Bioaccumulation of heavy metals in tea marketed in Nigeria was investigated. Four major and most consumed brand of tea were selected for the present study. Both aqueous and dry methods were used. Total contents of met...Bioaccumulation of heavy metals in tea marketed in Nigeria was investigated. Four major and most consumed brand of tea were selected for the present study. Both aqueous and dry methods were used. Total contents of metal were determined by digesting 1g of each brand using a mixture (3:1) concentrated nitric acid (NNO3) and hypochlorous acid (HCLO4). The second method involved hot water extract of tea samples. After boiling and filtration, the residue was evaporated to near dryness and digested with concentrated HNO3 and HCLO4 as described above. Results indicate that Zn, Cd, Cu, and Pb were present in lowest concentrations in ascending order for which there were two significant differences between the four sources of samples. The general characteristics of heavy metal concentrations in aqueous extract showed high level of Fe and Mg in a descending order. Going by the correlation study of our result indicates that there is no significant relationship between the two elements of Fe and Mg, though, the numerical values of the two elements varied widely among the samples. These differences may have major impact on human health. However, the beneficial effects of tea are in a fairly narrow concentration range between the essential and the toxic level. In conclusion, the variations in heavy metals content of tea brands may be due to geographical, seasonal changes and the chemical characteristics of the growing regions.展开更多
Superfine green tea powder is a new kind of tea product that can be eaten directly.It provided most of the benefits of whole green tea leaves,with all of the bioactive ingredients.This paper highlighted the characteri...Superfine green tea powder is a new kind of tea product that can be eaten directly.It provided most of the benefits of whole green tea leaves,with all of the bioactive ingredients.This paper highlighted the characteristics and health benefits of superfine green tea powder,and its applications in food industry.展开更多
Tea polyphenols and catechins have gained prominence in determination of tea quality. Tea leaves contain large amounts of catechins and their derivatives and these have shown positive effects on human health. An exper...Tea polyphenols and catechins have gained prominence in determination of tea quality. Tea leaves contain large amounts of catechins and their derivatives and these have shown positive effects on human health. An experiment was carried out to determine the level of catechins and polyphenols in 20 new clones found in two distinct tea growing areas. The trial comprising twenty clones was established in two distinct sites in Kenya using randomized complete block design with three replicates and consisted of 10 popular cultivars widely cultivated in the Lake Victoria Basin and additional 10 newly improved clones. Tea leaf samples were collected across two seasons;dry and wet seasons. Tea quality parameters entailing catechins, caffeine and total polyphenols was generated for the 20 clones across the two seasons and sites. The ISO 14502-1 and ISO 14502-1:2005 procedures were used for polyphenol and catechin analyses, respectively. The ANOVA results generated indicated that the level of catechins and polyphenols in tea were significantly different (p 0.05) and varietal dependent. Generally, the assam varieties had higher levels of catechins and polyphenols than the chinary and cambod varieties, indicating why they are popularly cultivated in the East African region and whose tea quality is highly regarded. Furthermore, the results from principle component analysis (PCA) grouped the clones into three major clusters with one comprising of high quality assam varieties, a mixture of moderate quality assam, cambod and chinary varieties and low catechin content assam anthocyanin-rich variety. It is concluded that the level of catechins in tea plants are varietal dependent, although environmental stress has effects on the synthesis of flavanoids. The results demonstrated that the differences in the accumulation of catechins among the tea clones could be important for the discrimination of clonal diversity.展开更多
Theanine is a non-protein amino acid representing as much as 50% of the total amino acids in black tea and 1% - 2% of dry weight in green tea. It has been shown to be able to reduce high blood pressure, promote relaxa...Theanine is a non-protein amino acid representing as much as 50% of the total amino acids in black tea and 1% - 2% of dry weight in green tea. It has been shown to be able to reduce high blood pressure, promote relaxation, and inhibit caffeine’s side effects among others. This current study explored the effects of sunlight and withering durations on theanine levels in tea shoots. Theanine content from three leaves and a bud, two leaves and a bud and internodes were detected and quantified by using High Performance Liquid chromatography (HPLC). Sunlight exposure experiment was started at dawn (0600 HRS, GMT + 3.00) when the light intensity was low and tea was collected at three-hour interval throughout the day to (1800 Hrs, GMT + 3.00) when the light intensity had dropped. At the start of the experiment, the theanine levels were significantly high but as the intensity of sunlight increased during the day there was a significant drop in theanine levels, and as the sun set the theanine levels increased significantly again in all samples. The results also showed that theanine levels were significantly increased after 15 hours of withering. Three leaves and a bud withered for 3 hours had mean theanine levels of 1.41% and those withered for 15 hours had mean theanine levels of 3.11%. Internodes exhibited higher mean theanine levels than those of leaves. In the light of these results, it’s evident that withering for a longer period of time and harvesting of tea when the light intensity is low ensure high amount of theanine in tea.展开更多
Background: Irritable bowel syndrome (IBS) is a common disorder impairing patient’s quality of life. Currently, there is no effective treatment for this syndrome. Coltect is a dietary supplement containing curcumin, ...Background: Irritable bowel syndrome (IBS) is a common disorder impairing patient’s quality of life. Currently, there is no effective treatment for this syndrome. Coltect is a dietary supplement containing curcumin, green tea and selenomethionine. Aim: To investigate the effects of Coltect on IBS symptoms. Methods: A randomized, prospective, placebo-controlled, double blinded, crossover study. The study population included patients diagnosed with IBS by Rome criteria. Subjects were randomized to receive either Coltect or placebo for 4 weeks, and then received the opposite treatment for 4 weeks following a washout period of 2 weeks. The placebo was a pill, identical in color and size to the Coltect pill, with no active ingredients. Patients completed IBS health-related quality of life, severity score and IBS symptom questionnaires before and after each treatment period. Results: The study included 22 patients, ages 22 – 77 years. Coltect had a positive effect on patients’ satisfaction with their bowel habits (as measured on a scale from 0—Very satisfied to 100—Very unsatisfied). Average score was 70.4 ± 33.1 before and 61.8 ± 29.3 after Coltect treatment (p = 0.037). Other parameters, including abdominal pain, bloating, and effects of IBS on daily activity, symptoms, IBS-related quality of life and general health quality of life were unchanged. Conclusion: Coltect seems to have a positive effect on satisfaction with bowel habits.展开更多
The current work imitates the trivial method which intricates the abstraction along with classification of caffeine accessible in variability of decoction shrubberies which are expended in two different states of Indi...The current work imitates the trivial method which intricates the abstraction along with classification of caffeine accessible in variability of decoction shrubberies which are expended in two different states of India (Telengana & Uttar Pradesh). As per observation individuals of both the states are identical tender of consumption of tea. Abstraction progression tangled variability of stages which are discoursed in the work. In addition, the outcome of drinking of caffeine or the permitted ingestion of caffeine over tea has also been conferred through the work and linked the data with the literature data. In this study, we used a UV-visible spectrophotometer as well as liquid-liquid extraction method to determine the caffeine content in various tea samples. The significance of this study lies in the fact that accurate determination of caffeine content is essential for quality control and labeling of tea products. The UV-visible spectrophotometer method was found to be simple, reliable, and sensitive for the detection of caffeine in tea samples.展开更多
文摘Bioaccumulation of heavy metals in tea marketed in Nigeria was investigated. Four major and most consumed brand of tea were selected for the present study. Both aqueous and dry methods were used. Total contents of metal were determined by digesting 1g of each brand using a mixture (3:1) concentrated nitric acid (NNO3) and hypochlorous acid (HCLO4). The second method involved hot water extract of tea samples. After boiling and filtration, the residue was evaporated to near dryness and digested with concentrated HNO3 and HCLO4 as described above. Results indicate that Zn, Cd, Cu, and Pb were present in lowest concentrations in ascending order for which there were two significant differences between the four sources of samples. The general characteristics of heavy metal concentrations in aqueous extract showed high level of Fe and Mg in a descending order. Going by the correlation study of our result indicates that there is no significant relationship between the two elements of Fe and Mg, though, the numerical values of the two elements varied widely among the samples. These differences may have major impact on human health. However, the beneficial effects of tea are in a fairly narrow concentration range between the essential and the toxic level. In conclusion, the variations in heavy metals content of tea brands may be due to geographical, seasonal changes and the chemical characteristics of the growing regions.
基金supported by Zhejiang Provincial Natural Science Foundation of China (LQ12C20007)Scientific Research Fund of Zhejiang Provincial Education department (Y201226032)Zhejiang Provincial key program for Tea Innovation and Technology group (No.2011R50024)
文摘Superfine green tea powder is a new kind of tea product that can be eaten directly.It provided most of the benefits of whole green tea leaves,with all of the bioactive ingredients.This paper highlighted the characteristics and health benefits of superfine green tea powder,and its applications in food industry.
文摘Tea polyphenols and catechins have gained prominence in determination of tea quality. Tea leaves contain large amounts of catechins and their derivatives and these have shown positive effects on human health. An experiment was carried out to determine the level of catechins and polyphenols in 20 new clones found in two distinct tea growing areas. The trial comprising twenty clones was established in two distinct sites in Kenya using randomized complete block design with three replicates and consisted of 10 popular cultivars widely cultivated in the Lake Victoria Basin and additional 10 newly improved clones. Tea leaf samples were collected across two seasons;dry and wet seasons. Tea quality parameters entailing catechins, caffeine and total polyphenols was generated for the 20 clones across the two seasons and sites. The ISO 14502-1 and ISO 14502-1:2005 procedures were used for polyphenol and catechin analyses, respectively. The ANOVA results generated indicated that the level of catechins and polyphenols in tea were significantly different (p 0.05) and varietal dependent. Generally, the assam varieties had higher levels of catechins and polyphenols than the chinary and cambod varieties, indicating why they are popularly cultivated in the East African region and whose tea quality is highly regarded. Furthermore, the results from principle component analysis (PCA) grouped the clones into three major clusters with one comprising of high quality assam varieties, a mixture of moderate quality assam, cambod and chinary varieties and low catechin content assam anthocyanin-rich variety. It is concluded that the level of catechins in tea plants are varietal dependent, although environmental stress has effects on the synthesis of flavanoids. The results demonstrated that the differences in the accumulation of catechins among the tea clones could be important for the discrimination of clonal diversity.
文摘Theanine is a non-protein amino acid representing as much as 50% of the total amino acids in black tea and 1% - 2% of dry weight in green tea. It has been shown to be able to reduce high blood pressure, promote relaxation, and inhibit caffeine’s side effects among others. This current study explored the effects of sunlight and withering durations on theanine levels in tea shoots. Theanine content from three leaves and a bud, two leaves and a bud and internodes were detected and quantified by using High Performance Liquid chromatography (HPLC). Sunlight exposure experiment was started at dawn (0600 HRS, GMT + 3.00) when the light intensity was low and tea was collected at three-hour interval throughout the day to (1800 Hrs, GMT + 3.00) when the light intensity had dropped. At the start of the experiment, the theanine levels were significantly high but as the intensity of sunlight increased during the day there was a significant drop in theanine levels, and as the sun set the theanine levels increased significantly again in all samples. The results also showed that theanine levels were significantly increased after 15 hours of withering. Three leaves and a bud withered for 3 hours had mean theanine levels of 1.41% and those withered for 15 hours had mean theanine levels of 3.11%. Internodes exhibited higher mean theanine levels than those of leaves. In the light of these results, it’s evident that withering for a longer period of time and harvesting of tea when the light intensity is low ensure high amount of theanine in tea.
文摘Background: Irritable bowel syndrome (IBS) is a common disorder impairing patient’s quality of life. Currently, there is no effective treatment for this syndrome. Coltect is a dietary supplement containing curcumin, green tea and selenomethionine. Aim: To investigate the effects of Coltect on IBS symptoms. Methods: A randomized, prospective, placebo-controlled, double blinded, crossover study. The study population included patients diagnosed with IBS by Rome criteria. Subjects were randomized to receive either Coltect or placebo for 4 weeks, and then received the opposite treatment for 4 weeks following a washout period of 2 weeks. The placebo was a pill, identical in color and size to the Coltect pill, with no active ingredients. Patients completed IBS health-related quality of life, severity score and IBS symptom questionnaires before and after each treatment period. Results: The study included 22 patients, ages 22 – 77 years. Coltect had a positive effect on patients’ satisfaction with their bowel habits (as measured on a scale from 0—Very satisfied to 100—Very unsatisfied). Average score was 70.4 ± 33.1 before and 61.8 ± 29.3 after Coltect treatment (p = 0.037). Other parameters, including abdominal pain, bloating, and effects of IBS on daily activity, symptoms, IBS-related quality of life and general health quality of life were unchanged. Conclusion: Coltect seems to have a positive effect on satisfaction with bowel habits.
文摘The current work imitates the trivial method which intricates the abstraction along with classification of caffeine accessible in variability of decoction shrubberies which are expended in two different states of India (Telengana & Uttar Pradesh). As per observation individuals of both the states are identical tender of consumption of tea. Abstraction progression tangled variability of stages which are discoursed in the work. In addition, the outcome of drinking of caffeine or the permitted ingestion of caffeine over tea has also been conferred through the work and linked the data with the literature data. In this study, we used a UV-visible spectrophotometer as well as liquid-liquid extraction method to determine the caffeine content in various tea samples. The significance of this study lies in the fact that accurate determination of caffeine content is essential for quality control and labeling of tea products. The UV-visible spectrophotometer method was found to be simple, reliable, and sensitive for the detection of caffeine in tea samples.
