Flavour and Fragrance Journal最新文献

To explore the flavour characteristics and their different molecular mechanisms of different types of Hehong tea (Gongya, GY; Congou, CG and Laocong, LC) from the perspective of dry tea, we investigated their volatile compounds and sensory aroma sub-attribute characteristics by headspace–solid phase microextraction–gas chromatography–mass spectrometry (HS-SPME-GC–MS), quantitative description analysis (QDA), and chemometrics. A total of 42 volatile compounds were identified in Hehong tea, of which alcohol content was the highest, the number of esters was the largest and pyrrole showed the largest differences. The volatile components of GY and LC differed, whereas those of CG and LC were more similar. There were 34 volatile components with a significant difference in the three types of Hehong tea. We established the aroma quantitative system of Hehong tea by using QDA. We found that sweety was probably the symbolic aroma sub-attribute of Hehong tea, and woody was the characteristic sub-attribute of LC, and there was a certain correlation among the aroma sub-attributes. A total of 21 volatile components importantly contributed to the aroma sub-attributes of Hehong tea. Furthermore, we screened out 18 marker volatile compounds that may be used as important indicators for distinguishing the three types of Hehong tea. Our findings add to our understanding of the flavour characteristics and aromas of the three types of Hehong tea and provide new strategies and thoughts for the evaluation of tea flavour using dry tea.

High melting point and hydrophilicity of phenolic acids limit their application in lipophilic environments such as fat-containing cosmetics and foods. The esterification of the carboxyl group with fatty and aromatic alcohols has been considered as an effective way to enhance the lipophilicity of phenolic acids and thus enable better location of the antioxidant moiety into membranes and interface of emulsion systems where oxidation is expected to occur. Therefore, this study aims to evaluate the catalytic properties of six solid acids (HND-34, HND-6, HND-580, HND-2, HND-8 and HND-26) for the synthesis of benzyl cinnamate. Results show that HND-26 was the most effective solid acid to catalyse the esterification reaction of cinnamic acid with benzyl alcohol. By using response surface methodology, the influence of key experimental factors on the yield of benzyl cinnamate was investigated and the maximum yield (95.1%) was obtained under the optimized conditions (58°C, cinnamic acid/benzyl alcohol 1:20 (mol/mol), HND-26 loading 13.8% and 25 hours). The activation energy of cinnamic acid conversion with benzyl alcohol was 30.3 kJ/mol. Obtained results provide a cost-effective way of green synthesis of benzyl cinnamate and highlights the potential applications of HND-26 as an efficient catalyst for the production of phenolic acid esters with broad usage in cosmetic industry.

Coffee filters and drippers advertised with various functions such as balanced flavour, sweeter taste and plentiful coffee scene are popular options for hand-brewed coffee lovers. This study investigated the flavour of filtered coffee brewed by various coffee filters including Hario V60 filter, Kalita filter, flannel cloth filter and stainless-steel (screen) filter based on the physical and chemical properties of the beverages. The results showed that the extraction time of V60 and flannel cloth filter were shorter. Kalita filter offered longer extraction time and obtained the highest amount of chlorogenic acids than other drippers. In the volatile profiles of aroma compounds, flannel cloth and stainless-steel filters obtained higher total volatile compounds that may due to less volatiles were absorbed by filter material compared with paper filters, V60 and Kalita. Combined physical and chemical data among four extraction methods, partial least squares-discriminant analysis (PLS-DA) was able to separate samples into approximate four clusters. 2-Acetylfuran and 3-methyl-phenol were found fluctuated wildly among samples and would be important factors for the differentiation of pour-over coffee. This study suggested that the four coffees brewed by different filters have their own characteristic aroma profiles and did show their differences based on the chemical compositions caused by dripping speed and the interactions with filters.

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.

Coriander essential oil has several biological characters those make it an important place as a source of natural product. Due to the lack of natural products, many essential oil compounds are imitated by others made of cheap chemicals, which studies have shown to have a great danger to human health. From this point of view, it is necessary to search for new ways to increase natural products, the most important of which are essential oils. One of these methods is the use of bioregulators to modify the production of essential oil and its components to increase its biological use area. Thus, the variations of coriander green fruits essential oil were evaluated under different rates of glutathione and α-tocopherol to determine the possibility of using them in the production of essential oil from coriander green fruits. Coriander plants were treated during cultivation at rates of glutathione (0, 0.2, 0.4 and 0.6 g L⁻¹) without or with α-tocopherol (0.4 g L⁻¹). Green fruits essential oil was separated by hydro-distillation and analysed by gas chromatography and gas chromatography/Mass spectrometry; data were statistically analysed by two ways analysis of variance. Plants treated with 0.6 g L⁻¹ glutathione with α-tocopherol gave the maximum values of green fruits yield and essential oil content (% and yield per plant). The major essential oil constituents were linalool, undecan-3-ol and yomogi alcohol; while oxygenated monoterpenes were the main fractions. Plants exposed to glutathione with α-tocopherol doses resulted in higher values of major components and main fraction than those subjected to glutathione rates. This trial ascertained that the subordination of coriander plants to glutathione and α-tocopherol rates led to variations in green fruits essential oil, and this, in turn, affected its biological activities.

Adulteration is a crucial issue being faced by essential oil and allied industries, especially for high-value essential oil such as agarwood oil. The recommended analysis in trading essential oils involves visual inspection, olfactory analysis, physico-chemical characterization and gas chromatography coupled with mass spectroscopy (GC–MS). However, some subtle high-boiler adulterants like vegetable oils and synthetic polymers go unnoticed via these analyses leading to the penetration of adulterated essential oil in the market. In the current study, the thermogravimetric analysis (TGA) and differential thermogravimetric analysis (DTGA) were utilized and suggested as a rapid, convenient and precise technique for the detection of high-boiler adulterants in essential oils using the most expensive agarwood oil as a case study. The TGA pattern of pure samples reveals single-stage volatilization (agarwood oil: 110–260°C, castor oil: 340–500°C, coconut oil: 330–450°C and polyethylene glycol-400: 260–390°C), whereas the adulterated sample exhibits two-stage volatilization in both lower- and higher-temperature zone owing to the presence of agarwood oil and high-boiler adulterant. The DTGA of pure agarwood oil shows only one point of major weight loss, whereas that of the adulterated sample shows two points of major weight loss corresponding to both oil and adulterant. Different percentages of adulterants (5%, 10%, 30% and 50%) have been quantified using TGA and DTGA with the highest accuracy. Further, the method optimization study was conducted to determine the minimum time required for adulterated sample analysis with precise accuracy. TGA can be proposed as a handy and efficient tool for the quality control analysis of essential oils.

It is widely recognized that wine aroma critically influences wine quality, yet the extent to which volatile compound composition in wine determines wine quality has proven difficult to define, beyond the negative influence of taint compounds. While some relationships between concentration of volatile aroma compounds and wine quality have been made, this has been usually based on single molecules, in laboratory wines and without reference to experienced wine panels. Here, we collected and analysed 157 commercial Shiraz wines from a competitive show over 2 years. We found significant (P < .05) correlations between specific volatiles and the panel's wine quality scores. However, these correlations were not always consistent between years. We could not explain medals given to wine entries solely based on multivariate analysis of their composite volatile composition. Here, we suggest that aroma determination in judging wine quality does not completely explain the assessment of wine, and appearance (colour, clarity) and taste may be more influential factors. There are considerable practical difficulties in establishing a convincing wine quality prediction model based on analysis of volatile compounds alone.

The volatile compounds inherent to wild-type pennycress seeds were determined using solvent-assisted flavour extraction (SAFE), combined with gas chromatography-olfactometry (GC-O) and aroma extraction dilution analysis (AEDA). In this research, twenty-nine aroma-active compounds were detected via GC-O. With the aid of gas chromatography–mass spectrometry (GC-MS), retention indices, aroma descriptors and standard chemical verification, ten volatile compounds were positively identified: 2,5−/2,6-dimethyl-3-methoxypyrazine (grassy), allyl isothiocyanate (mustard, horseradish, onion), hexanal (green), (E)-2-octenal (earthy), acetic acid (sour), (E)-2-nonenal (woody), 1-octanol (grassy), 1-nonanol (green), 2-methylbutanoic acid/3-methylbutanoic acid (cheesy) and phenethyl alcohol (rose-like). By matching odour descriptions, mass spectra and retention indices, seven additional volatile compounds were tentatively identified: 1-pentanol, octanal, (E)-2-penten-1-ol, (E)-2-heptenal, (Z)-3-hexen-1-ol, (E, E)-3,5-octadien-2-one and pentanoic acid. These results provide an aroma analysis of pennycress, which can be useful in providing direction for pennycress breeding programs or tailored processing steps to eliminate the undesirable aroma components limiting the use as a food ingredient.

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.

This study reports the aroma profile of Litopenaeus vannamei under different processing conditions such as raw, boiled, hot air dried, microwave dried and roasted using SPME-GC-MS. A total of 86 volatile compounds were identified, among which 38 compounds reported as aroma-active compounds (AAC) having the odour activity value (OAV) greater than one. The microwave-dried shrimp meat (MSM) exhibited the highest summation of odour activity value, and roasted shrimp meat (RSM) showed the highest concentration of aroma-active compounds (3448.78 μg/g). The partial least square regression (PLSR) analysis and cluster analysis (CA) showed that MSM and RSM are related to each other in their aroma characteristics while boiled shrimp meat (BSM) is different than these samples. The results of this study illustrate the typical volatile markers and the impact of processing methods on flavour generation in L. vannamei, which should be examined for the assessment of its freshness and product development based on shrimp flavour.