Authentication and discrimination of green tea samples using UV–vis, FTIR and HPLC techniques coupled with chemometrics analysis

This study aimed to develop a simple method for assessing the quality of green tea samples obtained from the South and the East Asian regions. The UV–vis, FTIR and HPLC data from 38 samples were subjected to multivariate analyses using the unsupervised recognition techniques comprising Hierarchical Cluster Analysis (HCA) and Principal Component Analysis (PCA). The model for their authentication was constructed and validated by applying the supervised recognition techniques as Soft Independent Modeling of Class Analogy (SIMCA) and Partial Least Square Discriminant Analysis (PLS-DA). The percentages of caffeine in the identified samples were determined using a validated HPLC assay in addition to in vitro determination of their antioxidant activity using DPPH radical-scavenging capacity assay. HCA and PCA based on UV data successfully distributed the tested samples into informative clusters. However, that obtained from visible data could only differentiate samples with respect to their powdered condition. On the contrary, PCA from FTIR and HPLC data could hardly discriminate any of the samples. The models constructed using SIMCA and PLS-DA showed a good class separation between the South and the East Asian samples. The percentages of caffeine in the identified samples and the IC50 in DPPH assay are greatly diverse among all the tested samples. Thus, UV spectroscopy and chemometrics have provided a simple and quick tool for the quality control of commercial green tea sample...
Source: Journal of Pharmaceutical and Biomedical Analysis - Category: Drugs & Pharmacology Source Type: research

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ConclusionsTreating physicians should include vascular malformations in differential diagnosis regarding bone tumors. A non-invasive angiographic method could be included in the preoperative work-up.
Source: Interdisciplinary Neurosurgery - Category: Neurosurgery Source Type: research
27 new pubmed citations were retrieved for your search. Click on the search hyperlink below to display the complete search results: Ann Oncol These pubmed results were generated on 2019/11/13PubMed comprises more than millions of citations for biomedical literature from MEDLINE, life science journals, and online books. Citations may include links to full-text content from PubMed Central and publisher web sites.
Source: Ann Oncol - Category: Cancer & Oncology Tags: Report Source Type: research
Publication date: February 2020Source: Journal of Experimental Child Psychology, Volume 190Author(s): Rachel C. Croce, Janet J. BoseovskiAbstractResearch indicates that children often show a positivity bias, or a tendency to favor positive information over negative information, in assessments of informant credibility in social and nonsocial situations. The current study investigated whether young children prioritize positive informant traits (i.e., nice vs. mean informant) as compared with positive speech content (i.e., positive vs. negative evaluation) in conflicting assessments of a work product. A total of 123 4- to 8-y...
Source: Journal of Experimental Child Psychology - Category: Child Development Source Type: research
This study investigates the following question: how does development – specifically socioeconomic and gender equity indicators – affect women’s share of enrollment in specific STEM and STEM-related fields? Merging two sources of national data, we leverage provincial census figures and institutional administrative data to estimate women's enrollment share in STEM as well as in specific fields (i.e., accounting, information technology, and health). Findings show women’s share of STEM and information technology majors is larger outside the capital. Further, socioeconomic development and urbanization in...
Source: International Journal of Educational Development - Category: Child Development Source Type: research
ConclusionsSocial media monitoring has potential for use in identifying individuals at-risk for substance abuse and those who may be perpetuating unhealthy substance use norms.
Source: Journal of Adolescence - Category: Child Development Source Type: research
Publication date: January–February 2020Source: Journal of Applied Developmental Psychology, Volume 66Author(s): Katharine Bailey, Nancie Im-BolterAbstractThe current study investigated contributors to social perspective taking during social problem solving in younger (M = 8.20, n = 111) and older (M = 12.05, n = 112) school-aged children. Results indicated a developmental progression in social perspective taking for different aspects of social problem solving. The findings suggest that social perspective taking is more difficult for some aspects of social problem solving than others. Moreover, syntact...
Source: Journal of Applied Developmental Psychology - Category: Child Development Source Type: research
Publication date: January 2020Source: Trends in Food Science &Technology, Volume 95Author(s): Ali Atamaleki, Mohsen Sadani, Amir Raoofi, Ali Miri, Saeed Gharibian Bajestani, Yadolah Fakhri, Zoha Heidarinejad, Amin Mousavi KhaneghahAbstractBackgroundThere is an increasing trend in the consumption of egg on a worldwide scale, however, it can be a source of potentially toxic elements (PTEs) which could threaten the health of consumers.Scope and approachThe related studies on the concentration of PTEs in eggs by databases including PubMed, Scopus, Web of Science and Embase in a global scale were retrieved and following met...
Source: Trends in Food Science and Technology - Category: Food Science Source Type: research
In conclusion, Germany shows itself to be only moderately prepared to accept cultured meat.
Source: Meat Science - Category: Food Science Source Type: research
The objective of this study was to investigate the levels of bioactive amines in eight fresh edible commercial mushrooms species. An ion-pair HPLC method with post-column derivatization with o-phthalaldehyde and fluorescence detection was fit for the purpose. Seven out of nine amines were present and levels varied among species. Spermidine was ubiquitous to mushrooms, with highest content in Black Shimeji (12.4 mg/100 g). The levels of spermidine in mushrooms classify them as high polyamines sources, which is valued due to its association with growth, health promotion and antioxidant properties. Agmatine was ...
Source: Journal of Food Composition and Analysis - Category: Food Science Source Type: research
Publication date: Available online 12 November 2019Source: Journal of Food Composition and AnalysisAuthor(s): Larissa São Bernardo Carvalho, Caroline Santos da Silva, Joaquim Araújo Nóbrega, Elane Santos Boa Morte, Daniele Cristina Muniz Batista Santos, Maria Graças Andrade KornAbstractThis paper presents the use of microwave induced plasma optical emission spectrometry (MIP OES) for food analysis. A method for determination of Cu, K, Mg, Mn, P, and Zn in instant soups by MIP OES with N2 plasma was developed. Sample preparation procedure consisted of microwave-assisted digestion with dilute nitr...
Source: Journal of Food Composition and Analysis - Category: Food Science Source Type: research
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