Caffeine in Your Drink: Natural or Synthetic?
ABSTRACT Owing to possible adulteration and health concerns, it is important to discriminate between natural and synthetic food ingredients. A new method for compound-specific isotope analysis (CSIA) by coupling high-temperature reversed-phase liquid chromatography to isotope ratio mass spectrometry (HT-RPLC/IRMS) was developed for discrimination of natural and synthetic caffeine contained in all types of drinks. The analytical parameters such as stationary phase, column inner diameter, and column temperature were optimized for the separation of caffeine directly from drinks (without extraction). On the basis of the carbon isotope analysis of 42 natural caffeine samples including coffee beans, tea leaves, guaraná powder, and maté leaves, and 20 synthetic caffeine samples from different sources by high-temperature reversed-phase liquid chromatography coupled to isotope ratio mass spectrometry, it is concluded that there are two distinguishable groups of caffeine δ(13)C-values: one between -25 and -32‰ for natural caffeine, and the other between -33 and -38‰ for synthetic caffeine. Isotope analysis by HT-RPLC/IRMS has been applied to identify the caffeine source in 38 drinks. Four mislabeled products were detected due to added but nonlabeled synthetic caffeine with δ(13)C-values lower than -33‰. This work is the first application of HT-RPLC/IRMS to real-world food samples, which showed several advantages: simple sample preparation (only dilution), high throughput, long-term column stability, and high precision of δ(13)C-value. Thus, HT-RPLC/IRMS can be a very promising tool in stable isotope analysis of nonvolatile compounds.
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ABSTRACT: In the past few years, the number of studies regarding the application of ionic liquids (ILs) as alternative solvents to extract value-added compounds from biomass has been growing. Based on an extended compilation and analysis of the data hitherto reported, the main objective of this review is to provide an overview on the use of ILs and their mixtures with molecular solvents for the extraction of value-added compounds present in natural sources. The ILs (or IL solutions) investigated as solvents for the extraction of natural compounds, such as alkaloids, flavonoids, terpenoids, lipids, among others, are outlined. The extraction techniques employed, namely solid–liquid extraction, and microwave-assisted and ultrasound-assisted extractions, are emphasized and discussed in terms of extraction yields and purification factors. Furthermore, the evaluation of the IL chemical structure and the optimization of the process conditions (IL concentration, temperature, biomass–solvent ratio, etc.) are critically addressed. Major conclusions on the role of the ILs towards the extraction mechanisms and improved extraction yields are additionally provided. The isolation and recovery procedures of the value-added compounds are ascertained as well as some scattered strategies already reported for the IL solvent recovery and reusability. Finally, a critical analysis on the economic impact versus the extraction performance of IL-based methodologies was also carried out and is here presented and discussed.Green Chemistry 08/2014; 46(5). DOI:10.1039/C4GC00236A · 6.85 Impact Factor
Article: Emerging evidence for tea benefits[Show abstract] [Hide abstract]
ABSTRACT: Tea is the most commonly consumed beverage in the world, after water. Associations between regular tea drinking and a reduced risk of coronary heart disease are well established. The mechanism may relate to bioactive compounds found in tea, which exert anti‐arteriosclerotic, anti‐oxidative and anti‐inflammatory effects. However, evidence for other diverse health benefits is emerging. The aim of this review was to evaluate research on three new areas of interest in relation to tea drinking: (1) weight management (and glycaemic control); (2) oral health; and (3) gut health. Databases were searched for meta‐analytical, human intervention and epidemiological studies published between 1990 and 2013. For weight management, modest, positive effects were found for green tea when ingested by overweight/obese adults, possibly related to thermogenic effects. Epidemiological studies indicate that tea drinking in general may protect against tooth loss, certain oral/digestive cancers and Helicobacter pylori infection, although the studies were few in number with differing methodologies. A growing body of mechanistic studies suggests that tea has anti‐cariogenic, anti‐adhesive, anti‐bacterial and possible pre‐biotic effects – all with the potential to impact positively on the pathogenesis of chronic diseases. Clearly, larger trials are needed to confirm these effects in humans and establish optimal intakes. In the meantime, tea drinking appears to be a simple and beneficial way to support health.09/2013; 38(3). DOI:10.1111/nbu.12040
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ABSTRACT: The popularity of coffee as a beverage has its origin in the stimulant effect of caffeine. However, a market for decaffeinated (decaf) coffee developed when a variety of health problems appeared to be related with caffeine consumption. The caffeine obtained from the decaffeination is mainly used by pharmaceutical, cola-type soft drinks and cosmetic industries and although decaf coffee amounts to about 10% of the global coffee market, the need for caffeine by these industries is much bigger than is produced. With the increasing consumer appeal for natural products, which is related to a healthier life style, natural caffeine is missing in the market and is being replaced by the synthetic molecule, as has been shown by modern detection techniques. Here, I briefly discuss that while much attention has been paid on decaf coffee, perhaps natural caffeine has become more important and the by-product may now be decaf coffee.07/2012; 1(1). DOI:10.1002/fes3.4