The black tea could be stored for a long time, and subsequently affects the flavor characteristics. In the present study, the effects of storage years (1, 2, 3, 4, 5, 10, 17 and 20 years) on the chemical profiling and taste quality of keemun black tea (KBT) were compared by metabolomics and quantitative sensory evaluation. The main polyphenols were degraded during the storing, especially 10-year storage, but caffeine and theobromine were stable. The intensity of bitterness, astringency, umami was negatively correlated to storage years, with correlation coefficient at -0.95, -0.91 and -0.83 respectively, whereas sweetness had positive correlation coefficient at 0.74. Quinic acid, galloylated catechins, linolenic acid, linoleic acid, malic acid, palamitic acid, and theaflavin-3́-gallate were marker compounds which were responsible for distinguishing short and long time preserved KBT. The contents of fatty acids were positively correlated to storage time and sweet intensity.
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http://dx.doi.org/10.1016/j.foodchem.2021.129950 | DOI Listing |
Front Plant Sci
December 2024
Tea Research Institute, Guangdong Academy of Agricultural Sciences, Guangdong Provincial Key Laboratory of Tea Plant Resources Innovation and Utilization, Guangzhou, Guangdong, China.
In tea (), anthocyanins are important secondary metabolites that are linked to leaf color. Anthocyanin biosynthesis is a complex biological process, in which multiple genes including structural and regulatory genes are involved. Here, we describe the cloning and characterizing of a new R2R3-MYB transcription factor gene, , isolated from purple tea variety ''.
View Article and Find Full Text PDFClin Chem Lab Med
December 2024
Royal College of Pathologists of Australasia Quality Assurance Program, St Leonards, NSW, Australia.
Objectives: This paper further explores the Sigma Metric (SM) and its application in clinical chemistry. It discusses the SM, assay stability, and control failure relationship.
Content: : SM is not a valid measure of assay stability or the likelihood of failure.
Cancer
December 2024
Division of Public Health, Department of Family & Preventive Medicine, University of Utah School of Medicine, and Huntsman Cancer Institute, Salt Lake City, Utah, USA.
Introduction: The relations between coffee and tea consumption and head and neck cancer (HNC) incidence are unclear. With increasing global HNC burden, this study aims to examine the association between coffee, tea, and HNC.
Methods: A pooled analysis of 9548 HNC cases and 15,783 controls from 14 individual-level case-control studies was conducted from the International Head and Neck Cancer Epidemiology consortium.
Biomater Sci
December 2024
Hunan Provincial Key Laboratory of Micro & Nano Materials Interface Science, College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, China.
Epigallocatechin gallate (EGCG), an important active component extracted from green tea, has attracted much attention due to its multiple biological activities such as antioxidant, antibacterial, anti-inflammatory, and antitumor effects. Meanwhile, metformin (Met), a classic drug for the treatment of type 2 diabetes, exhibits additional benefits such as hypoglycemic, antioxidant, anti-inflammatory, and antitumor effects. However, metformin often causes gastrointestinal reactions when used alone, affecting patients' quality of life.
View Article and Find Full Text PDFJ Sci Food Agric
December 2024
School of Food and Biological Engineering, Jiangsu University, Jiangsu, People's Republic of China.
Background: Accurate tea blending assessment and sample matching are critical in the tea production process. Traditional methods face efficiency and accuracy challenges, which can be addressed by advances in computer vision and deep learning. This study developed an efficient and non-destructive method for fast tea grading classification, blending ratio evaluation, and sample matching.
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