Maillard reaction inducing amino acids degradation can adjust the flavour characteristic of black tea.

Drying is the step that is to be used to adjust and control the formation of flavour and quality in black tea processing. In the present work, the comprehensive two-dimensional gas chromatography with mass spectrometry (GC × GC-MS) and gas chromatography olfactometry with mass (GC-O-MS) were used to determine the dynamic change of the volatile compounds in black tea during drying at 90, 120, 150 °C for 1 h. Results showed that the ratio of esters and aldehydes largely declined when temperature was elevated from 90 °C to 150 °C, while the ratio of heterocycles was increased to 22.

Evaluation of key taste components in Huangjin green tea based on electronic tongue technology.

A random forest algorithm combined with correlation analysis, was employed to identify key taste compounds in Huangjin green tea by using an electronic tongue. A total of 45 commercial Huangjin green teas were analysed for their amino acids, catechins, gallic acid, and caffeine using an amino acid analyser and HPLC. In this study, taste compounds of 30 were quantified, and 16 of these compounds exhibited taste activity values greater than 1 in the tea samples, including 6 amino acids, 8 catechins, as well as gallic acid and caffeine.

Lipidomic profiles of shaking-withering black tea and their metabolic conversion during tea processing.

Shaking-withering is a new technique in black tea manufacturing, which enables promoting aroma quality. Lipids are important tea aroma precursors. However, the lipids metabolism and its contribution to aroma formation of shaking-withering black tea (SBT) remain unknown.

Exploration of the effects of geographical regions on the volatile and non-volatile metabolites of black tea utilizing multiple intelligent sensory technologies and untargeted metabolomics analysis.

Geographical regions profoundly influence the flavor characteristics of Congou black tea (CBT). In this study, 35 CBT samples from 7 geographical regions were comprehensively characterized by integrated multiple intelligent sensory technologies and untargeted metabolomics analysis. A satisfactory discrimination was achieved through the fusion of multiple intelligent sensory technologies (RY = 0.

Research on Rapid Detection Methods of Tea Pigments Content During Rolling of Black Tea Based on Machine Vision Technology.

As a crucial stage in the processing of black tea, rolling plays a significant role in both the color transformation and the quality development of the tea. In this process, the production of theaflavins, thearubigins, and theabrownins is a primary factor contributing to the alteration in color of rolled leaves. Herein, tea pigments are selected as the key quality indicators during rolling of black tea, aiming to establish rapid detection methods for them.

New insights into the role of lipids in aroma formation during black tea processing revealed by integrated lipidomics and volatolomics.

Lipids are important tea aroma precursors. Due to the complexity of black tea processing involving both enzymatic and thermal reactions, the role of lipids in black tea aroma formation remained unclear. Herein, the dynamic changes of lipids and volatiles during black tea processing were simultaneously analyzed by lipidomics and volatolomics using ultra-high-performance liquid chromatography coupled to Q-Exactive Orbitrap mass spectrometry (UHPLC-Q-Exactive) and gas chromatography-tandem mass spectrometry (GC-MS/MS).

Uncovering the effects of spreading under different light irradiation on the volatile and non-volatile metabolites of green tea by intelligent sensory technologies integrated with targeted and non-targeted metabolomics analyses.

Spreading serves as a pivotal process in the flavor development of green tea. In this study, the effects of spreading under five light irradiation on the volatile and non-volatile metabolites of green tea were comprehensively investigated using intelligent sensory technologies integrated with targeted and non-targeted metabolomics analyses. The incorporation of yellow light irradiation into spreading process significantly improved the overall quality of green tea.

Non-target and target quantitative metabolomics with quantitative aroma evaluation reveal the influence mechanism of withering light quality on tea aroma and volatile metabolites evolution.

Withering is the first and key process that influences tea quality, with light quality being a key regulatory factor. However, effects of withering light quality (WLQ) on transformation and formation pathways of tea aroma and volatile metabolites (VMs) remain unclear. In the present study, four WLQs were set up to investigate their effects on tea aroma and VMs.

miR-135b-5p promotes gastric carcinogenesis by targeting CLIP4-mediated JAK2/STAT3 signal pathway.

Background: Gastric cancer (GC) is a common cancer worldwide; however, its molecular and pathogenic mechanisms remain unclear. MicroRNAs (miRNAs), which target key genes in GC, are associated with tumor promotion or suppression. Therefore, identifying new miRNA mechanisms could improve the novel diagnostic and therapeutic strategies for patients with GC.

Targeted quantitative metabolomic and flavor objective quantification technique reveal the impact mechanism of shaking on black tea quality and non-volatile metabolites.

Shaking constitutes a pivotal technique for enhancing black tea quality; nevertheless, its impact on the transformation mechanism of non-volatile metabolites (NVMs) in black tea remains obscure. The present study aimed to investigate the impact of shaking-withering methods (SWM) and traditional-withering methods (TWM) on black tea quality and NVMs conversion. A total of 57 NVMs and 14 objective quantitative indicators were obtained.

Antiurolithiatic effect of triptonide in ethylene glycol-induced urolithiasis in rats.

Urolithiasis is one of the most prevalent benign urological disorders globally with a high incidence rate. Male Sprague-Dawley rats were chemically induced to have urolithiasis and treated with triptonide and the standard antiurolithic drug cystone. Kidney weight was measured to detect calculi formation, and urinary parameters such as pH, 24-h urine volume, and protein content were measured to analyze the urolithiasis induction in rats.

Volatolomics-assisted characterization of the key odorants in green off-flavor black tea and their dynamic changes during processing.

Aroma plays a pivotal role in the quality of black tea. However, the acceptability of black tea is greatly limited by the green off-flavor (GOF) resulting from the inappropriate processing control. In this study, the key odorants causing GOF were investigated by volatolomics, and their dynamic changes and formation pathways were in-depth understood.

Comprehensive investigation on the dynamic changes of volatile metabolites in fresh scent green tea during processing by GC-E-Nose, GC-MS, and GC × GC-TOFMS.

Processing technology plays a crucial role in the formation of tea aroma. The dynamic variations in volatile metabolites across different processing stages of fresh scent green tea (FSGT) were meticulously tracked utilizing advanced analytical techniques such as GC-E-Nose, GC-MS, and GC × GC-TOFMS. A total of 244 volatile metabolites were identified by GC-MS and GC × GC-TOFMS, among which 37 volatile compounds were concurrently detected by both methods.

Key umami taste contributors in Longjing green tea uncovered by integrated means of sensory quantitative descriptive analysis, metabolomics, quantification analysis and taste addition experiments.

Umami taste is a key criteria of green tea quality evaluation. The aim of this study was to comprehensively explore the key umami taste contributors in Longjing tea. The taste and molecular profiles of 36 Longjing green tea infusions were characterized by sensory quantitative descriptive analysis and LC-MS based metabolomics, respectively.

Research progress of multi-enzyme complexes based on the design of scaffold protein.

Multi-enzyme complexes designed based on scaffold proteins are a current topic in molecular enzyme engineering. They have been gradually applied to increase the production of enzyme cascades, thereby achieving effective biosynthetic pathways. This paper reviews the recent progress in the design strategy and application of multi-enzyme complexes.

Uncovering the Dynamic Alterations of Volatile Components in Sweet and Floral Aroma Black Tea during Processing.

Aroma is an indispensable factor that substantially impacts the quality assessment of black tea. This study aims to uncover the dynamic alterations in the sweet and floral aroma black tea (SFABT) throughout various manufacturing stages using a comprehensive analytical approach integrating gas chromatography electronic nose, gas chromatography-ion mobility spectrometry (GC-IMS), and gas chromatography-mass spectrometry (GC-MS). Notable alterations in volatile components were discerned during processing, predominantly during the rolling stage.

Contents of ɑ-dicarbonyl compounds in commercial black tea and affected by the processing.

The species and contents of ɑ-dicarbonyls in commercial black tea were examined, along with the effects of the manufacturing process and drying temperature on the formation of ɑ-dicarbonyls. Ten ɑ-dicarbonyls were quantified in commercial and in-process black tea samples by using UPLC-MS/MS and their derived quinoxalines. The ɑ-dicarbonyls content in commercial black tea decreased significantly (p < 0.

Recent Advances in 2-Keto-l-gulonic Acid Production Using Mixed-Culture Fermentation and Future Prospects.

Vitamin C, also known as ascorbic acid, is an essential vitamin that cannot be synthesized by the human body and must be acquired through our diet. At present, the precursor of vitamin C, 2-keto-l-gulonic acid (2-KGA), is typically produced via a two-step fermentation process utilizing three bacterial strains. The second step of this traditional two-step fermentation method involves mixed-culture fermentation employing 2-KGA-producing bacteria () along with associated bacteria.

Effect of shaking on the improvement of aroma quality and transformation of volatile metabolites in black tea.

Shaking is an innovative technology employed in black tea processing to enhance flavor. However, the effects of shaking on the evolutionary mechanisms of volatile metabolites (VMs) remain unclear. In this study, we compared the effects of a shaking-withering method with those of traditional withering on the flavor and VMs transformation of black tea.

The influence of rolling pressure on the changes in non-volatile compounds and sensory quality of congou black tea: The combination of metabolomics, E-tongue, and chromatic differences analyses.

Rolling represents an essential stage in congou black tea processing. However, the influence of rolling pressure on tea flavor and non-volatile compounds remains unclear. Herein, a combination of untargeted metabolomics, tea pigments quantification, E-tongue, colorimeter and sensory evaluation was used to evaluate the effect of rolling pressure on black tea quality.