Search

In order to investigate the effect of wrapping-rolling on the quality of Tieguanyin oolong tea, non-volatile and volatile metabolites in rolled tea leaves before and after repeated wrapping-twisting for up to three times were analyzed by widely targeted metabolomics based on headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS). The results showed that a total of 973 non-volatile metabolites belonging to 12 categories were identified, including 468 differential metabolites. The total amount of non-volatile metabolites showed a decreasing trend during the wrapping-twisting process. Particularly, the decrease in the content of differential metabolites such as flavonol glycosides and phenolic acids contributed to the reduction in bitterness and astringency during the wrapping-twisting process. The content of differential lipids increased, which provided favorable conditions for the conversion of volatile fatty acids during the subsequent drying process. A total of 47 volatile components belonging to six categories were identified. During the wrapping-twisting process, the contents of β-red myrcene, heptanal, (E)-2-hexenyl hexanoate and cis-3-hexenyl isobutyrate, responsible for fatty or grassy aroma, decreased, while the contents of methyl jasmonate, benzyl benzoate, geranyl acetone and 3,7-dimethyl-1,5,7-octatrien-3-ol, contributing to floral or fruity aroma, increased. It was noteworthy that the odor activity value (OAV) of the major aroma components in Tieguanyin oolong tea, such as linalool, jasmonolactone, cis-jasmonone, α-farnesene and basilene, were still greater than 1 at the end of the wrapping-twisting process although their contents decreased during this process. It could be seen that the wrapping-twisting process was beneficial to purify the quality of Tieguanyin tea, and provided it with a more mellow taste and more obvious floral and fruit aromas. This study provides new insights into the metabolite changes and the flavor formation of oolong tea during the wrapping-twisting process.

Copyright of Shipin Kexue/ Food Science is the property of Food Science Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Mopan persimmon brandy with an alcohol content of 42% (V/V), prepared by fermentation and distillation, was aged after being added with 5–20 g/L of Chinese-made moderately roasted oak chips. The volatile and non-volatile components of persimmon brandy were analyzed by gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-mass spectrometry (LC-MS), the total phenol content and antioxidant activity were determined, and sensory evaluation was also performed. The results showed that a total of 33 volatile components were identified by GC-MS, among which the major components were ethyl acetate, ethyl decanoate, and ethyl laurate. The content of volatile components was the highest upon the addition of 10 g/L of oak chips. The results of LC-MS showed that the number of non-volatile substances increased by 183 after aging. The total phenol content and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging capacity increased with increasing addition of oak chips, but was basically stable after 90 days of aging. In the sensory evaluation, persimmon brandy with 15 g/L of oak chip scored the highest (72.5 points).

Taiping Houkui green tea is mainly made from the young shoots of the sextual tea line ‘Shidacha’. In the present study, the differences in the quality and genetic evolution of green tea made from the young shoots of five ‘Shidacha’ varieties (Gaojiazao, Huangzhong, Shidacha No.2, Shidacha No.6, and Guangyangzao) and two non-‘Shidacha’ tea varieties (Fuzao No.2 and Shuchazao) were explored. The volatile and non-volatile metabolites of the seven tea samples were analyzed, and the differences in genome-wide transcriptional levels and genetic background among the seven tea varieties were analyzed using RNA sequencing (RNA-seq). No significant differences in catechin content or the total content of free amino acids were found among all tea samples except Shuchazao, whereas caffeine content differed significantly among all samples. The contents of floral aroma compounds such as linalool, linalool oxide, geraniol and jasmone were relatively high in the infusion of ‘Shidacha’ green tea. RNA sequencing results showed that the genome-wide transcriptional level of Guangyangzao was close to that of the non-‘Shidacha’ tea varieties. In principal component analysis (PCA), Guangyangzao and the other ‘Shidacha’ varieties were distributed in different quadrants. Phylogenetic analysis showed that the non-‘Shidacha’ tea varieties had a close genetic relationship with each other as well as Gaojiazao and Huangzhong, but was far away from the other ‘Shidacha’ varieties. The transcriptional levels of most of the key enzyme genes involved in the biosynthesis of linalool, indole, nerolidol and jasmone lactone were higher in the ‘Shidacha’ tea varieties than in the non-‘Shidacha’ ones. This study provides important theoretical support for the breeding of excellent ‘Shidacha’ varieties and provides a theoretical basis for follow-up research on the formation mechanism of floral aroma compounds in tea leaves.

Nine tea cultivars planted in Enshi were selected and processed into “Lichuan black tea”. Sensory evaluation showed that cultivar had the greatest influence on taste and aroma quality, including sweetness, umami and concentration of taste, as well as sweet and floral fragrances of aroma. The non-volatile and volatile components were identified by UPLC-Q-TOF/MS and GC–MS, and PCA analysis showed good separation between cultivars, which could cause the difference in quality. Baiyaqilan, Meizhan and Echa 10 had a floral aroma, with obvious difference in their aromatic composition from other cultivars. Moreover, Echa 10 also had a strong sweet aroma. The key aroma components in Echa 10 (with the largest cultivation area) were further investigated by GC-O-MS combined with odor activity value (OAV) analysis, included β-damascenone, phenylethylaldehyde, nonenal, geraniol, linalool, jasmonone, (E)-2-nonenal, β-cyclocitral, (E)-β-ocimene, methyl salicylate, β-ionone, 2,6,10,10-tetramethyl-1-oxaspiro[4.5]dec-6-ene, citral, β-myrcene, nerol, phenethyl alcohol, benzaldehyde, hexanal, nonanoic acid, and jasmin lactone.

Copyright of Shipin Kexue/ Food Science is the property of Food Science Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Shipin Kexue/ Food Science is the property of Food Science Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In China, huajiao, a traditional industrial crop, is categorized as red huajiao (RHJ; Zanthoxylum bungeanum maxim.) and green huajiao (GHJ; Zanthoxylum armatum DC.) based on the peel color. There were significant differences in sensory and biological activities between RHJ and GHJ in practical application. However, there is no sufficient and comprehensive metabolome-based explanation for these differences so far. The gas chromatography-mass spectrometry (GC-MS), ultra-performance liquid chromatography-linear trap quadrupole-orbitrap mass spectrometry (UPLC-LTQ-Orbitrap-MS/MS), and high-performance liquid chromatography-photodiode array detection (HPLC-DAD) were employed in this study to analyze the differences in fatty acids (FAs), volatile components (VCs) and non-volatile components (non-VCs) between 6 RHJ and 9 GHJ. The findings demonstrated that 12 FAs, 68 VCs, and 101 non-VCs were detected in huajiao, of which 5 FAs, 28 VCs, and 46 non-VCs were identified as differential metabolites (DMs) between RHJ and GHJ. And the DMs were enriched in multiple metabolic pathways by KEGG analysis. Moreover, kaempferol, kaempferide, berberrubine, scoulerine, saponaretin, naringenin, and 3-P-coumaroylquinic acid were identified as key bioactive DMs based on the Traditional Chinese Medicine Systems Pharmacology (TCMSP) database and analysis platform. In this study, the possible reasons for the differences in sensory and biological activities between RHJ and GHJ were comprehensively revealed at the metabolic level using non-targeted and targeted metabolomics, and the results provide a better theoretical understanding of the different application of them. [Display omitted] • Analysis of variation in metabolites between red and green huajiao. • 12 fatty acids, 68 volatile and 101 non-volatile components were detected. • 79 metabolites were screened as differential metabolites based on PLA-DA. • KEGG and pharmacological platform analyses were performed on differential metabolites. [ABSTRACT FROM AUTHOR]

[Display omitted] • The aroma of A. tsao-ko honey (ATH) was characterized as mildly flowery and fruity. • ATH's marker was chemically identified as isorhamnetin 3-O-neohesperidoside. • The content of the marker ranged from 3.62 to 9.38 mg/kg by UHPLC-MS/MS. The precious medicinal plant, Amomum tsao-ko Crevost et Lemarié, is the nectariferous plant from which the rare Amomum tsao-ko Crevost et Lemarié honey (ATH) is produced. Presently, chemical markers for authentication of this honey are not available due to the lack of data on its chemical composition. Here, we analyzed the volatile components and their odor activity values (OAVs), which revealed that the unique aroma was mildly flowery and fruity, accompanied by subtle sweet and fresh undertones. Since non-volatile chemicals are more reliable markers for routine authentication, we used a metabolomic approach combined with NMR-based identification to find and confirm a suitable compound to unambiguously distinguish ATH from other honeys. Isorhamnetin 3-O-neohesperidoside ranged from 3.62 to 9.38 mg/kg in ATH and was absent in the other tested honeys. In sum, the study uncovered unique chemical characteristics of ATH that will be helpful to control its quality. [ABSTRACT FROM AUTHOR]

In recent years, the antibacterial and anti-inflammatory effects of the Labiatae plants have been widely recognized, and have been used in clinical practice, and their anti-tumor effects are also very significant, and receiving more and more attention. At present, malignant tumors are still the first killer threatening human health. Because of the long-term use of chemical anti-tumor drugs with certain drug resistance and obvious side effects, finding high-efficiency anti-tumor active ingredients from natural plants and Chinese herbal medicines has become a hot spot in the field of pharmacy. Literature survey indicates that the active ingredients in Labiatae plants have anti-tumor effects. Therefore, this paper summarized and discussed the anti-tumor types, mechanisms and active components of the Labiatae plants, so as to provide a basis and reference for the development of new anti-tumor drugs or preparations. [ABSTRACT FROM AUTHOR]

Cereal vinegar is a type of traditional Chinese vinegar, the most famous of which include Zhenjiang aromatic, Shanxi aged, Sichuan bran, and Zhejiang rose vinegar. Sichuan Sun vinegar is a bran vinegar with a unique flavour. At present, few studies have been conducted on its flavour substances. This study aimed to identify the characteristic components of Sichuan Sun vinegar. The volatile and non-volatile components of corresponding vinegars were investigated using liquid chromatography-mass spectrometry (LC-MS/MS) and gas chromatography-mass spectrometry (GC-MS), and the metabolites of vinegars were analysed using multivariate statistical analysis methods. In total, 89 and 488 types of volatile and non-volatile components were revealed, respectively. Multivariate data analysis showed that there were 8 volatile and 18 non-volatile characteristic substances in Taiyuanjing Sun vinegar and 6 volatile and 8 non-volatile characteristic substances in Sipo Sun vinegar. 2-Methyl-5-isopropylpyrazine, Pro-Glu, and D-mannitol have been identified as characteristic substances of Sichuan Sun vinegar. Concurrently, various physiologically active substances in vinegars were identified. The results of the study provide information for the purification and strengthening of beneficial substances in vinegar. • Sun vinegar is a traditional vinegar in China. • 2-Methyl-5-isopropylpyrazine, Pro-Glu and D-mannitol are characteristic substances of Sichuan sun vinegar. • Several bioactive substances were found in traditional Chinese cereal vinegar. [ABSTRACT FROM AUTHOR]

Radio frequency (RF) is an efficient uniformity heating method that can be used for pasteurization. Information on how RF heating influences the physicochemical properties of agricultural product is limited. In this study, the effect of RF heating treatment combined with hot-air (HA) drying (50 °C, 55 °C and 60 °C) on the physicochemical properties of Sichuan pepper was assessed. Sichuan pepper was subjected to RF treatment combined with HA drying, and the performance was compared with HA drying alone (50 °C, 55 °C and 60 °C) in terms of drying kinetics, volatile components, non-volatile components (OH-α-sanshool, polyphenols and flavonoids) and antioxidant activity (ABTS and ferric reducing antioxidant power). RF heating had no negative effects on OH-α-sanshool for the 50 RF-HA group but it could significantly reduce the loss of polyphenols (12.27% at 55 °C, RF-HA group) and flavonoids (15.08% at 60 °C, RF-HA group). Compared with fresh Sichuan pepper, the 50 RF-HA group retained a similar aroma profile. RF heating treatment followed by HA drying is a prospective technique for obtaining high-quality dried Sichuan pepper. • Radio frequency (RF) treatment did not change the drying kinetics or shorten total drying time. • The levels of d -limonene and linalool were not affected by RF treatment. • The OH-α-sanshool content reduced due to disruption of oil droplets and drying temperature. • RF treatment reduced the loss of polyphenols content and flavonoids content in the hot-air drying process. [ABSTRACT FROM AUTHOR]

Withering process is one of the most crucial steps in Keemun black tea (KBT) manufacturing, which is the foundation of quality formation. This study investigated the effects of conventional static withering and innovative dynamic withering on the volatile and nonvolatile compounds of KBT. Overall, 79 volatile compounds were identified in five tea samples (FL: fresh leaf for control; SW7h, SW15h: leaves of static withering 7 h and 15 h; and DW7h, DW15h: leaves of dynamic withering 7 h and 15 h) by using HS-SPME/GC-MS. Orthogonal projections to latent structures discriminant analysis (OPLS-DA) were used to classify samples, and 36 key markers in volatile compounds were selected. Quantitative descriptive analysis (QDA) of KBT aroma showed that in dynamic withering, dense, floral and fruity aroma were significantly improved. The 14 odor-active compounds were speculated as the cause of QDA differences in aroma between dynamic and static withering. Meanwhile, theaflavins were generated and accumulated earlier in dynamic withering. Notably, the contents of aspartic acid, serine, glycine, arginine, cysteine, methionine, lysine, isoleucine, and leucine significantly increased after dynamic withering. Our study provides a comparative investigation metabolite of dynamic and static withering processes, offering innovative dynamic withering methods to improve the quality of KBT. • A novel dynamic withering process of Keemun black tea is firstly investigated. • The changes of metabolite content in different withering processes were compared. • Fourteen key markers as odor-active compounds (OAV>1) were identified. • Dynamic withering improved the floral and fruity aroma of Keemun black tea. • Amino acids and theaflavins significantly increased after dynamic withering. [ABSTRACT FROM AUTHOR]