Tea is the most popular daily drink consumed globally, with a high concentration of caffeine and polyphenols. In this study, the effects of ultrasonic-assisted extraction and quantification of caffeine and polyphenols from green tea were investigated and optimized using 2 -full factorial design and high-performance thin-layer chromatography. Three parameters were optimized to maximize the concentration of caffeine and polyphenols extracted using ultrasound: crude drug-to-solvent ratio (1:10-1:5), temperature (20-40°C), and ultrasonication time (10-30 min). The optimal conditions achieved from the model for tea extraction were as follows: crude drug-to-solvent ratio, 0.199 g/ml; temperature, 39.9°C; and time, 29.9 min; the extractive value was found to be 16.8%. Images from scanning electron microscopy showed that the matrix underwent a physical alteration and cell wall disintegration, which intensified and accelerated the extraction. This process might be simplified using sonication, which results in a higher extractive yield and a significant concentration of caffeine and polyphenols than the traditional approach, with a smaller quantity of solvent and faster analytical times. The result of high-performance thin-layer chromatography analysis proves a significant positive correlation between extractive value and caffeine and polyphenol concentrations.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1002/bmc.5698 | DOI Listing |
Foods
December 2024
College of Horticulture, South China Agricultural University, Guangzhou 510642, China.
Different origins and qualities can lead to differences in the taste and aroma of tea; however, the impacts of origin and quality on the taste and aroma characteristics of Wuyi rock tea and Huizhou rock tea have rarely been studied. In this study, high-performance liquid chromatography (HPLC), gas chromatography-mass spectrometry (GC-MS), and sensory evaluation methods were used to compare the quality components of Wuyi rock tea and Huizhou rock tea. The sensory evaluation showed that they each have their own characteristics, but the overall acceptability of Wuyi rock tea is ahead of Huizhou rock tea ( < 0.
View Article and Find Full Text PDFInt J Biol Macromol
January 2025
State Key Laboratory of Tea Plant Biology and Utilization, Joint Research Center for Food Nutrition and Health of IHM and Anhui Provincial Key Laboratory of Food Safety Monitoring and Quality Control, Anhui Agricultural University, Hefei 230036, PR China; College of Food and Nutrition, Anhui Agricultural University, Hefei 230036, PR China. Electronic address:
To mitigate the risk associated with water-soluble fluoride in tea and to have less influence on the contents of tea infusion, a highly selective lanthanum modified silk fibroin (SF) and polyvinyl alcohol (PVA) composite film (SF/PVA-La) was prepared to remove fluoride from brick tea infusion. Notably, SF/PVA-La could remove about 48 % of the fluoride from in brick tea infusion within 30 min. Importantly, the reduction in total tea polyphenols in brick tea did not exceed 10 %, and the reduction in caffeine was only 0.
View Article and Find Full Text PDFSci Rep
January 2025
Faculty of Chemistry, Department of Analytical Chemistry, Gdańsk University of Technology, Gabriela Narutowicza 11/12 Str., 80-233, Gdańsk, Poland.
The main aim of this work was to study the chemical composition of eighteen ground coffees from different countries and continents with regard to the content of hazardous substances as radioactive elements (K, Ra, Ra, U, U and Cs), metals, including heavy metals, aluminum and some microelements (V, Cr, Mn, Fe, Co, Ni, Cu, Zn) as well as substances that have a positive effect on human health and well-being (polyphenols, proteins, fats and caffeine). The tests were carried out before and after the brewing process using the following techniques: gamma and beta spectrometry, a microwave-induced plasma optical emission spectrometer (MIP-OES), gravimetric method, UV-Vis spectrophotometry as well as thin-layer chromatography. The leaching percentage of certain elements/compounds in coffee infusions was also measured.
View Article and Find Full Text PDFFront Hum Neurosci
December 2024
Mood and Performance Group, Department of Brain Health, Nestlé Research, Nestlé Institute of Health Sciences, Lausanne, Switzerland.
The brain's response to cognitive demands hinges on sufficient blood flow, with changes in brain hemodynamics serving as a reflection of this process. Certain bioactive compounds found in our diet, such as caffeine, polyphenols, and nitrate, can acutely impact brain hemodynamics through diverse neural, vasoactive, and metabolic mechanisms. Functional Near-Infrared Spectroscopy (fNIRS) offers a non-invasive and real-time method to investigate these effects.
View Article and Find Full Text PDFNutrients
November 2024
College of Food and Bioengineering, Zhengzhou University of Light Industry, Zhengzhou 450001, China.
Alzheimer's disease (AD) is a complex multifactorial neurodegenerative disease. With the escalating aging of the global population, the societal burden of this disease is increasing. Although drugs are available for the treatment of AD, their efficacy is limited and there remains no effective cure.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!