Determination of bisphenol A in, and its migration from, PVC stretch film used for food packaging

Bisphenol A (BPA) is used as an additive in polyvinyl chloride (PVC) products, including stretch films used for food packaging. The BPA contents were investigated of several brands of stretch film bought locally but marketed internationally or throughout Spain and which were presumably produced at different manufacturing plants. Their major components were identified by FTIR (Fourier Transform Infrared Spectrometry) and horizontal attenuated total reflectance, and the migration of BPA from these materials into the standard European Union food simulants was determined by high-performance liquid chromatography (HPLC) using both fluorescence (FL) and ultraviolet (UV) detection, the identity of the analyte being confirmed by gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-mass spectrometry (LC-MS). The two HPLC detection methods had different detection limits (30 μg l^-1 for UV, 3 μg l^-1 for FL), but afforded virtually identical BPA determinations for the samples tested. BPA contents ranging from 40 to 100 mg kg^-1 were found in three of the five PVC-based films analysed, and a content of 500 mg kg^-1 was found in a fourth; for these determinations, extraction into acetonitrile was used. In standard tests of migration into water, 3% acetic acid and olive oil over 10 days at 40°C, migration from a given film was in all cases greatest into olive oil. Migration from the films with non-zero BPA contents ranged from 3 to 31 μg dm^-2, values higher than those reported for many other food-contact materials, but lower than the European Union specific migration limit for BPA. PVC stretch film nevertheless may make a significant contribution to contamination of foodstuffs by BPA, and should be taken into account in estimating BPA intake or exposure to this substance.     

Effect of different extraction methods on the recovery of chlorogenic acids,caffeine and Maillard reaction products in coffee beans

Water and ethanolic extracts were obtained from green and roasted (3 different roast degrees) Arabica and Robusta coffee beans. Three types of water extracts were prepared from the examined, finely ground material through: (a) brewing with boiling water, (b) boiling in water, and (c) boiling in water under elevated pressure. All these extracts were lyophilized. Two types of ethanolic extracts were derived from the examined material through (a) extraction of the finely ground coffee beans and (b) extraction of the solid residue that remained after boiling the coffee beans in water under elevated pressure. These ethanolic extracts were dried. Both water and ethanolic extracts were analyzed for concentration of potential antioxidants such as chlorogenic acids and caffeine (by HPLC) and Maillard reaction products (measurements of absorbance at 420 nm). Concentration of chlorogenic acids in Robusta extracts varied between 0.4 and 36.0 g × 100 g⁻¹ dry extract weight (db.), while in Arabica extracts it ranged from 0.1 to 22.4 g × 100 g⁻¹ db. Extracts of dark roasted Arabica contained more chlorogenic acids than those of Robusta. Concentration of caffeine, which in green and roasted coffee beans is maintained at the similar level, tended to increase in Robusta extracts with the roast degree and temperature of extraction with water, while in case of Arabica extracts there was no noticeable tendency. Caffeine concentrations varied between 0.12 and 8.41 g × 100 g⁻¹ db. and between 0.03 and 6.53 g × 100 g⁻¹ db. in Robusta and Arabica extracts, respectively. Ethanolic extracts were characterized by relatively higher caffeine concentrations and lower contents of brown pigments and chlorogenic acids as compared to water extracts. The richest in antioxidants were extracts of green Robusta coffee beans derived through boiling in water under elevated pressure.     

Effect of sterilisation and storage conditions on the migration of bisphenol A from tinplate cans of the Lebanese market

The use of bisphenol A (BPA) in lacquer coating of food cans has been restricted by different authorities in many countries, such as in Europe. However, such regulation does not exist in many other countries including Lebanon. Due to the lack of data on the quality of Lebanese can production; this study investigates the migration of BPA from two types of tinplate cans manufactured in Lebanon, before and after sterilisation. Cans were analysed under different storage conditions (time and temperature) and filled with an aqueous simulant. The determination of BPA was carried out using UPLC with fluorescence detection, and further confirmed by MS detection. After sterilisation BPA levels drastically increased from an average of 0.15 to 109 µg/kg, giving a BPA migration around 10.5 µg/dm² for both types of cans. Storage temperature and time had no significant influence on BPA levels in sterilised cans (p-value > 0.05); however, these factors significantly affected BPA levels in non-sterilised cans.     

The Kinetics and mechanism of caffeine infusion from coffee: Hydrodynamic aspects

Hydrodynamic flow conditions were controlled by means of large horizontal rotating discs. These were coated with ground and sieved Kenyan Arabica coffee, and rotated at various speeds in distilled water at 25°C. The rate of extraction of caffeine was measured in each experiment. At a constant rotation speed, the first order rate constant rose steeply with decreasing size of coffee particle and was found to be inversely proportional to the square of the particle radius. For a given particle size, however, the rate constants were independent of the rotation speed. These two findings show that the rate-determining step for extraction from coffee-coated discs was the diffusion of caffeine through the bean particle and not its diffusion through the Nernst layer. The same mechanistic conclusion can be drawn for stirred coffee suspensions by applying the hydrodynamics of turbulent flow.     

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.     

The kinetics and mechanism of caffeine infusion from coffee: The effect of particle size

Measurements have been made of the rate of infusion of caffeine into distilled water from medium roast Kenyan Arabica coffee beans and from eight sieved fractions of the ground beans at 25.8°C. The first-order rate constants increased dramatically as the particle size decreased. For one of the size fractions the rate constants were then measured at various temperatures up to 84.1°C and were found to rise eight-fold over this temperature interval. The partition coefficients of caffeine between ground beans and water were also determined. These results, interpreted by a new steady-state theory of extraction, show that the rate-determining step in the infusion is diffusion of caffeine through the swollen coffee particles. The low magnitude of the diffusion coefficient and its high activation energy demonstrate that caffeine diffusion within the bean particles is a hindered process.     

Fast simultaneous analysis of caffeine, trigonelline, nicotinic acid and sucrose in coffee by liquid chromatography–mass spectrometry

A rapid liquid chromatography–mass spectrometry method for the simultaneous quantification of caffeine, trigonelline, nicotinic acid and sucrose in coffee was developed and validated. The method involved extraction with hot water, clarification with basic lead acetate and membrane filtration, followed by chromatographic separation using a Spherisorb^® S5 ODS2, 5 μm chromatographic column and gradient elution with 0.3% aqueous formic acid/methanol at a flow rate of 0.2 mL/min. The electrospray ionization source was operated in the negative mode to generate sucrose ions and in the positive mode to generate caffeine, trigonelline and nicotinic acid ions. Ionization suppression of all analytes was found due to matrix effect. Calibrations curves prepared in green and roasted coffee extracts were linear with r² > 0.999. Roasted coffee was spiked and recoveries ranged from 93.0% to 105.1% for caffeine, from 85.2% to 116.2% for trigonelline, from 89.6% to 113.5% for nicotinic acid and from 94.1% to 109.7% for sucrose. Good repeatibilities (RSD < 5%) were found for all analytes in the matrix. The limit of detection (LOD), calculated on the basis of signal-to-noise ratios of 3:1, was 11.9, 36.4, 18.5 and 5.0 ng/mL for caffeine, trigonelline, nicotinic acid and sucrose, respectively. Analysis of 11 coffee samples (regular or decaffeinated green, ground roasted and instant) gave results in agreement with the literature. The method showed to be suitable for different types of coffee available in the market thus appearing as a fast and reliable alternative method to be used for routine coffee analysis.     

Correlation between cup quality and chemical attributes of Brazilian coffee

Brazilian arabica coffee is classified for trading according to the quality of the beverage obtained after roasting and brewing. In the present study, Brazilian green and roasted coffee beans were investigated for possible correlations between cup quality and the levels of sucrose, caffeine, trigonelline and chlorogenic acids, determined by HPLC analysis. Trigonelline and 3,4-dicaffeoylquinic acid levels in green and roasted coffee correlated strongly with high quality. To a lesser extent, caffeine levels were also associated with good quality. On the other hand, the amount of defective beans, the levels of caffeoylquinic acids (predominantly 5-caffeoyilquinic acid), feruloylquinic acids, and their oxidation products were associated with poor cup quality and with the Rio-off-flavor. The fact that similar correlations between cup quality and chemical attributes were observed in green and light roasted samples – the latter used for coffee cup classification – indicates that chemical analysis of green beans may be used as an additional tool for coffee quality evaluation.     

酶联免疫法检测食品中的双酚A残留

建立检测双酚A(BPA)的间接竞争酶联免疫检测法(icELISA),探讨其在实际样品检测中的灵敏性及准确性。以抗BPA的腹水单抗建立BPA的icELISA法,利用该法对市面上聚碳酸酯(PC)制包装材料中BPA向食物的迁移量进行检测,并与高效液相色谱法检测结果相比较。BPA的icELISA法检测范围为2.817 ng/mL～1.212×106ng/mL,IC50为1 847.9 ng/mL,检测限为0.324 ng/mL,该法测定罐装鱼肉和蔬菜中BPA分别为1 015.25 ng/mL和207.22 ng/mL。     

罐头食品中双酚A和双酚F环氧衍生物残留的高效液相色谱分析

建立了一种高效液相色谱分析罐头食品中双酚A(BPA)和双酚F(BPF)环氧衍生物的方法。样品经微波辅助萃取后过PPL(填料为苯乙烯-二乙烯苯(SDVB)聚合物)固相萃取柱进行净化试验。结果表明,微波辅助萃取法的提取效果理想;采用PPL固相萃取回收率在73.26%~104.98%,除杂效果明显。将微波辅助—PPL固相萃取净化法应用于多种食品进行分析,结果表明该方法适用于食品中双酚A和双酚F环氧衍生物残留分析。     

The kinetics and mechanism of caffeine infusion from coffee: The hindrance factor in intra-bean diffusion

Green and medium-roast Kenyan arabica coffees were ground and sieved, and the 0·85–1·8 mm size fractions partially converted into two water-swollen forms by an appropriate series of treatments. The first form still contained a mix of coffee solubles, the second only caffeine. The rates of caffeine infusion into water at 80°C were then measured for the dry coffee and for the two water-swollen preparations. The caffeine was extracted two to three times faster from the solute-free water-swollen preparation than from the dry material Analysis of the results showed that counterflow of water the swelling of coffee particles, caffeine association with other solubes and physical restraints within the bean matrix all contribute to the low diffusion coefficient of caffeine inside the coffee particles. The behaviour of the green and the medium roast coffees was surprisingly similar.     

Stability of ochratoxin A (OTA) during processing and decaffeination in commercial roasted coffee beans

The fate of ochratoxin A (OTA) during the processing of artificially contaminated green coffee beans, the effect of decaffeination on the production of OTA in green and roasted coffee beans, and the effect of caffeine on the growth and OTA production by Aspergillus ochraceus were studied. The data indicated that the roasting, milling and decoction (brewing and Turkish coffee making) processes caused different percentage reductions in OTA. Decaffeinated samples showed a significantly higher concentration of OTA production than the caffeinated ones. A significantly higher percentage of OTA was reduced when the decaffeination process was performed before roasting treatment. Caffeine at 1.0 and 2.0% concentrations completely prevented OTA production and completely inhibited A. ochraceus growth in YES medium after 3-21 days.     

The impact of roasting on the ochratoxin A content of coffee

Roasting coffee led to a drop in the ochratoxin A (OTA) concentration, as measured by the reference method, especially for dark type roasts. The way the beverage was prepared also affected the OTA content, which could paradoxically be higher than that of the initial roasted coffee. Assays on the thermal stability of pure OTA showed that it ought to be found in larger quantities in roasted coffee. This suggested that OTA was masked by reactions with the substrate during roasting. The absence of OTA in green coffee is therefore the best guarantee of safety.     

Oxidative Degradation of Bisphenol A by Fruit Homogenates

ABSTRACT: The oxidative degradation of bisphenol A (BPA) by several fruit homogenates was investigated. Their homogenates were incubated with BPA at 25 °C for 0 to 120 min, and the acetone extracts were analyzed by high-performance liquid chromatography (HPLC) with a photodiode array detector (200 to 650 nm). The 2 degradation products (UK-1 and UK-2) from BPA were detected on HPLC chromatograms (280 nm). UK-1 and UK-2 were identified to be 2-(3,4-dihydroxyphenyl)-2-(4-ydroxyphenyl) propane, (3-OH-BPA) and 4-[1-(3,4-dihydroxyphenyl)-isopropyl]benzene-1,2-diol, (3,3'-diOH-BPA), respectively, by HPLC-MassPectrometry (LC-MS). In the process of incubation, the peak of 3-OH-BPA attained the maximum value in the 1st 20 min, and that of 3,3'-diOH-BPA increased more slowly, attaining the maximum in 50 min. On the other hand, incubation of 3-OH-BPA (instead of BPA) with grape homogenates gave the maximum peak of 3,3'-diOH-BPA in only 10 min. 3, 3'-diOH-BPA was a polyphenol compound that contained 4 hydroxyl groups. These results suggested that BPA would be degraded (converted) to brown pigments through the compounds of 3-OH-BPA and 3, 3'-diOH-BPA in some fruit homogenates.     

Cause of bisphenol A migration from cans for drinks and assessment of improved cans

In the previous investigation, we found that some cans for coffee and black tea drinks released large amounts of bisphenol A (BPA) into their contents. Equivalent cans were obtained and the cause of BPA migration was investigated. Equivalent cans A, B and D contained high levels of BPA in the side seam, in the bottom, and in the bottom and the side seam, respectively, while can C contained some level of BPA in the body, which has a large area, therefore, all of them contained high amounts of BPA in their coatings. In the migration test, there was no BPA migration from the cans into water at 60 and 95 degrees C for 30 min, into 20% ethanol at 60 degrees C for 30 min, or into n-heptane at 25 degrees C for 60 min. However, at 120 degrees C for 30 min, equivalent cans released 35-124 ng/mL BPA into the water. The total migration was similar to the total residues of BPA in the can coating and was close to the total amount of BPA in the drinks. Thus, BPA migration from the can coating requires heating to more than 105 degrees C, which is the glass transition temperature of the epoxy resin. Improved cans which contained less than 1/10 as much BPA as the equivalent cans showed very low migration levels, i.e., 3-6 ng/mL.     

Determination of Bisphenol A diglycidyl ether (BADGE) and its hydrolysis products in canned oily foods from the Austrian market

 Bisphenol A diglycidyl ether (BADGE) is determined in canned oily foods from Austria using a new simplified HPLC method. Samples are extracted with pentane, back extracted with methanol, and finally dissolved in the mobile phase (cyclohexane/tert–butyl methyl ether). Separation is performed on a normal-phase HPLC column using fluorescence detection. Verification of the BADGE-containing peak is carried out by using off-line GC-MS. Additionally, the synthesis and determination of BADGE hydrolysis products, Bisphenol A bis(2,3-dihydroxypropyl) ether (BADGE.2H₂O) and Bisphenol A glycidyl (2,3-dihydroxypropyl) ether (BADGE.H₂O) are presented. From 67 analyzed cans, containing various fatty meat or fish products, 16% were above the maximum quantity of 1 mg/kg tolerated by the European Community, 45% were in the range between 0.1–1 mg/kg, 24% between 0.02 and 0.1 mg/kg, and in 15% the BADGE concentrations were below the detection limit of 0.02 mg/kg. The hydrolysis product BADGE.H₂O was not detected in any sample, whereas BADGE.2H₂O was found in some samples up to a concentration of 0.5 mg/kg. Received: 11 May 1998 / Revised version: 1 July 1998     

Ochratoxin A (OTA) in coffee: nation-wide evaluation of data collected by German Food Control 1995-1999

The evaluation process involved data collected by Official Food Control Laboratories during the period 1995 until 1999. A total of 613 samples analysed for ochratoxin A and complying with a detection limit lower than 0.6 microg/kg were evaluated. With the assistance of statistical process analysis the median concentrations for green coffee (0.4 microg/kg), for roasted coffee (0.6 microg/kg), for decaffeinated roasted coffee along with low-acid decaffeinated roasted coffee (0.4 microg/kg) as well as for soluble coffee (0.7 microg/kg) were determined. The result is a mean daily total intake per consumer of 9 ng OTA.     

罐头涂料铁罐双酚A二缩水甘油醚及其衍生物迁移规律研究

研究了罐头涂料铁罐双酚A二缩水甘油醚及其衍生物在特定食品模拟物中的迁移规律。采用50%（v/v）乙醇溶液为食品模拟物,应用高效液相色谱-串联质谱法进行双酚A二缩水甘油醚及其衍生物的定性定量分析,并应用基于Fick扩散第二定律的D.Chung模型和基于概率与数理统计方法的Weibull模型进行了预测。结果表明:贮存条件对迁移总量变化影响显著,温度越高越快达到平衡,迁移平衡值为1.28 mg/kg;D.Chung模型中扩散系数D与贮存温度符合阿伦尼乌斯动力学模型,该模型预测值与实验值的拟合优度（R²）小于0.23,而Weibull模型拟合优度（R²）能达到0.90以上。因此,Weibull模型比D.Chung模型更接近实际迁移结果,为评估涂料铁罐的安全性提供参考。      

Bioactive composition and antioxidant potential of different commonly consumed coffee brews affected by their preparation technique and milk addition

Coffee is one of the most popular beverages in the world, prepared and consumed in many different ways. Taste, aroma and composition of the coffee brew vary depending on the preparation method. Therefore, this study investigates the effect of different brewing methods on the polyphenol and methylxanthine composition and antioxidant capacity of thirteen different coffee brews. The content of total phenols and flavonoids was determined spectrophotometrically and the content of chlorogenic acid derivates (3-CQA, 4-CQA and 5-CQA) and caffeine using the high performance liquid chromatography (HPLC-PDA). Antioxidant capacity of coffee brews was evaluated by using the ABTS (2,2-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid)) and FRAP (ferric-reducing antioxidant power) assays. Instant coffee brews showed the highest values in content of total phenols, chlorogenic acid derivates, caffeine and antioxidant capacity, which significantly decreased by milk addition. The antioxidant capacity of coffee brews was in compliance with the total phenol content and content of chlorogenic acid derivates.     

A deep eutectic solvent based liquid phase microextraction for the determination of caffeine in Turkish coffee samples by HPLC-UV

ABSTRACT

A novel liquid-phase microextraction procedure for the determination and extraction of caffeine using a deep eutectic solvent based liquid-phase microextraction method (DES-LPME) was developed. A deep eutectic solvent consisting of choline chloride-phenol (1:3) and tetrahydrofuran as a dilution solvent were used for the extraction of caffeine from Turkish coffee samples. The quantitative recoveries were obtained when the DES volume was 400 µL, and the volume of tetrahydrofuran that was used as an emulsifier solvent was 800 µL. The limit of detection and the limit of quantification were found to be 0.12 and 0.40 µg mL^?1, respectively. Linear dynamic range was 0.5–100 µg mL^?1, and coefficient of determination (R²) was 0.9998. The relative standard deviation (RSD) was 2.20% when the standard solution concentration was 1.0 µg mL^?1. The fact that the determination coefficient obtained from the calibration curve was greater than 0.9998 gives information about the accuracy of the method. Also, in order to determine the accuracy of the developed method, selected coffee samples were spiked with 25 and 50 µg mL^?1 caffeine.