Flavour and Fragrance Journal最新文献

Agarwood ‘Qi-Nan’ is commonly regarded as the highest quality agarwood, and has been highly valued for its fragrance. With the increasing amount of cultivated agarwood ‘Qi-Nan’ in recent years, evaluation of the aroma compounds was drawn attention. Therefore, the volatile compounds in three cultivated ‘Qi-Nan’ agarwood samples were extracted by simultaneous distillation-extraction (SDE) and analysed by GC-O-MS, combined with aroma extract dilution analysis (AEDA). A total of 70 volatile compounds were identified from three samples, in which sesquiterpenes and aromatics were characterized as key aroma-active components. Nine compounds were considered as common aroma-active volatiles in these three essential oils according to their flavour dilution (FD) activity and relative flavour activity (RFA) value, and among them, dihydro-β-agarofuran and 4-methoxy-benzaldehyde were the most important aroma-active compounds. Additionally, three ‘Qi-Nan’ agarwood samples showed different aroma specificity. TD agarwood was characterized by sweet sandalwood odour due to the dominant aroma-active compound of β-Santalol. WS agarwood was distinguished by its woody odour because α-kessyl acetate was its primary aroma. HQ agarwood was featured by woody, spicy and balsamic odour on account of its main aroma compounds of agarospirol and β-elemene.

The aim of this paper was to evaluate the antidiabetic and antioxidant activities of methanolic extracts, n-hexane, dichloromethane, ethyl acetate, butanol, aqueous subextracts and essential oils of flowers, roots, leaves and aerial parts of Thymbra spicata subsp. spicata, which has been utilized in the public medicine systems of Turkey, Greece, Egypt and Rome for the treatment of asthma and bronchitis, as well as for flavour and aroma in the food industry and protection. Quantitative determination of secondary metabolites in the most effective samples of the plant was also analysed by LC–MS/MS. Moreover, the chemical composition of essential oils of different parts of the plant was analysed via GC-FID and GC/MS. The main constituents in the flower, leaf and aerial part were found to be carvacrol (75.6%), γ-terpinene (10.5%), carvacrol (73.3%), γ-terpinene (9.5%), p-cymene (8.6%), carvacrol (76.1.8%) and p-cymene (7.3%), respectively. Quinic acid, caffeic acid, vanillic acid, naringin, hesperidin and rosmarinic acid were measured in four ethyl acetate subextracts, and rosmarinic acid was found to have the highest amount in the flower subextract with a value of 48095.1083 ng/mL. The ethyl acetate extract of flowers showed the best activity with a 326 ± 12 μg/mL IC₅₀ value, while the standard acarbose IC₅₀ value was 4143 ± 243 μg/mL. It was determined that the leaf ethyl acetate extract, in particular, had a very high % inhibition value on ABTS^·+ (99.137 ± 0.011% inhibition) and DPPH^• (41.068 ± 0.031% inhibition). It is thought that the plant, which has been used as a spice in the kitchen for centuries by the public, can be safely used due to its high antidiabetic and antioxidant effects.

The aim of this study was to investigate the effects of ultrasound (US) combined with mild heat (T) and potassium sorbate (PS) on Pichia membranaefaciens in soy sauce and the quality of soy sauce. The maximum reduction of P. membranaefaciens was 5.34 ± 0.15 log after thermoultrasound (TS, 300 W, 10/3 s, 20 + 40 kHz, 60°C) + PS (0.1 mg/mL) treatment for 20 min. Physicochemical properties, including pH and total acid of soy sauce, did not change significantly after TS + PS treatment. Electronic nose analysis showed changes in the flavour of soy sauce after different treatments. A total of 122 and 125 volatile compounds were detected by SPME-GCMS before and after TS + PS treatment respectively. T₉₀ (soy sauce processed at 90°C) treatment decreased the content of the flavour compounds greatly, while TS + PS decreased the content of the flavour compounds slightly in soy sauce. TS + PS treatment inactivated P. membranaefaciens effectively in soy sauce and maintained and partially improved the sensory and flavour characteristics of soy sauce, which indicates that this combination technology has potential application in the commercial processing of soy sauce.

The self-administration of nicotine using e-cigarettes involves the use of liquids containing both solvent and aroma. The vaping appeal is enhanced by the sensory perception of flavours. Thus, an important attention may be paid to the choice of the refill liquid. For this purpose, this study aimed to evaluate the potential of 1,3-propanediol (PDO, vegetal solvent) and 1,3-butanediol (BDO, vegetal solvent), in replacing the chemical one such 1,2-propanediol (PG) while maintaining sensory pleasure and ensuring the wellbeing. The work was conducted with 30 participants accustomed to vaping. Three flavours have been selected, menthol, vanillin and pyrazine, respectively, to provide the most preferred perceptions which are respectively mint, sweet and tobacco. The Rate-All-That-Apply (RATA) method was chosen since it is rapid and robust. Menthol/PDO and menthol/PG exhibited a close olfactive profile, described as minty, cold and sweet. A similar finding has been observed for vanillin/PDO and vanillin/PG. The use of BDO provided different perceptions in comparison with PDO and PG regardless of the type of flavour. It was found to be the most suitable for pyrazine perception. These results were enhanced by the application of the agglomerative hierarchical clustering (AHC). The obtained dendrogram was composed of three groups according to their similarities, where e-liquids containing PDO, and PG belongs to the same groups for both menthol and vanillin.

Investigation of genetic diversity between and within populations is the first step in plant breeding programs. The present study focused on the phytochemical variation of essential oils of half-sib families within a plant population of Nepeta crassifolia species, collected from north of Tehran province, Iran. Air-dried aerial parts of several half-sib progenies were water distilled to extract their essential oils. Quantification and qualification of the essential oils constituents were carried out using gas chromatography (GC) and gas chromatography coupled to mass spectrometry (GC/MS). Dried plant materials, yielded from 0.09% to 0.73% (v/w) of essential oils. In half-sib families between 9 and 19 compounds were observed. In all of the studied families the extracted oils were predominated by oxygenated monoterpenes, and regarding the main phytochemical components, three chemotypes were recognized in the studied population. In most of the half-sib families, 4aα,7α,7aβ-nepetalactone isomer was dominant composition (38.7%–87.6%), while in two families 4aα,7α,7aα-nepetalactone isomer (41.6%) and 1,8-cineol (42.1%) were dominant constitutes. Significant correlation was not seen between biomass, essential oil yield and nepetalactone isomers. Comparing the presented results with essential oil components of other Nepeta species, such as N. cataria, revealed that N. crassifolia can be considered as a commercial source of nepetalactone isomers. Thus, promoting domestication and cultivation of N. crassifolia as industrial and medicinal species should be noticed.

Headspace solid-phase microextraction and gas chromatography mass spectrometry (HS-SPME-GCMS) was performed to study the aroma volatile profile of fresh-cut jackfruit under different storage temperature conditions (4 and 10°C). Total viable counts (TVC) and yeast and mould count (Y&M) were also simultaneously estimated. Sensory analysis revealed a loss in texture along with an increase in ripeness during storage at both the storage temperatures. It was observed that the volatile profile demonstrated significant changes at different storage temperatures during storage. Principal component analysis performed on volatile compounds allowed to differentiate fresh samples from stored samples, the differential pattern of correlation with volatiles was observed at 4 and 10°C. During storage the ester content increased linearly at both temperatures, however acetate esters predominated initially at 4°C, followed by other non-acetate esters. In the case of 10°C storage, higher levels of ethyl ester derivatives along with other esters were obtained in the later period of storage due to enhanced microbial activity.

The aldol condensation of acetaldehyde with methyl ethyl ketone was studied for the production of methyl pentenone in the presence of cationic resin, Amberlyst-15. Methyl pentenone (MPO) is an important intermediate used for the synthesis of Iso-E-Super, which is a precursor in sandalwood fragrances. Amberlyst-15 used as an alternative heterogeneous catalyst for conventional corrosive sulphuric acid was found to get deactivated with prolonged use. In this work, major possible causes of catalyst deactivation, such as desulphonation, coking, grafting, metal deposition and thermal degradation, are investigated. Characterization of fresh and used catalysts is performed for surface area, mass deposited and elemental composition (CHNS and ICP). The results confirm that multiple causes, i.e., desulphonation, metals exchange and oligomers deposition, are responsible for the catalyst deactivation. The presence of metal promotes desulphonation; the desulphonation along with metal exchange appears to be the major contributors to catalyst deactivation; and avoiding exposure to metal impurities may enhance the catalyst life significantly. Catalyst regeneration was also explored, and the catalyst site density is reclaimed from 0.5–0.6 meq/g to 4.1–4.2 meq/g, which is closer to the fresh Amberlyst-15 (4.5–4.6 meq/g). The study provides a way to develop the resin-based green technology for catalytic reactions.

To develop a new class of enol diketone esters, succinic acid monoesters were synthesized using the reaction of succinic anhydride with various aromatic alcohols. Subsequently, six types of methyl cyclopentenolone succinate diesters were synthesized using dicyclohexylcarbodiimide (DCC) as the condensation agent and 4-dimethylaminopyridine (DMAP) as the catalyst for the condensation reaction with methyl cyclopentenolone. The target compounds were characterized by nuclear magnetic resonance (¹H NMR, ¹³C NMR), infrared spectroscopy (IR) and high-resolution mass spectrometry (HRMS). The aromas characteristics of esters were evaluated using gas chromatography–mass spectrometry-olfactometer (GC–MS-O). Compounds 5a ~ 5c, which had a strong aroma, were conducted with thermogravimetry-derivative thermogravimetry (TG-DTG) to analyse their heating-stability. Additionally, these compounds were studied by pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) to analyse their pyrolysis behaviours at 300, 350 and 400°C. Results showed that methyl cyclopentenolone and a large number of small molecular flavouring substances were formed by 5a ~ 5c at the set temperature. The synthesis of methyl cyclopentenolone succinate diester can not only slow down the volatilization of methyl cyclopentenolone and aromatic alcohol, but also effectively enhance the aroma, improve the smoking taste of cigarettes, reduce the irritation and miscellaneous gas of smoking and provide more choices for cigarette flavouring.

Seasonal variations of yield and composition in microwave extracts from mature and immature Eucalyptus bosistoana leaves were monitored for 2 years. The highest yield (average 16.7 μL/g (fresh)) and percentage of 1,8-cineole (average 67.1%) were obtained from the leaves collected during summer and the lowest during winter. Mature leaves contained a significantly higher (p ≤ .001) proportion of 1,8-cineole in their extract (60.9%) than immature leaves (44.6%). Total yield ranged from 3.0 to 27.0 μL/g (fresh) in mature leaves and from 6.0 to 26.7 μL/g (fresh) in immature leaves. Significant differences between half-sibling families were observed, indicating genetic control of these traits. E. bosistoana leaf extracts could be comparable in quality and quantity to that of E. globulus, the species dominating global essential eucalyptus oil production. Oil quality and quantity could be optimized by harvesting mature leaves during summer from superior families.

Due to the disadvantages of low fragrance threshold and high volatility of pyrrole monomer under high-temperature process in tobacco or food, it cannot meet the market requirements. In order to develop pyrrole flavour precursors, 2,5-dimethyl-N-pyrroleacetic acid was synthesized by the Paal–Knorr reaction using 2,5-hexanedione and glycine as raw materials. Various pyrrole fragrance precursors such as 2-ethyl-4-oxo-4H-pyran-3-yl 2-(2,5-dimethyl-1H-pyrrol-1-yl)acetate (5a), 4-formyl-2-methoxyphenyl 2-(2,5-dimethyl-1H-pyrrol-1-yl)acetate (5b), pyridine-2-ylmethyl 2-(2,5-dimethyl-1H-pyrrol-1-yl)acetate (5c) and thiophen-2-ylmethyl 2-(2,5-dimethyl-1H-pyrrol-1-yl)acetate (5d) were synthesized by esterification from 2,5-dimethyl-N-pyrroleacetic acid with ethyl maltol, vanillin, 2-pyridinemethanol and 2-thiophenemethanol, respectively. As part of the study, IR, NMR and HRMS were used to characterize the target compounds. Using gas chromatography–mass spectrometry-olfactometer (GC–MS-O), the pyrrole esters obtained were evaluated for the characteristics of their aromas. The thermal stability was analysed using thermogravimetric analysis and pyrolysis gas chromatography/mass spectrometry. In addition, the pyrolysis mechanism was speculated. With TG-DTG results, the main mass loss phase of 5a occurred between 108°C and 450°C, with a dramatic mass loss reduction of 83.07%. At 118.60°C and 450°C, 5b showed a mass loss reduction of 60.80%. Furthermore, according to the Py-GC/MS analysis results, compounds 5a and 5b formed 8 and 7 pyrolysis products. The main pyrolysis products of 5a and 5b were 1-ethyl-2,5-dimethyl-1H-pyrrole, ethyl maltol, and vanillin, which are all aroma components used to blend cigarette smoke, can slow down the rate at which aromas are lost and mask unpleasant smoke. Study results provide a reference for the tobacco industry to further develop new high-temperature release aroma ingredients.