Identification Of Key Odorants Research Articles

Analysis of the Ability to Produce Pleasant Aromas on Sour Whey and Buttermilk By-Products by Mold Galactomyces geotrichum: Identification of Key Odorants.

Currently, there is a growing demand for flavorings, especially of natural origin. It is worth paying attention to the biotechnological processes of flavor production, characterized by simplicity, high efficiency and relatively low cost. In this study, we analyzed the ability of the Galac tomyces geotrichum mold to transform by-products of the dairy industry: sour whey and buttermilk to complex flavour mixtures with pleasant, honey-rose aroma. Furthermore, the aroma complexity of the fermentation product has been carefully identified applying a sensomic approach involving the use of gas chromatography-olfactometry (GC-O), gas chromatography-mass spectrometry (GC-MS) and stable isotope dilution assay (SIDA) to identify and quantify aroma compounds. Based on the calculation of odor activity value (OAV), 13 key aroma compounds were present in both tested variants. The highest OAVs were found for phenylacetaldehyde (honey-like) in the buttermilk variant (912) and 2-phenylethanol (rose-like) in the sour whey variant (524). High values of this indicator were also recorded for phenylacetaldehyde (319) and 3-methyl-1-butanol with a fruity aroma (149) in the sour whey culture. The other compounds identified are 3-methylbutanal (malty), 2,3-butanedione (cheesy), isovaleric acid (cheesy), 3-(methylthio)-propanal (boiled potato), butanoic acid (vinegar), (E)-2-nonenal (fatty), ethyl furaneol (burnt sugar), dimethyl trisulfide (cabbage), and acetic acid (vinegar).

Identification of key odorants in traditional Shaoxing-jiu and evaluation of their impacts on sensory descriptors by using sensory-directed flavor analysis approaches

To determine the key odorants of a popular Chinses rice wine, Shaoxing-jiu, volatile compounds were analyzed by using sensory-directed flavor approaches, including gas chromatography-mass spectrometry (GC-MS), gas chromatography-flame photometric detector (FPD), gas chromatography olfactometry (GC-O), aroma recombination and omission experiments, and odorant addition experiments. Fifty-five volatile compounds were detected in traditional Shaoxing-jiu via GC-MS, more than those in mechanical Shaoxing-jiu. Thirty-four aroma-active compounds in traditional Shaoxing-jiu were determined via GC-O. According to aroma recombination and omission experiments, the aroma profile of the recombination model constructed by these aroma-active compounds at their detected concentrations was similar to that of traditional Shaoxing-jiu, and 15 of them were affirmed as key odorants. Among the key odorants, phenylethyl alcohol, furfural, γ-nonalactone and dimethyl trisulfide presented very highly significant aroma contributions, indicating that their omission would cause great aroma differences. Then odorant addition experiments highlighted the aroma impacts of these four paramount key odorants on sensory descriptors in traditional Shaoxing-jiu.

Identification of key odorants in honeysuckle by headspace-solid phase microextraction and solvent-assisted flavour evaporation with gas chromatography-mass spectrometry and gas chromatograph-olfactometry in combination with chemometrics.

At present, the identification of honeysuckle aroma depends on experienced tasters, which results in inconsistencies due to human error. The key odorants have the potential to distinguish the different species and evaluate the quality of honeysuckle. Hence, in this study, a more scientific approach was applied to distinguish various honeysuckles. The volatile compounds of different species and parts of honeysuckle were separately extracted by headspace-solid phase microextraction (HS-SPME) and solvent assisted flavor evaporation (SAFE). Compounds with greater volatility such as aldehydes, limonene, γ-terpinene, and terpinolene were preferentially extracted by HS-SPME. As a complementary extraction method to HS-SPME, SAFE was found to recover comparatively more polar compounds such as eugenol, decanoic acid, and vanillin. Subsequently, key odorants with the highest flavour dilution (FD) factors were detected by aroma extract dilution analysis (AEDA). These were benzaldehyde, 4-ethylphenol, decanoic acid, vanillin, 3-methyl-2-butenal, and β-ionone in honeysuckle flowers and γ-octalactone, 4-ethyl phenol, and vanillin in honeysuckle stem. Finally, principal component analysis (PCA) was conducted to analyze not only the key odorants of species and parts of honeysuckle but also their different origins. The results of PCA suggested that the species of honeysuckle contributed much more to variations in aroma rather than their origins. In conclusion, the application of the key odorants combined with PCA was demonstrated as a valid approach to differentiate species, origins, and parts of honeysuckle.

Identification of key odorants in complex mixtures occurring in nature

Covering: up to 2019Soon after the birth of gas chromatography, mass spectrometry and olfactometry were used as detectors, which allowed impressive development to be achieved in the area of odorant determinations. Since the mid-80s, structured methods of gas chromatography-olfactometry have appeared, allowing the determination of which odor constituents play a key role in materials. Progressively, numerous strategies have been proposed for sample preparation from raw materials, the representativeness evaluation of extracts, the identification of odor constituents, their quantification, and subsequently, the recombination of the key odorants to mimic the initial odor. However, the multiplicity of options at each stage of the analysis leads to a confusing landscape in this field, and thus, the present review aims at critically presenting the available options. For each step, the most frequently used alternatives are described, together with their strengths and weaknesses based on theoretical and experimental justifications according to the literature. These techniques are exemplified by many applications in the literature on aromas, fragrances and essential oils, with the initial focus on wine odorants, followed by a short overview on the molecular diversity of key odorants, which illustrates most of the facets and complexities of odor studies, including the issues raised by odorant interactions such as synergies.

Smell of Stress: Identification of Induced Biochemical Pathways Affecting the Volatile Composition and Flavor Quality of Crops.

Recent research has shown that the biosynthesis of several key odorants is controlled by genes whose expression is altered or even induced by biotic or abiotic stress. These new findings provide a roadmap for improvement of flavor quality by the application of moderate, well-controlled stress. This strategy aims at reducing the flavor deficiencies in modern commercial varieties as a "green" alternative to genetic engineering. The workflow for a successful implementation of this approach, from the identification of key odorants by molecular science techniques to the investigation of mechanisms controlling their biosynthesis, is complex and calls for interdisciplinary research.

Identification of Key Odorants in Semi-Fermented Tea Made in Taiwan by Using Solvent-Assisted Flavor Evaporation Apparatus under High Vacuum and Application of the Aroma Extract Dilution Analysis

Identification of Key Odorants in Semi-Fermented Tea Made in Taiwan by Using Solvent-Assisted Flavor Evaporation Apparatus under High Vacuum and Application of the Aroma Extract Dilution Analysis

Identification of Key Odorants in Used Disposable Absorbent Incontinence Products.

PURPOSE:The purpose of this study was to identify key odorants in used disposable absorbent incontinence products.DESIGN:Descriptive in vitro studySUBJECTS AND SETTING:Samples of used incontinence products were collected from 8 residents with urinary incontinence living in geriatric nursing homes in the Gothenburg area of Sweden. Products were chosen from a larger set of products that had previously been characterized by descriptive odor analysis.METHODS:Pieces of the used incontinence products were cut from the wet area, placed in glass bottles, and kept frozen until dynamic headspace sampling of volatile compounds was completed. Gas chromatography–olfactometry was used to identify which compounds contributed most to the odors in the samples. Compounds were identified by gas chromatography–mass spectrometry.RESULTS:Twenty-eight volatiles were found to be key odorants in the used incontinence products. Twenty-six were successfully identified. They belonged to the following classes of chemical compounds: aldehydes (6); amines (1); aromatics (3); isothiocyanates (1); heterocyclics (2); ketones (6); sulfur compounds (6); and terpenes (1).CONCLUSION:Nine of the 28 key odorants were considered to be of particular importance to the odor of the used incontinence products: 3-methylbutanal, trimethylamine, cresol, guaiacol, 4,5-dimethylthiazole-S-oxide, diacetyl, dimethyl trisulfide, 5-methylthio-4-penten-2-ol, and an unidentified compound.

Analysis of free and glycosidically bound compounds of ash gourd ( Benincasa hispida): Identification of key odorants

Free and glycosidically bound aroma compounds of ash gourd were investigated. Gas chromatography–mass spectrometry (GC/MS) analysis of the free aroma compounds isolated by both steam distillation and high vacuum distillation revealed the presence of acetoin as the major constituent in both the oils. Acetoin was also identified as the major constituent existing as glycosidic conjugate. GC–olfactometry (GC–O) of the volatile oil based on detection frequency (olfactometry global analysis) was further used to characterise odour active compounds of the vegetable. Based on odour activity value (OAV) measurements the potent odorant among these were identified as acetoin (9522.5), octanal (8571) and nonanal (24,000). The region corresponding to the characteristic ash gourd aroma when collected by cryotrapping from a packed GC column and subsequently analysed by GC/MS was found to be mainly comprising of acetoin suggesting the role of this compound as the key odour active compound of this vegetable.

Identification of Key Odorants in Withering-Flavored Green Tea by Aroma Extract Dilution Analysis

This research aims to identify key odorants in withering-flavored green tea. Application of the aroma extract dilution analysis using the volatile fraction of green tea and withering-flavored green tea revealed 25 and 35 odor-active peaks with the flavor dilution factors of≥4, respectively. 4-mercapto-4-methylpentan-2-one, (E)-2-nonenal, linalool, (E,Z)-2,6-nonadienal and 3-methylnonane-2,4-dione were key odorants in green tea with the flavor dilution factor of≥16. As well as these 5 odorants, 1-octen-3-one, β-damascenone, geraniol, β-ionone, (Z)-methyljasmonate, indole and coumarine contributed to the withering flavor of green tea.

Flavour and off-flavour compounds of Swiss Gruyère cheese. Identification of key odorants by quantitative instrumental and sensory studies

Potent odorants of a typical sample of Gruyere cheese and of a Gruyere exhibiting a potato-like off-flavour were quantified by isotope dilution analysis. The studies of sensory models revealed that 2-/3-methylbutanal, methional, dimethyltrisulphide, phenylacetaldehyde, 2-ethyl-3,5-dimethylpyrazine, 2,3-diethyl-5-methylpyrazine, methanethiol, as well as acetic, propionic, butyric, 3-methylbutyric and phenylacetic acids comprise the typical flavour of Gruyere cheese. The potato-like character of one sample showing an aroma defect, however, was mainly attributed to a too high concentration of methional.