Odor Activity Values Research Articles

Effects of Loquat Juice Addition on Sensory Characteristics and Volatile Organic Compounds of Loquat Beer.

Beer, as an ancient and widely consumed alcoholic beverage, holds a rich cultural heritage and history. In recent years, fruit beer has gained significant attention as a distinct beer type produced by incorporating fruit juice into traditional beer ingredients. This study employed headspace solid-phase microextraction-gas chromatography-mass spectrometry techniques, redundancy analysis, and orthogonal projections to latent structures discriminant analysis to analyze the sensory evaluation, physicochemical properties, organic acids, and volatile organic compounds (VOCs) of loquat beer with different proportions of loquat juice. The results shown that the addition of an appropriate amount of loquat juice (40%) enhanced the overall sensory quality of the beer; as the proportion of loquat juice increased, the contents of malic acid and tartaric acid significantly increased (p < 0.05). A total of 100 VOCs were identified, among which 23 key VOCs (VIP > 1, p < 0.05) represented the most important characteristic flavor components in loquat beer based on their odor activity value (OAV). This study holds significant importance for the value-added processing and economic development of loquat.

The changes of fungal community and flavor substances in Yunnan-style sausages: A comparative analysis of different drying methods

This study aimed to investigate alterations in the fungal community and flavor substances in Yunnan-style sausages subjected to natural air-dried fermentation (NF), variable-temperature drying (VT), and constant-temperature drying (CT) and analyze the potential relationship between fungal community and flavor substances. The findings revealed that the NF group and VT group were more conducive to enhancing the accumulation of dominant fungi and characteristic flavor substances in Yunnan-style sausages. Glu, Ala, His, and Lys were identified as key taste substances based on their taste activity values (TAV ≥ 1). A total of 272 volatile compounds(VOCS) were detected in the sausage samples, while 28 key aroma compounds were screened based on the odor activity value (OAV ≥ 1). Multivariate statistical analysis showed that 12 key aroma compounds (VIP > 1) could be considered discriminative compounds, including (E,E)-2,4-nonadienal, nonanal, heptanal, benzaldehyde, Dodecanal, cyclohexanol, and hexyl-Benzene, etc. Furthermore, Wickerhamoomyces and Debaryomyces were positively correlated with most of the key flavor substances and physicochemical indices (|r| > 0.6, P < 0.05), which were potential flavor-contributing fungi in Yunnan-style sausages.

Investigation of the quality of rapeseed oil derived from different varieties and growth periods based on GC-IMS technique

Rapeseed oil is consumed worldwide, and its quality is closely related to the raw rapeseed material. In this work, the quality and flavor differences of rapeseed oil from twelve varieties with two growth periods were studied. The results showed that different varieties responded differently to changes in growth periods, with the GXY1 variety having the greatest combined effect. Shortening the growth period may reduce the moisture and protein content and increase the oil content of rapeseed. It may also enhance the oleic acid content and decrease the linoleic acid content. A total of 62 aroma compounds were identified by gas chromatography-ion migration spectrometry (GC-IMS), with aldehydes being the main flavor compounds. The flavor fingerprint of rapeseed oil derived from different varieties was effectively constructed. Seven key aroma compounds with relative odor activity value (ROAV) > 1 were identified, which significantly influenced the flavor of rapeseed oil. This work may provide new insights for selecting favorable rapeseed varieties for industrial production of high-quality rapeseed oil.

Impact of Mechanical and Manual Peeling on the Volatile Profile of White Pepper (Piper nigrum L.).

Mechanical peeling is more efficient and environmentally friendly compared to manual peeling. However, comparative studies on the quality of mechanically peeled pepper and manually peeled pepper are limited. This study utilized GC-MS to investigate the effects of immersion, steaming, and peeling machinery speed on the volatile composition of white pepper. A total of thirteen monoterpenes and seven sesquiterpenes were detected, with 3-carene, D-limonene, and sabinene being the most abundant monoterpenoids and β-caryophyllene, δ-elemene, and α-copaene being the most abundant sesquiterpenes. The total volatiles increased with longer steaming times and higher peeling machinery speeds. Compared to manual peeling or steaming followed by mechanical peeling, the volatile content of pepper was higher when using mechanical peeling alone. Additionally, relative odor activity values showed that 3-carene and D-limonene were the main contributors to flavor, with 3-carene, β-caryophyllene, and α-copaene being key volatiles responsible for flavor distinctions. This research aims to provide theoretical support for developing a superior and environmentally friendly mechanical method to replace manual labor.

The dynamic changes of flavor characteristics of sea cucumber (Apostichopus japonicus) during puffing revealed by GC–MS combined with HS-GC-IMS

To improve the ease of eating sea cucumbers, we investigated the impact of puffing temperature (190 °C - 250 °C) and time (1–5 min) on their quality and flavor. As temperature and time increased, sea cucumber puffing significantly enhanced. The microstructure of the puffed sea cucumber exhibited a uniform porous structure at 230 °C for 4 min. However, further puffing treatment caused the void to collapse. A total of 81 volatile organic compounds (VOCs) were identified using HS-GC-IMS, and 18 VOCs with Relative odor activity value (ROAV) ≥1 were identified. The content of fishy compounds, such as dimethyl sulfide, 1-octanal, and 1-nonanal in sea cucumbers gradually decreased with increasing temperature and time. Combined with GC–MS analysis indicating that the flavor of sea cucumbers puffed at 250 °C for 5 min was superior. Our findings suggest new avenues for sea cucumber processing and address the limited research on puffing techniques for protein-based raw materials.

Sniffing the wine differences: The role of Starmerella bacillaris biofilm-detached cells

This study investigated the impact of 10 strains of Starmerella bacillaris, co-inoculated as planktonic or biofilm-detached cells with Saccharomyces cerevisiae, on the volatilome of a red wine. The wines produced with St. bacillaris biofilm-detached cells exhibited a greater concentration of glycerol and a lower quantity of ethanol than the other wines. Furthermore, these wines exhibited elevated levels of higher alcohols, organic acids, esters, terpenes, and norisoprenoids. Based on the odor activity value and relative odor contribution, isoamyl acetate, ethyl octanoate, ethyl isobutanoate, and methyl decanoate were the main aroma components of wines made with planktonic cells. The main compounds characterizing the wines obtained with biofilm-detached cells were: phenethyl alcohol, β-damascenone, citronellol, β-ionone, and nerol. The sensory analysis revealed that the wines produced with biofilm-detached cells had higher scores for mouth-feel, spicy, floral, and raspberry notes than the others. The present study provides evidence that St. bacillaris biofilm-detached cells released specific volatile compounds in red wines.

Volatile flavor profiles of douchis from different origins and varieties based on GC-IMS and GC-O-QTOF/MS analysis

The present study comprehensively characterized the flavor differences between different varieties of douchis from different origins using headspace gas chromatography-ion mobility spectrometry (HS-GC-IMS) coupled with gas chromatography-olfactometry-quadrupole time-of-flight mass spectrometry (GC-O-QTOF/MS). A total of 91 volatile organic compounds (VOCs) were identified using HS-GC-IMS and 70 VOCs were identified using GC-O-QTOF/MS, mainly including acids, aldehydes, esters and alcohols. Additionally, 23 key aroma-presenting compounds were screened in five douchi species using relative odor activity value (ROAV) and the aroma compounds that contributed the most to the aroma varied among the five douchi species. Comparative analysis of the GC-IMS and GC-O-QTOF/ MS results yielded 13 VOCs that were detected by both techniques. Nonanal, hexanal, eucalyptol, 1-octen-3-ol, isoamyl acetate, and 2-pentylfuran were identified as key VOCs in the douchi species using both methods. These findings will provide deeper insights for exploring flavor differences in douchi from different geographic sources.

Characterisation of aroma‐active compounds in wheat flour by molecular sensory science

SummaryFour different extraction methods were used to extract aroma compounds from flour. It was found that dynamic headspace sampling (DHS) was a better method for extracting aroma‐active compounds in flour. Hexanal, decanal, butanoic acid, 2,3‐pentanedione, 2‐acetyl‐1‐pyrrolinoline, and 3‐octen‐2‐one were found to be the important aroma‐active compounds in flour by olfaction (O) in two‐dimensional gas chromatography–olfactometry–mass spectrometry (GC×GC‐O‐MS). Dynamic headspace dilution analysis (DHDA), odour activity value (OAV), recombination and omission experiment further verified that these compounds can roughly simulate the overall aroma profile of flour. In this study, we determined the aroma‐active compounds in flour by molecular sensory science to improve the sensory preference of flour and enhance the quality of flour aroma, which will provide analytical ideas for future research on flour aroma and improve the production process.

Impact of Bacillus subtilis on Chinese yellow rice wine (Huangjiu) fermentation: Method variations and flavor analysis

This investigation explores the impact of various fermentation techniques and the inoculation of Bacillus subtilis spores on the physicochemical properties and principal flavor profiles of Huangjiu. Employing sensory analysis, headspace solid-phase microextraction, gas chromatography-tandem mass spectrometry (HS-SPME-GC–MS), and orthogonal partial least squares discriminant analysis (OPLS-DA), we observed that these variables significantly alter the physicochemical attributes of Huangjiu. Our analysis, integrating volatile organic compounds (VOCs) with odor activity values (OAV), revealed that while B. subtilis inoculation modifies the concentrations of key flavor compounds, it does not affect their types. Notably, the inoculation enhances the concentrations of 13 primary flavor compounds, thereby enriching floral and fruity notes while reducing higher alcohol levels. These findings contribute valuable insights into the flavor formation mechanisms of Huangjiu and guide the optimization of fermentation processes.

The volatile composition, aroma profile and antioxidant capacity of Yijiangzi (Aatragalus sinicus L.) monofloral honey and its correlation with the flower

Yijiangzi honey is a well-known monofloral honey in China and also known as Chinese milk vetch (Aatragalus sinicus L.) honey (CMVH). In this study, GC-IMS and GC-O-MS methods were employed to identify the volatile and aroma active compounds of the CMVH and the flower (CMVF). For GC-IMS analysis, 23 of 27 detected volatiles in the CMVH could be observed in the CMVF, indicating that most of the volatiles might be derived directly from the flower. For GC-O-MS, 6 volatiles were identified as aroma-active compounds of CMVH due to their high odor activity values (OAVs), and ethyl 3-phenylpropionate was identified in the honey for the first time. Moreover, the CMVH and CMVF revealed efficient antioxidant capacities that might attribute to the relatively high contained total flavonoids contents (TFC) and total phenolic contents (TPC). The obtained results would be conducive to better understanding of the aroma profile and bioactivity of CMVH.

Identification of key physicochemical properties and volatile flavor compounds for the sensory formation of roasted tilapia

Tilapia is suitable for industrial roasting production because of its good flavor and processing adaptability. In this study, the key physicochemical properties and volatile compounds for sensory formation of roasted tilapia were identified after roasting condition optimization. The highest sensory score was obtained at 215 °C, 45 min, and 4% oil. During roasting, the a*, b*, hardness, chewiness, and oxidation of proteins and lipids significantly increased, the moisture content decreased, and the myofibrillar protein aggregation was observed by scanning electron microscope. After identification and quantification by headspace-gas chromatography-ion mobility spectrometry, 10 compounds with odor active value ≥1 were selected as characteristic flavor compounds. The correlation network indicated that the sensory formation mainly resulted from Maillard reaction, myofibrillar protein aggregation, and improvement of pleasant volatile flavor compounds induced by oxidation of proteins and lipids and water loss. This study provides an important theoretical basis and technical support for roasted tilapia production.

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.

The Light-Intensity-Affected Aroma Components of Green Tea during Leaf Spreading.

Leaf spreading is a key processing step that affects the aroma formation of green tea. The effects of a single-light wavelength on the aroma and taste of tea have been extensively studied. Less attention has been paid to the effect of different complex light intensities on the formation of green tea's volatile aroma during leaf spreading. The current study was designed to evaluate how leaf spreading under different complex light intensities relates to the quality of green tea. Using headspace solid-phase micro-extraction and gas chromatography-mass spectrometry (HS-SPME/GC-MS), volatile flavor compounds in green tea were analyzed during leaf spreading in five different light conditions. Multivariate statistical analysis and odor activity values (OAVs) were used to classify these samples and identify key odors. Eight distinct groups, including ninety volatile compounds, were detected. The most prevalent volatile compounds found in green tea samples were hydrocarbons and alcohols, which accounted for 29% and 22% of the total volatile compounds, respectively. Fourteen volatile compounds (OAV > 1) were identified as key active differential odorants. The chestnut-like aroma in green tea was mostly derived from 3-methyl-butanal and linalool, which were significantly accumulated in medium-intensity light (ML).

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.

Comparative analysis of the differences in volatile organic components of three lavender essential oils in Ili region using sensory evaluation, GC-IMS and GC-MS techniques

Lavender (Lavandula angustifolia Mill.) is a widely utilized aromatic plant, with the economic value of its essential oil (EO) largely dependent on its aroma. This study investigated the differences in volatile organic compounds (VOCs) within the EOs of three species of lavender (H70-1, French blue, Taikong blue) in Ili region from 2019 to 2023 with the combination of sensory evaluation, gas chromatography-ion mobility spectrometry (GC-IMS), and gas chromatography-mass spectrometry (GC-MS). The EO from Taikong blue lavender exhibited greater stability in VOC composition compared to the other two varieties. Orthogonal Partial Least Squares Discriminant Analysis (OPLS-DA) effectively distinguished the aromas of the three EOs aroma. Combining odor activity value (OAV) and variable importance in projection (VIP) values identified five VOCs crucial for discriminating among the three lavender EO types. This study provides theoretical support for the cultivation and commercialization of lavender as an industrial crop, as well as for quality control of EO production in the Ili region.

Effects of Fermentation with Eurotium cristatum on Sensory Properties and Flavor Compounds of Mulberry Leaf Tea.

Mulberry leaf tea (MT) is a popular Chinese food with nutrition and medicinal functions. Solid-state fermentation with Eurotium cristatum of MT (FMT) can improve their quality. Differences in chromaticity, taste properties, and flavor characteristics were analyzed to evaluate the improvements of the sensory quality of FMT. After fermentation, the color of the tea infusion changed. The E-tongue evaluation results showed a significant decrease in unpleasant taste properties such as sourness, bitterness, astringency, and aftertaste-bitterness, while umami and saltiness taste properties were enhanced post-fermentation. Aroma-active compounds in MT and FMT were identified and characterized. A total of 25 key aroma-active compounds were screened in MT, and 2-pentylfuran showed the highest relative odor activity value (ROAV). A total of 26 key aroma-active compounds were identified in FMT, and the newly formed compound 1-octen-3-one showed the highest ROAV, which contributed to FMT's unique mushroom, herbal, and earthy flavor attributes. 1-octen-3-one, (E)-2-nonenal, trimethyl-pyrazine, 2-pentylfuran, and heptanal were screened as the potential markers that contributed to flavor differences between MT and FMT. E. cristatum fermentation significantly altered the sensory properties and flavor compounds of MT. This study provides valuable insights into the sensory qualities of MT and FMT, offering a theoretical basis for the development of FMT products.

Characterization of aroma and aroma-active compounds of black carrot (Daucus carota L. ssp. sativus var. atrorubens Alef.) pomace by aroma extract dilution analysis

The aim of this study was to characterize the aroma and aroma-active compounds of black carrot pomace, a valuable by-product of black carrot juice industry. Aroma compounds were analyzed using GC-MS-O and extracted via the SAFE technique. The extract samples were determined to represent the odor of black carrot pomace quite well according to the results of the representative test. Accordingly, the aromatic extract scored 77.7 mm for intensity and 87 mm for similarity on a 100 mm unstructured scale. A total of 47 volatile constituents were identified and quantified including terpenes (20), alcohols (11), acids (7), esters (4), ketones (4), and lactone (1). It was observed that terpenes were the major aroma group. The use of aroma extract dilution analysis (AEDA) revealed only 29 of these compounds as aroma-active constituents. Phenylethyl alcohol (FD:512, OAV: 2488, rose) and phenylethyl acetate (FD:256, OAV:280, rose) were the aroma substances providing the strongest rose odor. Following these compounds, acetic acid (vinegar), dimethyl-propanedioic acid (pungent), (E)-β-caryophyllene (salty cheese) and elemicin (spicy) were identified as other strong aroma-actives with FD values of 128 contributing to the characteristic odor of the black carrot pomace samples. The odor activity values (OAVs) ranged from 1 to 2488. The highest OAVs represent the high aromatic active compounds (FD ≥ 128). The distinctive aroma and rich color of black carrot pomace make it a recommended choice for enhancing flavor and adding natural coloring to food products.

Olfactory-chemical establishment using odour wheels and fingerprints to manage odor pollution for the petrochemical industry

The odor nuisance may cause major environmental issues, so identifying the odor characteristics is important for odor management and traceability in the petrochemical industry. In this study, odour wheels and fingerprints were applied to manage odor pollution in the petrochemical industry. First, the odor profile method and portable electronic nose evaluation were applied to analyze the flavour sensory profiles of five upstream and downstream petrochemical plants, in order to grasp the odor natures of plants. Second, 375 organized and unorganized samples of 5 plants were analyzed by gas chromatography-mass spectrometry (GC–MS) technology, and a total of 583 odorants were obtained, including sulfur compounds, alcohols, esters, aldehydes, ketones, acids, alkanes, alkenes, halogenated hydrocarbons, aromatic hydrocarbons, nitrogen compounds, and other compounds. Third, the key odorants were identified by gas chromatography-olfactory (GC-O) and odor activity value (OAV) analysis. Fourth, the fingerprint spectras were developed by the identification of key odorants and process sources through principal component analysis. For plant A, 21 odorants were confirmed, including naphthalene, 1-methylnaphthalene, 2-methylnaphthalene, 1-methylindene, and 2-methylindene. Methyl methacrylate, acetophenone, isobutene, 4-vinyl-1-cyclohexene, acrylonitrile, and styrene were key element for plant B. The fingerprint factor of plant C had 20 odorants, including methanol, butanol, 2-ethylhexanol, acetic acid, and ammonia. And there were 21 odorants for plant D and 14 odorants for plant E, respectively, with similar substance types, including 2-ethyl-2-hexenal, 3-methyl-4-heptanone, isobutyl butyrate, and 1,2,3,5-tetraethylbenzene. Finally, the odor wheels were established by the correlation analysis between odorants and malodor, and compounds in fingerprint spectra weaker related to malodor of plants were removed. Hence, the characteristic odorants of each plant were further clarified, and the odors were associated with compounds, achieving rapid diagnosis and traceability of odor pollution in the petrochemical park. This provided new ideas and technical methods for odor pollution monitoring and identification.

Research on pollution identification and safety thresholds based on the olfactory effect on a halogenated hydrocarbon contaminated site

To effectively address odor control issues at sites contaminated with halogenated hydrocarbons, it is essential to establish an odor risk prediction system for evaluating potential risks that may impact future planning. This research focuses on a representative halogenated hydrocarbon-contaminated site, examining the spatial and temporal distribution characteristics of key pollutants in soil gas. By analyzing odor contribution rates, the study identifies significant odorants in soil gas, which enables the derivation of both probabilistic and deterministic safety thresholds for soil and groundwater based on olfactory effects. The findings indicate that 1,1-dichloroethylene, vinyl chloride, chloroform, and 1,1-dichloroethane are prevalent throughout the contaminated site, displaying elevated concentration levels and substantially influencing the overall contamination extent. These substances are highlighted as critical pollutants requiring attention. Correlation analysis (P < 0.05) reveals a strong relationship between the concentrations of vinyl chloride, 1,1-dichloroethane, and chloroform with groundwater depth and air temperature. Additionally, the analysis of odor activity values (OAV) identified 1,1-dichloroethene, 1,4-dichlorobenzene, chlorobenzene, chloroform, and vinyl chloride as key olfactory factors at the site. The corresponding probabilistic safety thresholds are 0.68, 1.65, 0.50, 7.87, and 3.72 mg kg−1 for soil, and 9.29, 3.46, and 1.09, 69.55, and 47.01 mg L−1 for groundwater, respectively. Among them, the odor risks of chlorobenzene and 1,1-dichloroethylene warrant more attention than soil contamination risks; regarding 1,4-dichlorobenzene, it is recommended to concurrently consider odor risks during human health risk assessment; as for vinyl chloride and chloroform, their odor risks can be largely eliminated based on human health-oriented pollution management.

Urea for removing the aldehydes and ketones in leather VOCs and recycling performance of ethanol eluent

Hexanal, found in high-grade leather sofas, has a high odor activity value of 21285.8. Thus far, a method to remove hexanal from leather VOCs has not been reported. In this study, we developed a hexanal removal method that involves the elution of hexanal with an eluent of urea and ethanol (EtOH). We achieved the best hexanal removal rate with a urea concentration of 14 g/L, a liquid ratio of 75, a reaction time of 120 min, a temperature of 60 °C, an ultrasonic environment, and the presence of anhydrous CaCl2. The mechanism of hexanal removal by urea was confirmed via quartz crystal microbalance with dissipation monitoring, Fourier-transform infrared spectroscopy, and 1H NMR. Moreover, the EtOH eluent exhibited excellent recyclability over five cycles, where EtOH was distilled after every cycle and fresh eluent was prepared with the recycled EtOH. The physicochemical properties of the leather also remained unchanged after this treatment. Our strategy based on the Schiff base reaction between urea and carbonyl compounds can be extended to other aldehydes and ketones of leather VOCs to improve the air quality in leather environments.