Studies on Umami Taste of Tea

Umami is one of the five basic tastes and an important taste attribute of green tea.Amino acids are major components contributing to umami taste and the top three amino acids in tea are theanine,glutarnic acid and aspartic acid.Trace of umami taste components adenosine monophosphate （AMP） and guanosine monophosphate （GMP） were detected in tea.Levels of umami taste components varied with tea cultivar,environmental conditions,fertilizer and processing method.The taste threshold of amino acids differentiated greatly and its DOT （dose over threshold） is an important indicator evaluating its contribution to umami taste.     

Effect of Different Drying Methods on the Volatile Compounds Jinmudan Oolong Tea

Jinmudan,a new tea variety from Fujian Province has an excellent quality with a unique aroma like magnolia frogrance.To monitor the changes in the tea volatile compounds during the Jinmudan Oolong tea manufacturing （drying） process,the volatiles of tea samples were extracted and analyzed.Characteristic volatile compounds in Jinmudan Oolong tea were nerolidol,α-famesene,linolenic acid,palmitic acid,indole,phenylacetaldehyde,cisjasmone,β-phenylethanol,etc.The content of nerolidol was the highest in four tested samples.The composition of the volatile compounds in microwave drying sample was simple,but its concentration was high,in which the main volatile compounds were alcohols and esters.The processing with combination of traditional drying craft and modem aroma-improvement technique could obviously improve the tea aroma,especially in level of epoxy linalool and jasmine lactone.     

Study on the Retention Rate of Green Tea Catechins Components and Tea Polyphenol by Different Processing Technology

The aim of this research was to explore the effect of fixation,rolling,and drying processing technology on the retention rate of green tea catechins components and tea polyphenol.Different fixation processes （rotary drum-firing,microwave,steam-blasting）,rolling process （weight of rolling,gently press rolling and traditional rolling）,drying process （stove drying,roasting dehydration,baked fried drying） were adopted.The effect of different tea processing technology on the retention rate of catechins component and tea polyphenol was analyzed.It showed that the microwave fixation process,gently press rolling process,baked fried dry process were beneficial to keep high levels of EGCG,C,EGC,EC,ECG.     

Volatile Flavor Components and the Body Weights of Rats in the Green Tea Added Miner Ingredients

In order to change for the good flavor in green tea of middle or low grade,roast naked barley （miner ingredient） was added to it.To make tea having functional property,mixed roast naked barley-green tea with one medicinal herb （MH,miner ingredient）.This study was performed to investigate the effect of drinking extracts of naked barley-MH-green tea （A group） and adlay-Angelica gigas Nakai-green tea （B group） on the body weights of rats,and volatile flavor components of best effective extract on weight reduction.Forty-eight male Sprague-Dawley rats divided into six groups were fed five different green tea extracts for 8 weeks.The result obtained in the experiment indicated that the change of body weights of rats was affected by A group,B group and others.A group showed highest reduction rate of body weights （36.40％）.Reduction rate of body weights on the B group （10.10％） was much lower than A group （36.40％）.Aroma compounds were extracted by the SDE method.The concentrated aroma extracts were analyzed and identified by GC and GC-MS.The main aroma components of the green tea blended with naked barley and MH were 12 pyrazines having roasty note,methyl butanals having sweet note,hexanal having briskness greenish note,and nerolidol and3-ionone having floral note.     

Effects of Brewing Conditions on Quality of Pu＇erh Tea Infusion

To brew tea correctly is very important to absorb the tea nutrition for people.The dynamic changes of the main compositions in brewing Pu＇erh tea processing with different conditions were studied.Three different temperatures and eight times were designed to study the effects on the tea infusion quality.The index t0.5 min （50％ concentration of compounds in tea infusion） was used to evaluate the extract speed of compound in this experiment.The results showed that caffeine solubility speed at 80℃ was the highest to compare with tea polyphenols,amino acid,caffeine,soluble sugar,theaflavins and theabrownine,t0.5min of caffeine was 4.8 min,amino acid 10.3min was the second,the third one was tea polyphenols,soluble sugar was the lowest.We also found in different infusion temperature the t0.5min of compounds was distinguishing.With increasing the temperature all t0.5min of six compounds were shorter.However,the change regulations of t0.5min for all compounds in 90℃ and 100℃ were similar to in 80℃.Total quality score （TQS） were applied to evaluate the quality of tea infusion.The results found the TQS score of infusion was higher with the temperature rising,and the temperature to brew best quality infusion was 100℃ for 4-5min.According to the multiple regression analysis between sensory assessments and chemical components of Pu＇erh tea we suggested the TQS was mainly affected by theaflavins,amino acid,soluble sugar and theabrowine four factors in 100℃.     

Functional Components of Tea （Camellia Sinensis） Germplasms Collected in Korea

This study was carried out to obtain useful information and to search quality related components for breeding of tea by analysis of Korean local tea leaves at Sulloc-Cha R＆D center in Jeju Island,Korea.It was also conducted to measure the major agronomic characteristics of 300 local germplasms.These results allowed us to select some superior lines as genetic resources for green-tea breeding and research genotypes.     

Effect of Drinking Green Tea on Mental State of Humans

Tea is one of the most widely consumed beverages in the world,among which green tea is most common in China and Korea.Green tea constituents possess a great value to human health wherein lots of clinical studies and investigations were conducted by researchers and experts.However,there are still increasing demands and interest on the health properties of green tea,especially its effects on mental state of human brains.Based on the collated clinical studies,green tea was used to improve mental alertness and thinking.Thus,higher consumption of green tea was associated with a lower prevalence of cognitive impairment.This review summarizes the effects of drinking green tea on the mental state of human brains.Green tea contains a unique set of L-theanine and epigallocatechin gallate （EGCG） that possess biological activities in antioxidant,anti-memory loss,and antiproliferative assays potentially relevant to the prevention and treatment of various forms of brain damage.Theanine in green tea may play a role in reducing stress.The use of highly innovative method of reading and mental behavior of the human brain＇s response with the intake of green tea thru neuroimaging was also covered in this review.     

Advances in Preparation of Theanine

Theanine is an important component affecting tea quality and it has many health benefits for human being.Chemical synthesis of theanine had high productivity,but its application needed efficient raceme resolution technique.Although only L-theanine will be synthesized through exogenous/endogenous enzymes or microbe fermentation,low yield is the main shortage of this technique.Extraction of theanine from tea leaves is a conventional and efficient preparation technique,and highly purified theanine can be achieved when extraction and separation procedures are suitable.     

The Beauty of Elegance ‘Pungnyu＇ in the Tea Culture of Korea

‘Tea culture＇ broadly includes ‘providing tea＇,‘ the tea ceremony＇,‘ tea ritual＇,‘ tea artistry＇ and ‘ tea party＇.The concept of ‘Pungnyu＇ in Korea was proposed by Choi Chi-won （857 ～ 894？）,who pointed out that ＂there is a profound truth ‘ Tao＇ in Korea,which was considered to be ‘ Pungnyu＇ or the beauty of elegance.The origin of ‘Pungnyu＇ can be traced back to the history of hermits.‘Pungnyu＇ includes the teachings of Buddhism,Confucianism and Taoism.     

Discussion and Evaluation of How ＂Tea Culture＂ is Defined

The essence of tea culture stems from the meeting of tea＇s inherent morality,its roots in nature,and human cultural activity.Because it is intertwined with traditional philosophy,Chinese tea culture is well-established and flourishing.The definitions and delineations of tea culture are varied,but any definition should reflect tea culture＇s relativity in space and time and human-centered nature,especially the spiritual needs of humans.     

Tea Consumption and Antihypertensive Effects

Tea consumption is a major source of flavanoids for a wide large population.Any physiological effects of tea,like antihypertension,could have a significant impact on population health.The effects of tea on blood pressure are less consistent.Results of population studies and long term controlled studies are consistent with a blood pressure-lowering effect of tea.However,some of the short-term intervention trials,mainly in normotensive individuals,have not demonstrated significant blood pressure reduction with tea.The focus of this review is on the mounting evidence from human studies that tea can lower blood pressure.     

Tea Seed and Its Bioactive Functions

Tea seed is a byproduct in tea production and also a source of nutritional and bioactive compounds.There have been studies showing that extracts of tea seeds offered many physiological functions including anti-inflammatory,anti-oxidant,anti-tumor,anti-obesity,hepatoprotective and gastroprotective effects.The tea seed oil is also an acceptable biodiesel and the saponin-rich tea seed meal can be used as vermicide to expel earthworms from the soil of golf courses and sports fields.The bioactive functions of tea seed extracts and their potential uses in agricultural and industrial sectors were reviewed in the present paper.     

Protective effects of EGCG on Bifenthrin-Induced Oxidative Stress in the Human Embryonic Lung Fibroblast Cell Line HFL-I

Bifenthrin （BF） is an important type I synthetic fluorinated pyrethroid insecticide and acaricide.Previous investigations have indicated that the metabolisms of BF in human cells were through oxidative processes,and cytotoxicity was induced by the oxidative stress.In this study,the protective effects of EGCG,which is a major individual of green tea polyphenols,on the human embryonic lung fibroblast cell line HFL-I exposed to BF were investigated.The results showed that BF could induce oxidative stress leading to cytotoxicity in HFL-I cells.The pretreatment of EGCG at low concentrations significantly recovered the cell viability and morphology,inhibited excess generation of ROS,enhanced antioxidant enzyme activities and avoided loss of mitochondrial membrane potential.The results suggested that EGCG might eliminate the BF-induced damage in HFL-I cells.     

Multiple Seasonal Modifications in Enzymatic Flavour Formation in Tea

Carotenoid cleavage enzymes isolated from Japanese Camellia sinensis leaves （cultivar Yabukita） were used for investigating the structural patterns of carotenoid cleavage enzymes.Fresh tea leaves were used for the isolation of active enzymes and purified to single band stage in SDS PAGE gels after isoelectric focusing.The specific activity of the carotenoid cleavage enzymes was tested and the active fractions selected for further analysis.The sugar content and the amount of phosphate present in the purified enzymes were elucidated by the following methods：Phosphates were detected by phosphatase assays,fluorescence marker kits and ammoniumheptamolybdate complex measurements after incineration of the samples.Sugars were detected in gels using PAS reagent （periodide acid/ Schiff reagent） staining and by GC-MS after hydrolysation of the proteins with trifluoric acid.Phosphorylations as well as glycosylations of the samples could be detected in all cases,thus giving evidence for an increasing phosphorylation level of proteins in Camellia sinensis from spring （1.84 g/mg） to autumn （2.39 g/rg） as well as the presence of at least four different sugars （arabinose,xylose,galactose and ribose）.These secondary modifications of the carotenoid cleavage enzymes and their dependency on the harvesting season may well correspond to the changes on the functional level which were detected between spring （Michaelis Constant （Km） =9.45 mol/1） and autumn （K =17.16 mol/l） harvests.     

Volatile Compounds in Two Camellia chrysantha （Hu） Tuyama Species

In the study,the volatile compounds in two Camellia chrysantha （Hu） Tuyama species were extracted and analysed by simultaneous steam distillation and extraction （SDE） and gas chromatography mass spectrometry （GC-MS）,respectively.The relative contents of the chemical constituents in the volatile components were quantified by peak area normalization and NIST database.A total of 60 volatile components were identified,45 for Camellia nitidissima and 26 for Camellia euphlebia.Aldehydes and acids were the most dominant volatiles in Camellia nitidissima,but for Camellia euphlebia there were hydrocarbons and ketones.Hexanoic acid,4-（2,6,6-trimethyl-1-cyclohexenyl）-3-buten-2-one,cis-2-decenal,4-[2,2,6-trimethyl-7-oxabicyclo [4.1.0] hept-1-yl]-3-buten-2-one,phenylacetaldehyde,eicosane,alpha-ionone,geranylacetone 2,6-di-tert-butyl-4-methylphenol,7,9-di-tert-butyl-1-oxaspiro[4,5] deca-6,9-diene-2,8-dioi and tetradecanal were both in two Camellia chrysantha （Hu）Tuyama species.     

Effect of Chelated Vanadium Spray on Concentration of Vanadium and Organic Compounds in Tea Shoots

The study aimed to develop vanadium tea products and evaluated the potential of chelated vanadium （V） absorption by tea shoots and effect of vanadium accumulation on tea quality during the first crop season.Chelated V application with three times foliar sprays at 5 days intervals starting from 15 days before plucking showed a significant increase in V content of new young shoots,which was much effective at higher concentration.However,one or two times sprays had no increase in V content regardless of spray concentration compared to non-treated.Despite V accumulation in the treated at 3 to 9 times higher that of than the non-treated plants,there were no significant changes in contents of total amino acids,theanine,caffeine,total polyphenols,crude fiber,and cathechins between the treated and the non-treated.     

Analysis of the Volatile Chemicals of Longjing Tea from Different Production Locations Using Electronic Nose

Electronic nose has been applied in analysis of food products by monitoring their flavours.But it gives an overall response to a mixture of volatile components.In this work,multianalysis and chemometrics technique were employed to analyse the E-nose and GC-MS data of Longjing tea produced in different locations in Zhejiang province,China.A good discrimination of Longjing tea samples was obtained by E-nose according to the producing area,and a total of 38 compounds were commonly identified from the GC-MS data.Each individual volatile component was related to E-nose response using PLSR and the significance of each component was evaluated by the coefficient R2.Results indicated that isoamyl isovalerate,cis-3-hexenyl hexanoate,cadinene,phenylethylalcohol and linalool played an important role in response on E-nose sensors.It was possible to give a complementary information concerning the individual chemicals interacts with the sensors of E-nose instead of the total volatile components.     

Effects of Soil Characters on the Tea Quality in the Tea Region of Qin-Ba Mountain,Hubei Province,PR China

Based on the analysis of physical and chemical properties of soil,nutrient elements and biochemical compositions of tea leaves,the relationship between soil characters and tea quality was studied.The results showed that soil total phosphorus,potassium,available potassium,copper and zinc were the main factors which affected and limited the content of nutrient elements of tea leaves.Furthermore,soil pH,organic matter,total nitrogen,potassium,exchangeable calcium,magnesium,available copper and zinc were the main factors affecting and limiting the content of biochemical compositions in tea leaves.Tea quality could be improved by controlling these soil factors.     

A Study on Thought of Tea of Hanjae Yi-mok＇s Da-bu

The Da-bu of Hanjae Lee mok （1471-1498） is known as an original masterpiece,which is predominantly documented in Korean tea books.He had always spared no effort to put Confucianists＇ theories and thoughts into practice during his 28-year career.Da-bu tea magnificently reflected his concepts of Confucianism in conjunction with tea-drinking activities.The main contents of Da-bu have included written authors,tea species and production,landscape of tea cultivation,tea plants and leaves,ways of tea-drinking and three-grade tea,tea song of seven cups,5 merits and 6 moralities of tea,benefits of tea-drinking,tea comprehension,etc.According to the views of contents,tea of Hanjae Leemok is the only partner with which we can share life and it can also be beneficial to healthy diets.Not only does it have become part of our daily life,but also be a medicine for our physical and mental disease.He composed the tea song of seven cups,which sufficiently expressed a real practice of the pursued ideal state of Confucianism and Taoism.He also promoted a drinking tea for health enrichment of Confucianists.According to the analytical results of Da-bu,Hanjae＇s tea has recognizably become the personally real practice of Confucianism and state.He had reached the enlightenment for the state of birth and death.After consuming tea,his body and mind immediately changed to the state of joys and wonderland,and also he illustrated that this feeling is not a one-off state,it always comes out whenever drinking.Therefore,based on Hanjae Lee mok,tea drinking is not only the regiment for healthy benefits,but also it is a training method,＂ Dado in My Heart＂,for individuals to train their mind,body,and morality.