Evaluation of bioactive amine and mineral levels in Turkish coffee

Coffee is one of the most popular drinks across the world and its enormous commercial and social importance is obvious. The levels of nine bioactive amines and five minerals, as well as pH, color, total ash and dry matter characteristics, were determined in different brands of ground and brewed Turkish coffees for the first time. Turkish coffee is a method of preparation, not a kind of coffee. Furthermore, this paper reported the estimated daily mineral intake of five elements. The amines were extracted with trichloroacetic acid (TCA) and quantified by reversed-phase high performance liquid chromatography (HPLC), pre-column derivatization with benzoyl chloride. Of the nine bioactive amines under study putrescine, cadaverine, tyramine and serotonin were detected in all coffee samples. Serotonin was the prevailing bioactive amine in both ground and brewed coffees. The total amine levels in the ground coffee varied from 126.0 mg/kg to 352.2 mg/kg. The total amine levels in the brewed coffee varied from 5.679 mg/L to 48.88 mg/L. The concentrations of five minerals (Mg, Mn, Zn, Na, K) were determined after dry mineralization of both ground and brewed coffee samples. The total mineral contents were analyzed by high-resolution continuum source flame atomic absorption spectrometry (HR-CS-FAAS). Potassium was the prevailing mineral in both ground and brewed coffees. The mean total mineral contents of ground and brewed coffees were 12673.2 mg/kg and 1014.8 mg/L, respectively. Significant differences were obtained between bioactive amines, minerals (except Na), color values (L*, a*, b*), total ash and total dry matter contents of ground and brewed Turkish coffee samples (P < 0.05).     

Aluminium content of beers

 The aluminium (Al) concentration in different brands of beers packaged in Al cans and glass bottles was measured at the end of the shelf-life of the beer, by the Zeeman graphite furnace atomic absorption spectrophotometry (ZGFAAS) method. The results show that in all cases a brand of beer packaged in an Al can has a higher Al content than the same brand bottled in glass. The measurements of the Al concentration in some Al-canned beers throughout 12 months of storage show that a relatively small increase of the Al concentration in beers occurs throughout storage. All these results indicate that some Al is taken up by the beer in Al cans, presumably through the slight and slow dissolution of Al from the can wall, due to some defects in the protective lacquer layer. The evaluated daily intake of Al (0.256 mg) possible through the consumption of beer was practically negligible in relation to both the total daily dietary Al intake and the tolerable daily Al intake. Thus, beers are an insignificant source of dietary Al intake and it appears that the Al intake from beers (due to the low content of Al in beers and its low bioavailability) should not be a cause for concern with regard to Al toxicity for the human body. Received: 22 April 1996     

Aluminium content of beers

 The aluminium (Al) concentration in different brands of beers packaged in Al cans and glass bottles was measured at the end of the shelf-life of the beer, by the Zeeman graphite furnace atomic absorption spectrophotometry (ZGFAAS) method. The results show that in all cases a brand of beer packaged in an Al can has a higher Al content than the same brand bottled in glass. The measurements of the Al concentration in some Al-canned beers throughout 12 months of storage show that a relatively small increase of the Al concentration in beers occurs throughout storage. All these results indicate that some Al is taken up by the beer in Al cans, presumably through the slight and slow dissolution of Al from the can wall, due to some defects in the protective lacquer layer. The evaluated daily intake of Al (0.256 mg) possible through the consumption of beer was practically negligible in relation to both the total daily dietary Al intake and the tolerable daily Al intake. Thus, beers are an insignificant source of dietary Al intake and it appears that the Al intake from beers (due to the low content of Al in beers and its low bioavailability) should not be a cause for concern with regard to Al toxicity for the human body. Received: 22 April 1996     

Aluminium in food and daily dietary intake assessment from 15 food groups in Zhejiang Province,China

Aluminium was measured in 2580 samples of 15 food groups and dietary exposure was estimated. Samples were purchased and analysed during 2010 to 2014. High aluminium levels were found in jellyfish (mean 4862 mg/kg), laver (mean 455.2 mg/kg) and fried twisted cruller (mean 392.4 mg/kg). Dietary exposure to aluminium was estimated for Zhejiang residents. The average dietary exposure to aluminium via 15 food groups in Zhejiang Province was 1.15 mg/kg bw/week, which is below the provisional tolerable weekly intake of 2 mg/kg bw /week. Jellyfish is the main Al contributor, providing 37.6% of the daily intake via these 15 food groups. This study provided new information on aluminium levels and assessment of aluminium (Al) dietary exposure in Zhejiang Province of China.     

Aluminium in wild mushrooms and cultivated Agaricus bisporus

 The aluminium content in wild mushrooms (n = 271, 19 species) and in cultivated Agaricus bisporus (n = 15) was determined by graphite furnace atomic absorption spectroscopy. With an aluminium content of 30 – 50 μ/g dry matter (DM) Boletus and Xerocomus species, the most well-known and most popular mushrooms, proved to be poor in aluminium. Several species of the genus Suillus, Macrolepiota rhacodes, Hypholoma capnoides as well as individual samples of Russula ochroleuca and Amanita rubescens contained high aluminium concentrations of about 100 μg/g DM and more. Cultivated Agaricus bisporus had the lowest aluminium content, i. e. 14 μg/g DM. The site, its geological origin as well as the mushroom species influenced the aluminium content in the fruitbodies: these factors require further investigation. Mushrooms do not contribute significantly to aluminium intake by humans. Received: 23 January 1997     

Tea and coffee consumption among Russian population

Aim of present study was the getting data on black and green tea and coffee consumption among Russian population in 1995-2003. The consumption of beverages tea and coffee was estimated by 24-hour recall of dietary intake in course of Russian Longitudinal monitoring surveys of economics and health. About 82% of population have consumed the black tea and only 2.2%--the green tea. Mean daily black and green tea intake among all population were 446 ml and 10 ml, correspondingly. The prevalence of black tea consumption was decreased and green tea and coffee consumption were increased from 1995 to 2003.     

Total content and speciation of aluminium in tea leaves and tea infusions

A total of 29 tea samples of different origin, 13 green tea samples, 13 black tea samples, two semi-fermented and one white tea, imported to the Czech Republic, were collected and analysed for total content of aluminium (Al) in tea leaves and tea infusions, as well as for Al compounds in these infusions. The total content of metals in tea leaves differs according to the type of tea (green or black) and is probably influenced by many factors, e.g., soil properties. The HPLC/IC speciation of Al in tea infusions was performed for all samples. The addition of Al³⁺ to the tea infusion proved that Al³⁺, Al(Y)²⁺ and Al(X)¹⁺ species can be determined in tea infusions. Increased extraction time did not show any affect on Al speciation, neither did the addition of sugar. After the addition of lemon juice, the speciation changed in one sample of black tea and five samples of green tea. These findings suggest that lemon juice as an additive can significantly influence Al speciation in tea infusions.     

Coffee and tea choices and intake patterns in 20-to-40 year old adults

The main aim of this study was to analyze coffee and tea intake patterns considering body weight status and polymorphism of genes involved in bitter taste sensitivity. A group of normal weight and overweight or obese subjects aged 20–40 (n = 411) was recruited in Poznań, Poland. Three-day dietary records were used to assess daily intakes. Single nucleotide polymorphisms (SNPs) were genotyped using TaqMan SNP probes (TAS2R38: rs713598, rs1726866, rs10246939) or the high-resolution melting method (CA6 rs2274333). 67.2% of the group drank coffee and 70.6% drank tea. Drinking only coffee was associated with higher body mass index (BMI) (OR = 4.81, p = 0.041). BMI ≥ 25 kg/m² was associated with higher coffee intake (p = 0.010) and lower tea intake (p = 0.003). Higher taste-sensitivity of TAS2R38 gene was associated with a preference for bitter white coffee (OR = 1.74, p = 0.033). Over 50% of respondents ate sweet snacks while drinking coffee or tea. Consumption of sweet snacks was associated with drinking bitter black coffee (p = 0.044, OR 1.97) and sweet white coffee (p = 0.003, OR 2.92) and with BMI below 25 kg/m² (p = 0.016, OR = 0.51).Coffee and tea intake differed by body weight status. PAV haplotype (TAS2R38) was associated with a preference for bitter white coffee. The majority of the study group drank coffee and tea with additives (sugar, milk etc.) and ate sweet snacks with them.     

Caffeine daily intake from dietary sources in Brazil

A survey on the potential intake of caffeine was carried out in Campinas, SP, Brazil, in the summer of 1993. The survey was based on a representative sample of 600 individuals, 9-80 years old, who were asked about their habitual usage of coffee, tea, chocolate products and carbonated beverages. Caffeine levels in the products were determined by high performance liquid chromatography with a UV-visible detector at 254 nm. Individual daily intakes (mg/kg b.w.) of caffeine were calculated from the consumption data generated by the survey and the caffeine content of the analysed products. Of all those interviewed, 81% consumed soft drinks regularly, 75% coffee, 65% chocolate products and 37% tea. Of the analysed products, coffee showed the highest amount of caffeine. The average and median potential daily intake of caffeine by the studied population were, respectively, 2.74 and 1.85mg/kg b.w. Coffee, tea, chocolate products and carbonated beverages accounted for median individual daily intakes of 1.90, 0.32, 0.19, and 0.19mg/kg b.w., respectively. These data show that coffee is the most important vehicle for caffeine intake within the studied population.     

Detection and quantification of pentosidine in foods

 Pentosidine, a crosslink amino acid in which one arginine and one lysine residue are linked together by a pentose, has been detected in foods for the first time using ion-exchange chromatography with direct fluorescence detection and subsequent ninhydrin derivatization. The method allows the simultaneous quantification of pentosidine along with all other amino acids of acid hydrolyzates at levels lower than 50 μg kg protein. Levels of pentosidine in all food samples investigated were very low (milk products between not detectable and 2–5 mg/kg protein; roasted coffee and some bakery products up to 35 mg/kg protein), indicating that pentosidine does not play a major part in the polymerization of food proteins. Received: 26 March 1996     

Detection and quantification of pentosidine in foods

 Pentosidine, a crosslink amino acid in which one arginine and one lysine residue are linked together by a pentose, has been detected in foods for the first time using ion-exchange chromatography with direct fluorescence detection and subsequent ninhydrin derivatization. The method allows the simultaneous quantification of pentosidine along with all other amino acids of acid hydrolyzates at levels lower than 50 μg kg protein. Levels of pentosidine in all food samples investigated were very low (milk products between not detectable and 2–5 mg/kg protein; roasted coffee and some bakery products up to 35 mg/kg protein), indicating that pentosidine does not play a major part in the polymerization of food proteins. Received: 26 March 1996     

Commercial peppermint (Mentha × piperita L.) teas: Antichlamydial effect and polyphenolic composition

The qualitative and quantitative polyphenolic contents in the infusions of the commercial peppermint tea (Mentha × piperita L.) samples (n = 27) from different countries were studied using HPLC–UV-MS/MS analysis. The most abundant polyphenolics in the peppermint infusion were eriocitrin, 12-hydroxyjasmonate sulfate, luteolin-O-rutinoside and rosmarinic acid. In order to evaluate the content of samples by finding chemosystematic markers, the essential oil composition was studied by GC. The analyses showed that the 24 (89%) peppermint tea samples contained peppermint, whereas three samples may contain Mentha spicata, different from that claimed on the package.The effects of seven peppermint tea extracts against respiratory tract pathogen Chlamydia pneumoniae were investigated in vitro. All seven selected tea extracts were active against C. pneumoniae, the growth inhibition ranging from 20.7% to 69.5% at extract concentration of 250 μg/ml. In most cases, the antichlamydial activity was related to the peppermint teas having also high content of luteolin and apigenin glycosides. This study supports the consumption of peppermint tea to potentially elicit beneficial health effects on acute respiratory tract infections.     

传统滇红工夫红茶与野生滇红工夫红茶的品质分析

为了解传统滇红工夫红茶与野生滇红工夫红茶品质特点的差异，本文收集了5个传统滇红工夫红茶和5个野生滇红工夫红茶，对其感官品质和生化品质成分进行了分析。感官审评表明，供试样品的外形、汤色、叶底均符合滇红工夫红茶的特征，即干茶色泽乌黑油润，茶汤红艳或橙红明亮，叶底嫩匀，但传统滇红滋味浓强，而野生滇红滋味醇和鲜爽。传统滇红工夫红茶的水浸出物、总儿茶素、咖啡碱含量分别为41.07%、18.53和14.60 mg/g，明显高于野生滇红的38.42%、10.58和9.54 mg/g；而游离氨基酸平均含量（3.92%）低于野生滇红（5.01%）；二者茶多酚平均含量分别为16.61%、16.56%，无明显差异；茶黄素、茶红素和茶褐素的平均含量分别为0.64%、6.75%、10.93%和0.61%、2.70%、11.80%，其中茶红素含量差异明显；槲皮素、芦丁、山柰酚、杨梅素的平均含量分别为0.09、0.67、0.01、0.07 mg/g和0.14、0.27、0.16、0.15 mg/g，差异明显。以19个生化成分含量为指标，进行了主成分分析（Principal component analysis，PCA）和聚类分析（Clustering analysis，CA），均能将传统滇红工夫红茶和野生滇红工夫红茶明显地分为两类，说明二者的生化成分含量具有明显差异。综合来看，传统滇红的水浸出物、儿茶素类、咖啡碱及黄酮醇类含量高，导致其滋味浓强；而野生滇红的游离氨基酸含量高，是其滋味鲜醇的原因。     

HPLC Determination of Caffeine and Theobromine in Coffee, Tea, and Instant Hot Cocoa Mixes

Popular brands of instant and ground coffee, instant and bag tea, and instant hot cocoa mixes were prepared according to manufacturer's directions and analyzed for caffeine and/or theobromine content. After extraction into boiling water, the methylxanthines were separated by high performance liquid chromatography using a reverse phase C₁₈ column and a mobile phase of acetonitrile and water (8:92, v/v). Caffeine content ranged from 32.4–35.0 mg/cup in instant tea, 30.2–67.4 mg/cup in bag tea, 1.0–7.8 mg/cup in instant hot cocoa mixes, 46.7–67.6 mg/cup in instant coffee, and 93.0–163.5 mg/cup in ground coffee. Theobromine concentrations ranged from 1.4–2.3 mg/cup in instant tea, 1.2–4.4 mg/cup in bag tea, and 39.5–79.5 mg/cup in instant hot cocoa mixes.     

Fluoride in tea from Shandong Province,China and exposure assessment

ABSTRACT

In this study fluoride in 170 tea samples from Shandong province (China) was determined using a selective ion electrode. The fluoride concentrations ranged from 31.2 to 338 mg/kg with an average of 119 mg/kg. The mean fluoride concentrations were 164, 121, 98.7 and 96.8 mg/kg, which corresponded to Pu’erh tea, green tea, oolong tea and black tea, respectively. Moreover, 4.7% of the analysed samples exceed the legal limit of 200 mg/kg recommended by China. The estimated daily intake of fluoride via drinking tea for an adult was between 0.655 and 1.07 mg/person/day, which were lower than the provisional maximum tolerable daily intake value of 3.5 mg/person/day set by the National Health and Family Planning Commission of the People’s Republic of China. In future, maintaining a surveillance programme to monitor the trend of fluoride in tea is necessary for food safety and human health.     

Simultaneous Determination of Sodium, Potassium, Manganese and Bromine in Tea by Standard Addition Neutron Activation Analysis

Standard addition method was applied for neutron activation analysis of tea leaves. Four brands of tea leaves were analyzed for its Na, K, Mn, and Br contents by this method. The Na, K, Mn, and Br concentrations were found to be in the 90–120 μg/g, 1.8–2.1% w/w, 150–500 and 3–7 μg/g ranges, respectively. The extraction efficiency of these elements, during the infusion, was calculated by analysis of tea leaves before and after the infusion process. It was observed that about 90% of the Na, K, and Br elements were extracted to water during the infusion process. The drinking tea is a rich source of Mn (despite of an extraction efficiency of 50% for this element).     

Evaluation of aluminium concentrations in samples of chocolate and beverages by electrothermal atomic absorption spectrometry

Samples of chocolate, cocoa, tea infusions, soft drinks and fruit juice have been examined by, electrothermal atomic absorption spectrometry (ETA-AAS) for the presence of aluminium (Al). Fruit juices and chocolate were analysed after an adequate sample preparation; the other products were evaluated directly. Sampling was performed in duplicate for 248 independent samples. The mean Al concentration in chocolate was 9.2 +/- 7.5 mg kg(-1), and individual values were correlated with the per cent of cocoa in samples (Y = 0.63 + 0.27X, r = 0.78, p < 0.0001). Al concentration in commercial tea infusions ranged from 0.9 to 3.3 mg l(-1) (mean = 1.80 +/- 65 mg l(-1), whereas in laboratory-prepared samples it was 2.7 +/- 0.93 mg l(-1). In soft drinks, the concentrations of Al were lower, ranging from 9.1 to 179 microg l(-1); the highest values were observed in samples of orange squash (mean = 114 +/- 56 microg l(-1)). Apricot juice showed the highest Al level (mean = 602 +/- 190 microg l(-1)), being statistically, different from that of pear (mean = 259 +/- 102 microg l(-1)), but not different from that of peach juice (mean = 486 +/- 269 microg kg(-1)). Toxicologically, the amount of Al deriving from the consumption of these products is far below the acceptable daily intake of 1 mg kg(-1) body weight indicated by the FAO/WHO, and it is a verv low percentage of the normal Al dietary intake.     

Antioxidant properties and total phenolics content of green and black tea under different brewing conditions

 The antioxidant activity and the total phenolics content of various tea extracts were analysed. Green and black tea were brewed from 0.5 min up to 10 min under different brewing conditions (stirring the extract, chopping the tea leaves before brewing). For measuring the antioxidant activity, the Trolox equivalent antioxidant capacity (TEAC) test and the low density lipoprotein (LDL) oxidation test were used. In all cases the antioxidant activity as well as the content of the phenolics increased with the brewing time. In black tea (brewed without stirring or chopping), the total phenolics increased from 33.8 mg/100 ml after 0.5 min up to 68.4 mg/100 ml after 10 min brewing time. Stirring during brewing led to higher phenolic yields in the extract. Thus, phenolics in stirred black tea ranged from 44.5 mg/100 ml (0.5 min) to 96.7 mg/100 ml (10 min). Chopping the tea leaves resulted in the highest content of phenolics. Antioxidant activity was well correlated with the corresponding total phenolics content. The results of the LDL oxidation test varied more than those of the TEAC test. Received: 27 May 1998 / Revised version: 15 July 1998     

Antioxidant properties and total phenolics content of green and black tea under different brewing conditions

 The antioxidant activity and the total phenolics content of various tea extracts were analysed. Green and black tea were brewed from 0.5 min up to 10 min under different brewing conditions (stirring the extract, chopping the tea leaves before brewing). For measuring the antioxidant activity, the Trolox equivalent antioxidant capacity (TEAC) test and the low density lipoprotein (LDL) oxidation test were used. In all cases the antioxidant activity as well as the content of the phenolics increased with the brewing time. In black tea (brewed without stirring or chopping), the total phenolics increased from 33.8 mg/100 ml after 0.5 min up to 68.4 mg/100 ml after 10 min brewing time. Stirring during brewing led to higher phenolic yields in the extract. Thus, phenolics in stirred black tea ranged from 44.5 mg/100 ml (0.5 min) to 96.7 mg/100 ml (10 min). Chopping the tea leaves resulted in the highest content of phenolics. Antioxidant activity was well correlated with the corresponding total phenolics content. The results of the LDL oxidation test varied more than those of the TEAC test.     

Caffeine in Chiang Rai tea infusions: Effects of tea variety,type, leaf form,and infusion conditions

Caffeine in Chiang Rai tea infusions was found to be dependent on infusion conditions (water temperature and infusion time), and leaf form (non-ground or ground) but independent of tea variety and type. For non-ground leaf samples, the higher the water temperature and the longer the infusion time, the higher the caffeine concentrations in tea infusions. After infusing for longer than 15 min, the dissolution rate of caffeine became slower and the concentration was essentially constant. For ground leaves, the caffeine content was not influenced by infusion time. Caffeine concentrations in tea infusions from Camellia sinensis var. sinensis (26.8 ± 0.81 and 22.3 ± 5.55 mg/100 ml for ground and non-ground samples, respectively) were not significantly different from that of Camellia sinensis var. assamica (24.4 ± 0.66 and 20.3 ± 5.07 mg/100 ml for ground and non-ground samples, respectively). The difference in caffeine concentration between green tea (28.1 ± 8.19 mg/100 ml) and oolong tea (20.3 ± 1.52 mg/100 ml) was not statistically significant.