Green Tea is prepared from the leaves of Camellia sinensis. Catechins of Green tea are well known as natural antioxidants and have effective beneficial on the body. One of the most important processes in the extraction of catechins and producing green tea beverage is brewing process. The object of this study is to investigating the effect of brewing temperatures (60٫70 and 80˚c) and duration (5٫10 and 15 min) also the season effect of plucking on green tea that was produced in the Tea Research foundation of lahijan. results of total phenolic content on brewed green tea, is showed that plucking in summer and spring seasons samples have much total phenolic content are rather than plucking in autumn season samples also percent extraction of brewing green tea at 15 minuets has most highest total phenolic content than other seasons and brewing times. brewing temperature are not significant effected on the total phenolic content.

Black tea, which is obtained from the leaves of small tree Camellia sinensis, is a popular drink that has been consumed for centuries all around the world. In this study, a sample of Iranian black tea was brewed by two methods of microwave and traditional brewing and their extracts were then assessed using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing/antioxidant power (FRAP) assays to determine their phenolic and flavonoid contents as well as heavy metal (HM) (copper, nickel, chromium, cadmium and lead) content. It was observed that there is a direct relationship between the antioxidant activity with their phenolic and flavonoid contents. The highest and lowest antioxidant activities were observed for samples brewed by microwave at 360 W for 2.5 min and 900 W for 7.5 min, respectively. As the brewing power and time increased, the antioxidant activity decreased. Brewing tea by microwave and traditional methods caused a significant reduction in the amount of heavy metals, which was lower than the allowable limit according to the Iranian national standards. These results demonstrate the importance of exposure time and radiation power when tea is prepared by microwave.

The human body gets Fluorine from a variety of sources including food and water. This element is essential in order to prevent tooth decay. However, high concentrations of this element led to a lot of dental fluorosis and skeletal injuries. This study aimed to measure the concentration of fluoride in water and tea consumed in the city of Qom. The present study is cross-sectional analysis water and high consumed tea brand samples in the city of Qom in 2012. Fluoride concentrations in water and tea samples were measured by HACH Model DR-4000 spectrophotometer and Ion selective method respectively. The data were analyzed using software SPSS-17. According to the experimental results, the average concentration of fluoride in the drinking water obtained between 0.07-0.63mg/l. The lowest concentrations were related to domestic water treatment systems.Concentration of fluoride in dry tea bag and granular tea were 138.9 and 153.71 mg/kg respectively. The concentration of this element in the tea bags and granular tea infusion were 1.29 and 1.5 mg/l respectively. Results of this study showed that the amount of fluoride in drinking water reduced by the domestic and industrial water treatment systems greatly. So drinking tea could partially compensate for the lack of fluoride in drinking water.

In this study, the effect of adding green tea extract (10%) on physicochemical, sensory, microbial and viability characteristics of probiotic bacteria in Pinacolada drink based on whey was investigated. The results showed that as a result of adding green tea extract, physicochemical properties such as pH, brix, dry matter and protein content of the drink did not change significantly, but the turbidity of the drink increased compared to the control sample (without green tea). The results of microbial evaluation showed that the sample containing green tea extract was free of microbial contamination compared to the control sample, which indicates the antimicrobial properties of green tea extract. Although CFU / ml 2 mold was observed in the control sample, but this amount is less than the standard and can be consumed. Unlike Bifidobacterium bifidum, the probiotic bacterium Lactobacillus acidophilus did not grow in beverages. Also, the survival of Bifidobacterium bacteria during 28 days of refrigeration and passing through stomach and intestinal conditions had a decreasing trend, which was more in the drink containing green tea extract than the control sample. However, until the 21st day, the viability of microorganisms in beverages containing green tea extract was maintained at the recommended level according to the Iranian National Standard (106 CFU / ml). An appropriate concentration of green tea extract can be used in the production of pinacolada probiotic drink based on whey as a new useful beverage.

Hibiscus Sabdariffa is widely cultivated in tropical areas and its red persistent calyx is the major component possessing a sour taste that is used in beverages and food colorants. As a traditional medicine, it is claimed to be effective against kidney stones and urinary bladder stones, and is also used for its antibacterial, antifungal, hypocholesterolemic, antispasmodic and antihypertensive actions. We conducted this study to evaluate the effects of sour tea on blood sugar, lipids and lipoproteins. This sequential double-blind randomized controlled clinical trial was conducted on 60 diabetic patients in the Yazd Diabetic Research Center. Patients were assigned randomly into two groups, the sour tea (ST) and the ordinary tea (OT) group. Sachets containing one spoonful of sour or ordinary tea were given to the patients, based on random numbers. They were instructed to consume one glass of boiled water, boiled for 20-30 min, 2 times daily between their meals in the morning and afternoon, for 30 days. Fasting blood samples were taken at the beginning and at the end of the study for measuring blood glucose, hemoglobin A1C, total cholesterol, HDL-C, LDL-C, triglycerides, Apo AI, Apo B100 and Lp(a). Data were analyzed using the SPSS statistical package. A total 60 patients were recruited, 53 of whom completed the study (27 in ST and 26 in OT). Except for Lp(a) and Apo AI, means of all lipids and lipoproteins at the beginning, were significantly decreased or increased (HDL-C) compared with the related means at of the end of the study in the sourtea (ST) group however, only the mean for HDL-C was significantly increased (approximately 16.7%) at the end of intervention in in the ordinary tea (OT) group. The mean for fasting blood glucose at the end of study did not differ significantly with the initial mean in both groups. In contrast, the mean of hemoglobin A1C was significantly decreased in the ST group. The results showed that sour tea has significant effects on blood lipid profiles in diabetic patients however, it did not have significant effects on blood glucose or hemoglobin A1C. Drinking sour tea can be recommended for diabetic patients.

Small amount of Fluoride is one of the most well-known factors being useful in controlling decay. Since high consumption of fluoride may cause fluorosis and osteoarthritis. Considering the high consumption of tea in Iran (as a national drink) and high degree content of fluoride in Iranian commonly-used teas, and considering non-awareness on the effect of brewing time on the degree of fluorine freed from tea, the present research aimed to determine the effect of brewing time on the amount of fluorine released from tea in academic year 2007-08 in Chemistry Laboratory of the Faculty of Pharmacology, Tehran University. This survey was done in experimental study. Out of 13 brands of tea in Iranian market two brands named Oghab and Doghazal which, in Iranian market in year 1386 (2007-08), were best seller brands of Iranian and foreign teas respectively were selected and three packs of each brand were purchased from three different places of Tehran City. From each type of the teas six samples were taken and brewed in different periods of time 3, 5, 15, 30, 60, and 120 minutes. In each brewing, one gram dry tea was added to 100 ml of boiling distilled water in a Teflon tea pot. For brewing tea, the tea pots were placed in a incubator at temperature of 80 degrees Celsius. When the pre-determined times passed, 10 ml tea extract was taken from each pot and filtered. Then TISAB II buffer at proportion of 1 to 1 was added to the filtered extract. The concentration of fluoride ion was measured in potentiometer method.The amount of the fluoride of tea for each brewing time and for each tea sample were studied with T-Test statistics in each section and between two teas in following up times through ANOVA Test. The average amount of fluoride in Doghazal tea was 0.77±0.04ppm and in Oghab tea was 2.6±0.11ppm. For all times, this difference was statistically meaningful (p‹0.001). The amount of fluoride freed from both brands (Oghab abd Doghazal) increased meaningfully along with increase in brewing time ((p‹0.001). As the brewing time increases, the amount of fluoride freed from tea increases. The best brewing time for tea is about 5 minutes. Furthermore, comparing Oghab tea with Doghazal tea indicates that fluorine content of Oghab tea is higher than other brand. The brewing time suggested by producing company of Doghazal tea (which has been printed on the packages) is 5 minutes which is suitable time. But the brewing time suggested for Oghab tea is 15 minutes which, as the results of this research indicates, leads to introducing of considerable amount of fluoride in the body and thus it does not seem to be advisable time for brewing tea.

The composition and biological activities of kombucha beverage depends on type of herbal tea, concentration of sucrose and the fermentation time. This study aimed to investigate the effect of different preparation conditions on antibacterial activity of heated kombucha beverages by Response Surface Methodology (RSM). Four types of herbal teas, including black tea, green tea, lemon verbena and peppermint were prepared with three concentrations of sucrose (2, 5 and 8%) and inoculated with active kombucha culture. After 7, 14 and 21 days, beverages were heated by autoclaving and their antibacterial activity against four bacteria including Escherichia coli, Shigella dysenteriae, Staphylococcus aureus and Bacillus cereus was evaluated by well method. The RSM was used to investigate the effect of sucrose concentration, fermentation time and type of herbal tea on antibacterial activity of heated beverages. Increasing sucrose concentration had significant effect (P<0.0001) on antibacterial activity of heated beverages against all tested bacteria. Increasing of fermentation time had significant effect (P< 0.0001) on antibacterial activity of heated beverages against E. coli and S. dysenteriae. Type of herbal tea had significant effect on antibacterial activity against S. aureus and S. dysenteriae. The highest antibacterial activity against E. coli and S. dysenteriae was observed in beverages prepared with lemon verbena. Beverages prepared with green tea showed highest antibacterial activity against S. aureus. The highest antibacterial activity against B. cereus was observed in heated beverages prepared with black tea and peppermint. In general, the results showed significant antibacterial activity of heated kombucha beverages against the tested bacteria.

Gilan’s black tea is obtained via the fermentation of the fresh leaves of Camelia sinensis var. assamica. In this study, the effect of tea production process and brewing methods, microwave and conventional methods were studied on their phenolic and flavonoid content and antioxidant activity (DPPH radical scavenging assay, iron atom reducing power). The results showed that due to the fermentation process, the antioxidant properties and phenolic content of tea were changed and also the tea brewing method was effective on these properties and the highest phenolic and flavonoid contents and antioxidant activity were determined in the rolling step on the microwave brewing method. While the lowest phenolic and flavonoid contents were observed in the withering step on microwave brewing method and the lowest antioxidant activity was related to the tea treatment under conventional brewing. Therefore, the microwave method with high extraction capability and reduced the processing time can be an alternative to the conventional methods in the food industry.

Background and The herbal tea is one of the most common hot beverages in the world. Tea poisoning as a result of saprophytic fungus contamination can cause many different diseases among human. This research was aimed at defining saprophytic fungus contamination rate of all kinds of tea which are being consumed in Babol, northern Iran. This research was carried out on 100 samples of tea using descriptive – analytical method. The samples were gathered from different regions of the city including both homes and shops. The properties of tea are registered in a table. To define the level of the contamination, 20 pieces of each tea sample were cultivated in Sabouraud Dextrose Agar (S) fields The grown fungus around tea pieces were recognized by an ordinary laboratory method, during daily observations of plates. The rate of contamination was measured based on the total amount of colony per100 mg of dry tea leaves. (P Value ≤ 0/05). All of the 100 cultivated tea samples were contaminated. The samples were classified into three groups of packed, unpacked and bagged tea, respectively. The maximum contamination rate was seen in bagged group. Statistical differences between groups were significant. (P< 0.001 (The most identified fungus were as follow: Aspergillus Niger, penisillium A. flavus, Mucur spp. Among tea samples which were collected from homes and shops, home samples were more polluted than shop samples, but there was not any significant difference (P=0.33). The unpacked tea samples were less polluted than firm packed tea samples but the difference was not significant (P=0.27). The result of this study indicates that the consuming tea in Babol is highly contaminated by saprophytic fungus which can be a serious threat because of the popularity of tea as a hot beverage. And so an accurate control over all various steps of harvesting, processing and distributing of tea is necessary and recommended.