong-flavor baijiu and presents a beautiful golden color and harmonious aroma. Lujiu is a type of alcoholic beverage similar to gin. In this study, the aroma profile of wild bitter melon lujiu (WBML) was determined through sensory evaluation, and important aroma-active compounds were identified through liquid–liquid extraction (LLE) coupled with gas chromatography–olfactometry–mass spectrometry (GC–O–MS) and aroma extraction dilution analysis (AEDA). A total of 42 aroma-active compounds were identified, and 28 of them with FD factor ≥ 3 were quantified. Sixteen compounds were pivotal aroma contributors, among which ethyl hexanoate, ethyl pentanoate, ethyl butanoate, ethyl octanoate, and acetic acid had the highest OAVs. Moreover, WBM-sourced aroma compounds were found in WBML, including dihydroactinidiolide, (E,E)-2,4-nonadienal, β-ionone, etc. The extraction parameters of vacuum-assisted sorbent extraction (VASE) were optimized for the first time to analyze lujiu aroma. The effect of homologous polysaccharide addition to the aroma of WBML was explored with VASE–GC–MS. The greasy off-odor was decreased due to the reduction of ethyl octanoate volatility by polysaccharide addition.

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.

Chemical composition, odor-active compounds and in vitro antioxidant activity of essential oils from leaves, fresh fruits and seed shells of Platycladus orientalis (L.) Franco

To investigate the volatiles and odor-active compounds (OACs) in essential oils (EOs) from leaves, fresh fruits and seed shells of Platycladus orientalis (L.) Franco, three EOs were extracted and analyzed by hydrodistillation combined with gas chromatography-mass spectrometry (GC-MS), gas chromatography-mass spectrometry-olfactometry (GC-MS-O) and GC. The yields of three EOs were 0.22%, 0.48% and 1.94%, respectively; a total of 77 compounds were identified by comparing their mass spectra and retention index with those of the authentic standards or the related data reported in the references, and 29 odorants were determined as OACs. Among them, 58 volatile components were identified in the leaf EO, accounting for 98.19% of the total volatiles, of which 18 compounds were screened as OACs; 47 volatile components were determined in the fruit EO, representing 98.98% of the entire volatile oil, of which 12 compounds were sniffed as OACs; 49 volatiles were found in seed shell EO, covering 97.26% of the whole volatiles, of which 19 compounds were detected as OACs. OACs in three EOs were significantly different, and the odorants with higher concentrations included α-pinene, sabinene, δ-3-carene, myrcene, β-caryophyllene, α-terpinyl acetate, cedrol, etc., which could be used as indexes for optimizing extraction process parameters of POF EOs and evaluating EO quality. The in vitro antioxidant activity of three EOs was tested by DPPH assay, ABTS assay and FRAP assay.

Unraveling the characteristic chestnut aroma compounds in MeiTanCuiYa green tea and their interaction mechanisms with broad-spectrum olfactory receptors using molecular docking

The important characteristics of chestnut aroma compounds in MeiTanCuiYa (MTCY) green tea were determined using gas chromatography-mass spectrometry-olfactometry (GC-MS-O), two-dimensional gas chromatography-quadrupole mass spectrometry (GC × GC-qMS), chiral analysis, and partial least squares-discriminant analysis (PLS-DA). The results indicated that geraniol, (S)-(−)-furaneol, benzothiazole, 2-ethyl-3,6-dimethylpyrazine, coumarin, (R)-(−)-linalool, (E)-geranylacetone, phenylacetaldehyde, 2-pentylfuran, 2-ethyl-5-methylpyrazine, β-cyclocitral, benzyl alcohol, β-ionone, 2,5-dimethylpyrazine, furfural, etc. were closely related to the chestnut aroma. Furthermore, the molecular docking was used to analyze the region, binding energy, and force of the interaction between the chestnut aroma compounds (geraniol, (S)-(−)-furaneol, benzothiazole, 2-ethyl-3,6-dimethylpyrazine and coumarin) and ORs (OR1G1, OR1W2, OR52D1, OR5M3, OR5K1). The average binding energies of these compounds on the five receptors were −4.14 kcal/mol, −4.42 kcal/mol, −4.36 kcal/mol, −4.96 kcal/mol, and −5.79 kcal/mol, respectively. Hydrogen bonding, hydrophobic interactions and π-π stacking are important driving forces. The mechanism of formation of chestnut aroma was revealed, which provides theoretical guidance for the regulation of chestnut aroma in MTCY.

Unraveling the Formation Mechanism of Egg's Unique Flavor via Flavoromics and Lipidomics.

Egg products after thermal treatment possess a unique flavor and are favored by consumers. In this study, the key aroma-active compounds of egg yolk products and their formation mechanism during thermal treatment were investigated. The volatile aroma compounds in egg yolks were monitored using an electronic nose, gas chromatography-mass spectrometry (GC-MS) and gas chromatography-olfactometry-mass spectrometry (GC-O-MS), and the lipid molecular species were explored using ultra-high-performance liquid chromatography- mass spectrometry with a Q-Exactive HF-X Orbitrap (UPLC-Q-Exactive HF-X). A total of 68 volatile compounds were identified. Boiled eggs mainly derived their flavor from hexanal, 2-pentyl-furan, 2-butanone, 3-methyl-butanal and heptane. Meanwhile, fried eggs relied mainly on 14 compounds, the most important of which were 2-ethyl-3-methyl-pyrazine, 3-ethyl-2,5-dimethyl-pyrazine, 2-ethyl-3,5-dimethyl-pyrazine, nonanal and 2,3-diethyl-5-methyl-pyrazine, providing a baked and burnt sugar flavor. A total of 201 lipid molecules, belonging to 21 lipid subclasses, were identified in egg yolks, and 13 oxidized lipids were characterized using a molecular network. Phosphoethanolamines (PEs) containing polyunsaturated fatty acids were the primary flavor precursors contributing to the development of egg yolks' flavor, participating in lipid oxidation reactions and the Maillard reaction and regulating the production of aldehydes and pyrazine compounds. This study provides reference and guidance for the development of egg yolk flavor products.

Characterization of honey-like characteristic aroma compounds in Zunyi black tea and their molecular mechanisms of interaction with olfactory receptors using molecular docking

The important characteristics of honey-like aroma compounds in six Zunyi black tea were determined by gas chromatography-mass spectrometry-olfactometry (GC-MS-O), odor activity value (OAV), gas chromatography-ion mobility spectrometry (GC-IMS) and partial least squares-discriminant analysis (PLS-DA) methods, including geraniol, 2-phenylethyl alcohol, 2-phenyl-2-butenal, furaneol, cinnamaldehyde, ethyl cinnamate, benzoic acid, ethyl pentanoate-M. Furthermore, the molecular docking was used to study the region, site, binding energy, and force of the interaction between the honey-like aroma compounds (geraniol, 2-phenylethyl alcohol, furanol, cinnamaldehyde, and ethyl cinnamate) and olfactory receptors (OR1A1, OR1G1, OR2W1, OR1D2, and OR5M3). The average binding energies of these compounds on the five receptors were −4.34 kcal/mol, −4.14 kcal/mol, −4.24 kcal/mol, −5.08 kcal/mol, and −5.33 kcal/mol, respectively. The experiment indicated the interaction sites of five characteristic compounds and key residues of ORs, such as geraniol and Tyr252 (OR1D2), 2-phenylethyl alcohol and Thr219 (OR1G1), furaneol and Asn155/Ser109 (OR2W1), furaneol and Phe166/Leu164/Val7 (OR5M3), and ethyl cinnamate and Asn155/Asn109 (OR1A1). Further research has found that hydrogen bonding and hydrophobic interactions are important driving forces for the binding of aroma compounds to ORs. By systematically studying the material basis, formation mechanism of honey-like aroma, theoretical guidance can be provided for the regulation of honey-like aroma in Zunyi black tea.

GC-MS olfactometry reveals sesquiterpenes α-humulene and δ-cadinene significantly influence the aroma of treated Aquilaria malaccensis essential oil

Aquilaria malaccensis is a tropical woody tree that produces agarwood, which is valued for its aromatic properties. Agarwood is widely used in traditional medicines and the cosmetics industry. Natural agarwood production in the wild, which occurs due to fungal infection, is scarce and cannot meet the market demand. Hence, many artificial techniques have been employed to stimulate the production of agarwood. Although many studies have determined the volatile compounds present in naturally produced agarwood, the characterisation of these compounds from differentially treated agarwood samples, particularly A. malaccensis, is still limited. This study was conducted to identify and differentiate the volatiles present in treated and healthy A. malaccensis wood and essential oil using the solid phase microextraction (SPME) and hydrodistillation techniques, respectively, coupled with gas chromatography-mass spectrometry (GC-MS) analysis. Subsequently, the olfactory active compounds in the treated agarwood essential oil were determined via gas chromatography-mass spectrometry, coupled with olfactometry analysis (GC-MS/O) with four panellists. The essential oil from the treated agarwood was found to be abundant in sesquiterpene and aromatic compounds (80.61%), which was a similar result to that obtained from the volatiles of the wood that yielded 86.94%. Among the major sesquiterpene constituents in the essential oil are α-cadinol (19.40%) and 10-epi-γ-eudesmol (13.39%), whereas α-humulene (13.33%), α-copaene (12.49%) and δ-guaiene (10.41%) predominated in the SPME extract. Meanwhile, GC-MS/O analysis revealed that the sweet, woody agarwood aroma is an orchestra of olfactory active compounds that are significantly influenced by sesquiterpenes such as α-humulene and δ-cadinene. This study highlights that although treated agarwood is rich in secondary metabolites, only a handful, particularly those belonging to sesquiterpenes, are actual aroma impact compounds

Identification of muttony-related compounds in cooked mutton tallows and their flavor intensities subjected to phenolic extract from thyme (Thymus vulgaris L.).

Mutton possesses a typical flavor, known as "muttony" or "goaty", which significantly limits consumers' acceptability and its further popularization. Generally, this unpleasant flavor originates from mutton tallow. Thus, we first characterized the key volatiles of the cooked mutton tallow (CMT) via gas chromatography-mass spectrometry/olfactometry (GC-MS/O) and odor activity value (OAV). Combined with aroma recombination and omission tests, eleven compounds, involving 4-methyloctanoic acid, 4-methynonanoic acid, octanoic acid, decanoic acid, hexanal, heptanal, (E)-2-octenal, (E)-2-nonenal, (E)-2-decenal, 2-nonanone and 2-penty-furan, were screened out to be responsible for the "muttony" flavor. The objective of this study was to investigate the sensory property and acceptability of CMTs, elaborated with 4 different levels of thyme phenolic extract (TPE), through descriptive sensory analysis and key muttony-related compounds identification. The results showed that, of different TPEs employed, CMT plus TPE3 was the most effective strategy to control the key "muttony" contributors, thereby to improve flavor profile of CMT.

Investigation on the key factors associated with flavor quality in northern strong aroma type of Baijiu by flavor matrix.

The strong aroma type of Baijiu is popular with its balanced flavor. However, the flavor characteristics of strong aroma type of Baijiu in different regions have significant diversities. Among them, the key aroma compounds in northern strong aroma type of Baijiu and the factors affecting the aroma profile and flavor quality are still unclear. In this study, a total of 78 aroma compounds were identified by gas chromatography-olfactometry-mass spectrometry (GC-O-MS). The quantitative analysis was completed and ethyl hexanoate (1003.24-4506.04mg/L) was the highest. Aroma profile was successfully simulated by reconstitution, and omission test was applied to investigate the effects of the important aroma compounds on the aroma profile. Additionally, the relationship between expression of aroma compounds and sensory characteristics of samples was illustrated by flavor matrix. The overall aroma profile of northern strong aroma type of Baijiu was formed by the key aroma compounds with different aroma expression.

Comparative flavor precursors and volatile compounds of Wenchang chickens fed with copra meal based on GC–O–MS

In the Wenchang chicken (WC) feeding process, copra meal is often added to improve chicken quality. To determine the effect of feeding with copra meal on the flavor formation of WCs, the experimental subjects were fed with 4.5 % and 7.5 % copra meal, and the control group was fed without copra meal. The electronic nose combined with gas chromatography–olfactometry mass spectrometry (GC–O–MS) was used to identify the volatile compounds from the samples. Compared with the control group, the pH of chickens fed copra meal was significantly decreased (P < 0.05) after slaughter. Aldehydes and alcohols were the main volatile compounds in muscle, among which hexanal and 1-octen-3-ol were the highest. Thirty-two and thirty-six compounds were identified in breast muscle and drumstick muscle, respectively. Twelve new volatile compounds were added, including 1-octanol, butanal, 1-heptanol, 3-ethylbenzaldehyde, 2,2-dimethylpentanal, hexanoic acid, 3-heptanone, 2,5-heptanedione, 2-ethylfuran, 2-propylfuran, 2-ethynylpyridine, and 1,2,4,5-tetrazine. The types and contents of volatile compounds in drumstick muscle increased with an increasing proportion of copra meal in the diet. In summary, the addition of copra meal changed the quality of WCs and increased the types and contents of volatile compounds. This study provides a reference for understanding the flavor profile of WC fed copra meal.

Study on the flavor of brown milk fermented by Lactobacillus paracasei K56 in different strain states

A comprehensive investigation of the differences in flavor profiles among different strains of fermented brown milk (FBM) is important to guide the improvement of the flavor quality of FBM. Seven samples were analyzed by dynamic headspace extraction (DHS) and gas chromatography–olfactometry–mass spectrometry (GC–O–MS), and a total of 73 odor compounds were identified. Key odor compounds including 3-methyl-1-butanol, ethyl acetate, linalool, furfuryl alcohol, 2-pentylfuran, hexanal, and 1-octen-3-ol, were screened by multivariate statistical analysis to reveal the flavor differences of FBM from different strains. 3-Methyl-1-butanol and ethyl acetate were found to be the key odor compounds distinguishing FBM by strain K56 from other strains, and the fermentation strains were found to be the key factors affecting the flavor of FBM compared to the fermentation substrate and fermentation process. This study provided a relatively systematic investigation of the flavor of FBM and could be used to monitor changes in odor components and sensory characteristics for product quality control.

Decoding the Different Aroma-Active Compounds in Soy Sauce for Cold Dishes via a Multiple Sensory Evaluation and Instrumental Analysis.

Screening the suitability of soy sauce for specific cooking methods from various products is beneficial for the fine development of the soy sauce industry. Multiple sensory evaluation and gas chromatography-mass spectrometry/olfactometry (GC-MS/O) analysis were combined to decode the suitability of soy sauces for cold dishes and characterize their differential aroma-active compounds. Thirty-two kinds of soy sauce with 42 sensory descriptors were determined via a check-all-that-apply analysis, and werefurther classified into six categories via a cluster analysis. The sensory evaluation results showed that seven soy sauce samples had the highest acceptance in each category. Solid-phase microextraction and solid phase extraction results combined with the GC-MS/O analysis results showed that a total of 38 aroma-active compounds were identified in seven soy sauce samples, among which 2-methoxy-phenol (6-93), ethyl acetate (2-48), 3-methyl-1-butanol (4-30), 3-methyl-butanal (5-24), methional (0-22), dimethyl trisulfide (5-19) and dimethyl disulfide (0-8) showed a higher relative odor activity value (ROAV). A partial least squares regression prediction combined with additional tests further confirmed that 2,5-dimethyl-pyrazine; 2,6-dimethyl-pyrazine; and 2-ethyl-6-methyl-pyrazine significantly contributed to the roasted attributes, methional significantly contributed to the sauce-like notes, ethanol significantly contributed to the alcoholic notes and 2-methoxy-phenol significantly contributed to the smoky notes. 2,5-Dimethyl-pyrazine; methional; 2,6-dimethyl-pyrazine and 2-ethyl-6-methyl-pyrazine significantly contributed to the caramel-like attributes.

Enzymatic synthesis of novel pyrrole esters and their thermal stability

In the present work a simple enzymatic approach (Novozym 435) for transesterification to synthesize pyrrole esters was reported. To generate the best reaction conditions, which resulted in the optimum yield of 92%, the effects of lipase type, solvent, lipase load, molecular sieves, substrate molar ratio of esters to alcohol, reaction temperature, reaction duration, and speed of agitation were evaluated. The range of alcohols was assessed under optimal circumstances. The spectrum observations conclusively demonstrated that the compounds could be generated with high yield under the circumstances utilized for synthesis. The odor characteristics of the pyrrolyl esters obtained were examined by gas chromatography–mass spectrometry-olfactometry (GC–MS–O). Among them, compounds of benzhydryl 1H-pyrrole-2-carboxylate (3j), butyl 1H-pyrrole-2-carboxylate (3k) and pentyl 1H-pyrrole-2-carboxylate (3l) present sweet and acid aroma. In addition, the thermal degradation process was further studied using the Py–GC/MS (pyrolysis–gas chromatography/mass spectrometry), TG (thermogravimetry), and DSC (differential scanning calorimeter) techniques. The outcomes of the Py–GC/MS, TG, and DSC techniques show that they have excellent thermal stability.

Condition optimization and kinetic evaluation of Novozym 435-catalyzed synthesis of aroma pyridine esters

A new method for rapid synthesis of pyridine esters without stirring based on Novozym 435 catalysis had been reported, which was from pyridine methanols and vinyl esters. Based on single factor experiment, the optimization of the enzymatic transesterification was received by response surface methodology (RSM). The high yield of 82% was still reached when Novozym 435 had been recycled 12 times. Under optimal conditions, a total of 22 pyridine esters were synthesized. The kinetic model of Novozym 435-catalyzed transesterification of vinyl acetate with 3-pyridinemethanol was established by enzymatic assay. It was discovered that the reaction followed the Ping-Pong Bi-Bi mechanism, and 3-pyridinemethanol inhibited the reaction. Gas chromatography-mass spectrometry-olfactometry (GC–MS-O) was used to analyze the synthesized pyridine esters, of which pyridin-3-ylmethylhexanoate (3e), pyridin-3-ylmethylcinnamate (3i), and 2-(pyridin-2-yl)ethyl acetate (3 s) possessed strong and excellent aromas. These three flavor compounds (3e, 3i and 3 s) were found to have good stability at the specified temperature by thermogravimetric (TG) analysis.

Investigation on the changes of odor-active compounds of Amomum tsao-ko during natural drying

To characterize the key odorants in Amomum tsao-ko (AT) and to investigate their changes during natural drying, volatile compounds of AT were extracted and analyzed by solvent extraction combined with solvent-assisted flavor evaporation and gas chromatographymass spectrometry–olfactometry. A total of 41 aroma-active compounds with flavor dilution factors ranging from 3 to 6561 were identified in AT. Fourteen odorants were determined to be the key odorants by quantitation analyses, odor activity value (OAV) calculations, recombination and omission experiments. To further investigate the changes in aroma components in AT during natural drying, the concentrations and OAVs of odor-active compounds were measured at 0, 2, 4, 6, 8, 12, 16, and 20 days. The results showed that the number of aroma-active components did not change during natural drying, but their content changed with different trends. The concentration of geraniol showed a continuous upward trend; those of hexanal, octanal, nonanal and pinocarvone decreased first and then increased; those of α-pinene, sabinene, 2-nonanone, (E)-2-octenal, 2-nonanol, 4-terpineol, epidolichodial and (E,E)-2,4-dodecadienal changed on a fluctuating trend, while those of the other 28 compounds showed a trend of first increasing and then decreasing. These results provide a theoretical basis for further utilization of AT.

Characterization of odor-active compounds in Dahongpao Wuyi Rock Tea (Camellia sinensis) by sensory-directed flavor analysis

Different methods for extraction and analysis of odor-active compounds in Dahongpao (DHP) Wuyi Rock Tea (WRT) were compared. The results showed that two-dimensional gas chromatography–olfactometry–mass spectrometry (GC×GC–O–MS) is a better method than GC–O–MS, stir bar sorptive extraction (SBSE) can extract more odor-active compounds. Aroma extraction dilution analysis (AEDA) and odor activity value (OAV) further indicated that 15 compounds were the most important odor-active compounds in DHP: phenethyl alcohol, (E)-β-ionone, nonanal, linalool, hexanal, geraniol, benzaldehyde, α-ionone, methyl salicylate, 6-methyl-5-hepten-2-one, geranylacetone, benzyl alcohol, tea pyrrole and hexyl hexanoate. The roasting process affected the overall odor characteristics of DHP, and appropriate roasting would enhance the sensory quality of DHP. As the roasting temperature increases, the contribution of compounds such as tea pyrrole, 2-ethyl-6-methylpyrazine, and 2,6-dimethylpyrazine to the roasted and burnt odor of the samples gradually increase, and the concentration of typical floral compounds such as phenethyl alcohol, (E)-β-ionone, α-ionone and linalool increase decidedly under light fire roasting, which was consistent with the sensory evaluation results. This study is helpful to further guide the production process of DHP.

Based on HS-SPME-GC-MS combined with GC-O-MS to analyze the changes of aroma compounds in the aging process of Citri Reticulatae Pericarpium

Citri Reticulatae Pericarpium (CRP) is a very well-known foodstuff. It can not only be drunk directly like tea, but also be used as a condiment for cooking food. This study used headspace solid-phase microextraction gas chromatography-mass spectrometry (HS-SPME-GC-MS), gas chromatography-olfactometry-mass spectrometry (GC-O-MS), and sensory evaluation to analyze and evaluate CRP over the six-year aging process (2, 5, 10, 15, 20, and 25 years). HS-SPME-GC-MS identified 93 volatile components, while GC-O-MS detected 42 aroma compounds. The results indicated that the aroma intensity (AI) of the spicy, woody, and herbal aroma compounds remained unchanged, while those with citrus and fruity notes gradually decreased and even disappeared with extended storage time, which could explain the unique CRP aroma. Orthogonal partial least squares discriminant analysis (OPLS-DA) showed that the CRP in the six-year aging process was clearly divided into three groups: young-aged samples (2Y), middle-aged samples (5Y and 10Y), and old-aged samples (15Y, 20Y, and 25Y). In addition, combining sensory evaluation and GC-O-MS fully reflected the changes during the different CRP aging stages. This study confirmed the potential of combining GC-O-MS and OPLS-DA as a reliable analytical selection technique to distinguish CRP age. Finally, 13 key aroma compounds were screened using VIP >1 and p < 0.05, including isopulegol, dodecanal, and α-calacorene.

Upcycling of Soy Whey with Ischnoderma benzoinum toward Production of Bioflavors and Mycoprotein.

Soy whey is becoming a worldwide issue as a liquid waste stream that is often discarded after tofu, soy protein, and soy-based dairy alternative manufacturing. This study established a model to produce a bioflavor and mycoprotein using fermentation of soy whey by a basidiomycete Ischnoderma benzoinum. Under the dedicated control of a fermentation system, an intense almond-like and sweetish aroma was perceived by a trained sensory panel (n = 10) after fermentation of pure soy whey within 20 h. By application of direct immersion-stir bar sorptive extraction combined with gas chromatography-mass spectrometry-olfactometry (DI-SBSE-GC-MS-O), around 1.0 mg/L benzaldehyde and 1.1 mg/L 4-methoxybenzaldehyde imparting a pleasant almond-like odor note were determined in the fermented soy whey with I. benzoinum. Concurrently, a certain of amount of the dry mass of I. benzoinum was accumulated with 73.2 mg/g crude protein and seven essential amino acids.

Characterizing key aroma‐active compounds of stewed mutton using gas chromatography‐olfactometry‐mass spectrometry coupled with odour activity value

AbstractStewed mutton is popular for its nutritional and special flavour qualities. To determine the key aroma‐active compounds of stewed mutton in different parts, six experimental groups (sheep fat, sheep bone, sheep brisket, sheep loin, sheep rib and sheep leg) were investigated by gas chromatography‐olfactometry‐mass spectrometry (GC‐O‐MS). Totally, 57 volatile compounds in mutton soup were identified. Of these, 22 aroma‐active compounds were identified as key aroma compounds with odour activity values (OAVs) &gt;1. The partial least squares regression (PLSR) results indicated that sheep fat (SF) was greatly related to most variables of sensory attributes, thus presented richer aroma. Among all samples, 3‐hydroxy‐2‐butanone and (E)‐2‐nonenal were the major aromatic compounds they shared. There were 22 unique key aromatic compounds, including 3‐methylthiopropana, (E)‐2‐decenal, γ‐decalactone, (E)‐2‐octenal and hydroxyacetone, and the differences in these compounds contributed to the flavour profiles of mutton soup. Our research extends the knowledge into the flavour characteristics of different parts of mutton and provides powerful information for improving the flavour of mutton products.