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Caffeine : chemistry, analysis, function and effects / [Edited by] Victor R Preedy, Royal Society of Chemistry (Great Britain),
Cambridge, U.K. : Royal Society of Chemistry, 2012
442 p. : illustrations
Ký hiệu phân loại (DDC): 615.785
Caffeine is known to stimulate the central nervous system but what other functions does it have? This book covers the latest scientific knowledge in a uniquely structured format and is specifically designed to link chemistry with health and nutrition to provide a broad, appealing book. Coverage begins with caffeine in relation to nutrition focussing on beverages, then concentrates on chemistry, crystal structures of complexes in caffeine and biochemistry. In the analysis chapters, assays are conducted by LC-MS, capillary electrophoresis, automated flow methods and immunoassay methods. The effects of caffeine on the brain, cognitive performance, sleep, oxidative damage, exercise and pulmonary function are all considered in the closing section of the book. Delivering high quality information, this book will be of benefit to anyone researching this area of health and nutritional science. It will bridge scientific disciplines so that the information is more meaningful and applicable to health in general. Part of a series of books, it is specifically designed for chemists, analytical scientists, forensic scientists, food scientists, dieticians and health care workers, nutritionists, toxicologists and research academics. Due to its interdisciplinary nature it could also be suitable for lecturers and teachers in food and nutritional sciences and as a college or university library reference guide
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Geographic origin classification and simultaneous determination of methylxanthines in vietnamese tea using chemometrics based on the near infrared reflectance spectroscopy / Tran Thi Hue, Bui Duc Tho, Nguyen Van Ri, Ta Thi Thao // Journal of Science and Technology - NTTU. - 2019. - p. 33-40. - ISSN: 2615-9015
Ho Chi Minh city : Nguyen Tat Thanh University, 2019
8 p.
Ký hiệu phân loại (DDC): 615.3
This paper reported the results of classification of geographic origin and simultaneous analysis of three methylxanthines (caffeine, theobromine, theophylline) in Vietnamese tea samples by the infrared reflectance spectrophotometry coupled with chemometrics. The spectral range was 10,000-4,000cm-1 and each spectrum was measured at 2 cm-1 intervals. For the purpose of geographic origin classification, this study used FT-NIR spectroscopy combined with Partial Least Squares Discriminant Analysis (PLS-DA), and Principal Component Analysis-Discriminant Analysis (PCA-DA). The ability to determine the origin of tea samples in the prediction set of PLS-DA model is 100%. Using the same IR spectral database combined with the partial least squares (PLS), three methylxanthines in tea samples are also quickly quantified. The PLS model based on the spectra of 24 tea samples in which the contents of 3 analytes were determined by high performance liquid chromatography- HPLC) were applied for simultaneous determination of caffeine, theobromine and theophylline in samples. The determination of methylxanthines in 7 tea samples in test set gave the good accuracy of the PLS model. The correlation coefficients (R2) in the prediction set were of 0.9582, 0.8894 and 0.9303 for theobromine, theophylline, and caffeine, respectively. This work demonstrated that infrared reflectance spectrophotometry combined with chemometrics could be applied to rapidly classify the geographic origin and simultaneous determination of main contents in green tea.
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