Caffeine levels in beverages from Argentina's market: application to caffeine dietary intake assessment

The caffeine content of different beverages from Argentina's market was measured. Several brands of coffees, teas, mates, chocolate milks, soft and energy drinks were analysed by high-performance liquid chromatography (HPLC) with ultraviolet detection. The highest concentration level was found in short coffee (1.38 mg ml^?1) and the highest amount per serving was found in instant coffee (95 mg per serving). A consumption study was also carried out among 471 people from 2 to 93 years of age to evaluate caffeine total dietary intake by age and to identify the sources of caffeine intake. The mean caffeine intake among adults was 288 mg day^?1 and mate was the main contributor to that intake. The mean caffeine intake among children of 10 years of age and under was 35 mg day^?1 and soft drinks were the major contributors to that intake. Children between 11 and 15 years old and teenagers (between 16 and 20 years) had caffeine mean intakes of 120 and 240 mg day^?1, respectively, and mate was the major contributor to those intakes. Drinking mate is a deep-rooted habit among Argentine people and it might be the reason for their elevated caffeine mean daily intake.     

饮料中咖啡因含量的测定

采用HPLC法,以水为溶剂,0.02mol/L醋酸铵溶液—甲醇(7525)为流动相,在254nm波长下,测定饮料中咖啡因含量。回收率>97%,与按国家标准GB/T16344—1996测定值比较,两种方法的相对偏差<2%。方法简便,有实用价值。     

山东省居民饮料中咖啡因暴露评估

目的评价山东省居民咖啡因的摄入水平及潜在的健康风险。方法检测8类共319份饮料样品中咖啡因含量数据,结合2013年2 523名山东省居民饮料消费量调查数据,采用确定性评估的方法,对山东省不同年龄-性别组人群的咖啡因摄入水平及其潜在风险进行评估。结果各类饮料咖啡因的平均含量为9 210.06 mg/kg,最大值为49 059.60 mg/kg。山东省全人群咖啡因的平均每日摄入量为61.62μg/kg BW,远低于咖啡因的安全摄入量(6.7 mg/kg BW)。不同年龄-性别组人群以60岁及以上年龄组男性每日摄入量最高,平均为166.55μg/kg BW,占安全摄入量的2.49%。全人群中高食物量消费人群的咖啡因每日摄入量(P97.5)为476.82μg/kg BW,远低于安全摄入量,各年龄-性别组人群高食物量消费人群的咖啡因每日摄入量范围为0.00～3 104.70μg/kg BW,最大值为13～17岁年龄组女性的摄入量。茶叶对于山东省居民饮料中咖啡因摄入的贡献率最高,达到74.19%。3～12岁儿童的咖啡因摄入主要来源为可乐。结论山东省居民饮料中咖啡因摄入的健康风险总体较低,其中茶叶和可乐分别为成年人和儿童的主要贡献食品。     

超高效液相色谱法测定饮料中咖啡因含量

目的 建立超高效液相色谱法测定饮料中咖啡因含量。方法 样品经预处理后, 所得溶液均过 0.22 μm滤膜, 经C18色谱柱分离, 以水和甲醇为流动相, 梯度洗脱, 流速为0.21 mL/min, 二极管陈列检测器进行分析。结果 咖啡因为1.0~100 μg/mL浓度范围内呈线性关系, 线性相关系数为0.9994, 加标回收率在90.3%~98.4 %之间, 相对标准偏差小于10 %(n=6), 检出限为0.05 mg/kg。结论 该方法操作简单、干扰小, 准确度可靠, 能够分析饮料中咖啡因。     

HPLC determination of caffeine in tea,chocolate products and carbonated beverages

Different brands of mate and black tea, chocolate products and carbonated beverages available on the Brazilian market were analysed for caffeine by high-performance liquid chromatography with a UV-vis detector at 254 nm. The column was a reverse phase C18 and the mobile phase consisted of methanol–water (30:70, v/v), acetonitrile–water (10:90, v/v) and methanol–water (25:75, v/v) for tea, chocolate products and soft drinks respectively. Caffeine content ranged from 1.05 to 15.83 mg per cup in mate tea, from 32.21 to 36.23 mg per cup in black tea, from 0.14 to 0.95 mg g⁻¹ in chocolate products from 2.73 to 7.49 mg per can in guaraná-type soft drinks and from 19.81 to 45.89 mg per can in cola soft drinks. These data indicate that the levels of caffeine in Brazilian teas, chocolates and soft drinks are within the ranges reported for similar products in other countries. © 1999 Society of Chemical Industry     

Survey of Canadian retail coffees for ochratoxin A

One-hundred and one specimens of coffee were gathered from retail outlets across Canada and analysed for ochratoxin A. Seventy-one specimens were roasted beans or roasted ground coffee, and 30 were instant (or 'soluble') coffees. All samples were extracted with methanol-sodium bicarbonate. The extracts were cleaned up either by immunoaffinity column chromatography or by a combination of solid-phase extraction and immunoaffinity column chromatography. Ochratoxin A was quantified by liquid chromatography (LC) with fluorescence detection. The minimum quantifiable level was 0.1 ng g^-1. Ochratoxin A was present, above the minimum quantifiable level, in 42 (59%) of 71 beans and ground coffee and in 20 (67%) of 30 instant coffees. The mean ochratoxin A level in the positive samples of beans and ground coffee was 0.6 ng g^-1, and the mean level in the positive samples of instant coffee was 1.1 ng g^-1.     

Development of a chemometric-assisted deep eutectic solvent-based microextraction procedure for extraction of caffeine in foods and beverages

ABSTRACT

In this research article, a novel and green deep eutectic solvent-based microextraction (DES-ME) procedure based on chemometric-assisted (CA) optimization was developed for the extraction of caffeine in foods and beverages prior to its spectrophotometric determination. Ultrasound was used to accelerate the extraction of caffeine. Deep eutectic solvents (DES), prepared in an ultrasonic bath at 20–60 min for 60–80°C, were used as extraction solvents. The important experimental variables (pH, DES amount, temperature, sonication time and metal concentration) were modelled and optimized using response surface methodology (RSM) based on central composite design (CCD). Under the optimum conditions, the proposed method allowed the determination of caffeine with limits of detection (LOD, 3s_blank/m) and quantification (LOQ, 3s_blank/m) of 7.5 and 25.0 µg L^?1, respectively. For 40 µg L^?1 and 100 µg L^?1 of caffeine (n = 5), relative standard deviations (RSDs%) and recoveries% were 1.2–1.6% and 96.7–98.2%, respectively. Validation studies (accuracy, precision, trueness, reliability and selectivity) of the method were performed before the analysis of real samples. The results showed that the combination of the CCD with the DES-ME can be considered as a new perspective for the extraction and determination of caffeine in foods and beverages.     

Survey of Clostridium difficile in retail seafood in College Station,Texas

The incidence and severity of disease associated with toxigenic Clostridium difficile have increased in hospitals in North America with the emergence of newer, more virulent strains. Toxigenic C. difficile has been isolated from food animals and retail meat with potential implications of transfer to humans. The objective of the present study was to investigate the prevalence of C. difficile in retail seafood from grocery stores in College Station, Texas. C. difficile was found in 4.5% (3/67) of shellfish and finfish samples. The positive samples included one each from fresh mussel, frozen salmon and frozen shrimp. The mussel and salmon isolates were characterized as toxinotype V and pulsed-field gel electrophoresis (PFGE) type-NAP7. The shrimp isolate was identified as toxinotype XII, but had an unknown PFGE type. Susceptibilities to 11 antimicrobial agents were identical for the mussel and salmon isolates and were sensitive to eight of 11 antimicrobials (including ampicillin) and intermediate to clindamycin. However, the shrimp isolate was resistant to clindamycin and ampicillin. This study demonstrates that seafood, like other food commodities, can be contaminated by C. difficile.     

Survey of di-(2-ethylhexyl)phthalate plasticizer contamination of retail Danish milks.

An investigation of residues of di-(2-ethylhexyl)-phthalate (DEHP) in retail whole milk in samples from one German and 14 Danish dairies is reported. The investigation was performed about six months after the use of DEHP-plasticized milk tubing was banned in Denmark. The results indicate a mean concentration of DEHP lower than 50 micrograms/litre in retail whole milk. Based on these data and the Tolerable Daily Intake (TDI) for DEHP of 25 micrograms/kg body weight laid down by the EEC Scientific Committee for Food, it is concluded that the intake of DEHP from milk and milk products does not, even through a whole life, constitute a danger to health for the Danish population.     

Investigation of ethyl carbamate levels in some fermented foods and alcoholic beverages

An analytical procedure has been developed for the determination of trace amounts of ethyl carbamate in fermented foodstuffs and alcoholic beverages. Concentrations were generally below the 1-5 micrograms/kg detection limit in bread, cheese, yoghurt, beer, gin and vodka. Higher concentrations were found in the other alcoholic beverages examined, which included whisky, fruit brandy, liqueur, wine, sherry and port.     

Prevalence and contamination levels of Listeria monocytogenes in retail foods in Japan

Retail foods in Japan were surveyed for the presence and contamination levels of L. monocytogenes. It was isolated from 12.2, 20.6, 37.0 and 25.0% of 41 minced beef, 34 minced pork, 46 minced chicken and 16 minced pork-beef mixture samples, respectively. MPN values were higher than 100/g in five (10.9%) minced chicken samples, but lower than 100/g in all minced beef, pork and pork-beef mixture samples. The organism was also isolated from 5.4% of the 92 smoked salmon samples at MPN values lower than 10/g, and from 3.3% of 213 ready-to-eat raw seafood samples at MPN values from lower than 0.3 to higher than 100/g. None of the 285 vegetable samples were contaminated with L. monocytogenes. These findings indicate that ready-to-eat raw seafoods are relatively high risk among the foods surveyed in this study.     

高效液相色谱法测定能力验证样品(饮料)中咖啡因含量不确定度评定

目的 对高效液相色谱法测定能力验证样品(饮料)中咖啡因含量的不确定度进行评定。方法 根据JJF1059.1-2012标准要求, 建立不确定度评估的数学模型, 通过对不确定度的各主要分量进行分析计算, 得出合成不确定度以及扩展不确定度, 最终进行测定结果的不确定度评定。结果 当能力验证样品中咖啡因的测定结果为156.9 mg/kg时, 在95%的置信区间下, 其扩展不确定度为5.8 mg/kg (k=2)。结论 采用高效液相色谱法测定饮料中咖啡因含量, 其不确定度的主要来源为标准溶液配制和标准曲线拟合, 该评估模型为检测饮料中咖啡因的不确定度评估提供了参考依据。     

Rapidly colorimetric detection of caffeine in beverages by silver nanoparticle sensors coupled with magnetic molecularly imprinted polymeric microspheres

Excessively intaking caffeine can harm human health, and it is imperative to develop a rapid method to identify caffeine for food safety. The magnetic molecularly imprinted polymeric microspheres (MMIPs) were prepared to pretreat samples before silver nanoparticles (AgNPs) colorimetric detection of caffeine. Using Fe₃O₄ as supporting core, mesoporous SiO₂ as intermediate shell, α-methylacrylic acid as functional monomer and caffeine as template, the prepared MMIPs were characterised by transmission electron microscopy, Fourier transform infrared spectroscopy and vibrating sample magnetometer. Adsorption process followed Langmuir adsorption isotherm with maximum adsorption capacity at 38.8 mg g⁻¹ under 298 K. The MMIPs extract caffeine from beverages, then the AgNPs colorimetric method rapidly screened and semi-quantified caffeine ≥5 mg L⁻¹ by naked eye, and accurately quantified caffeine ranging 0.1–5 mg L⁻¹ by UV-vis spectroscopy at 393 nm, which were consistent with HPLC analytical results. Thus, this method might be used to rapidly enrich and analyse caffeine in beverages.     

酒精饮料中氨基甲酸乙酯分析前处理技术研究进展

氨基甲酸乙酯(Ethyl Carbamate,EC)是一种多位点致癌物,酒精饮料中含有微量的氨基甲酸乙酯.为降低酒精饮料中氨基甲酸乙酯的含量,建立简便、快捷、准确的EC含量的检测方法有着重要的意义,尤其样品的前处理方法在检测中起着至关重要的作用.文章详细阐述了酒精饮料中氨基甲酸乙酯分析的萃取溶剂,液/液萃取、固液萃取、固相萃取及固相微萃取等前处理技术的研究概况,为酒精饮料中降低氨基甲酸乙酯含量提供了重要的分析技术依据.     

反相高效液相色谱和超高效液相色谱法测定 饮料中咖啡因含量的比较研究

目的对原反相高效液相色谱(RP-HPLC)方法进行转化并优化,建立超高效液相色谱(UPLC)方法,为饮料中咖啡因的含量测定提供更快速、高效、灵敏和环保的方法。方法分别采用RP-HPLC法和UPLC法测定饮料中咖啡因的含量,并对比二者的精密度、稳定性、重复性和加标回收率。结果 2种方法所得8种市售饮料中咖啡因的含量测定结果变化趋势一致,但UPLC法含量测定结果比RP-HPLC法含量测定结果偏高,二者精密度、回收率均符合要求。结论 UPLC法可以成功替代RP-HPLC法,为饮料中咖啡因的快速定性定量分析与检测提供新的途径。     

Survey of aflatoxins in retail samples of whole and ground black and white peppercorns

A total of 126 local and imported samples of commercial white and black pepper in Malaysia were analysed for aflatoxins B₁, B₂, G₁ and G₂ (AFB1, AFB2, AFG1, AFG2) content using high-performance liquid chromatography (HPLC) with a fluorescence detector (FD). An acetonitrile–methanol–water (17 : 29 : 54; v/v) mixture was used as a mobile phase and clean-up was using an immunoaffinity column (IAC). Seventy out of 126 (55.5%) samples were contaminated with total aflatoxins, although only low levels of aflatoxins were found ranging from 0.1 to 4.9 ng g^?1. Aflatoxin B₁ showed the highest incidence of contamination and was found in all contaminated samples. There was a significant difference between type of samples and different brands (p < 0.05). The results showed black peppers were more contaminated than white peppers.     

Survey of acrylamide levels in Chinese foods

A survey of levels of acrylamide (AA) in 349 food products obtained from the Chinese market was conducted. AA was determined by an liquid chromatography-tandem mass spectrometry (LC-MS/MS) method. The limit of detection (LOD) and the limit of quantification (LOQ) of the method in four different matrices ranged from 0.8 to 10 µg kg^?1 and from 4.0 to 25 µg kg^?1, respectively. The results from this survey indicated that AA was present in all samples except drinking water and tea. AA contents in different samples varied greatly according to the raw materials and processing conditions. The highest level of AA was found in potato products, with an average level of 1467 µg kg^?1. Preliminary estimates of AA exposure and risk assessment of AA from foods in the Chinese population were performed using a combination of data obtained in the present survey and 2002 dietary consumption survey carried out in 2002 for the Chinese population. The average dietary exposure of AA was estimated to be 0.38 µg kg^?1 body weight day^?1, which is relatively low compared with the result reported by the Food and Agricultural Organization/World Health Organization (FAO/WHO). Furthermore, the margin of exposure for neurotoxicity, reproductive toxicity, and carcinogenicity of AA was calculated to be 1318, 5250, and 787, respectively.     

Method development and analysis of retail foods and beverages for carotenoid food colouring materials E160a(ii) and E160e.

An analytical method using high-performance liquid chromatography with photodiode array detection was developed and applied to the determination of the permitted food colour additives beta-carotene(E160a(ii)) and beta-apo-8'-carotenal (E160e) in foods and beverages. The scope of previously reported methods has been broadened to cover a wide range of retail foods and enzymatic hydrolysis has been used in place of saponification for high-fat samples. Quantitative results (greater then 0.1 mg kg(-1)) are given for the major colour principals trans-beta-apo-8'-carotenal and trans-beta-carotene. Semiquantitative results are given for the various cis-isomers of each colorant for which authentic reference standards were not available. The method has been used successfully for the analysis of a wide range of foodstuffs with differing fat content without the need for saponification, except for moderate- to high-fat foodstuffs containing significant levels of emulsifiers, for which it was limited. The results suggest that beta-apo-8'-carotenal (E160e) does not have widespread use in the UK. None of the samples exhibited a total beta-carotene content greater than 20 mg kg(-1) and none of the high-fat samples and only one of the 17 low-fat/beverage samples contained total beta-carotene at levels less than 0.1 mg kg(-1). The total beta-carotene contents of the low-fat/beverage samples ranged from 0.4 +/- 0.03 to 8.4 i 0.71 mg kg(-1), and the total beta-carotene contents of the high-fat samples ranged from 0.1 +/- 0.01 (jelly confectionery) to 18.5 +/- 0.98 mg kg(-1) (processed cheese).     

Survey of the histamine content in fish samples randomly selected from the Greek retail market

The histamine content of fish sold in the Greek retail market was surveyed and the performance of high-performance liquid chromatography (HPLC) and enzyme-linked immunoabsorbant assay (ELISA) methods for the determination of histamine were compared. A total of 125 samples of fresh and canned tuna, fresh and canned sardines, deep frozen swordfish, smoked and deep frozen mackerel, anchovies, salted and smoked herring were analysed by HPLC (55 samples), ELISA (106 samples) and both methods (36 samples). Histamine levels as determined by HPLC, ranged from 2.7 mg kg^?1 to 220 mg kg^?1. The highest histamine concentrations obtained by HPLC were found in herring and anchovy samples. Eight out of the 55 samples (14.5%) analysed by HPLC, exceeded the US Food and Drug Administration (USFDA) limit (50 mg kg^?1), while 16 out of the 106 samples (15%) analysed by ELISA exceeded the limit. The results show that for histamine concentrations below 50 mg kg^?1, there is good agreement between the ELISA and HPLC but above 50 mg kg^?1 big differences were found.     

Nitrosamines in beverages

Traces of nitrosodimethylamine (NDMA) have been reported in many types of beer but are not normally found in beverages (other than those derived from malt) consumed in the UK. A range of control methods is now in use, and these have led to marked reductions in NDMA; the chemical and biochemical processes involved in NDMA formation in malt, and in the treatments which can minimise this, are discussed. Analytical methods for the measurement of NDMA and other volatile nitrosamines are now well established and can give high quality analytical data. Analysis of non-volatile nitrosamines at trace levels presents some novel problems; these are discussed along with some approaches to their solution. Data from a few samples illustrate some of the various questions which may require further consideration.