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Volatile compounds and non-phenolic metabolites (amino acids, organic acids, and sugars) of aqueous green tea extracts obtained by ultrasonic extraction (UE), agitation extraction (AE), hot water extraction (HWE), and conventional...
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Volatile compounds and non-phenolic metabolites (amino acids, organic acids, and sugars) of aqueous green tea extracts obtained by ultrasonic extraction (UE), agitation extraction (AE), hot water extraction (HWE), and conventional extraction (CE) were determined using SPME-GC-MS and HPLC, respectively. Significantly higher (P < 0.05) yields of volatiles and non-phenolic metabolites were obtained via UE and AE than via HWE and CE. UE, AE, HWE, and CE released 212, 201, 103, and 65 volatiles, respectively. Sum total of amino acid and organic acid in extracts was 54.57, 54.35, 27.11, and 12.67 (mg/100 g), and 5.96, 6.19, 3.81, and 1.68 (mg/100 g) for UE, AE, HWE, and CE, respectively. Volatiles except nitrogen-containing compounds had higher positive correlations with L-theanine, sucrose, malic acid, and catechins yields. Findings of the current study suggest that an efficient extraction technique may significantly increase volatile and non-phenolic metabolite yields in aqueous green tea extract.
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Routine consumption of green tea may help promote healthy teeth and gingivae, researchers report in the March issue of Journal of Periodontology.Investigators from Kyushu University, Fukuoka, Japan, analyzed the periodontal health...
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Routine consumption of green tea may help promote healthy teeth and gingivae, researchers report in the March issue of Journal of Periodontology.Investigators from Kyushu University, Fukuoka, Japan, analyzed the periodontal health of 940 men and found that those who drank green tea regularly had periodontal health superior to that of subjects who consumed less green tea.
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Routine consumption of green tea may help promote healthy teeth and gingivae, researchers report in the March issue of Journal of Periodontology.Investigators from Kyushu University, Fukuoka, Japan, analyzed the periodontal health...
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Routine consumption of green tea may help promote healthy teeth and gingivae, researchers report in the March issue of Journal of Periodontology.Investigators from Kyushu University, Fukuoka, Japan, analyzed the periodontal health of 940 men and found that those who drank green tea regularly had periodontal health superior to that of subjects who consumed less green tea.
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PURPOSE OF REVIEW: To summarize current knowledge of the protective effects of green tea and green tea constituents, particularly catechins, on the cardiovascular system. RECENT FINDINGS: Consumption of green tea has been inversel...
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PURPOSE OF REVIEW: To summarize current knowledge of the protective effects of green tea and green tea constituents, particularly catechins, on the cardiovascular system. RECENT FINDINGS: Consumption of green tea has been inversely associated with the development and progression of cardiovascular diseases and cardiovascular risk factors. Mechanisms that have been suggested as being involved in the antiatherosclerotic effects of green tea consumption primarily entail antioxidative, antiinflammatory, antiproliferative, and antithrombotic properties, as well as beneficial effects on endothelial function. Moreover, evidence exists for myocardial effects of tea constituents, including positive inotropic and antihypertrophic effects, and beneficial impact in myocardial ischaemia-reperfusion injury. SUMMARY: Green tea represents a promising tool for the prevention of cardiovascular disorders.
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BACKGROUND: The objective of this study was to evaluate whether addition of milk to green, black and decaffeinated black teas alters their antimutagenic activity. MATERIALS AND METHODS: Two model mutagens were used, the direct-act...
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BACKGROUND: The objective of this study was to evaluate whether addition of milk to green, black and decaffeinated black teas alters their antimutagenic activity. MATERIALS AND METHODS: Two model mutagens were used, the direct-acting N'-methyl-N'-nitro-nitrosoguanidine (MNNG) and the indirect-acting 2-amino-3-methylimidazo-[4,5-flquinoline (IQ), and their mutagenic activity was determined in the Ames test, in the presence of tea and milk/tea mixtures. Solids from the milk/tea mixtures were removed by centrifugation and the supernatant analysed by HPLC for individual catechins and gallic acid in green tea, and thearubigins, theaflavins and flavonol glycosides in black teas. RESULTS: Addition of skimmed milk to all the teas failed to influence their antimutagenic activity towards the two mutagens. Addition of milk to green tea resulted primarily in loss of (-)-epigallocatechin gallate whereas in the black teas it primarily reduced theaflavins levels. CONCLUSION: The antimutagenic activity of green and black teas is not modulated by the presence of skimmed milk, even at high concentrations.
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This study was conducted in order to compare the nutrient and chemical contents of two Korean teas: traditional Chungtaejeon tea (CTJ) with that of green tea (GT). Main bioactive compounds and the antioxidant activities using four...
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This study was conducted in order to compare the nutrient and chemical contents of two Korean teas: traditional Chungtaejeon tea (CTJ) with that of green tea (GT). Main bioactive compounds and the antioxidant activities using four radical scavenging assays (ABTS, CUPRAC, FRAP and DPPH) in methanol and acetone extracts of both teas were determined. It was found that the contents of vitamin C, amino acids and total nitrogen in CTJ were lower than that of GT (p < 0.05). Caffeine, reducing sugar and chlorophyll contents in CTJ were similar to GT. Catechin (C), epicatechin (EC), and epigallocatechin (EGC) contents were lower in CTJ than in green tea (p < 0.05), but gallocatechin (GC), epicatechin gallate (ECG), epigallocatechin gallate (EGCG) and catechin gallate (CG) showed no significant differences between CTJ and GT (p a parts per thousand yenaEuro parts per thousand 0.05). The contents of polyphenols, flavonoids, flavanols and tannins in CTJ methanol were 229.30 +/- 11.3 mg GAE/g dry weight (DW), 15.24 +/- 0.8 mg CE/g DW, 109.10 +/- 5.1 mg CE/g DW and 25.68 +/- 1.2 mg CE/g DW, respectively, and significantly higher than in acetone extracts (p < 0.05). Flavonoids (quercetin and kaempferol) were higher in GT than in CTJ and myricetin was higher in CTJ (p < 0.05). Threonine and aspartic acid was lower, and glutamic acid was higher in CTJ compared with GT (p < 0.05). Free amino acid content in CTJ and GT showed no significant difference. Potassium and magnesium in CTJ were lower compared to GT, but no significant difference was found for iron, manganese and calcium. Also, the level of the antioxidant activity by all four used assays was significantly higher in CTJ and in methanol was higher than in acetone extracts (p < 0.05). In conclusion, traditional fermented Korean tea Chungtaejeon contains high quantities of bioactive compounds and possesses high antioxidant activity. The contents of the bioactive compounds and the levels of antioxidant activities are significantly higher in methanol than in acetone extracts. 3-D fluorescence and FTIR- spectroscopy showed slight differences between the two investigated tea samples and can be used as additional tools for identification of polyphenols. Both studied teas can be recommended as a source of bioactive compounds.
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The purpose of this study is to identify Japanese's green tea consumption preferences among young people in Taiwan between the age of 18-30 and assess the possible tea market opportunities for Japanese's green tea in Taiwan, among...
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The purpose of this study is to identify Japanese's green tea consumption preferences among young people in Taiwan between the age of 18-30 and assess the possible tea market opportunities for Japanese's green tea in Taiwan, among young people.?? Questionnaire was used to collect data which were spread to 200 university students, aged between 18-30 years. Firstly, the tea product tasting survey provided four kinds of Japanese green tea. Next, the questionnaire was divided into four parts. Findings of this study show Taiwanese young people prefer taste attribute as the main factor to selecting their tea preference, to others who choose Minamisayaka mostly as their tea preference, with Benifuuki in second place. This study also aggregates the evaluation of Japanese green tea after tea tasting.Keywords: Green tea, Taiwanese, Japanese, preference.
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Aroma concentrates were prepared from four kinds of. green tea (roten, roten-kuki, kabuse, and ooishita), their roasted teas (light-roasted and medium-roasted), and two kinds of pan-fired tea (roten and kabuse), using a brewed ext...
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Aroma concentrates were prepared from four kinds of. green tea (roten, roten-kuki, kabuse, and ooishita), their roasted teas (light-roasted and medium-roasted), and two kinds of pan-fired tea (roten and kabuse), using a brewed extraction method. Following GC/MS analysis, the aroma patterns of each tea infusion were determined. Eighty-six compounds and forty-four compounds were newly identified in roasted and pan-fired tea, respectively. All green tea samples analyzed contained high amounts of indole pyridine, linalool, geraniol, benzyl alcohol, 2-phenylethanol, 2-ethylhexanoic acid, and maltol. Sulfinylbismethane and sulfonylbismethane seem to be the important compounds contributing to the characteristic green tea aroma. The roasted teas contained high amounts of pyrazines, pyrroles, furans, and pyrans, which are formed via the Maillard reaction. Together with 1-ethyl-3,4-dehydropyrrolidone, the aroma component that was present in highest concentrations in both roasted and pan-fired teas, these compounds contribute to the roasted and pan fired aroma. Kabuse pan-fired tea contained higher amounts of nitrogen heating products such as pyrazines and pyrroles than roten.
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Man has always been surrounded by countless microorganisms. The disease producing orgnisms are always trying to develop resistance to the various antimicrobial agents used for their control. Therefore, the chemotherapy of infectio...
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Man has always been surrounded by countless microorganisms. The disease producing orgnisms are always trying to develop resistance to the various antimicrobial agents used for their control. Therefore, the chemotherapy of infectious diseases has proved to be a continuous struggle. Scientists are always in search of new antimicrobial agents to cope up with the problem. Plants are potential source of pesticides, microbicides and pharmaceutical drugs. Tea (Camellia sinensis) is one such plant having many medicinal values and it has been in use for treatment of common cold, fever and headache. Tea has antimicrobial activity against various bacteria, viruses and fungi. Tea inhibits the growth of influenza virus, vaccinia virus herpex simplex virus, rota virus and polio virus. Tea leaves have been reported to have bactericidal activity against Streptococcus mutatis, Vibrio cholera, Helicobacter pylori, Clostridium botulinum, Staphylococcus aureus, Salmonella typhimurium. S. typhi etc. Phytopathogenic bacteria such as, Erwinia, Pseudomonas, Clavibacter, Xanthomonas, Agrobacterium, etc. which infect commonly cultivated vegetables are inhibited by tea. Thus tea can be used as safe potential agricultural chemical against various phytopathogenic bacteria.
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