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Flavor Characteristics of Lapsang Souchong and Smoked Lapsang Souchong, a Special Chinese Black Tea with Pine Smoking Process
Abstract
The major volatile constituents of lapsang souchong, smoked lapsang souchong, and smoked souchong, a group of special black teas in China, were analyzed with GC and GC-MS analyses. Forty-nine constituents were identified. Longifolene and alpha-terpineol were the most abundant compounds in the aroma. Due to its special production process, the compounds longifolene, longicyclene, guaiacol, 4-methylguaiacol, 4-ethylguaiacol, etc., were identified only in this kind of black tea. The aroma constituents of tea origin decreased during the smoking process, whereas the pine terpenoids and the thermal pyrolysis products of the pine wood increased markedly. The pine material for smoking was also analyzed for the volatile constituents showing apparent selectivity of the tea leaves to absorb. There were apparent differences among the tea samples in the contents of aroma constituents. The characteristics of the aroma of the teas are discussed with their processes and the features of sensory qualities.
... This is mainly because the processing of no. 18 requires a special smoking procedure using pine needles or pine firewood, which differs from the processing of other black teas [31,32]. This is why the color of certain odorants in block 3, including ethyl lactate, butyl propionate, pentyl acetate, 2-octanone, 1-hexanol, 2-butoxyethanol, 2-cyclohexenone, dimethyl trisulfide, and (E)-3-hexenol, appears intense in Figure 3. tea had same fingerprint, except for the samples No. 1 and No. 3, which was mainly because of the individual areas of block 6 (including odorants ethyl 3-methylbutanoate, 2,3pentanedione, 2-hexanol, acetic acid, methyl benzoate, 1-hydroxy-2-propanone, and (E)-3-hexenol) and block 4 (including odorants acrolein, diallyl disulfide, (E,E)-2,4-heptadienal, cyclohexanone, octanal, methyl heptanone, (E)-2-octenal, and nonanal), respectively. ...
... This is mainl because the processing of no. 18 requires a special smoking procedure using pine needle or pine firewood, which differs from the processing of other black teas [31,32]. This is wh the color of certain odorants in block 3, including ethyl lactate, butyl propionate, penty acetate, 2-octanone, 1-hexanol, 2-butoxyethanol, 2-cyclohexenone, dimethyl trisulfid and (E)-3-hexenol, appears intense in Figure 3. ...
Tea (Camellia sinensis) is one of the most popular beverages worldwide. Many types of tea products continuously emerge in an endless stream; so, the classification of tea becomes more difficult. Aroma is a vital indicator of tea quality. The present study deals with the identification of aroma compounds in 18 different kinds of tea belonging to three typical tea varieties, including green tea, oolong tea, and black tea, using GC-IMS and GC × GC-O-MS. Moreover, the clustering of all 18 tea samples and the in depth correlation analysis between sensory evaluation and instrumental data were performed using the PCA and OPLS-DA. The results revealed that in all 18 kinds of tea, a total of 85 aroma compounds were detected by GC-IMS, whereas 318 were detected by GC × GC-O-MS. The PCA result revealed that green tea, oolong tea, and black tea could be clearly separated based on their peak areas. The OPLS-DA result showed that a total of 49 aroma compounds with VIP value > 1.0 could be considered as the potential indicators to quickly classify or verify tea types. This study not only compared the aroma differences across different types of teas, but also provided ideas for the rapid monitoring of tea quality and variety.
... The free amino acids were determined with the ninhydrin dyeing method at 570 nm using glutamic acid as the standard [20,21]. The tea infusion (1.0 mL) was mixed with 0.5 mL of phosphate buffer (pH = 8.0) and ninhydrin solution (2%), and the mixture was kept in a water bath for 15 min. ...
... (E)-Geraniol is another important terpene and a great contributor to the odor of black tea [7,20,28]. The (E)geraniol content increased as the fresh leaves, were processed, reaching its highest level during rolling, indicating that withering and rolling can promote its release. ...
Wild black tea varieties with almond odors were found in Guangdong, China. Few previous studies have investigated their metabolic profile during processing. Herein, we assessed the variations in the chemical components including the volatile flavor compounds and nonvolatile flavor components during black tea processing. Benzaldehyde was responsible for the almond odor and could be used as an indicator for identifying black tea varieties with almond odors because of its relative stability. The contents of aromatic compounds with floral, sweet, and honey-like aromas, such as (E)-geraniol, phenylethyl alcohol, benzyl alcohol, β-ionone, α-terpineol, and (Z)-geraniol, were higher in the final drying process than they were in the plucking stage. However, the contents of β-linalool and its oxides and methyl salicylate tended to be lower in the dried black teas. PCA showed that 88.41% of the variation between the aromatic compounds and their odor attributes can be explained by PC1 and PC2. The almond flavor samples were differentiated from the control samples according to PCA. The contents of nonvolatile flavor components such as tea polyphenols, amino acids, soluble carbohydrates and caffeine were significantly lower in the dried black teas. The sensory evaluation suggested that XR black teas had strong and lasting almond odors, while DX-8 had floral and medicinal odors.
... The antimicrobial activities of both essential oils are assessed based on the rating system described by Gutierrez et al.,2013: (1)<(10) mm zone of inhibition is expressed as inactive; (10) to (13) mm zone of inhibition is expressed as partially active; (14) to (19) mm zone of inhibtiion is active; and >19 mm zone of inhibition is very active (Gutierrez et al.,2013). Results from the disc-diffusion assay are summarized in Table III. ...
... These terpene alcohols contributed different odor to the overall aroma of the oil. Beta-linalool is known to emit a floral fragrance while L-alpha-terpineol emits an odor that is very similar to lilac (Yao, et al.,2005). Another terpene alcohol, Terpinen-4-ol was detected in the PEO. ...
... It has a characteristic lilac odor, with a sweet taste reminiscent of peach on dilution. It is found in the composition of various essential oils [39,42] A simple aromatic carboxylic acid that occurs naturally in many plants and serves as an intermediate in the biosynthesis of many secondary metabolites, and it is found in postharvested strawberries up to 29 mg/kg [47]. ...
... It has a characteristic lilac odor with a sweet taste reminiscent of peach on dilution. It is found in the composition of various essential oils[39,42,51].It is found in cereals and cereal products. The 4-Acetyl-1methylcyclohexene is a flavoring ingredient. ...
Jams are appreciated worldwide and have become a growing market, due to the greater attention paid by consumers for healthy food. The selected products for this study represent a segment of the European market that addresses natural products without added sucrose or with a low content of natural sugars. This study aims to identify volatile organic compounds (VOCs) that characterize three flavors of fruit and five recipes using gas chromatography–mass spectrometry (GC–MS) and solid-phase micro-extraction (SPME) analysis. Furthermore, an innovative device, a small sensor system (S3), based on gas sensors with nanomaterials has been used; it may be particularly advantageous in the production line. Results obtained with linear discriminant analysis (LDA) show that S3 can distinguish among the different recipes thanks to the differences in the VOCs that are present in the specimens, as evidenced by the GC–MS analysis. Finally, this study highlights how the thermal processes for obtaining the jam do not alter the natural properties of the fruit.
... Concentration of this compound in myrtle leaves was arrived to 45.22 µg/ml. The other oil Terpineol is a naturally occurring monoterpene alcohol that has been isolated from a variety of sources such as cajuput oil, pine oil, and petitgrain oil [38]. Terpineol has a nice odor similar to lilac and is a common agent in perfumes, cosmetics, and flavors. ...
... Terpineol has a nice odor similar to lilac and is a common agent in perfumes, cosmetics, and flavors. α-Terpineol is one of the two most abundant taste constituents of lapsang souchong tea (a variety of souchong tea with a smoky flavor) the αterpineol construct in the pine fume used to dry the tea [38]. The Concentration of terpineol in myrtle leaves was arrived to 41.73 µg/ml. ...
Essential oils compounds were identified in leaves of Myrtus communis during flowering stage by HPLC method, results of this study appearing six major compounds were, 1,8-cineole, α-Pinene, α-terpineol, Eucalyptol, Geranyl acetate, Limonene, and linalool. Concentration of these compounds a ranged between 18.28 µg/ml in Geranyl acetate, and 45.22 µg/ml in Limonene, while α-Pinene have been distinguished by highest concentration among six essential oils under study was 308 µg/ml, this outcome data can be helpful as a significant medical and economic benefits
... The NO.18 sample (Zheng shan xiao zhong) from the black tea group, known for its strong burning aroma notes, was separated from other three black teas. That is mainly because the processing of NO.18 requires a special smoking procedure using pine needles or pine firewood, which differs from the processing of other black teas [30,31]. That is why the color of certain odorants in block 3, including ethyl lactate, butyl propionate, pentyl acetate, 2-octanone, 1-hexanol, 2-butoxyethanol, 2-cyclohexenone, dimethyl trisulfide, and (E)-3-hexenol, appears intense in Figure 3 ...
Tea (Camellia sinensis) is one of the most popular beverages worldwide. Many types of tea prod-ucts continuously emerge in an endless stream; so, the classification or verification of tea be-comes more difficult. Aroma is a vital indicator of tea quality. The present study deals with the identification of aroma compounds in 18 different kinds of tea belonging to three typical tea va-rieties, including green tea, oolong tea, and black tea, using GC-IMS and GC×GC-O-MS. More-over, the clustering of all 18 tea samples and the in-depth correlation analysis between sensory evaluation and instrumental data were performed using the PCA and OPLS-DA. The results re-vealed that in all 18 kinds of tea, a total of 85 aroma compounds were detected by GC-IMS, whereas 318 were detected by GC×GC-O-MS. The PCA result revealed that green tea, oolong tea, and black tea could be clearly separated based on their peak areas. The OPLS-DA result showed that a total of 49 aroma compounds with VIP value > 1.0 could be considered as the potential in-dicators to quickly classify or verify tea types. This study not only compared the aroma differ-ences across different types of teas, but also provided ideas for the rapid monitoring of tea qual-ity and variety.
... In that paper, after having boiled meat, a peculiar smoking treatment was then applied, using sugar with other materials (sucrose with apple-tree woodchips; sucrose with pear-tree woodchips; sucrose with green tea leaves; sucrose) (Zhang, 2022). In fact, leaves together with superficial sugars on meat could improve the flavor and color of smoked chicken (Yao, Guo, Lu, & Jiang, 2005). Recently, in Brazil, smoking with reforestation woods (Acacia mearnsii and Eucalyptus citriodora) was applied on bacon and did not negatively affect consumers liking, proving to be promising for companies exploring the viability of producing meat products smoked with reforestation woods (Merlo et al., 2020). ...
The sensory effects of grilling wood on consumers’ response are poorly understood, despite their potentiality in diversifying dishes. This study investigated both the effects of six materials (beech tree wood, Turkey oak wood, Sangiovese grapevine wood, olive wood, strawberry tree wood, charcoal briquettes) used to grill chicken breast meat on liking and sensory perception and consumers’ interest in using wood for grilling. A consumer test was conducted (n= 99 subjects, 45% males, aged from 18-65 years), applying a Rate-All-That-Apply test, a liking test, and a questionnaire exploring the interest, the perceived value and the sustainability of wood as part of the food processing. The type of wood clearly affected the consumers’ sensory perception and acceptability of meat. Strawberry tree wood was the most connoted and divisive sample. Turkey oak, olive tree and Sangiovese grapevine woods were associated to milder sensory profile. Two clusters were found (respectively with 54% participants in Cl1 and 46% in Cl2), with opposite preferences: while Cl2 preferred meat grilled with the most connotating wood (Strawberry tree wood) characterized by bitterness while Cl1 on the opposite preferred meat grilled with the milder woods. Consumers showed a high interest for grilling material, wood origin and wood botanical species, independently from the cluster. Strawberry tree wood was the material that most strongly connotated grilled meat and thus the most divisive one in terms of liking. Different varieties of wood and certified sustainable wood can valorize the grilling process in food services.
... Among them, black tea is the most consumed tea in the world, while oolong tea has the most variable fragrant aromas and tastes. Both of these teas originated on Wuyi Mountain, Southeast China [2,3]. It is also recorded in "All about Tea" that the earliest Chinese tea transported to Europe was produced on Wuyi Mountain [4]. ...
Wuyi Mountain in Southeast China is the origin of black tea and oolong tea. It is also considered the ‘treasure trove of tea cultivars’ because of its rich tea germplasm resources. In the present study, the population structure and genetic diversity of 137 tea germplasms from Wuyi Mountain and its adjacent areas were analyzed by SNPs. The information index (I), observed heterozygosity (Ho), expected heterozygosity (He) and fixation index (F) polymorphisms of the selected SNPs were high, stable and reliable. Ho had an average of 0.389, while He had an average of 0.324, indicating that Wuyi Mountain tea germplasms had rich genetic diversity. The AMOVA results showed that genetic variation came mainly from intrapopulation variation, accounting for 66% of the total variation. The differences in the Fst and Nei values of tea germplasm between Wuyi Mountain and its adjacent areas are similar to the geographical differences. Multiple analyses based on high-quality SNPs found that the landraces of tea plants on Wuyi Mountain had different genetic backgrounds from the wild-type landraces and the landraces of Wuyi Mountain tea plants underwent population differentiation. This study provides a basis for the effective protection and utilization of tea germplasms on Wuyi Mountain and lays a foundation for identifying potential parents to optimize tea cultivation.
... Camellia sinensis is a commercially significant plant that produces one of the most popular non-alcoholic beverages on the planet. As well as having a distinct flavor, tea is regarded as a healthy drink owing to its nutritional and therapeutic properties [16,17]. Tea has become one of the most prominent symbols of Chinese culture. ...
Anthocyanin and proanthocyanidins (PAs) are important components of flavonoids, secondary metabolites in plants with a wide range of industrial and pharmaceutical applications. DFR (dihydroflavonol 4-reductase) is a pivotal enzyme which plays an important role in the flavonoid pathway. Here, four CsDFRs genes were isolated from Camellia sinensis and their overexpression were analyzed in vitro and in vivo. Based on transcription and metabolic analyses, the CsDFRs expression is closely consistent with catechins and PAs accumulation. Moreover, the enzyme activity analyses revealed that the two recombinant proteins CsDFRa and CsDFRc exhibited DFR activity, which converts dihydroflavonols into leucocyanidin in vitro, but not CsDFRb1 and CsDFRb3. CsDFRa and CsDFRc overexpression in AtDFR mutants (tt3) revealed that CsDFRs are involved in the biosynthesis of anthocyanins and PAs, as CsDFRa and CsDFRc not only restored the petiole purple phenotype, but also the seed coat color. Site-directed mutagenesis revealed that the two amino acid residues S117 and T123 of CsDFRa play a prominent role in controlling DFR reductase activity. Enzymatic assays indicated that CsDFRa and CsDFRc exhibited a higher affinity for DHQ and DHK, respectively, whereas CsDFRb1N120S and CsDFRb1C126T exhibited a higher affinity for DHM. Our findings present comprehensive characterization of the DFRs from C. sinensis and shed light on their critical role in metabolic engineering.
... sinensis cv. Bohea) [1]. Black tea has been explored in recent years for its potential health benefits; obesity prevention, metabolic syndrome alleviation, colitis prevention, and cancer prevention are among them [2,3]. ...
Black tea was reported to alter the microbiome populations and metabolites in diet-induced obese mice and displays properties that prevent obesity, but the underlying mechanism of the preventative effect of black tea on high-fat diet (HFD) induced obesity has not been elucidated. Epigenetic studies are a useful tool for determining the relationship between obesity and environment. Here, we show that the water extract of black tea (Lapsang souchong, LS) reverses HFD-induced gut dysbiosis, alters the tissue gene expression, changes the level of a major epigenetic modification (DNA methylation), and prevents obesity in HFD feeding mice. The anti-obesity properties of black tea are due to alkaloids, which are the principal active components. Our data indicate that the anti-obesity benefits of black tea are transmitted via fecal transplantation, and the change of tissue gene expression and the preventative effects on HFD-induced obesity in mice of black tea are dependent on the gut microbiota. We further show that black tea could regulate the DNA methylation of imprinted genes in the spermatozoa of high-fat diet mice. Our results show a mechanistic link between black tea, changes in the gut microbiota, epigenetic processes, and tissue gene expression in the modulation of diet-induced metabolic dysfunction.
... Smoke drying significantly increases the role of internal organization enzymes in products, which achieves the aim of slow drying and hot working by exposing fruits in the smoke produced by burning wood, leaves, and waste products from crops. This drying method may enable fruits to absorb smoke composition to produce some additional ingredients or generate synthetic products through the material, and smoke components interact in long-time smoked processing (Yao et al., 2005). Hu et al. (2019) also found that the compounds in fumigated A. tsao-ko were richer and more complex, but the corresponding compound content was lower, which was consistent with our experimental results. ...
The effects of twelve different pre-drying and drying methods on the chemical composition in the pericarp and kernel of Amomum tsao-ko were studied. The volatile components were isolated from the samples by simultaneous distillation and extraction and analyzed by gas chromatography-mass spectrometry (GC-MS). Sixty and thirty-eight compounds were identified from pericarp and kernel, respectively, and the main constituents were oxygenated monoterpenes. These compounds were not only significantly affected by pre-drying and drying methods but also varied in content due to different tissue locations. The total volatile content of pericarp varied from 0.70 to 1.55%, with the highest obtained by microwave-dried samples (150 W) and the lowest in freeze-dried samples. The total volatile content of the kernel varied from 6.11 to 10.69%, with the highest content obtained during sun drying (SD) and the lowest content in samples treated with boiling water for 2 min. Oxygenated monoterpenes were the highest compounds in pericarp and kernel, which were also the most affected by drying methods. The highest content of oxygenated monoterpenes in the pericarp (0.77%) could be obtained by boiling water treatment for 5 min, and the highest content of oxygenated monoterpenes in the kernel (7.48%) could be obtained by SD. Additionally, the main components such as 1,8-cineole, 2-carene, ( Z )-citral, nerolidol, ( Z )-2-decenal, ( E )-2-dodecenal, citral, ( E )-2-octenal, 4-propylbenzaldehyde, and phthalan showed remarkable variations in pre-drying and drying methods.
... In that paper, after having boiled meat, a peculiar smoking treatment was then applied, using sugar with other materials (sucrose with apple-tree woodchips; sucrose with pear-tree woodchips; sucrose with green tea leaves; sucrose) (Zhang, 2022). In fact, leaves together with superficial sugars on meat could improve the flavor and color of smoked chicken (Yao, Guo, Lu, & Jiang, 2005). Recently, in Brazil, smoking with reforestation woods (Acacia mearnsii and Eucalyptus citriodora) was applied on bacon and did not negatively affect consumers liking, proving to be promising for companies exploring the viability of producing meat products smoked with reforestation woods (Merlo et al., 2020). ...
Food preferences are influenced by several factors including individual differences in the physiological perception of the sensory properties and genetic factors. This study was aimed to investigate the genetic bases underlying the perception of the soapy flavor, a sensory attribute identified as a driver of disliking for blue-veined cheese. Responses on soapy flavor perception (SFP) in six Gorgonzola Protected Designation of Origin (PDO) cheese samples were collected from 219 genotyped Italians (age 18-77 y) applying a Rate-All-That-Apply (RATA) test combined with a liking test.
Genome-Wide Association Studies (GWAS) were performed on three phenotypic traits: the SFP in at least one cheese (SFP_1), the number of cheese samples in which each individual perceived the soapy flavor (SFP_N) and the SFP in the cheese in which the highest number of individuals perceived the soapy flavor (SFP_P95).
Results showed that 144 individuals (65.8%) perceived the soapy flavor in at least one cheese. Our analysis allowed identifying four loci that resulted shared in all the three GWAS and have been confirmed by the SFP in at least other two Gorgonzola cheese samples. Particularly, we highlighted four genes (SYT9, PDE4B, AVL9 and HTR1B) that are involved in olfactory or taste processes, suggesting that they could play a relevant role in determining the individual differences in the SFP. In addition, a SNP near the HTR1B gene affected also the liking for Gorgonzola PDO cheese.
Overall, our work suggests possible candidate genes associated with the perception of soapy flavor, providing a starting point to better understand the individual differences in blue-veined cheese perception and expanding the current scientific knowledge in the emerging research area linking genetic individual differences to food perception and preferences.
... Eugenol carries sweet and phenolic flavor [29] and used in perfumes, flavorings, and essential oils [30]. -terpineol has pleasant odor and it is a commonly used ingredient in perfumes, cosmetics, and flavors [31]. ...
Tamarillo is a nutrient-dense fruit with a unique aroma from its volatile compounds (VCs). In this study, we aimed to compare the volatile profiles: (i) of fresh and freeze-dried tamarillo; (ii) detected using Thermal Desorption–Gas Chromatography–Mass Spectrometry (TD–GC–MS) and Solid-Phase MicroExtraction–Gas Chromatography-Mass Spectrometry (SPME–GC–MS); (iii) of freeze-dried pulp and peel of New Zealand grown tamarillo. The possible antibacterial activity of freeze-dried tamarillo extracts was also investigated. We show that freeze-drying maintained most of the VCs, with some being more concentrated with the loss of water. The most abundant VC in both fresh and freeze-dried tamarillo was hexanoic acid methyl ester for pulp (30% and 37%, respectively), and (E)-3-Hexen-1-ol for peel (36% and 29%, respectively). With the use of TD–GC–MS, 82 VCs were detected for the first time, when compared to SPME–GC–MS. Methional was the main contributor to the overall aroma in both peel (15.4 ± 4.2 μg/g DW) and pulp (118 ± 8.1 μg/g DW). Compared to water as the control, tamarillo extracts prepared by water and methanol extraction showed significant antibacterial activity against E. coli, P. aeruginosa, and S. aureus with zone of inhibition of at least 13.5 mm. These results suggest that freeze-dried tamarillo has a potential for use as a natural preservative to enhance aroma and shelf life of food products.
... Responsible for its occurrence is the drying process, where pine smoke is used. Not all consumers are satisfied with the slightly smoked aroma of this tea, reminiscent of smoked bacon or some peated whiskey from Scotland [64]. Only small amounts of natural terpineol are extracted from essential oils as an isolate. ...
This article is devoted to some aspects of the fragrant substances of plant origin applied in the food industry and perfumery as well. Since antiquity many extractive techniques have been developed to obtain essential oils. Some of them are still applied, but new ones, like microwave or ultrasound-assisted extractions, are more and more popular and they save time and cost. Independently of the procedure, the resulting essential oils are the source of many so-called isolates. These can be applied as food additives, medicines, or can be used as starting materials for organic synthesis. Some substances exist in very small amounts in plant material so the extraction is not economically profitable but, after their chemical structures were established and synthetic procedures were developed, in some cases they are prepared on an industrial scale. The substances described below are only a small fraction of the 2000–3000 fragrant molecules used to make our life more enjoyable, either in food or perfumes. Additionally, a few examples of allelopathic fragrant compounds, present in their natural state, will be denoted and some of their biocidal features will be mentioned as an arising “green” knowledge in agriculture.
... The hydroethanolic extract of the leaves and flowers of A. eriophora has hypotensive effects on rats (Anvari et al. 2016, Anvari et al. 2017. The hypotensive effect of the plant might be attributed to its 1,8-cineole (Lahlou et al. 2002) and flavonoid content (De Souza et al. 2011, Jiang et al. 2005, Morello et al. 2006. ...
... The hydroethanolic extract of the leaves and flowers of A. eriophora has hypotensive effects on rats (Anvari et al. 2016, Anvari et al. 2017. The hypotensive effect of the plant might be attributed to its 1,8-cineole (Lahlou et al. 2002) and flavonoid content (De Souza et al. 2011, Jiang et al. 2005, Morello et al. 2006. ...
Abstract
Background: Achillea eriophora DC. (Asteraceae) is a less-known medicinal plant endemic to South and East Iran. It is traditionally used for treating a variety of health problems by local people. This review aims to provide up-to-date information on A. eriophora, including its traditional uses, phytochemistry, and pharmacological properties, in exploring future therapeutic and scientific potentials.
Methods: The information on ethnobotany, phytochemistry, and pharmacological aspects of A.
eriophora was collected from the scientific literature
databases, Iranian Pharmacopoeia, published books, Ph.D. and MS dissertations.
Results: Achillea eriophora is traditionally considered
to have antipyretic, diuretic, and carminative effects.
It is also used to treat digestive problems, diarrhea,
fever, diabetes, bone pain, wounds, and insect bite.
It has considerable pharmacological properties,
including antimicrobial, hypotensive, wound healing,
and antioxidant. A total of 128 compounds such as
terpenes, sesquiterpenes, alcohols, esters, and
phenols have been isolated from this species. Its
major chemical components are 1,8-cineole and
camphor.
Conclusions: The high number of isolated
constituents signify considerable pharmacological
properties of Achillea eriophora. The present
pharmacological investigations of this plant are
limited and often lack exact information on active
compounds and their mechanisms of action. Most of
the medicinal properties attributed to A. eriophora,
such as healing digestive disorders, fever, and
diabetes have not yet been investigated and proven
under a scientific study. This highlights the
importance of A. eriophora as a valuable candidate
for future studies on medicinal plants. Due to its wide
range of traditional uses, the whole plant parts of A. eriophora, including roots, are harvested by local communities. Therefore, a conservation planning for this threatened species is needed.
... The hydroethanolic extract of the leaves and flowers of A. eriophora has hypotensive effects on rats (Anvari et al. 2016, Anvari et al. 2017. The hypotensive effect of the plant might be attributed to its 1,8-cineole (Lahlou et al. 2002) and flavonoid content (De Souza et al. 2011, Jiang et al. 2005, Morello et al. 2006. ...
Abstract
Background: Achillea eriophora DC. (Asteraceae) is
a less-known medicinal plant endemic to South and
East Iran. It is traditionally used for treating a variety
of health problems by local people. This review aims
to provide up-to-date information on A. eriophora,
including its traditional uses, phytochemistry, and
pharmacological properties, in exploring future
therapeutic and scientific potentials.
Methods: The information on ethnobotany,
phytochemistry, and pharmacological aspects of A.
eriophora was collected from the scientific literature
databases, Iranian Pharmacopoeia, published
books, Ph.D. and MS dissertations.
Results: Achillea eriophora is traditionally considered
to have antipyretic, diuretic, and carminative effects.
It is also used to treat digestive problems, diarrhea,
fever, diabetes, bone pain, wounds, and insect bite.
It has considerable pharmacological properties,
including antimicrobial, hypotensive, wound healing,
and antioxidant. A total of 128 compounds such as
terpenes, sesquiterpenes, alcohols, esters, and
phenols have been isolated from this species. Its
major chemical components are 1,8-cineole and
camphor.
Conclusions: The high number of isolated
constituents signify considerable pharmacological
properties of Achillea eriophora. The present
pharmacological investigations of this plant are
limited and often lack exact information on active
compounds and their mechanisms of action. Most of
the medicinal properties attributed to A. eriophora,
such as healing digestive disorders, fever, and
diabetes have not yet been investigated and proven
under a scientific study. This highlights the
importance of A. eriophora as a valuable candidate
for future studies on medicinal plants. Due to its wide
range of traditional uses, the whole plant parts of A riophora, including roots, are harvested by local
communities. Therefore, a conservation planning for
this threatened species is needed.
Keywords: Achillea, Asteraceae, digestive disorders,
ethnobotany, Iran, phytochemistry, pharmacology
... However, there were increases in the amount of almost all volatile compounds characteristic for the beer. The compound derived from hawthorn, which was found in the largest amount in BF, was α-terpineol, characterised by resinous and citrus aromas [42,43]. This constituent was found in the research about craft beers produced by mixed fermentation by Torulaspora delbrueckii non-conventional yeast and typical ale yeast [44]. ...
Beer with the addition of dotted hawthorn (Crataegus punctata) fruit and juice was prepared and analysed. The content of carbohydrates, glycerol and ethanol in beers was determined by high-performance liquid chromatography (HPLC). Analysis of the total content of polyphenols was also performed using the Folin-Ciocalteu method, as well as determining antioxidant capacity by DPPH• and ABTS+• assay, and the ability to reduce iron ions by FRAP assay. Content of volatile compounds was analysed by means of solid-phase microextraction and gas chromatography coupled with mass spectroscopy. Beers with addition of hawthorn, both juice and fruit, had higher antioxidative potential and higher polyphenols concentration compared to control beer. The content of polyphenols in beers was in the range 200.5–410.0 mg GAE/L, and the antioxidant activity was in the range of 0.936–2.04 mmol TE/L (ABTS+• assay), 0.352–2.175 mmol TE/L (DPPH• assay) and 0.512–1.35 mmol TE/L (FRAP assay). A sensory evaluation of beers was also carried out. Beer with hawthorn fruit addition obtained the best scores in sensory analysis for criteria such as aroma, taste and overall quality. This beer had the highest content of volatile compounds (287.9 µg/100 mL of beer), while the control beer had lowest concentrations (35.9 µg/100 mL of beer).
... conclusion (1) The law of change of the electrical characteristic parameters in the process of fermentation at each test frequency is clarified. During the process, the electrical impedance, reactance, impedance angle and loss factor all increase gradually, and the capacitance decreases with the extension of the fermentation cycle, indicating that more and more substances hinder the charge transfer during the process of fermentation. ...
Based on the electrical characteristic detection technology, the quantitative prediction models of sensory score and physical and chemical quality Index (theaflavins, thearubigins, and theabrownins) were established by using the fermented products of Congou black tea as the research object. The variation law of electrical parameters during the process of fermentation and the effects of different standardized pretreatment methods and variable optimization methods on the models were discussed. The results showed that the electrical parameters vary regularly with the test frequency and fermentation time, and the substances that hinder the charge transfer increase gradually during the fermentation process. The Zero-mean normalization (Zscore) preprocessing method had the best noise reduction effect, and the prediction set correlation coefficient (Rp) value of the original data could be increased from 0.172 to 0.842. The mixed variable optimization method (MCUVE-CARS) of Monte Carlo uninformed variable elimination (MC UVE) and competitive adaptive reweighted sampling (CARS) was proved that the characteristic electrical parameters were the loss factor (D) and reactance (X) of the low range. Based on the characteristic variables screened by MCUVE-CARS, the quantitative prediction models for each fermentation quality indicator were established. The Rp values of the sensory score, theaflavin, thearubigin and theabrownins of the predicted models were 0.924, 0.811, 0.85 and 0.938 respectively. The relative percent deviation (RPD) values of the sensory score, theaflavins, thearubigins and theabrownins of the predicted models were 2.593, 1.517, 1,851 and 2.920 respectively, and it showed that these models have good performance and could realize quantitative characterization of key fermentation quality indexes.
... One bud with two leaves TA B L E 1 Sample details in this research for the amino acids (Yao, Guo, Lu, & Jiang, 2005). Of 1.0 ml of tea infusion with 0.5 ml of ninhydrin solution (2%) and 0.5 ml of phosphate buffer (pH = 8.0) was heated in water bath for 15 min before cooling and fixing to 25 ml with water. ...
Volatile flavor compounds (VFCs) and nutrients in Viscum articulatum Burm.f. parasitic on ancient tea trees (named TM) were studied in this research by headspace solid‐phase microextraction (HS‐SPME)/gas chromatography–mass spectrometry (GC–MS) and conventional methods. Sixty‐six volatile compounds belonging to different classes were identified by GC–MS. The ketones, alcohols, and aldehydes were the principal aroma groups in TM according to principle component analysis (PCA). The most abundant aroma components in TM included benzaldehyde (9.64%), geranylacetone (7.92%), epoxy‐β‐ionone (7.71%), β‐linalool (7.35%), methyl salicylate (6.96%), and hotrienol (6.14%), significantly higher than CKs (p < .05). The positive PC1 and PC2 in TM were correlated with benzaldehyde, hotrienol, methyl salicylate, and geranylacetone. The mistletoes could be differentiated from CKs due to the difference in aroma compounds. Clean and fresh, woody and nutty odor with minor floral scent was the characteristics of TM. Analysis of the nutritional components showed that contents of polyphenols and catechins in TM were at trace levels, significantly lower than CKs (p < .05). The total contents of polyphenols, amino acids, carbohydrates, and caffeine in TM were significantly lower from the total soluble solids (p < .05), indicating that there were still lots of compounds undetected in TM. The sensory test showed that the taste and aroma in TM can be accepted, which indicates TM could be developed into alternative tea drinks in the future. This research studied the VFCs and nutrients in tea mistletoes. The VFCs were significant different from tea aromas as well as the nutritional qualities. This study sheds light on tea mistletoe and provides a scientific foundation for its further utilization.
... Two phenols, namely 5-pentylresorcinol and butylated hydroxytoluene, were detected in all samples. These compounds were previously identified in various tea samples (Kumazawa and Masuda, 2002;Yao et al., 2005). Estragole is a methoxyphenolic compound found in tea samples and was previously reported in ripened Pu-erh tea leaves (Du et al., 2014). ...
To explore the volatile profiles and the contents of ten bioactive components (polyphenols and caffeine) of sun-dried Pu-erh tea leaves from ancient tea plants on Bulang Mountain, 17 samples of three tea varieties were analyzed by headspace-solid phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) and high-performance liquid chromatography (HPLC). A total of 75 volatile components were tentatively identified. Laomaner (LME), Laobanzhang (LBZ), and other teas on Bulang Mountain (BL) contained 70, 53, and 71 volatile compounds, respectively. Among the volatile compounds, alcohols (30.2%–45.8%), hydrocarbons (13.7%–17.5%), and ketones (12.4%–23.4%) were qualitatively the most dominant volatile compounds in the different tea varieties. The average content of polyphenol was highest in LME (102.1 mg/g), followed by BL (98.7 mg/g) and LBZ (88.0 mg/g), while caffeine showed the opposite trend, 27.3 mg/g in LME, 33.5 mg/g in BL, and 38.1 mg/g in LBZ. Principal component analysis applied to both the volatile compounds and ten bioactive components showed a poor separation of samples according to varieties, while partial least squares-discriminant analysis (PLS-DA) showed satisfactory discrimination. Thirty-four volatile components and five bioactive compounds were selected as major discriminators (variable importance in projection (VIP) >1) among the tea varieties. These results suggest that chromatographic data combined with multivariate analysis could provide a useful technique to characterize and distinguish the sun-dried Pu-erh tea leaves from ancient tea varieties on Bulang Mountain.
... It has also been identified as the chemical component that contributes to spiciness of black pepper and is a major constituent of carrot seed oils, tea tree oil and in nutmeg. In addition, terpineol is a natural monoterpene alcohol that is found in cajuput, pine and petitgrain oils (Shan-Shan et al., 2005). There are four isomers, alpha-, beta-, gamma-terpineol and terpinen-4-ol. ...
Rice paddy herb, Limnophila aromatica Lam. Merr, is a tropical flowering plant in the plantain family, Plantaginaceae, and flourishes in a hot, watery environment, particularly rice fields. It is known to have a distinct flavour and aroma reminiscent of lemon/cumin, and used as salad in diet by Southeast Asian communities. The essential oil from L. aromatica from Tuaran (Sabah) was extracted and analysed, a total of 36 volatile organic constituents were identified. Detailed analysis revealed the presence of only seven major volatile compounds (amyl vinyl carbinol, terpinolene, β-linalool, sabinene, terpinen-4-ol, α-humulene, aromadendrene) in the range of 3.02 % to 30.06 %. These volatiles could be grouped into monoterpene (44.10 %), oxygenated monoterpene (32.15 %), sesquiterpene (20.87 %), oxygenated sesquiterpene (1.2 %) and oxygenated diterpene (2.27 %-1.5 1%). Interestingly, the presence of sabinene, terpinen-4-ol and α-humulene were found in a high percentage and could be suggested as chemotaxonomical markers of this herb.
... Its formation may be related to the oxidation of linoleic acid. Furthermore, the change of a-terpineol was similar to that of geraniol, which could also be produced by the hydrolysis of glycosidic aroma precursors [17,18]. ...
A total of 98 compounds including 20 aldehydes, eight arenes, six acids, 17 alcohols, 13 ketones, nine esters, nine methoxyphenolics, three alkenes, seven alkanes, and six other components were tentatively identified in six Chinese dark teas (CDTs) using gas chromatography–mass spectrometry. Multivariate statistical analysis revealed that dark teas from Yunnan and Guangxi provinces could be classified into one group, and other CDTs belonged to the other cluster. The diagnostic volatile compounds being responsible for CDTs' discrimination were observed as (E,E)-2,4-decadienal, methoxyphenolics, geraniol, α-terpineol, 2,4-heptadienal, cis-jasmone, linalool oxides, and 2-nonenal. Furthermore, mature tea leaves were separately fermented using Eurotium cristatum and Aspergillus niger. The results showed that E. cristatum increased the contents of cis-jasmone, α-terpineol, ß-ionone, nonanal, and 2-pentylfuran, whereas A. niger advanced the levels of geraniol, linalool oxides, 9,12-octadecadienoic acid, and ß-ionone after short-term fermentation. Fungus species may contribute to forming the flavor of Chinese dark teas by affecting the volatile compounds during postfermentation.
... These compounds have also been reported as important aroma constituents in Lapsang Souchong black tea. [33] Aldehydes, which contribute green, malty, fatty, sweet, floral, and fruity aromas to foods, [22] may make the flavour of black tea more prominent after baking. ...
Baking is the last, and yet most essential step in the formation of the final distinct flavour of most black tea products. In this study, the influence of baking on the volatile components of Dianhong black tea, which is one of the most popular black teas in China, was investigated. As a very fast, effective, and simple method for collecting volatiles, headspace solid-phase microextraction (HS-SPME) with a 65 µm PDMS/DVB fibre was used to extract the volatile compounds of Dianhong black tea, and the volatile components were further separated and identified by gas chromatography-mass spectrometry (GC-MS). The Results showed that the peak areas of alcohols, aldehydes, esters, and ketones were increased but that those of some alkanes, acids, and nitrogen compounds did not demonstrate an obvious increase after baking. The differences generated by baking process actually result in the distinct flavour of most black teas and can be used a model for analysing the chemical composition of special flavours, and for quality improvement and process control.
... It has a pleasant odor similar to lilac and is a common ingredient in perfumes, cosmetics, and flavors. α-Terpineol is one of the two most abundant aroma constituents of lapsang souchong tea; the αterpineol originates in the pine smoke used to dry the tea (Yao et al., 2005). ...
Essential oils of the fresh leaves and fruits of Fortunella margarita Lour. Swingle (Family: Rutaceae) were prepared by hydrodistillation method, which resulted with 0.27 and 0.30% respectively. The resulted oils of both organs were analyzed by GC/MS which revealed the presence of twenty compounds in the leaves oil representing 86.96% of the oil, from which gurjunene, eudesmol and muurolene were identified as major compounds. The fruit's oil was found to contain fourteen compounds representing 77.77% of the oil, of which terpineol, t-carveol, limonene, muurolene and cadinene represented the major compounds. The antiviral activity of the essential oils of both leaves and fruits was tested against avian influenza-A virus (H5N1), and the results revealed higher potency of fruits oil. Moreover, the essential oils of the leaves and fruits were investigated for their antimicrobial and antifungal activities. The oil of the leaves showed antimicrobial activity higher than that of the fruits at dilution (1:50 v/v) against Bacillus subtilis, Staphylococcus aureus, Sarcina luta and Streptococcus faecalis, also it has a moderate activity against Escherichia coli, Klebsilla pneumonia and Pseudomonas aeroginosa. On the other hand, the antifungal activity of the leaves and fruits revealed that the fruits exhibited higher activity than that of the leaves against Aspergillus niger and Candida albicans.
Background:
White tea has been more and more popular with consumers due to its health benefits and unique flavor. However, the key aroma-active compounds of white tea during aging process is still unclear. Thus, the key aroma-active compounds of white tea during aging process were investigated using gas chromatography-time of flight/mass spectrometer (GC-TOF/MS) and gas chromatography-olfactory (GC-O) combined with sensory-directed flavor analysis.
Results:
A total of 127 volatile compounds were identified from white tea samples with different aging years by GC-TOF/MS. 58 aroma-active compounds were then determined by GC-O, and 19 of them were further selected as the key aroma-active compounds based on modified frequency (MF) and odor activity value (OAV).
Conclusion:
Aroma recombination and omission testing confirmed that 1-octen-3-ol, linalool, phenethyl alcohol, geraniol, (E)-β-ionone, α-ionone, hexanal, phenylacetaldehyde, nonanal, (E, Z)-(2,6)-nonadienal, safranal, γ-nonalactone and 2-amylfuran were the common key aroma-active compounds to all samples. Cedrol, linalool oxide II and methyl salicylate were confirmed peculiar in new white tea, while β-damascenone and jasmone were peculiar in aged white tea. This work will offer support for further studies on the material basis of flavor formation of white tea. This article is protected by copyright. All rights reserved.
Gin is one of the most consumed distilled alcoholic spirits worldwide, with more than 400 million liters sold every year. It is most often produced through redistillation of agricultural ethanol in the presence of botanicals, most notably juniper berries, which give gin its characteristic flavor. Due to its natural ingredients, gin is a complex mixture of hundreds of volatile and nonvolatile chemical constituents. In this work, ultrahigh-resolution Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometry was used for the compositional analysis of 16 commercially produced gins. Two complementary ionization methods, namely, electrospray ionization (ESI) and atmospheric-pressure photoionization (APPI), were employed to cover a wider compositional space. Each gin provided unique chemical fingerprints by ESI and APPI, which allowed semiquantitative analysis of 135 tentatively identified compounds, including terpene hydrocarbons, terpenoids, phenolics, fatty acids, aldehydes, and esters. Most of these compounds have not been previously reported in gins. While chemical fingerprints were rather similar between most products, some products contained unique compounds due to their special natural ingredients or the production methods applied. For instance, a barrel-matured gin contained a high content of syringaldehyde and sinapaldehyde, which are typical phenolic aldehydes originated from oak wood. In addition, the relative abundance of vanillin, vanillic acid, gallic acid, coniferyl aldehyde, and syringaldehyde was clearly higher than in the other gin samples. Ultrahigh-resolution FT-ICR MS serves as a powerful tool for direct chemical fingerprinting of gin or any other distilled spirit, which can be used for rapid product quality screening, product optimization, or possible counterfeit product discovery.
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. This study established a Hehong tea aroma description system, combined with the volatile metabonomics to analyse the aroma differences of three types of Hehong tea and found their marker compounds.
Background
Pu-erh tea aroma is the comprehensive result of various volatile compounds (VCs). More than 1000 VCs were reported in Pu-erh tea. Pu-erh tea aroma was widely studied using sensory evaluation, instrumental analysis, odor activity value (OAV), aroma recombination, and omission test. The activities of microorganism is the key to the formation of Pu-erh tea aroma.
Scope and approach
The main purpose of this review is to elaborate on the volatile components contributing to the unique aroma, methods used for VCs extraction and evaluation, and metabolic mechanism of key odor-active compounds of Pu-erh tea. The reported VCs, odor-active compounds, and their extraction methods were summarized. Sensory evaluation, extraction methods, and analytical methods were elaborated concerning aroma analysis. The possible metabolic pathways of key odor-active compounds and related microorganisms were combed.
Key findings and conclusions
The composition of VCs varies greatly with different extraction methods. Combining multiple extraction methods will be an effective strategy to fully extract the VCs of Pu-erh tea. Sensory evaluation provides a fast and intuitive strategy to determine the aroma profile or aroma attributes. GC–O–MS combines with OAV, aroma recombination, and omission test can not only realize quantitative and qualitative detection but also realize the screening of key aroma compounds. E-nose combined with multivariate statistical provides an easier strategy for distinguishing Pu-erh tea aroma. Most VCs are formed by the activities of microorganisms, but their exact metabolic mechanisms are still unclear, which needs further exploration.
Dianhong tea (DHT) is popular for its pleasant caramel-like aroma. In this study, the aroma profile of high-grade DHT have been studied using gas chromatography-mass spectrometry (GC-MS) and gas chromatography-olfactometry (GC-O) combined with headspace solid phase microextraction (HS-SPME). A total of 52 aroma-active compounds were identified by GC-O coupled with aroma extract dilution analysis (AEDA) and odor specific magnitude estimation (Osme). Among them, quantification of 21 aroma-active compounds indicated that the content of linalool (5928 µg/kg) was the highest in high-grade DHT, followed by phenylethanol (3923 µg/kg) and phenylacetaldehyde (1801 µg/kg). Sensory-directed aroma recombination and omission tests further verified that phenylacetaldehyde, linalool, geraniol and 3-ethyl-2,5-dimethylpyrazine were important contributors to the overall sensory characteristics of high-grade DHT which dominated mainly by floral, sweet and caramel-like odors. This work will provide a theoretical reference for comprehensively understanding the aroma characteristic of DHT.
Thirty-seven volatiles were identified by gas chromatography-ion mobility spectrometry in sturgeon caviar. Alkenes (37, 43), alcohols (30, 36), aldehydes (9, 10), and esters (11, 13) were detected by two-dimensional gas chromatography–time-off-flight mass spectrometry in fresh and stored caviar, respectively. Alkenes (humulene, caryophyllene, longifolene, and D-limonene), aldehydes (heptanal, hexanal, pentanal, and 3-methyl butanal), and 2-ethyl-1-hexanol were sniffed and described as providing fresh, fatty, and fishy attributes by gas chromatography-olfactometry. The fungal genera of Apiotrichum, Penicillium, Filobasidium, Gibberella, and Cladosporium and 16 bacterial genera were significantly correlated with variations in the contents of 25 aldehydes and 11 ketones. Nine strains, 20 fatty acids, and 69 differential phospholipids were isolated and profiled. Glycerophosphoethanolamine (20:2/20:4), glycerophosphoethanolamine (22:6/22:5), and glycerophosphocholine (16:0/13:0) were significantly associated with the formation of odorants and the proposed mechanism of flavor formation from phospholipids is summarized. This study represents a foundation for achieving targeted preservation and flavor control of caviar.
Tea infusion is a colloidal system. As a first attempt to systematically characterize tea micro-nanoparticles, the effect of pH on colloidal properties of Lapsang souchong black tea infusion was investigated in this study. At the native pH 5 of black tea infusion, micro/nanoparticles were revealed by Cryo-TEM (Cryo-transmission electron microscopy) to be of a structure consisting of dominantly spherical polyphenol oxidase (PPO)-polyphenols complexes and surrounding linear polysaccharide chains with an average hydrodynamic diameter (Dh) of 128 nm and ζ-potential of −23.7 mV. It is the first time to demonstrate the black tea micelle consists of spherical and fibrous nanostructures, possibly responding to protein and polysaccharides. Increasing pH resulted in a decrease in polyphenols content and the disassembling of the micro/nanostructure. On the other hand, the decrease of pH through their respective isoelectric points led to the formation of PPO-polyphenols complexes, polysaccharide aggregation, and further aggregations among different molecules and their complexes and a drastic increase in the precipitation when pH was lower than pH 5. The predominant effect of pH on colloidal properties of black tea infusion reveals an electrostatic nature of intramolecular and intermolecular interactions among PPO, polysaccharides and polyphenols. Those results provide new clues to a practical and effective quality control of black tea products as well as an insight into health benefits of black tea.
This study investigated the effect of different types of smoking materials on the flavor, heterocyclic aromatic amine (HAA) content, and sensory attributes of smoked chicken drumsticks. All smoked samples showed lower pH and L*-value and higher a*-value and b*-value than the control sample (P < 0.05), but no significant differences in water content and water activity (P > 0.05). The samples smoked with sucrose combined with pear-tree woodchips (SP) or green tea leaves (ST) had higher overall acceptability than other samples (P < 0.05). Smoking increased the total HAA content, and the ST sample exhibited the highest total HAA content (P < 0.05). A total of 54 volatile compounds was identified. Overall, SP and ST are suitable for smoked chicken considering the sensory properties, while S and SA are proper for smoked chicken considering the minimization of HAAs, which may provide a theory basis for the production of smoked chicken.
In the present study, the high hydrostatic pressure was applied for the extraction of bioactive compounds from green, yellow, white, oolong and black tea. Extractions were carried out varying solvent (ethanol and water), pressure level (200 and 500 MPa) and pressure holding time (5 and 10 min). Total phenolic content (TPC) and antioxidant capacity were determined spectrophotometrically, while the content of individual catechins and caffeine were determined by HPLC‐DAD methodology. Among investigated teas, the highest TPC was determined in the ethanolic extract of green (3327.27 mg GAE L‐1) and white tea (3136.36 mg GAE L‐1) combining pressure of 200 MPa during 5 min, while the highest epigallocatechin gallate (1446.38 mg L‐1), epicatechin gallate (354.17 mg L‐1) and caffeine (862.58 mg L‐1) contents were determined in the ethanolic extract of white tea PMT obtained also using lower pressure level but with longer pressure holding time.
This study investigated the effects of different woodchip types (beech, oak, pear, and apple) on the volatile compounds and sensory characteristics of smoked bacon. The volatile compounds were influenced by woodchip types and the total content of ketones and phenols in pear-smoked bacon were higher than in bacon smoked with other woodchips (P < 0.05). The E-tongue combined with E-nose can effectively distinguish the difference in the flavor of bacon smoked with different woodchip types by the signal intensities. Sensory analysis showed that smoking increased bacon's redness, saltiness, and smoky flavor compared with the control (unsmoked bacon) (P < 0.05) and it had little impact on off-odor (P > 0.05). Correlation analysis showed that the E-nose and E-tongue data were highly correlated with contents of alcohols, aldehydes, and ketones. This study revealed that the different smoked materials greatly influenced the flavor and sensory properties of bacon.
A known monoterpene, named γ-terpineol, was incorporated in mixed Langmuir monolayers composed of dipalmitoyl-phosphoethanolamine (DPPE) and peptidoglycans as a model of microbial membranes. Surface pressure and surface potential isotherms, dynamical surface rheology, Brewster angle microscopy (BAM), and infrared spectroscopy were employed to characterize the compound-membrane interactions. The compound expanded monolayers denoting repulsive interactions. At 30 mN/m, the monolayer presented lower viscoelastic and in-plane elasticity parameters and an increased all-trans/gauche conformers ratio for the alkyl chains, confirming molecular order. The morphology of the monolayer was analyzed by BAM, which revealed a heterogeneous distribution of γ-terpineol along the mixed monolayer, which tends to segregate. In conclusion, the compound changes the thermodynamic, electric, rheological, morphological, and structural properties of the peptidoglycan-DPPE monolayer, which may be essential to understand, at the molecular level, the action of bioactives in selected membrane models.
Lactuca longidentata Moris (Asteraceae) is an endemic species growing only on Mesozoic limestone of central Sardinia. In the present study, the essential oil of the epigeal part of the plant was analyzed by gas chromatography-mass spectrometry (GC/MS). The main volatile components were α-terpineol (27.64%) and limonene (25.8%). The essential oils showed a noteworthy ability of scavenging free radical species (1,1-diphenyl-2-picrylhydrazyl (DPPH) test systems) with a mean half maximal inhibitory concentration IC50 of 32.24 μg/mL. More significant was the inhibition of lipid oxidation that corresponded to an activity 1.5 times lower than that of 2,6-bis(1,1-dimethylethyl)-4-methylphenol (BHT). The essential oil was also assayed on Staphylococcus aureus, Bacillus subtilis, Enterococcus faecalis, Escherichia coli, and Candida albicans by the microdilution broth method and was particularly active against B. subtilis, with a minimal inhibitory concentration (MIC) value of 100 μg/mL.
The compound γ-terpineol, which presents potential as microbicide and anticancer drug, was incorporated in cholesterol Langmuir monolayers, pure or mixed with DPPC. The compound expands the monolayers at higher molecular areas, but condenses them at lower areas, indicating a structural molecular rearrangement of γ-terpineol at the-water interface upon compression. Such effect was confirmed with rheological, surface potential, Brewster angle microscopy and infrared data, which indicated, respectively, reduction of the compressional modulus of the lipid monolayer, decrease of the surface potential, formation of aggregates, and alteration of the trans/gauche conformers for methylene groups. Distinctive effects were observed for cholesterol monolayers without or with the presence of DPPC. Such results may help understand how the interaction of γ-terpineol with lipidic surfaces is modulated by lipids able to mediate the packing state of biointerfaces.
In this paper, γ-terpineol, a known monoterpene with biological activity, including in lipidic interfaces, was incorporated in Langmuir monolayers of selected phospholipids as a model for cellular membranes. Surface pressure-area isotherms showed that selected amounts of γ-terpineol expand DPPC and DPPE monolayers and decreased the monolayer elasticity, confirming the lipid/compound interaction. Characterization with vibrational spectroscopy and Brewster angle microscopy pointed that γ-terpineol adsorbs on the polar heads of the phospholipids, affecting the gauche conformations of the aliphatic chains, and different patterns were observed for DPPC and DPPE monolayers, indicating a characteristic molecular accommodation of γ-terpineol along the polar head of the phospholipids. Therefore, distinctive interactions with DPPC and DPPE could be observed regarding the incorporation of γ-terpineol with each lipid, leading to particular molecular arrangements at the air-water interface and pointing the modulation of the interaction according to the chemical composition of the monolayer.
Tulsi (Ocimum sanctum) is one of the oldest aromatic herbs of the family Lamiacaceae. It is popularly known as "holy basil or sacred basil" and is present in almost every household in Indian sub-continent due to its medicinal, nutritional and spiritual properties. It is also known as "the incomparable one, mother of natural medicine and the queen of herbs." It has great medicinal importance. The leaves and flowers have good nutritional sources of fatty acid, β-carotene, calcium, vitamin C, and volatile substances which maintain our body healthy. Hindus use the wood or seeds of tulsi to make garland, which are strings of beads used to help in meditation, focusing of mind, chanting a devotional practice which connects the body, mind and spirit. This review focuses on the beneficial effects such as medicinal, nutritional and spiritual properties of tulsi.
Tulsi (Ocimum sanctum) is one of the oldest aromatic herbs of the family Lamiacaceae. It is popularly known as "holy basil or sacred basil" and is present in almost every household in Indian sub-continent due to its medicinal, nutritional and spiritual properties. It is also known as "the incomparable one, mother of natural medicine and the queen of herbs." It has great medicinal importance. The leaves and flowers have good nutritional sources of fatty acid, β-carotene, calcium, vitamin C, and volatile substances which maintain our body healthy. Hindus use the wood or seeds of tulsi to make garland, which are strings of beads used to help in meditation, focusing of mind, chanting a devotional practice which connects the body, mind and spirit. This review focuses on the beneficial effects such as medicinal, nutritional and spiritual properties of tulsi.
Dianhong teas produced from fresh leaves of different tea cultivars (YK is Yunkang No. 10, XY is Xueya 100, CY is Changyebaihao, SS is Shishengmiao), were compared in terms of volatile compounds and descriptive sensory analysis. A total of 73 volatile compounds in 16 tea samples were tentatively identified. YK, XY, CY, and SS contained 55, 53, 49, and 51 volatile compounds, respectively. Partial least squares–discriminant analysis (PLS-DA) and hierarchical cluster analysis (HCA) were used to classify the samples, and 40 key components were selected based on variable importance in the projection. Moreover, 11 flavor attributes, namely, floral, fruity, grass/green, woody, sweet, roasty, caramel, mellow and thick, bitter, astringent, and sweet aftertaste were identified through descriptive sensory analysis (DSA). In generally, innate differences among the tea varieties significantly affected the intensities of most of the key sensory attributes of Dianhong teas possibly because of the different amounts of aroma-active and taste components in Dianhong teas.
To characterise the volatile aroma compositions of Chinese congou black teas, four types were analysed by quantitative descriptive sensory analysis, gas chromatography–mass spectrometry (GC–MS) and gas chromatography–olfactometry (GC–O). The aroma of Chinese congou black tea was described using six sensory terms: ‘Roasted’, ‘Sweet’, ‘Malty’, ‘Green grassy’, ‘Floral’ and ‘Woody’. A total of 64 compounds including alcohols (20), aldehydes (12), ketones (12), esters and lactones (9), pyrazines (7) and other compounds (4) were identified and quantified in four Chinese black tea samples. The highest amount of volatile aroma compounds was found in Tanyang congou black tea (TY) (29.8 mg/kg), followed by Dianhong congou black tea (DH) (29.4 mg/kg), Keemun congou black tea (KM) (24.1 mg/kg) and Yixing congou black tea (YH) (23.6 mg/kg). Through aroma extract dilution analysis (AEDA) on the black tea extract, the flavour dilution factor (FD factor) ranged from 41 to 46. Trans-linalool oxide in DH, geraniol in TY, DH and KM were identified with the highest flavour dilution (FD = 4096) factors. The relationship between tea samples, sensory attributes and aroma-active compounds was modelled by partial least squares regression (PLSR), and the PLSR analysis revealed that pentanal showed a significant and positive correlation with the ‘Malty’ attribute, (Z)-3-hexen-1-ol showed a significant and negative correlation with the ‘Green grassy’ attribute, 2-methylpyrazine showed a significant and negative correlation with the ‘Floral’ attribute, cis-linalool oxide, trans-linalool oxide and nerolidol showed a significant and positive correlation with the ‘Woody’ attribute, cis-6-nonen-1-ol and 2-methylpyrazine showed a significant and negative correlation with the ’Woody‘ attribute.
Essential oils are complex mixtures of volatile compounds produced by aromatic plants and extracted by distillation or expression. More than 3000 essential oils are known with about 300 being commercially relevant as perfume, cosmetic, cleaning, food, and pharmaceutical products. The main trade oils (over 1000 t/year) are those extracted from Citrus aurantifolia, Citrus limon, Citrus sinensis, Cymbopogon nardus, Cymbopogon winterianus, Eucalyptus citriodora, Eucalyptus globulus, Lavandula × intermedia, Mentha canadensis, Mentha × gracilis, Mentha × piperita, Ocotea odorifera, Pogostemon cablin, Sassafras albidum and Syzygium aromaticum. A remarkable progress in the development of analytical methods has contributed to a precise and more reliable characterization of essential oils. Volatile compounds of terpenoid origin, primarily monoterpenes and sesquiterpenes, have been identified as hydrocarbons and their oxygenated derivatives in the form of alcohols, aldehydes, ketones, esters, ethers, peroxydes, and phenols. Also, non-terpenoid compounds namely phenylpropanoids, fatty acids and their esters and, more rarely, nitrogen- and sulfur-containing compounds are also present. Numerous parameters (physiological, environmental, and genetic factors) influence essential oil composition and in order to ensure the best quality of commercialized oils, specific guidelines have been developed and should be considered.
This chapter attempts to shed light on essential oils chemistry by pointing out biosynthetic aspects, relevant compounds in essential oil composition, and the major global trade oils.
Aroma components in Wuyishan black tea (Jinjunmei, Yinjunmei, Feizixiao and Jinzhenmei) were extracted and analyzed by simultaneous distillation-extraction (SDE) and gas chromatography-mass spectrometry(GC-MS). The results show that the main compounds in the four samples are similar, including geraniol, linalool oxides, linalool, phenylethyl alcohol, and (E)-2-hexenal. However, the volatile constituents in Wuyishan black tea have apparent difference from those of Yunnan Jinjunmei and Sri Lanka broken black tea due to the factors of area, tea plant variety and fermentation procedure.
It is a challenging task to discriminate raw pu-erh tea, notably aged raw tea, from ripened pu-erh tea, both of which are the two primary types of pu-erh teas, only based on the taster's sensory evaluation. In the current study, a workflow was proposed to differentiate those two clusters of pu-erh teas, as well as to point out and verify the markers responsible for the discrimination. Initially, an electronic nose was utilized for the rapid discrimination. Then, an efficient method based on ultrasound-assisted extraction-dispersive liquid–liquid microextraction-gas chromatography-mass spectrometry (UAE-DLLME-GC-MS) coupled with chemometric methods was developed to disclose the metabolic profiles and pinpoint the markers for discrimination. Afterwards seven methoxyphenolic derivatives were simultaneously determined in both pu-erh teas. The role of volatile components in the classification of pu-erh teas was proved using the electronic nose (E-nose). Diverse parameters were optimized for UAE-DLLME-GC-MS, and a total of 84 volatile constituents were detected and identified. The methoxyphenolic derivatives as well as some alcohol derivatives were screened out as the primary markers by principle component analysis, and significant differences were revealed for the contents of methoxyphenolic compounds in these two types of pu-erh teas. Taken together, methoxyphenolic compounds as well as alcohol derivatives were found and verified as the markers for the differentiation between raw and ripened pu-erh teas, and either an E-nose or UAE-DLLME-GC-MS could be applied as a reliable tool to achieve the discrimination.
Aroma volatiles from ripened and raw pu-erh tea were extracted by headspace solid-phase microextraction (HS-SPME) and simultaneous distillation-extraction (SDE). They were then characterized and identified using gas chromatography-olfactometry (GC-O) and gas chromatography-mass spectrometry (GC-MS). The conditions of HS-SPME including fiber selections and sampling condition optimization have been previously investigated. With the two methods, 39 and 33 aroma-active compounds were detected and characterized in ripened and raw pu-erh tea samples, respectively. The aroma-active compounds with similar sensory descriptors were grouped into the same category, and the sum of individual aroma intensity values within each category showed that the floral aroma (33.01 %), stale/musty aroma (25.24 %), and woody aroma (11.17 %) were the major aroma categories in ripened pu-erh tea. Alcohols (floral aroma notes), methoxyphenolic compounds (stale/musty aroma notes), and ketones (woody or floral aroma notes) play a vital role in the special flavor of ripened pu-erh tea. In raw pu-erh tea, the floral aroma (38.62 %) and fruity aroma (16.55 %) were the major aroma categories. These aromas were closely related to the characteristics of raw pu-erh tea aroma and its sensory perception.
Transformation of renewables has received major research interest in recent years, opening up completely new research areas, in particular in the field of oxidation and deoxygenation. For the oxidation reaction, rhenium complexes, in particular methyltrioxorhenium, are well known for their potential as catalysts, but they are also potent catalysts for the deoxygenation reaction. The application of organometallic rhenium complexes in both the oxidation and deoxygenation reactions using a broad range of substrates derived from renewable resources, such as terpenes, oils, fats, lignin, and sugar alcohols, is reviewed in this chapter.
The emissions of volatile organic compounds (VOCs) from air-dried Scots pine wood and from heat-treated Scots pine wood were compared with GC-MS analysis. Air-dried wood blocks released about 8 times more total VOCs than heat-treated (24h at 230degreesC) ones. Terpenes were clearly the main compound group in the air-dried wood samples, whereas aldehydes and carboxylic acids and their esters dominated in the heat-treated wood samples. Only 14 compounds out of 41 identified individual compounds were found in both wood samples indicating considerable changes in VOC emission profile during heat-treatment process. Of individual compounds a-pinene. 3-carene and hexanal were the most abundant ones in the air-dried wood. By contrast, in the heat-treated wood 2-furancarboxaldehyde, acetic acid and 2-propanone were the major compounds of VOC emission, Current emission results reveal that significant chemical changes have occurred, and volatile monoterpenes and other low-molecular weight compounds have evaporated from the wood during the heat-treatment process when compared to air-dried wood. Major chemical changes detected in VOC emissions are explained by the thermal degradation and oxidation of main constituents in wood. The results suggest that if heat-treated wood is used in interior carpentry, emissions of monoterpenes are reduced compared to air-dried wood, but some irritating compounds might be released into indoor air.
Pine resources are abundant in Greece and Turkey. Pinus halepensis Mill., P. brutia Ten. and P. pinea L. are the main species for gum oleoresin production. Chemical composition of oleoresins of these species were studied by GC and GC-MS, using DB-5 capillary column. The results show that these oleoresins have common characteristics of that of subgen. Pinus, but all their amount of abietic acid are more than 20%. The monoterpene compounds in P. pinea oleoresin consists mainly of limonene.
The study of the components of a solid smoke flavouring preparation was carried out using several techniques. The sample was extracted by means of an ultrasonic bath and by successively using dichloromethane and water as solvents. Observation by microscope, of the initial sample and the residues of extractions, indicate that the carrier of this preparation consists of two components insoluble in dichloromethane. One of these consist of small transparent globular particles, and the other of irregular particles of a gold colour, the latter is soluble in water. Fourier Transform infra-red spectra of the solid smoke flavouring preparation, its extracts and residues, were obtained and studied. From these it can be concluded that the two components of the carrier are saccharides, one of them similar to starch and the other with reducing ability owing to the presence of carbonyl groups. Also, from the infra-red spectrum of the flavouring mixture extracted with dichloromethane, ratios between the absorbances of carbonyl and phenol functional groups are obtained, and compared with those of an aqueous smoke flavouring. Finally, the composition of the volatile fraction of the extract in dichloromethane was studied by gas chromatography-mass spectrometry and gas chromatography techniques. Carbonyl compounds, namely ketones, aldehydes, and furan and pyran derivatives, are the major components and constitute approximately 60% of the volatile fraction of the extract. Also, phenol derivatives are present in the sample. Guaiacol and syringol derivatives constitute approximately 25% of the volatile fraction. Some compounds, not previously detected in wood smoke, were identified in this flavouring. However, polycyclic aromatic hydrocarbons were not detected in the sample. Quantitative data from gas chromatography and infrared spectroscopy agree, and show the close relationship between the composition of the soluble fraction in dichloromethane and the odour of the sample.
“Cecina” is a traditional intermediate moisture food prepared by salting, drying and, occasionally, smoking meat pieces. The stability and long shelf-life of these products are due to their low water activity (aw), ranging from 0.90 to 0.60. The headspace volatile compounds from samples of dry meats from venison, beef, horse and goat cecina were analysed by gas chromatography–mass spectrometry (GC/MS) to characterise the volatile profile of these meat products. In general, about 110 volatile compounds were identified and quantified. Typical breakdown products derived from lipid oxidation, amino acid catabolism and carbohydrate fermentation were the main volatiles detected in all cecinas, together with the volatiles generated by the smoking process. However, horse cecina also presented important concentrations of esters and showed very few volatiles coming from the smoke.
The volatile extracts from needles of two varieties of Anatolian black pine, Pinus nigra subsp. pallasiana var. pallasiana and pyramidata were investigated by GC–MS. Generally, the composition of extracts was similar but the proportion of some compounds differed. The increased proportion of β-pinene is distinct in the variety pallasiana, whereas higher percentages of germacrene-d and cadinene isomers were found in pyramidata. Higher levels of monoterpenes and their derivatives exist in variety pallasiana than sesquiterpenes and the opposite is true for the variety pyramidata. Diterpenes occur at about 1% of extracts, although epimanool was detected in a couple of trees of pallasiana at higher levels. Furthermore, the comparison of the results with those in the literature suggests that Anatolian black pine is related to European counterparts grown in Italy, Alps and Greece.
Chemical studies on the oleoresins from 22 species of Chinese pines showed that α-pinene, β-pinene, limonene, longifolene, caryophyllene, pimaric acid, communic acid, sandaracopimaric acid, isopimaric acid, palustric/levopimaric acids, dehydroabietic acid, abietic acid and neoabietic acid were among the main constituents. Each of the pine oleoresins in this study had unique characteristics in the composition of its oleoresin. The presence of lambertianic acid was the main difference between oleoresins of sect. Strobus and sect. Pinus. Communic acid and cembrene were detected for the first time in Chinese oleoresins.
We present a theoretical analysis of electron and hole escape mechanisms from a quantum well (QW) in an external electric field. The influence of carriers and dopant ion charges on the band structure is simulated with a self-consistent Poisson-Schrödinger solver. A new escape mechanism called the phonon-assisted sequential tunneling is proposed as an alternative to direct tunneling and thermionic emission from the QW ground state. Our calculation shows that at high forward biases, POP phonon-assisted sequential tunneling and thermionic emission dominate the electron and hole escape times. At high reverse biases, direct electron tunneling from the QW ground state to the reservoir determines the turn-off time constant, while heavy holes take a longer time to escape than electrons.
The volatile components of hickory wood tar were fractionated by preparative gas chromatography. Individual fractions were analyzed on a Carbowax 20M 50 ft × 0.02 in. support coated open tubular column (SCOT) coupled to a mass spectrometer. The following compounds are among those being reported for the first time from hickory wood tar: 2-methyl-2-butenoic acid; benzaldehyde; 2-acetylfuran; 2-cyclohexenone; 4-propylguaiacol; 4-methylveratrol; 3-methyl-2-cyclopenten-1-one; 2,3-pentanedione; acetophenone; resorcinol; vinylphenol; 2,6-dimethylphenol; and 2-ethylphenol. A total of six aldehydes, eight ketones, four esters, six furans, 12 aromatic hydrocarbons, 32 phenols, and 13 acids were identified.
The thermal decomposition of ferulic acid has been studied by thermal gravimetric analysis. The decomposition products were separated by gasliquid chromatography and identified by GLC retention time and infrared spectral comparison with authentic materials. Combined gas-liquid chromatography-mass spectrometry and thin-layer chromatography were used as supplementary tools in product analysis. Unsubstituted, 4-methyl-, 4-ethyl-, and 4-vinylguaiacols were identified as products from the decomposition of ferulic acid in air and nitrogen atmospheres. Vanillin, acetovanillone (4-hydroxy-3-methoxyacetophenone), and vanillic acid were formed only in the air atmosphere. A mechanism is proposed for a portion of the ferulic acid decomposition.
An aqueous smoke flavouring from Thymus vulgaris L was obtained. The qualitative and quantitative composition of its dichloromethane extract was studied by gas chromatography and gas chromatography/mass spectrometry. In addition to the common smoke components such as aldehydes, ketones, diketones, esters, acids, furan and pyran derivatives, alkyl aryl ethers, phenol, guaiacol and syringol derivatives, some terpenic compounds were detected. Differences between this aqueous liquid smoke and others from various kinds of wood are due not only to the absence or presence of some compounds but also to the proportions of the different groups of components present in the mixture. Some aldehydes, esters, guaiacol and its derivatives and terpenic compounds contribute to the overall odour of this liquid smoke more significantly than the ketones, furan and pyran derivatives, acids, phenol and its derivatives and syringol. The yield in smoke components obtained from the pyrolysis of Thymus vulgaris L at 488 °C is of a similar order to that obtained from other woods. © 1999 Society of Chemical Industry
Flavour components from Chinese traditional smoke-cured bacon were trapped by condensing and dissolving in organic solvent (ether and n-pentane), using the nitrogen purge-and-steam distillation (NPSD) method. Qualitative and quantitative characterizations of the extract were performed by means of gas chromatography-mass spectrometry and gas chromatography with a flame ionization detector, respectively. Using Chinese traditional smoke-cured bacon, under the condition of stewing, the identification of 27 constituents which were not reported in a previous paper was achieved by the steam distillation method on Chinese traditional smoke-cured bacon and 4 phenols was not previously reported. The use of NPSD technique not only serves as a carrier of aroma constituents but also provided a medium which prevented the oxidation of the cellular components. This study indicates that must of the volatiles from Chinese traditional smoke-cured bacon are phenolic-derivatived. The volatiles in Chinese traditional smoke-cured bacon, however, are very different from fresh pork and Jinhua ham. The phenolic derivatives volatiles in Chinese traditional smoke-cured bacon should be related to smoking during manufacturing.
Carotenoid content of tea leaves ranges from 36 to 73 mg/100 g dry weight, and is dominated mainly by β-carotene, lutein and zeaxanthin. Among the cultivars, China contained the maximum and Assam clone the least. Carotenoid fractions were found to degrade to different extents at different stages of tea processing. The carotenoid content was as low as 25 mg/100 g in the made tea. Only a small quantity was leached into the brew, the remaining being retained in the infused leaf/tea residue. The high stability of carotenoid in tea is mainly due to the presence of antioxidants, such as polyphenols and catechins. Carotenoid degradation was found to be greater in the CTC (Crush, Tear, Curl) process than the orthodox process, greater in withered than unwithered, and in the order β-carotene > zeaxanthin > lutin. Vitamin A value was greater in orthodox tea than CTC tea and it varied with clones. The carotenoid degradation was found to yield large quantities of desirable aroma volatiles in made tea, giving a high grown flavour status. An increase in endogenous carotene content enhanced all the quality parameters of tea, the VFC (volatile flavour compounds) index, almost being doubled. The tasters' evaluation also revealed the same trend. It was found that a 1:1 NK application at the rate of 300 kg/ha/year enhanced the carotenoid content of green leaves in the second week after application, with subsequent decline.
The impact of various cultural and manufacturing techniques on volatile flavour composition was studied in order to optimize the conditions for production and retention of aroma in relation to tea quality. The Flavour Index was in the order: clonal variation—Assam > > Cambod > China Shoot maturity—Bud + 1st leaf > > > 2nd leaf > > 3rd leaf; plucking interval 7 day > 14 day; processing—green leaf > withered leaf—fermented dhool < dried tea < < tea brew; withering—soft < normal < hard. VFC Group I was in general dominated by trans-2-hexenal and Group II by linalool, phenylacetaldehyde and geraniol. Fresh green leaf had a high content of hexanol, hexanal, hexenol, hexenal and methyl salicylate. Upon withering, a sharp increase in Group I was noticed, the most remarkable being in hexenol. Group II also increased, but the extent was less except for linalool. During fermentation, Group I alcohols showed a sharp reduction with concomitant increases in aldehydes, especially trans-2-hexenal. In Group II, all compounds increased except methyl salicylate and the ionones. In the firing stage, high losses of Group I and Group II were registered. All the Group I compounds showed a decline with the progress of withering, but the opposite applied to Group II compounds, except for the alcohols. Mechanical injury during handling of leaf before cutting increased the Group I content enormously. The addition of exogenous fatty acids, mainly linoleic acid, produced substantial amounts of Group I compounds, dominated by trans-2-hexenal and hexanal. The inhibition of lipoxygenase totally reduced the formation of Group I volatiles.
An aqueous smoke flavouring from oak (Quercus sp.) sawdust was obtained on the laboratory scale. Its qualitative and quantitative composition was studied by gas chromatography after previous extraction. A high number of compounds (215) was detected. In addition to the well-known smoke components, others, only recently described as smoke components, were also detected. In the first group there are aldehydes, ketones, diketones, esters, alcohols, acids, furan and pyran derivatives, syringol, guaiacol, phenol and pyrocatechol derivatives, alkyl and aryl ethers; in the second group the presence of some furan and pyran derivatives is noteworthy, as well as a significant number of lignin dimers in low proportion, a considerable number of anhydrosugars in very high proportion and some nitrogenated derivatives in low proportions. Differences between this oak aqueous liquid smoke and others previously obtained from several woods, under similar operative conditions, are due, not only to the absence or presence of some compounds, but also to the proportions of the different groups of components present in the preparation.
The precursors responsible for tea quality, such as polyphenols, were found to increase in the first year and thereafter declined in content with time from pruning. While the green pigment content and ash content increased, the lipoxygenase activity showed substantial and progressive decline with time from pruning. The content of carotenoids were found to increase in the first 3 years after pruning and then showed a decline. A quantitative assessment of the various biochemical and quality parameters, such as theaflavin content (TF), total liquor colour (TLC), and water extract, showed progressive increase with time from pruning. The polyunsaturated fatty acids showed a marked decrease in their contents with decrease in the total fatty acids and various lipid fractions with time from pruning. However, C (18: 0) showed an increasing trend. While the sum of VFC Group II showed an enhancement, that of Group I showed a decline with time from pruning. As a result, the flavour index value was found to increase with time from pruning. The sensory evaluation supported the trends observed in the analytical data.
Some essential oils obtained from the branches of four Pinus species (P. pinea L., P. halepensis Mill., P. pinaster Soil in Ait., and P. nigra Arnold) have been evaluated for their acaricidal activity by aerial diffusion against the stored food mite Tyrophagus putrescentiae (L.). All the essential oils showed a good efficacy, but P. pinea oil and its two constituents 1,8-cineole and limonene were the most effective compounds, showing 100% acaricidal activity at 8 microL; 1,8-cineole showed the same activity at 6 microL.
Variations of fatty acid compositions, glycosides precursors, and lipoxygenase and glycosidase enzymatic activities were used simultaneously to differentiate for nine genetically different cultivated teas, four seasonal changes, and the affect of leaf maturity. The muscatel flavor of second-flush teas was associated with increased activities of glycosidase and several terpenes, phenolics, and aliphatic compounds bound to glycosides, whereas high levels of fatty acids and lipoxygenase activity biosynthesized more green volatiles in monsoon teas. Sequential hydrolysis of lipids and lipoxygenase-mediated reactions, during withering and rolling, showed a 3-fold increase of hexenol, hexenal, and related volatiles, but they decreased to the levels of fresh leaf during drying. However, a 4-fold increase of the floral bend of volatiles found in black tea developed due to the hydrolysis of the glycoside precursors throughout processing stages. About 45 key volatiles were monitored for flavor superiority among different clones. Various parameters affecting yield of volatiles were optimized and recommended.
Preliminary studies on flavour volatiles in Qimen black tea
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Aroma composi-tion of original Chinese black tea, Zheng Shan Xiao Zhong and other black teas
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Chemical utilization of turpentine IV: syntheses of perfumes
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Chemical composition of oleoresin of Pinus sylVestrissthe main pine species for oleoresin production in Russia
- Z Q Song
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- Y Wang
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Song, Z. Q.; Liang, Z. Q.; Wang, Y.; Liu, X. Chemical composition of oleoresin of Pinus sylVestrissthe main pine species for oleoresin production in Russia. Chem. Ind. For. Prod. 1996, 16 (1), 11-14.
The Far-Flung kingdom of Indian tea
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Pine resources in Peru and their oleoresins composition
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Study on smoked flavor of Souchong black tea
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Study on preparation of high-purity longifolene from heavy-turpentine
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