摘要:

Capillary electrophoresis (CE) was utilized in the characterization of various galactomannans. Standards of gums were extracted with 50% CH3CN to remove the residual proteins from the gum matrix. Separation buffers were optimized with respect to pH, buffer concentration and presence of sodium dodecyl sulphate, yielding protein profiles from which the desired information could be obtained. Examples are given of the profiles generated by various gums and gum blends to aid in the verification of component presence, and to demonstrate levels of adulteration detectable under the buffer conditions used.

ISSN:0265-203X    

DOI:10.1080/026520300415255

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

A review is presented to show the advantages involved in the use of Flow Injection Analysis (FIA) for the determination of artificial sweeteners. The FI methods proposed for the determination of artificial sweeteners are described and compared on the basis of the detection technique used. Analytical data of interest and interferences are discussed for each sweetener.

ISSN:0265-203X    

DOI:10.1080/026520300415264

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

The xylanase used in this study was produced by a submerged fermentation of Fusarium venenatum and contained a gene code originating from Thermomyces lanuginosus. The enzyme was subject to a 13-week toxicological test in rats and in vitro tests to document its safety in use. The enzyme is to be applied as a processing aid in the baking industry to improve handling and stability of dough. The enzyme was not found to be mutagenic in the Salmonella typhimurium reverse mutation assay, nor did it cause chromosomal aberrations in cultured human lymphocytes. Oral administration to rats of up to 10.0ml/kgbw/day (equivalent to a Total Organic Solids dosage of 1.12g/kgbw/ day or a xylanase dosage of 89422FXU(W)/kgbw/day) for 13 weeks did not cause any adverse effect.

ISSN:0265-203X    

DOI:10.1080/026520300415273

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

The possibility of using automated equipment for solid phase extraction of isoniazid from milk has been investigated. This equipment provides two noteworthy advantages: it shortens the time of analysis and avoids SPE column plugging, stabilizing flow rates. After setting the correct programme on software controlling the equipment, some validation parameters have been determined to obtain recovery and repeatability data. The mean recovery for spiked samples resulted in the range 75–95%, the standard error ranged from -5 to -20% while the RSD varied from 2 to 22%. Therefore the method can be considered reliable and fast.

ISSN:0265-203X    

DOI:10.1080/026520300415282

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

The obvious toxicity of cadmium and lead is at the basis of compulsory concentration determinations for lixiviation solutions of ceramic and earthenware household receptacles such as cups, plates, bowls and others. Concentrations in the food simulant which exceed 0.100 ± 0.005mg Cd dm-2and 1.00 ± 0.05 mg Pb dm-2for flat receptacles, 0.500± 0.025 mg Cd l-1and 5.00± 0.25 mg Pb l-1for low volume (< 5 l) receptacles and 0.250 ± 0.025 mg Cd l-1and 2.50 ± 0.25 mg Pb l-1for high volume (> 5 l) receptacles are not acceptable and measures were taken by the EU member state authorities to enforce these norm concentrations. Generally, the uncertainty on the results forwarded by the legislation amounts to 5%. This value does not at all match the pronounced variability observed for several ‘identical’ trade samples, but rather represents the inherent variability of spectrometric analyses alone. Considering that the coefficients of variation can be as high as ˜30%, either the ranges of acceptable concentrations or the maximal allowable concentrations should be corrected. Aware of the negative health e? ects of heavy metal contamination and of the risk increase due to dietary intake, a downward adjustment of the acceptable concentration ranges to 0.07mg Cd dm-2± 12%, 0.30mg Cd l-1± 12% and 0.10 mg Cd l-1± 12% and to 0.8mg Pb.

ISSN:0265-203X    

DOI:10.1080/026520300415291

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Total, organic and inorganic arsenic and lead were measured from the muscle of different kinds of fish: skate (Raje spp.), hake (Merluccius merluccius) and blue whiting (Micromesistius poutassou), caught in the South Adriatic Sea (South Italy) in the period June–August 1995. The highest levels of total arsenic were found in skate (Raje spp.) whose values ranged from 14.4 to 61.5mg/kg ww, followed by blue whiting (M. poutassou) and hake (M. merluccius) that showed lower levels ranging from 8.5 to 21.5mg/kg ww and from 5.9 to 16.1mg/kg ww, respectively. In all the species examined most of this element was present as organic compounds while inorganic arsenic was only a very modest percentage (0.47–3.5%) of the total arsenic present. Lead in all species analysed was at small concentrations with mean values ranging from 0.12 to 0.15mg/kg ww. According to the rules in force in Italy no samples showed concentrations of lead exceeding the peak value of 2 mg/kg.

ISSN:0265-203X    

DOI:10.1080/026520300415309

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

New analytical procedures and sample mineralizations for the determination of copper, lead, cadmium, zinc and mercury in matrices such as mussels, clams and fishes are proposed. An H2SO4HNO3acidic mixture was used for the determination of copper, lead, cadmium and zinc. In the case of mercury, the sample digestion was performed using a concentrated supra pure H2SO4K2Cr2O7mixture and the results compared with those from other conventional methods. Differential pulse anodic stripping voltammetry (DPASV) was employed for simultaneously determining copper, lead, cadmium and zinc, while the mercury determination was carried out by cold vapour atomic absorption spectrometry (CV-AAS) with reduction with SnC2, using an innovative method for sample dissolution. The analytical quality control procedures have been verified on three reference standard materials: Oyster Tissue NIST 1566, Mussel Tissue BCR-CRM 278 and Cod Muscle BCR-CRM 422. For all the elements in the certified matrices, the precision, expressed as relative standard deviation (Sr), and the accuracy, expressed as relative error (e), were of the order of 3–5%, while the detection limits were in the range 0.010–0.080 μg/g.

ISSN:0265-203X    

DOI:10.1080/026520300415318

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Concentrations of aluminium, arsenic, cadmium, chromium, copper, lead, mercury, nickel, selenium, tin and zinc were determined in samples from the 1997 UK Total Diet Study and used to estimate dietary exposures of the general UK population. Population average dietary exposures to aluminium (3.4mg/day), arsenic (0.065mg/day), cadmium (0.012mg/day), chromium (0.10mg/day), copper (1.2mg/day), mercury (0.003mg/day), nickel (0.13mg/day), tin (1.8mg/ day) and zinc (8.4mg/day) are similar to those from previous UK Total Diet Studies and are below the appropriate PTWIs, PMTDIs and TDIs. Dietary exposure of the UK population (0.026 mg/day) to lead is falling as a result of measures taken to reduce lead contamination of the environment and food and is well below the PTWI. There has been little change in UK estimates of selenium exposure since the 1994 Total Diet Study but current estimates (0.039mg/day) are lower than those derived from earlier Total Diet Studies.

ISSN:0265-203X    

DOI:10.1080/026520300415327

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Vibrio vulnificus and V. parahaemolyticus are natural inhabitants of estuarine environments and may be transmitted to humans by ingestion of raw oysters. This study focused on the use of low temperature pasteurization, to reduce these Vibrio spp. to nondetectable levels, thus reducing the risk of infection associated with raw oyster consumption. Artificially inoculated V. vulnificus and V. parahaemolyticus and naturally-contaminated V. vulnificus in live oysters were pasteurized at 50°C for up to 15min. Samples of processed and unprocessed oysters were enumerated for V. vulnificus, V. parahaemolyticus, and aerobic spoilage bacteria for 0–14 days. Low temperature pasteurization was effective in reducing these pathogens from > 100000 to non-detectable levels in less than 10min of processing. Spoilage bacteria were reduced by 2–3 logs, thus increasing the shelf-life for up to 7 days beyond live unprocessed oysters. Vibrio vulnificus in control oysters was reduced by 102during ice storage alone. Following pasteurization and during a temperature storage abuse study (24h at 22°C), V. vulnificus was not recovered. During this storage period spoilage bacteria exceeded 1 million/g oyster meat.

ISSN:0265-203X    

DOI:10.1080/026520300415336

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

The results of more than 450 samples taken from the literature and 400 samples tested by our own investigations have been taken into account to quite extensively describe the situation of OTA contamination of wine. According to these data OTA is much more commonly detected in red wines than in rose and white wines and the OTA concentration is remarkably higher than in the last two. Thus OTA could be detected in 25% of white wine samples whereas it was detected in 40% of rose and 54% of red wine samples. The same result was found when comparing the wines from southern and northern regions. Here the red wine samples from the northern cultivating area showed a contamination of 12% in contrast to those from the southern area which showed a contamination of about 95%.

ISSN:0265-203X    

DOI:10.1080/026520300415345

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor