Brick Tea Samples Research Articles

Interannual variation and exposure risk assessment of lead in brick tea in Hubei, China

Lead (Pb) exposure may cause severe health outcomes such as decreased fertility, joint pain and neurological disorders. It is important to know the Pb exposure level in tea and the risk assessment for local residents who drink brick tea daily. This study detected sixteen brick tea samples over 26 years and fifteen green tea samples in 2011 in a southeast city of Hubei province. The Pb content in brick tea was found to increase rapidly with the fast development of industrial activities represented by car sales from 1985 to 2011, which was less susceptible to gasoline. The concentrations of Pb in 16 brick tea were in the range of 1.77–17.8 mg/kg with a mean value of 11.1 mg/kg. Their percentiles P50, P90, and P95 were 13.22, 16.95, and 17.21 mg/kg. A regressional model was built, suggesting strong correlation between the Pb content in brick tea and the car sales. The concentrations of Pb in 15 green tea samples were between 0.36–1.30 mg/kg with a mean value of 0.66 mg/kg and the percentiles P50, P90, and P95 were 0.62, 1.05, and 1.23 mg/kg. The MOE values of brick tea and green tea were all greater than 1 just considering tea consumption which displayed low Pb exposure risk. By adding the Pb exposure by food, the MOE values for green tea were still greater than 1 while the MOE values of brick tea were less than 1 suggesting a potential risk of Pb exposure to the people drinking brick tea daily, who should pay more attention.

Prevalence of Brick Tea-Type Fluorosis in the Tibet Autonomous Region.

BackgroundThe prevalence of brick tea-type fluorosis is high in Tibet because of the habit of drinking brick tea in this region. Brick tea-type fluorosis has become an urgent public health problem in China.MethodsA cross-sectional survey was conducted to investigate prevalence of brick tea-type fluorosis in all districts of Tibet using a stratified cluster sampling method. Dental fluorosis in children aged 8–12 years and clinical skeletal fluorosis in adults were diagnosed according to the national criteria. A total of 423 children and 1320 adults participated in the study. Samples of drinking water, brick tea, brick tea infusion (or buttered tea), and urine were collected and measured for fluoride concentrations by the fluoride ion selective electrode method.ResultsThe fluoride level in all but one of the brick tea samples was above the national standard. The average daily fluoride intake from drinking brick tea in all seven districts in Tibet was much higher than the national standard. The prevalence of dental fluorosis was 33.57%, and the prevalence of clinical skeletal fluorosis was 46.06%. The average daily fluoride intake from drinking brick tea (r = 0.292, P < 0.05), urine fluoride concentrations in children (r = 0.134, P < 0.05), urine fluoride concentrations in adults (r = 0.162, P < 0.05), and altitude (r = 0.276, P < 0.05) were positively correlated with the prevalence of brick tea-type fluorosis. Herdsmen had the highest fluoride exposure and the most severe skeletal fluorosis.ConclusionsBrick tea-type fluorosis in Tibet is more serious than in other parts of China. The altitude and occupational factors are important risk factors for brick tea-type fluorosis.

基于DGGE技术的茯砖茶发花过程细菌群分析

Denaturing gradient gel electrophoresis( DGGE) is one of the most important and commonly used techniques in studies of microbial molecular ecology. DGGE has been widely used in the analysis of community structures and biodiversity of bacteria,cyanobacteria,archaea,miniature eukaryotes,eukaryotes,and viruses. This technique can be used for the reliable analysis of multiple samples at the same time. It is suitable for the surveillance of microbial population changes over both space and time,and is used to probe microbial community composition by DNA sequence analysis. This technology can overcome the limitations associated with traditional analysis techniques,such as cultivation,purification,and microscopy.In this research,DGGE spectra analysis was used to examine the microbial diversity during the Fahua-fermentation process of Fuzhuan Brick Tea production. To explore the bacterial community structure during this process,we collected Fuzhuan Brick Tea samples at days 0,2,4,6,8,10,12,and 14 of the Fahua-fermentation process. Total genomic DNA was extracted from each of the samples,and the V3 variable region of the 16S rDNA gene was amplified. The amplified products were separated by DGGE. The separated DGGE bands were extracted and gel-purified then ligated into the pEASY-T vector. Resultant plasmids were transformed into electrocompetent Escherichia coli DH5α cells,and positive clones were identified by blue white screening experiment. Plasmids from the positive clones were then extracted and sequenced,and the resulting sequences were submitted to the GenBank database. Using the BLASTN tool to carry out homology comparisons,we identified sequences in the database that were most similar to the 16S rDNA sequences amplified from theFahua-fermentation community samples. The results showed three distinctive kinds of bacterial community structure,correlating to fermentation times of 0—4 days,6—8 days,and 10—14 days. Alignments of the V3 variable regions of the16S rDNA genes showed that samples contained Brevundimonas aurantiaca, Millisia brevis, Novosphingobium sp,Clostridium ultunense, Pseudomonas veronii, Lactobacillus plantarum, Klebsiella pneumoniae, uncultured Epsilonproteobacteria,uncultured Saprospiraceae bacterium,uncultured Myxococcales bacterium,uncultured Rhizobiales bacterium,and six kinds of unculturable bacteria. This analysis technique provided a detailed spectrum of bacteria at the different time periods during the Fahua-fermentation process,and showed that bacterial species present during this stage of Fuzhuan Brick Tea production are abundant. Amongst the bacterial species,nine strains belonged to the Proteobacteria,three strains were identified as Firmicutes,one strain belonged to the Actinobacteria,and one strain belonged to the phylum Bacteroidetes. We also identified six strains with the greatest similarity to unknown unculturable bacteria,which will require further analysis. This study also identified K. pneumoniae,B. aurantiaca,P. veronii,and a Myxococcales bacterium in the Fahua-fermentation process samples,all of which are generally considered to be conditionally pathogenic bacteria. The roles of these species during the fermentation process remain unknown and will require further investigation. Overall,the results of the current study indicate that DGGE fingerprinting is a useful technique to obtain a comprehensive,detailed bacterial community structure and estimate of diversity variation from samples collected during Fahua-fermentation in the production of Fuzhuan Brick Tea.

Analysis of the major chemical compositions in Fuzhuan brick-tea and its effect on activities of pancreatic enzymes in vitro

Fuzhuan brick-tea, a fungal-fermented tea, is commonly consumed in northwest China; in places such as Sinkiang and Tibet and is thought to be helpful in digestion. To better understand Fuzhuan brick-tea and its function on digestion, the Fuzhuan brick-tea’s chemical compounds were surveyed at pivotal process phases, and its effects on pancreatic enzymes in vitro were studied. Most of the changes in amino acids, proteins, polyphenols, catechins and organic acids were found during fungal fermentation phase. All the infusions of Fuzhuan brick-tea samples had promotional effects on pancreatic amylase and protease and no effect on pancreatic lipase. Correlation analysis and principle component analysis between the main compounds of Fuzhuan brick-tea and the activities of two pancreatic enzymes were performed. The results showed that among ten significantly related compounds, the catechins and organic acids were particularly correlated with these two pancreatic enzymes’ activities. The present work confirmed the importance of microbial fermentation in the compositional changes of Fuzhuan brick-tea and its effects on two pancreatic enzymes in vitro, and suggested the possible application of microbial fermented tea such as Fuzhuan brick-tea in digestive aid. Key words: Fuzhuan brick-tea, chemical composition, pancreatic enzyme, principal component analysis.

Intervened observation of low-fluoride brick-tea on the population in drinking-tea type fluorosis areas in Akesai County of Gansu Province

Objective To evaluate the intervention effects of low-fluoride brick tea in the population, and to provide data for the prevention and control of the brick-tea type fluorosis. Methods Eighty-six Kazakh families with 5-12 years old children were selected and divided into two groups in the severe brick-tea type fluorosis areas of Akesai County of Gansu Province. Forty-six households were intervened by drinking low-fluoride brick tea as intervention group and another 40 households drank general brick tea as control group. The fluoride content in water, tea and urine was monitored and the total daily fluoride intake of adults and children was calculated by the fluoride content of the tea before and during intervention. The baseline prevalence of dental fluorosis was surveyed in all Kazakh school students aged 5 - 12 years before intervention, dental fluorosis prevalence were surveyed in two groups after the intervention. The fluoride content in water, urine,tea, and brick-tea samples was detected by iron electrode method, and dental fluorosis was diagnosed by Dean's method. Results The fluoride content of water were 0.36,0.50 mg/L respectively before and 42 months after intervention. The total daily fluoride intake of adults and children in the intervention group (being 4.39,5.12,5.38,4.49 mg in adults and 1.90,2.33 in children, 2.33, 1.94 mg for four calculations) were lower than those in control group (8.42,9.07,8.35,7.92 and 3.65,3.93, 3.62,3.43 mg). Except the second batch (530.4 mg/kg), the average fluoride content of the other 3 batches of low-fluoride brick tea(239.3,222.88,154.7 mg/kg) was lower than that of 4 batches of market brick tea(366.9,412.2, 286.0,379.6 mg/kg). The fluoride content of low-fluoride brick tea samples was in accordance with the national standard(< 300 mg/kg) in 16 of 21 samples in 4 the batches, and the qualifying rate was 76.19%(16/21). Only 5 of 21 market brick tea samples in 4 batches was qualified, accounting for 23.80%(5/21), both were significantly different(χ2= 11.52, P < 0.01). In 12, 36, 42 months after intervention, urine fluoride content in the intervention group of adult(1.84,1.23,1.77 mg/L) and children(1.55,0.65,1.10 mg/L) was less than that of the control group (adults: 3.37,3.68,3.02 mg/L, children: 2.64,1.64,2.62 mg/L), both being statistically significant (t value were 2.94,2.43,3.91,3.29,2.31,4.42, P < 0.01 or 0.05). The detective rate of dental fluorosis was 69.02%(127/184)at baseline among children. After the intervention, it lowered to [44.83% (13/29) in the intervention group, significantly lower than that in the control group[71.88%(23/32), χ2 = 4.60, P < 0.05]. Conclusion Low-fluoride brick tea can reduce the fluoride intake of the residents who drink brick tea, and alleviate excessive fluoride and the damage of high-fluoride. Key words: Fluoride poisoning; Tea; Intervention studies; Outcome assessment