The catechins profile and antioxidant activity in different types of green tea bags

Tea and mainly green tea as a rich source of antioxidants has been widely known for some time. The antioxidant capacity of tea including green tea is mainly due to its catechins content. The objective of this study was to determine the relationship between the ORAC value and the catechins content. Regular and decaffeinated commercial green tea bags commonly consumed in the United Kingdom (UK) have been examined using Reversed-Phase High-pressure Liquid Chromatography (RP-HPLC). Teabags were purchased from different local supermarkets in the UK and extracted with natural mineral water at temperature 100°C for 9 minutes at the pre-adjusted pH 4. The level of four catechins (Epi-structured) for the thirteen types of green tea were separated and determined by HPLC analysis, i.e. ()-epigallocatechin (EGC), ()-epicatechin (EC), ()-epigallocatechin-3-gallate (EGCG) and ()-epicatechin gallate (ECG). The standard graphs were validated using certified reference catechins supplied by the Laboratory of the Government Chemist (LGC). The levels of total catechins and oxygen radical absorbance capacity (ORAC) values varied from 34.61to 204.55 mg/g, 830.19- 4197.81 Trolox equivalents/g tea bags for thirteen types of green teas respectively. It was clear from the results of this study that there was a significant linear and positive correlation (r = 0.951, df = 12, p < 0.05) is found to exist between the total catechins contents and ORAC values. It can be concluded that the results of catechins measurements coupled to this; the well-known ORAC assay was successfully modified to measure the antioxidant capacity of the green tea extracts throughout this study. Furthermore, the higher the level of catechins the higher is the antioxidant capacity of the tea. This may stimulus consumers in selecting the type of tea and tea brewing times, exhibiting more health benefits. Nevertheless, the differences between the studied brands are owing to shelf life, production and storage conditions.

Almond or Mahaleb? Orthogonal Allergen Analysis During a Live Incident Investigation by ELISA, Molecular Biology, and Protein Mass Spectrometry

It is now well known that an incident investigated in the United Kingdom in 2015 of cumin alleged to be contaminated with almond, a risk for people with almond allergy, was caused by the Prunus species, Prunus mahaleb. In the United Kingdom, the Government Chemist offers a route of technical appeal from official findings in the food control system. Findings of almond in two official samples, cumin and paprika, which had prompted action to exclude the consignments from the food chain, were so referred. Herein are described the approaches deployed to resolve the analytical issues during the investigation of the incidents. The cross-reactivity of ELISA to Prunus species was confirmed, and although this is useful in screening for the genus, orthogonal techniques are required to identify the species and confirm its presence. Two novel PCR assays were developed: one specific for P. mahaleb and the other a screening method capable of identifying common Prunus DNA. Peptides unique to almond and mahaleb were identified, permitting LC-tandem MS and criteria were developed for peptide identification to forensic standards. This work enables a staged approach to be taken to any future incident thought to involve Prunus species and provides a template for the investigation of similar incidents.

Conclusions: Bringing It All Together

If you have read this book, whether a few pages at a time, by jumping back and forth, or meticulously from beginning to end, the aim of this chapter is to draw together the methods, concepts, and ideas to help you answer the question, how do I make a good analytical measurement? If nothing else, you will have discovered, like the answers to the greater questions of life, that there is not a simple prescription for quality assurance that if followed leads to success. Even knowing if you have the right answer is not always vouchsafed; is customer satisfaction sufficient? Does the continuing solvency of your business say that something must be going well? Does staying within ± 2σ in interlaboratory studies cause you happiness? The best laboratories do all of this and more. At the heart of a good laboratory is an excellent manager who has recruited good staff, set up a culture of quality, and who understands the science and business of chemical analysis and the requirements of his or her clients. I do not believe laboratories can be run by people with only managerial skills; at some point a chemical analyst is going to have to take responsibility for the product. In this reprise of the book’s contents I revisit the six principles of valid analytical measurement (VAM) so cleverly enunciated by the Laboratory of the Government Chemist. But first some words about clients and samples. As has been stressed throughout this book, many problems can be solved by chemical analysis, and the point of chemical analysis is therefore not to do chemistry for its own sake, but to contribute to the solution of those problems. Clients, or customers as now found in ISO/IEC 17025, come in many shapes and sizes, from people who gladly admit no scientific knowledge at all to fellow professionals who can discuss the analysis as equals. The first kind are more difficult to work with than the latter, although colleagues who meddle are never totally welcome. An apparently simple request to analyze something might require extensive negotiation about exactly what is needed.