Occurrence of caffeine,saccharin, benzoic acid and sorbic acid in soft drinks and nectars in Portugal and subsequent exposure assessment

A reliable method for the determination of benzoic and sorbic acids, caffeine and saccharin in soft drink and nectars using high performance liquid chromatography and UV detection was validated. The chromatographic separation was achieved with a C18 column (250 × 4.6 mm) and one buffered mobile phase, KH₂PO₄ 0.02 M/ACN (90:10)/phosphoric acid at pH 4.2. The effluent was monitored at 220 nm.     

A screening method for the determination of ascorbic acid in fruit juices and soft drinks

A simple and rapid liquid chromatographic method based on a new stationary phase Teknokroma, Tr-010065 Mediterranea sea₁₈ (15 cm × 0.4 cm, id 3 μm), to determine ascorbic acid in beverages is reported. With the proposed method the samples were analysed by direct injection without a previous treatment. The total analysis time does not exceed 6 min. The method showed a good repeatability (RSD < 2%: n = 6) and an excellent sensitivity (LOD = 0.01 mg/l). Seventeen samples were analysed, including fruit juices, soft drinks and isotonic beverages. Ascorbic acid contents ranged from 6.6 to 840 mg/l. The ascorbic acid stability in some beverages during their shelf-life was also evaluated. Degradation of about 54% was observed in a tea drink.     

Improved method for the determination of benzene in soft drinks at sub-ppb levels

An automated, simple, and reproducible method based on isotope dilution headspace gas chromatography/mass spectrometry developed previously for the determination of benzene in soft drinks was further improved by adding sodium sulfate to samples, lowering the gas chromatography oven starting temperature to narrow benzene peak width, and increasing sample injection volume. This improved method had a lower detection limit (0.016 µg l^-1) and good repeatability, and was used in a follow-up survey to assess benzene levels in 139 samples of soft drink products. Benzene was detected in 67% of the 139 products tested. Compared with the previous survey, the average benzene concentrations in most products from this survey were lower, and only a few products had benzene at elevated levels.     

Identification and quantification of Class IV caramels using capillary electrophoresis and its application to soft drinks

A capillary electrophoresis method was developed for the analysis of Class IV caramels using sodium carbonate buffer at pH 9·5. A relationship was established between the migration time of the coloured ‘caramel’ peak and the caramel's sulphur content. There was also a linear relationship between the concentration of caramel solids in water and the peak area of the ‘caramel’ peak in the range 0·1–10 g litre⁻¹. A range of soft drinks was analysed for caramel. Seven non-diet and 12 diet cola products had Class IV caramel of high-sulphur, high-nitrogen content at concentrations estimated to be between 0·57 and 0·82 g solids litre⁻¹. © Crown Copyright 1998.     

Aluminium content of soft drinks from aluminium cans

The aluminium (A1) content of soft drinks from A1 cans has been measured during 12 months of storage, by the graphite furnace atomic absorption spectrophotometry (GFAAS) method. The results show that the A1 content in all soft drinks increased during the whole storage time. This increase was a result of dissolution of A1 from the can wall due to the presence of aggressive ingredients in the soft drinks, mainly acids. The A1 content rose with increasing acid concentration and decreasing pH value of the soft drinks. The evaluated possible daily intake of A1 (0.8 mg) through consumption of these drinks was practically negligible in relation to total daily dietary Al intake, as well as to tolerable daily intake. Thus, soft drinks from A1 cans are an insignificant source of dietary A1 intake and it appears that the A1 intake from this source should not be a cause for concern in regard to A1 toxicity for the human body.

---

Alnminiumgehalte in Erfrischungsgetränken aus Aluminiumdosen

Zusammenfassung Es wurde der Aluminiumgehalt in Erfrischungsgetränken aus Aluminiumdosen im Laufe von zwölf Monaten Lagerzeit durch GFAAS gemessen. Der Aluminiumgehalt nimmt in allen Proben im Laufe der erwähnten Lagerungszeit zu als Folge des Lösens von der inneren Dosenseite her durch das VorhandenScin von aggressiven Bestandteilen in Erfrischungsgetränken, vor allem durch Säuren. Der Aluminiumgehalt steigt mit der Säurekonzentration, d. h. mit der Abnahme des pH-Wertes, in Getränken. Die Tagesaufnahme von Aluminium (0,8 mg) durch den Konsum dieser Getränke ist allerdings bedeutungslos im Vergleich mit der Gesamttagesaufnahme von Aluminium durch die Nahrung sowie im Vergleich mit der zugelassenen Tagesaufnahme. Aus diesem Grunde stellen Erfrischungsgetränke aus Aluminiumdosen keine beachtenswerte Quelle der Aluminiumaufnahme dar.

     

Determination of total arsenic in soft drinks by hydride generation atomic fluorescence spectrometry

A highly sensitive and simple method has been developed for the determination of total arsenic, by continuous hydride generation and atomic fluorescence spectrometry (HGAFS), in refreshing drink samples as colas, teas and fruit juices. Samples were mixed with concentrated HCl and KI to obtain final concentrations of 2 mol l⁻¹ and 1%, respectively. These solutions were aspirated and merged with a reducing NaBH₄ 3% (m/v) solution, with sample and NaBH₄ flow rates of 12.5 and 1.5 ml min⁻¹, respectively. The hydride generated in a 170 cm reaction coil was transported to the detector with an Ar flow of 400 ml min⁻¹. The recovery values of added concentrations, from 0.1 to 0.9 ng ml⁻¹, of arsenic in colas, teas and fruit juices were 94 ± 5, 101 ± 9 and 94 ± 6, respectively, achieving variation coefficients between 0.1% and 9%, confirming the accuracy of developed procedure. Detection limit, ranged from 0.01 to 0.03 ng ml⁻¹. On comparing the direct determination with a reference procedure made after dry ashing operation it can be noticed that the direct approach provides a simplification of the handling and time consuming, achieving statistically comparative results.     

Determination of synthetic phenolic antioxidants in soft drinks by stir-bar sorptive extraction coupled to gas chromatography-mass spectrometry

The synthetic phenolic antioxidants butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT) and tert-butyl hydroquinone (TBHQ) were pre-concentrated by stir-bar sorptive extraction and thermally desorbed (SBSE-TD) before analysis by GC-MS. Several parameters affecting the derivatisation step and both SBSE extraction and thermal desorption were carefully optimised. When the analyses of BHA and TBHQ in their acetylated, silylated and underivatised forms were compared, the best results were obtained when the in-situ derivatisation procedure with acetic anhydride was employed. Quantification was carried out using carvacrol as the internal standard, providing quantification limits of between 0.11 and 0.15 ng ml^?1, depending on the compound. Recovery assays for samples spiked at two concentration levels, 1 and 5 ng ml^?1, provided recoveries in the 81–117% range. The proposed method was applied in the analysis canned soft drinks and the analytes were found in five of the 10 samples analysed.     

钛胶反相高效液相色谱法测定饮料中的咖啡因

建立了利用钛胶反相柱快速测定饮料中咖啡因的含量的高效液相色谱方法.色谱条件:分离柱为Titania Sachtopore - RP柱(250mm×4.6mm i.d.,5μm),柱温30℃,流动相为水∶甲醇=83∶17 (V/V),流速1 mL/min,检测波长273nm.线性范围为12 - 900μg/mL,此范围内标准曲线线性良好(R2=0.9998).最低检出限(S/N =3)为0.03 μg/mL,样品加标回收率范围为98.6％～102.2％,精密度即相对标准偏差(n=9)小于0.23％.本法简单易操作、分析速度快,精密度和准确度均取得满意效果,适用于各种饮料样品中咖啡因的定量分析.本研究不仅是对食品中咖啡因检测方法的补充,更重要的是发挥了钛胶固定相不可比拟的优势.     

运动饮料的开发

论述了运动饮料配方设计的理论基础,举例说明了一种运动饮料的开发,并对运动饮料的发展方向提出了建议。     

安神降脂功能性饮料的研制

安神降脂功能性饮料是针对目前日益增加的危害或者影响到人们健康的两大公共卫生:血脂异常以及睡眠不好而研制的功能性饮料。该饮料以山楂汁为基础饮料加入银杏叶提取物、酸枣仁提取物以及由高粱麸皮酿制的陈醋,并且加入低热量的醇类甜味剂麦芽糖醇,使得产品不仅适合正常人群也适合糖尿病人群食用。     

Determination of three dyes in commercial soft drinks using HLA/GO and liquid chromatography

Allura Red, Sunset Yellow, and Tartrazine usually present in commercial soft drinks were accurately quantified using HLA/GO method, a net analyte signal-based method, without the need for solutes separation. The obtained percent recoveries (R.S.D.) of dyes were 99.8 (2.8), 102 (3.3), and 100 (4.5) for Allura Red, Sunset Yellow, and Tartrazine, respectively. The calibration method was applied for analysis of food dyes in powdered soft drinks with minimum sample preparation measures. The proposed HLA/GO method was validated against a standard HPLC method. Statistical analyses showed insignificant differences between the results of two methods. The developed HLA/GO method offers a simple and rapid procedure for determination of food dyes in powdered soft drinks in comparison with HPLC methodology.     

Simultaneous determination of Sunset yellow and Tartrazine in soft drinks using gold nanoparticles carbon paste electrode

The monitoring of synthetic dyes in foods is very important due to their potential harmfulness to human beings. Herein, a carbon-paste electrode (CPE) that is chemically modified with gold nanoparticles (nAu) was fabricated and used for the determination of Sunset yellow (SY) and Tartrazine (Tz). Cyclic and differential pulse voltammetry (CV and DPV) results revealed two well-resolved anodic peaks for SY and Tz with remarkably increase in oxidation signals of these colourants. Based on this, a novel electrochemical method was developed for the simultaneous determination of SY and Tz. High sensitivity and selectivity, sub-micromolar detection limit, high reproducibility and regeneration of the electrode surface by simple polishing make the nAu-CPE electrode very suitable for the determination of SY and Tz in commercially available soft drinks. The detection limits was 3.0 × 10⁻⁸ and 2.0 × 10⁻⁹ mol l⁻¹ for SY and Tz, respectively, which are remarkably lower than those reported previously for SY and Tz using other modified electrodes.     

酸性含乳饮料中蛋白质稳定性的研究进展

综述了不同类型的卡拉胶和果胶在乳饮料中与酪蛋白的作用机理，并介绍了影响酸乳饮料稳定性的主要因素。     

植物蛋白饮料增稳研究

增稳是植物蛋白饮料加工中最为关键技术,该文介绍植物蛋白饮料失稳机理,并从饮料体系组成性质和加工工艺两方面综述植物蛋白饮料开发中增稳关键事项。     

Rapid enumeration of low numbers of moulds in tea based drinks using an automated system

Aseptically prepared cold drinks based on tea have become popular worldwide. Contamination of these drinks with harmful microbes is a potential health problem because such drinks are kept free from preservatives to maximize aroma and flavour. Heat-tolerant conidia and ascospores of fungi can survive pasteurization, and need to be detected as quickly as possible. We were able to rapidly and accurately detect low numbers of conidia and ascospores in tea-based drinks using fluorescent staining followed by an automated counting system. Conidia or ascospores were inoculated into green tea and oolong tea, and samples were immediately filtered through nitrocellulose membranes (pore size: 0.8 μm) to concentrate fungal propagules. These were transferred onto potato dextrose agar and incubated for 23 h at 28 °C. Fungi germinating on the membranes were fluorescently stained for 30 min. The stained mycelia were counted selectively within 90 s using an automated counting system (MGS-10LD; Chuo Electric Works, Osaka, Japan). Very low numbers (1 CFU/100 ml) of conidia or ascospores could be rapidly counted, in contrast to traditional labour intensive techniques. All tested mould strains were detected within 24 h while conventional plate counting required 72 h for colony enumeration. Counts of slow-growing fungi (Cladosporium cladosporioides) obtained by automated counting and by conventional plate counting were close (r² = 0.986). Our combination of methods enables counting of both fast- and slow-growing fungi, and should be useful for microbiological quality control of tea-based and also other drinks.     

微波制取香蕉绿茶饮料的研究

以香蕉、番茄、绿茶、蒸馏水等为主要原料,采用微波技术制作香蕉绿茶饮料,并对香蕉果肉中多酚氧化酶的活性及香蕉与番茄配比、维生素C和EDTA-2Na添加量等因素对香蕉绿茶饮料品质的影响进行了研究。通过正交实验,确定香蕉绿茶饮料的最佳配方为茶水比1∶125、香蕉汁10％、本糖醇1．5％、维生素C0．01％、EDTA- 2Na100mg/L,产品汤色清澈明亮、香气纯正、有明显香蕉风味。     

Migration measurement and modelling from poly(ethylene terephthalate) (PET) into soft drinks and fruit juices in comparison with food simulants

Poly(ethylene terephthalate) (PET) bottles are widely used for beverages. Knowledge about the migration of organic compounds from the PET bottle wall into contact media is of interest especially when post-consumer recyclates are introduced into new PET bottles. Using migration theory, the migration of a compound can be calculated if the concentration in the bottle wall is known. On the other hand, for any given specific migration limit or maximum target concentration for organic chemical compounds in the bottled foodstuffs, the maximum allowable concentrations in the polymer C _P,0 can be calculated. Since a food simulant cannot exactly simulate the real migration into the foodstuff or beverages, a worse-case simulation behaviour is the intention. However, if the migration calculation should not be too overestimative, the polymer-specific kinetic parameter for migration modelling, the so-called A _P value, should be established appropriately. One objective of the study was the kinetic determination of the specific migration behaviour of low molecular weight compounds such as solvents with relatively high diffusion rates and, therefore, with high migration potential from the PET bottle wall into food simulants in comparison with real beverages. For this purpose, model contaminants were introduced into the bottle wall during pre-form production. The volatile compounds toluene and chlorobenzene were established at concentrations from about 20–30 mg kg^?1 to 300–350 mg kg^?1. Phenyl cyclohexane was present at concentrations of 35, 262 and 782 mg kg^?1, respectively. The low volatile compounds benzophenone and methyl stearate have bottle wall concentrations of about 100 mg kg^?1 in the low spiking level up to about 1000 mg kg^?1 in the highly spiked test bottle. From these experimental data, the polymer specific parameters (A _P values) from mathematical migration modelling were derived. The experimental determined diffusing coefficients were determined, calculated and compared with literature data and an A _P′ value of 1.0 was derived thereof for non-swelling food simulants like 3% acetic acid, 10% ethanol or iso-octane. For more swelling condition, e.g. 95% ethanol as food simulant, an A _P′ value of 3.1 seems to be suitable for migration calculation. In relation to PET recycling safety aspects, maximum concentrations in the bottle wall were established for migrants/contaminants with different molecular weights, which correspond with a migration limit of 10 μg kg^?1. From the experimental data obtained using food simulants and in comparison with beverages, the most appropriate food simulant for PET packed foods with a sufficient but not too overestimative worse-case character was found to be 50% ethanol. In addition, it can be shown that mass transport from PET is generally controlled by the very low diffusion in the polymer and, as a consequence, partitioning coefficients (K _P/F values) of migrants between the polymer material and the foodstuff do not influence the migration levels significantly. An important consequence is that migration levels from PET food-contact materials are largely independent from the nature of the packed food, which on the other hand simplifies exposure estimations from PET.     

Aluminium contents in baked meats wrapped in aluminium foil

In this investigation, the effect of cooking treatments (60 min at 150 °C, 40 min at 200 °C, and 20 min at 250 °C) on aluminium contents of meats (beef, water buffalo, mutton, chicken and turkey) baked in aluminium foil were evaluated. Cooking increased the aluminium concentration of both the white and red meats. The increase was 89–378% in red meats and 76–215% in poultry. The least increase (76–115%) was observed in the samples baked for 60 min at 150 °C, while the highest increase (153–378%) was in samples baked for 20 min at 250 °C. It was determined that the fat content of meat in addition to the cooking process affected the migration of aluminium (r² = 0.83; P < 0.01). It was also found that raw chicken and turkey breast meat contained higher amounts of aluminium than the raw chicken and turkey leg meat, respectively. Regarding the suggested provisional tolerable daily intake of 1 mg Al/kg body weight per day of the FAO/WHO Expert Committee on Food Additives, there are no evident risks to the health of the consumer from using aluminium foil to cook meats. However, eating meals prepared in aluminium foil may carry a risk to the health by adding to other aluminium sources.     

Classification of stevia sweeteners in soft drinks using liquid chromatography and time-of-flight mass spectrometry

The aim of this study was to develop a comprehensive analytical method for the characterisation of stevia sweeteners in soft drinks. By using LC and time-of-flight MS, we detected 30 steviol glycosides from nine stevia sweeteners. The mass spectral data of these compounds were applied to the analysis to determine steviol glycosides in nine soft drinks. On the basis of chromatographic data and principal-component analysis, these soft drinks were classified into three groups, and the soft drinks of each group, respectively, contained high-rebaudioside A extract, normal stevia extract or alfa-glucosyltransferase–treated stevia extract.     

羧甲基纤维素钠对酸性乳饮料稳定作用的研究

通过测定添加不同含量的羧甲基纤维素钠(CMC)对酸性乳饮料的沉淀率、粘度、粒径分布、水分子流动性及Zeta电位的影响,研究了CMC对酸性乳饮料的稳定作用。结果表明,CMC对酸性乳饮料的稳定作用表现为使产品的沉淀率降低,粘度升高,在微观性质上表现为使产品的粒径减小,水分流动性减弱,Zeta电位的绝对值升高。