To better understand the mechanism of palmitoleic acid oxidation into volatile compounds during heating, volatile profiling was investigated by combining thermal-desorption cryo-trapping with gas chromatography–mass spectrometry. A total of 49 volatile compounds were detected and identified during this process, including aldehydes (18), ketones (14), alcohols (9), furans (3) and acids and ester (5). The forming temperature of each volatile was determined. Most of the volatiles with short carbon chains were generated at low temperatures, while those with long carbon chains were generated at high temperatures. Results of principal component analysis show that nearly all of the identified volatiles were considered as the characteristic ones of the high temperature points. Meanwhile, the oxidative products of the C7–C11 saturated and unsaturated aldehydes were also detected and identified during heating to intensively investigate the oxidative mechanism of palmitoleic acid during heating. Results demonstrated that only the C10 saturated and unsaturated aldehydes could continue to be oxidized during heating. Therefore, the oxidation reactions above the secondary level of lipids mainly occurred in the C10 saturated and unsaturated aldehydes.

In China, Lu'an Guapian (LAGP) tea consists of tea leaves without tea buds or stems. In this study, we evaluated the aromatic characteristics of LAGP by sensory analysis, aroma extract dilution analysis (AEDA), and odor activity values. The sensory analysis revealed that LAGP had cooked soybean-like, cooked chestnut-like, roasted, cooked corn-like, fishy, fruity, floral, and grass aromas. Aroma-active compounds from LAGP were identified by solvent extraction-solid phase extraction (SE-SPE) and headspace-solid phase microextraction (HS-SPME), and subjected to AEDA. A total of 91 aroma-active compounds were identified by SE-SPE-AEDA with flavor dilution (FD) factors ranging from 1 to 4096. A total of 66 aroma-active compounds were identified by HS-SPME-AEDA with FD of 1 to 128. Nine compounds with FD ≥64 and OAVs ≥1 were major aroma-active compounds to the aroma of LAGP tea: raspberry ketone (raspberry), (E)-β-ionone (floral, raspberry), dimethyl sulfide (cooked corn-like), indole (animal), phenylacetaldehyde (floral, honey-like), 2-ethyl-3,5-dimethylpyrazine (roasted), (Z)-4-heptenal (cooked soybean-like, fishy), (Z)-jasmone (jasmine), and geraniol (rose).

Temperature-sensitive nanocapsules with controllable release properties were synthesized through miniemulsion free radical polymerization method. Temperature-sensitive N,N-diethylacrylamide/N,N-dimethylacrylamide (DEA/DMA) copolymer were systematically synthesized as shell materials, and the fragrance-dementholized peppermint oil (DPO) was encapsulated as hydrophobic core material. The as prepared nanocapsules had high encapsulation efficiencies of more than 90% and small average diameters of less than 150 nm, as well as narrow polydispersity index (PDI) below 0.17. Furthermore, decreased DEA contents in shell material resulted in higher phase transition temperature and slower release rate of fragrance under the same temperature. By varying the copolymer composition of shell materials, the controllable release property of as prepared nanocapsules were also varied under different temperatures.

A novel automated flow-cell coupled dynamic solid-phase microextraction (SPME) method was developed to study the emission of volatile fragrance compounds from fabric samples in a microchamber. Calibration curves were developed with the liquid-inner tube diffusion-film-emission (LIFE) vial technique to quantify the gas-phase concentration of nine significant volatile fragrance compounds. The linearity range for the various volatile fragrance compounds ranged from 0.001 to 37.9 mg/m3. The limit of quantitation (LOQ) for each fragrance compound was determined as ~3.6–12.1 μg/m3. Using this method, we obtained comprehensive emission curves of target volatiles to quantify the volatile emission profiles of fabric samples. Compared with traditional chamber test method procedures, this work provides a novel and automated method to allow the online monitoring of the emission of various volatiles from multiple samples in one experiment. The repeatability and sensitivity of the method are comparable to or better than existing offline techniques.

The study aims to develop wash-resistant antibacterial cotton fabrics without using synthetic chemicals. Therefore, natural active agents of thyme, thymol and carvacrol were selected. The inclusion complexes were formed with β-cyclodextrin using kneading method which is a simple and reproducible method for the encapsulation with high production yield. Differential scanning calorimeter analysis showed that 1:1 and 1:2 β-CD: Guest Molecule (M:M) for thymol and carvacrol from different ratios studied has the highest complexation degree as 50% and 100%, respectively. It is also revealed that the volatile agents are retained and showed better thermal stability as a result of complexation. Carvacrol inclusion complexes were found relatively more stable (Zeta potential: −28.2 mV) than thymol complexes with smaller particle sizes (204.9 nm). Chemical structures of the inclusion complexes were revealed with Fourier transform-infrared spectroscopy and nuclear magnetic resonance analyses. The optimum formulations for each active agent were applied to cotton fabrics as per the impregnation method and the capsule treated fabrics were washed 1, 10 and 20 times. The images exhibited the presence of inclusion complexes on the fabrics after 20 washing cycles. Although the antibacterial efficacy of fabrics decreased with increasing washing, the fabrics showed the antibacterial effect after 20 washes against Klebsiella pneumoniae and Staphylococcus aureus. This study showed that the developed products can be an alternative to the other products in the market as the long-lasting fragrant natural antibacterial.

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.

This study aimed to investigate the effect of different simmering times, salt and sugar addition on the quality of the Morchella soup. The change in the released contents of nutrients and flavour compounds in the Morchella soup within 120 min was studied. The automatic amino acid analyser, solid-phase microextraction–gas chromatography–mass spectrometry, phenosulphuric acid method, acid–base neutralization principle and 1,1-dipheny2-picrylhydrazyl scavenging activity were used to determine the changes in free amino acids, volatile flavour compounds, total sugar, titratable acids and antioxidant activities in the Morchella soup respectively. The results showed that the amount of amino acids, volatile flavour compounds, titratable acid, antioxidant capacity and total sugar in the Morchella soup were significantly higher at 40-min simmering time than at other simmering times. At 40-min simmering time, the salt and sugar addition increased the amounts of umami amino acids (54.33%, 23.48%) and total amino acids (40.83%, 20.02%), organic acids (211.6%, 127.74%), sulphur-containing compounds (130.40%, 237.20%), titratable acids (43.3%, 16.7%), and total sugar (23.8%, 16.7%) and antioxidant activity (87.5%, 23.8%) in the Morchella soup respectively. This study revealed the influence mechanism of simmering time, salt and sugar addition on the Morchella soup and provided a basis for further processing the Morchella soup.

Lipoxygenases (LOX) catalyse allylic oxidations and epoxidations of a co-substrate in the presence of an unsaturated fatty acid containing a 1,4-pentadiene moiety. One- and two-step enzyme assays were established to verify the role or involvement of LOX in such co-oxidations. It was shown that LOX is only involved in the formation of reactive hydroperoxides, but not in the oxidation of a co-substrate, assuming a mechanism involving free peroxy radicals for the latter. Ten mono- and sesquiterpenes were used as co-substrates and the resulting products were analysed by mass spectrometry. A semi-preparative approach was developed using (+)-valencene as an example, and the resulting products were isolated by preparative GC and their structures elucidated by NMR spectroscopy.

The essential oils of Lavender (Lavandula angustifolia) and Tropical Basil (Ocimum basilicum) are characteristically high in both linalool and linalyl acetate esters, key constituents determining essential oil (EO) quality and activity. The enrichment of these products in linalyl acetate has a great interest in the industry. Herein, we report the production of linalyl acetate using the free lipase PPL as a catalyst in a solvent-free medium. Parametric studies referring response surface methodology (RSM) were applied to optimize the conversion. The optimal experimental condition for (R)-linalool acylation (temperature at 60°C, catalyst amount at 150 mg, volume of acetic anhydride at 1 mL, and reaction time at 5 days) was obtained from an experimental design analysis. Under these conditions, the enzymatic acylation was carried out for both pure linalool, Lavandula angustifolia and O. basilicum essential oils as substrates. 24.94% conversion of pure linalool to linalyl acetate was obtained; however, essential oils gave lower conversions (conv = 13%).

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.

A statistical approach was successfully applied to optimize the acylation of l-menthol 1 in the presence of natural kaolin as an eco-compatible catalyst. The influence of the main variation of the operating parameters, namely solvent volume, amount of the acyl donor, temperature and the catalytic rate of kaolin, was studied. A full factorial design (FFD) was used to search for the optimum of each parameter affecting the evolution of l-menthol 1 acylation. A quadratic polynomial regression model was applied to analyse the experimental data with a p-confidence level <.05 (95%). Statistical analysis of the data confirmed that temperature (T), acyl donor/acceptor ratio (Qa), kaolin mass (Qc) and solvent volume (V) were the significant factors affecting the l-menthol catalytic acylation process. The determination coefficient of the adopted model was in the order of 98%. A set of optimal reaction conditions was established, and experimental tests were performed to validate the optimal conditions; the threshold of 100% was reached. Monitoring the kinetic profile of the reaction by gas chromatography (GC) showed complete conversion after 30 min of reaction. An upgrade of this developed environmentally benign process was applied to some monoterpenic alcohols, and the corresponding acetates were yielding at 45%–90%.

8-methyldecanal is a characteristic ingredient of Australian finger lime (Citrus australasica), and has found important applications in flavour and fragrance industry. A novel and practical preparation method of 8-methyldecanal is presented. Starting from cheap and readily available 6-chloro-1-hexanol, 8-methyldecanal was prepared in five steps with an overall yield of 50.7%.

Saffron is a spice derived from the flower of Crocus sativus L., which has a special aroma, colour and odour influencing positively its economic value. In this context, ten saffron ecotypes were screened for their biochemical composition and antioxidant activity. The samples were also analysed using GC-MS and LC-MS to determine their content of volatile and phenolic compounds, respectively. The results revealed statistically significant differences among samples based on moisture (9.09%-11.23%), total phenols (31.62-62.71 mg EAG/g), total flavonoids (23.02-40.02 mg ER/mg), total carotenoids (66.12-155.05 μg/g), picrocrocin (88.99-121.53), crocin (137.44-228.39) and safranal (26.56-53.04). The radical scavenging activity ranged from 17.09% to 29.53% for DPPH assay, and oscillated from 0.128 mmol AAE/g to 0.239 mmol AAE/g for ABTS test, while the ferric reducing antioxidant potency (FRAP) varied from 0.974 to 1.989 mmol Fe2+/g. Gas chromatography-mass spectrometry (GC-MS) analysis identified 66 volatile compounds, among which the Safranal and Isophorone were the most abondant. The ES1 from Taliouine recorded a very distinct volatile composition compared to the others ecotypes with 22 authentic volatile compounds. Moreover, liquid chromatography- mass spectrometry (LC-MS) analysis revealed 14 phenolic compounds with picrocrocin and crocin were found to be the major compounds. The principal component analysis classified the investigated ecotypes into two mean distinctive sets with ES1 and ES9 were distinguished as a single items. The α-pinene, β-pinene, limonene, anethole, acetic acid, ketoisophorone, isophorone, safranal, thymoquinone, total flavonoids, FRAP and total carotenoids, are the main discriminant variables. The two-dimensional analysis of the clustered heatmaps divided showed a relatively similar patterns as the principal component analysis (PCA) and confirmed the singularity of the sample ES1 based on its particular volatile profile dominated mainly by α-terpinyl acetate, methyleugenol, copaene, anethole, limonene, methyl-cyclopentane, which were not identified in the other samples even at minor levels. These findings herein found revealed the high quality of Moroccan saffron, which is very important for the species breeding and valorization.

Fragrant rice has unique aroma characteristics appreciated by many consumers. In order to extract exclusive flavour fingerprints from Guangxi fragrant rice and to further verify its effectiveness by allowing the rapid identification of fragrant rice from two main production regions (Guangxi and Wuchang), gas chromatography-ion mobility spectrometry (GC-IMS) technology was applied to analyse flavour components of 53 fragrant rice samples. Based on the two-dimensional GC-IMS map, characteristic variables of flavour components from Guangxi fragrant rice were screened via image pretreatment and automatic threshold segmentation algorithm. The extracted variables were further processed by using principal component analysis and quadratic discriminant analysis to establish a non-linear model for discriminating two types of fragrant rice. The results showed that a total of 46 characteristic variables were extracted from Guangxi fragrant rice, and the first two principal components showed that the two types of rice samples had their own corresponding regions. 2-Butanone, 2-heptanone, pinene, 1-heptanal, 2-methyl-1-butanol acetate and octanal were the key different flavour components. The established model had an excellent recognition rate, which could be used to determine the geographical region of fragrant rice. The proposed method could achieve quick, non-destructive and accurate analysis of fragrant rice geographical properties. It can be further applied in feature extraction from the two-dimensional fingerprint map generated by other similar combined instruments.

Artemisia dracunculus L. (tarragon) is valuable for its medicinal uses such as antimalarial, antibacterial and anticancer. Biotechnological methods need to be developed for the production of phytochemical compounds in plants with high and stable quality. Elicitation is one of the best tools for increasing secondary metabolites in various in vitro cultures. The current study determines the application of different concentrations of chitosan (25, 50, 100 and 150 mg/L) and UV-C (5/10, 5/15, 10/10 and 10/15 min/cm) as biotic and abiotic elicitors in tarragon leaf callus cultures. The main aim was to increase the accumulation of artemisinin, quercetin, caffeic acid and essential oil content. For this purpose, callus formation rates and morphological features were also investigated. The results show that highest callus formation, weight and diameter were observed in UV-C treated cultures. HPLC analyses revealed significant high accumulation of artemisinin (1.9 μg/g), quercetin (4.2 μg/g) and caffeic acid (2.9 μg/g) contents in 5/10 min/cm UV-C treated samples. GC–MS analyses of callus cultures indicate high production of total amount of monoterpenes in all chitosan applications, best in 25 mg/L (90.75%). The major compound was β-phellandrene in chemical composition of tarragon (19.61%) and increased the most in 10/15 min/cm UV-C application (43.39%). The results show that the physical elicitor UV-C can be effectively used in tarragon callus culture for enhancing pharmacologically active compounds in industrial production.

Evening primrose oil (EPO) is rich in linolenic acid, which has important physiological activity and attracted more and more attention. As a cold sterilization technology, irradiation is widely used in food preservation. However, the effect of irradiation on the flavour quality of EPO is unclear. The volatile aroma compounds examined by gas chromatography-mass spectrometry (GC-MS), combined with the odour activity value, are used to identify important odours in EPO. Principal component analysis (PCA), cluster heatmap analysis, and orthogonal partial least squares discriminant analysis are used to analyse the data to illustrate the impact of different radiation doses. The results show that the types and composition of volatile substances have changed, among which aldehydes have increased the most. Hexanal, (E,Z)-2,4-decadienal, and (E)-2-octenal, 1-octen-3-ol were confirmed to play an important role in the formation of the green, fast, oily, and fishy aroma profile of EPO. In addition, the cluster analysis and PCA analysis showed that the flavour of 5 and 10 kGy was similar, but it was different from that of 1 kGy. In general, after the irradiation treatment, the flavour quality of EPO deteriorates, and the content of undesirable flavour substances increases. Additionally, the potential formation pathways and mechanism of volatile compounds were discussed. The research will help us to understand the change of the violate compounds under the γ-irradiate process.

Stewed 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) >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.

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.

The majority of people have a bitter taster phenotype, they perceive substances such as phenylthiocarbamide (PTC). This could be associated with a lower preference for bitter foods. The ability to detect bitter taste is due to TAS2R28 receptor. The aim of this study was to determine the preferences for basic flavours, taste combinations and bitter taste-related foods in a sample of Chilean university students and to relate it to their PTC taster phenotype and genotype. A 5-point Likert-type online survey on taste and food preferences was applied to 149 Chilean university students (19.2 years; 69.8% women; 29.5% men and 0.7% prefer-not-to-say). It classified students as strong taster (ST), intermediate taster (IT) or non-taster (NT) through a PTC taste test. To assess the relationship between phenotype or genotype and students' preferences, we analysed frequency tables using Fisher's exact test. To genotype determination, it extracted DNA from buccal mucosal cells of 25 students (18.9 years; 72% female and 28% male). A fragment of TAS2R38 gene amplified (PCR) and digested (HaeIII). Our results show that 85.9% of students had a PTC taster phenotype (37.6% ST, 48.3% IT vs. 14.1% NT). Sweet taste was the most preferred, while bitter taste was the least. There was no association between taste and food preferences with student's phenotype or genotype. ST students presented homozygous taster genotype (55.6%); IT students, heterozygous taster genotype (75%); and NT students, homozygous non-taster genotype (50%). Both the PTC taster phenotype and genotype associated are not related to a lower preference for bitter taste and foods studied. Our results will allow us to generate promotion and education strategies for healthy eating, through the inclusion of bitter foods.