scholarly journals Guanine deaminase provides evidence of the increased caffeine content during the piling process of pu'erh tea

RSC Advances ◽  
2019 ◽  
Vol 9 (62) ◽  
pp. 36136-36143 ◽  
Author(s):  
Si-an Pan ◽  
Ying Sun ◽  
Mengmeng Li ◽  
Wei-Wei Deng ◽  
Zheng-Zhu Zhang
Keyword(s):  
Caffeine Content ◽  
Guanine Deaminase

Wet piling is a key process for producing pu'erh tea because various components change under the action of microorganisms.

scholarly journals Influence of Various Factors on Caffeine Content in Coffee Brews

Foods ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1208
Author(s):  
Ewa Olechno ◽  
Anna Puścion-Jakubik ◽  
Małgorzata Elżbieta Zujko ◽  
Katarzyna Socha
Keyword(s):  
Literature Review ◽  
Water Temperature ◽  
Geographical Origin ◽  
Cold Water ◽  
Water Type ◽  
Robusta Coffee ◽  
Caffeine Content ◽  
Type Water ◽  
Brewing Time ◽  
Coffee Brews

Coffee brews are one of the most popular drinks. They are consumed for caffeine and its stimulant properties. The study aimed to summarize data on the influence of various factors on caffeine content in brews prepared with different methods. The study was carried out using a literature review from 2010–2020. PubMed and Google Scholar databases were searched. Data on caffeine content was collected by analyzing the following factors: the influence of species, brewing time, water temperature, pressure, degree of roast, grinding degree, water type, water/coffee ratio as well as other factors (such as geographical origin). To sum up, converting caffeine content to 1 L of the brew, the highest content is that of brews prepared in an espresso machine (portafilter), with the amount of 7.5 g of a coffee blend (95% Robusta + 5% Arabica), and water (the volume of coffee brew was 25 mL) at a temperature of 92 °C and a pressure of 7 bar, but the highest content in one portion was detected in a brew of 50 g of Robusta coffee poured with 500 mL of cold water (25 °C) and boiled.

scholarly journals Crystal Structure of Bacillus subtilis Guanine Deaminase

2004 ◽  
Vol 279 (34) ◽  
pp. 35479-35485 ◽  
Author(s):  
Shwu-Huey Liaw ◽  
Yu-Jui Chang ◽  
Cheng-Tsung Lai ◽  
Hui-Chuan Chang ◽  
Gu-Gang Chang
Keyword(s):  
Crystal Structure ◽  
Bacillus Subtilis ◽  
Guanine Deaminase

Insights into the Dual Shuttle Catalytic Mechanism of Guanine Deaminase

2021 ◽  
Author(s):  
Asmita Sen ◽  
Vandana Gaded ◽  
Prabha Jayapal ◽  
Gopalan Rajaraman ◽  
Ruchi Anand
Keyword(s):  
Catalytic Mechanism ◽  
Guanine Deaminase

scholarly journals Effect of Home Grinding on Properties of Brewed Coffee

2014 ◽  
Vol 4 (1) ◽  
pp. 77
Author(s):  
Christopher Murray ◽  
Thamara Laredo
Keyword(s):  
Particle Size ◽  
Fourier Transform ◽  
Distribution Density ◽  
Particle Surface ◽  
Particle Surface Area ◽  
Present Evidence ◽  
Caffeine Content ◽  
General Recommendation ◽  
Grinding Time ◽  
Ground Coffee

<p>We present measurements of particle size distribution, density, loss of coffee on brewing and caffeine content in brewed coffee (as measured using Fourier Transform Infrared Spectroscopy) as a function of grinding time using a blade-type grinder. In general, there is not a lack of correlation between coffee properties and grinding for grinding times in excess of 42 s, but mass loss on brewing and caffeine content are both increased with grinding times between 0 and 42 s. In addition, we present evidence that this dependence of the composition of brewed coffee on grinding time is a function of increased coffee particle surface area that results from grinding, rather than increased loss of grounds into the brewed beverage or increased percolation time. Finally, we present a general recommendation for determining equivalency between small amounts of finely ground coffee and larger amounts of coarser-ground coffee.</p>

scholarly journals Theanine and Caffeine content of infusions prepared from commercial tea samples

2016 ◽  
Vol 12 (45) ◽  
pp. 75 ◽  
Author(s):  
Dezső Csupor ◽  
Klára Boros ◽  
Nikoletta Jedlinszki
Keyword(s):  
Caffeine Content

scholarly journals Upregulated Guanine Deaminase Is Involved in Hyperpigmentation of Seborrheic Keratosis via Uric Acid Release

2021 ◽  
Vol 22 (22) ◽  
pp. 12501
Author(s):  
Kyung Ah Cheong ◽  
In Sup Kil ◽  
Hyuk Wan Ko ◽  
Ai-Young Lee
Keyword(s):  
Uric Acid ◽  
The Elderly ◽  
Epidermal Keratinocytes ◽  
Seborrheic Keratosis ◽  
Human Epidermal Keratinocytes ◽  
Skin Hyperpigmentation ◽  
Guanine Deaminase ◽  
Acid Release ◽  
Skin Specimen

Seborrheic keratosis, which is a benign tumor composed of epidermal keratinocytes, develops common in the elderly. Uric acid generated by upregulated guanine deaminase (GDA) has been identified to cause UV-induced keratinocyte senescence in seborrheic keratosis. Seborrheic keratosis is also frequently pigmented. Growing evidences indicate that hyperuricemia is a risk factor of acanthosis nigricans, an acquired skin hyperpigmentation. The objective of this study was to investigate role of GDA and its metabolic end product, uric acid, in hyperpigmentation of patients with seborrheic keratosis using their lesional and non-lesional skin specimen sets and cultured primary human epidermal keratinocytes with or without GDA overexpression or uric acid treatment. GDA-overexpressing keratinocytes or their conditioned media containing uric acid increased expression levels of MITF and tyrosinase in melanocytes. Uric acid released from keratinocytes was facilitated by ABCG2 transporter with the help of PDZK1 interaction. Released uric acid was taken by URAT1 transporter in melanocytes, stimulating melanogenesis through p38 MAPK activation. Overall, GDA upregulation in seborrheic keratosis plays a role in melanogenesis via its metabolic end product uric acid, suggesting that seborrheic keratosis as an example of hyperpigmentation associated with photoaging.

scholarly journals Prediction of Caffeine Content in Liberica Coffee Green Bean by NIR Spectroscopy Using Kubelka-Munk Model

2020 ◽  
Vol 7 (3) ◽  
pp. 119
Author(s):  
Ei Mon Kyaw ◽  
I Wayan Budiastra ◽  
Sutrisno Sutrisno ◽  
Samsudin Samsudin ◽  
Dheni Mita Mala
Keyword(s):  
Chemical Analysis ◽  
Nir Spectroscopy ◽  
Consumer Preference ◽  
Data Transformation ◽  
Calibration Method ◽  
Partial Least Square ◽  
Green Bean ◽  
Calibration Model ◽  
Second Derivative ◽  
Caffeine Content

<p>Liberica is one of coffee species that is becoming popular and increasingly in demand in present days due to its unique characteristics. Caffeine is one of the important coffee quality parameter which determines the coffee flavor, consumer preference and market price. Caffeine content is usually analyzed by chemical method which is destructive, time consuming, expensive and involving a lot of procedures. NIR Spectroscopy is one of the non-destructive techniques to overcome these disadvantages. This study was conducted at the Department of Mechanical and Biosystem Engineering, IPB University for NIR measurement and the Center of Agro-based Industry (BBIA), Bogor for chemical analysis from August to November 2019. The study aimed to determine the best calibration model for the prediction of caffeine content in Liberica coffee green bean powder. In this study, FT-NIRS in the wavelength of 1000-2500 nm was used for NIR measurement and HPLC tool was used for chemical analysis. Kubelka-Munk (K/S) and Absorbance (Log 1/R) were used as data transformation, whereas Standard Normal Variance (SNV) and Second derivative of Savitzky-Golay (dg2) as data pretreatment. In addition, Partial Least Square (PLS) and Multiple Linear Regression (MLR) were applied for multivariate calibration method. The best calibration model for the prediction of caffeine content of Liberica coffee green bean powder was obtained by the spectral data pretreated with second derivative of Savitzky-Golay (dg2) and Kubelka-Munk data transformation using PLS calibration method with the results of r = 0.90, RPD = 2.24, CV = 2.01%.</p>

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