摘要:

A method for identifying refined vegetable fats added to chocolate (cocoa butter equivalents, CBEs) was combined with established quantitative methods for determining the level of vegetable fat added to cocoa butter with the aim of providing improved precision. The identification of fats was based on the analysis of sterol and triterpene alcohol degradation products formed during the processing of the fat. The procedure was able to successfully discriminate between 95% of pairs of fats from a set (33) of CBE-type vegetable fats. Subsequent analysis of 80 mixtures of four CBEs with chocolate successfully identified, on cross-validation, 94% of the samples. Combining the qualitative procedure with established quantitative methodology, based on the analysis of triacylglycerols, improved the method precision from ± 2.1% to ± 0.3% (5% addition of CBE at 95% confidence). Identifying the fat analytically permits the use of quantitative methods for determining the level of added fat in chocolate that have improved precision in comparison with the measurement of an unidentified fat. This may obviate the need to use factory inspection as a means to identify the ingredients of a product and monitor compliance with proposed legislation.

ISSN:0265-203X    

DOI:10.1080/02652030050083178

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Raw materials, intermediates and subsidiary colours in Food Yellow No. 5 (Sunset Yellow FCF) were determined using liquid chromatography/mass spectrometry (LC/MS) with electrospray ionization. A gradient consisting of acetonitrile and 0.04% aqueous ammonium carbonate solution was used for the HPL C mobile phase. Quasi-molecular ions of impurities were used as monitor ions. It was necessary to use fragment ions of the sodium salts of 6-hydroxy-5-phenylazo-2-naphthalenesulphonic acid (SS-AN) and 4-(2- hydroxy-1- naphthylazo) benzenesulphonic acid (2N-SA) as monitor ions because the compounds are not resolved by chromatography and have the same molecular weight. Fifteen samples of commercial Sunset Yellow FCF were examined. The results obtained by UV-Vis spectroscopy were in good agreement with the results of LC/MS analyses. The detection limits of the impurities in Sunset Yellow FCF ranged from 0.01 to 0.1%.

ISSN:0265-203X    

DOI:10.1080/02652030050083187

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Raw milk samples collected from tanker trucks are routinely screened for β-lactam antibiotic drug residues using rapid screening tests. If drug residues are detected, the milk may be shipped on ice blocks to a laboratory for further analysis. A study was conducted to determine the stability of ampicillin in raw milk stored at +4°C in order to predict if shipping the milk would result in the degradation of ampicillin residues. Milk samples were spiked with 20ppb ampicillin, stored at +4°C and -70°C for 1–6 days, and then analysed by HPLC with fluorescence detection. No loss of ampicillin residues was found in milk stored at +4°C for 1–6 days.

ISSN:0265-203X    

DOI:10.1080/02652030050083196

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

The cadmium content of muscle, liver, kidney and blood samples from 62 horses slaughtered in Italy was investigated. Cadmium was determined by graphite furnace atomic absorption spectrometry (GFAAS) after wet digestion of the samples. The mean and median contents of all samples were (on a fresh weight basis) 75 and 41 μgkg-1for muscle, 2.46 and 2.10 mgkg-1for liver, 20.0 and 13.5 mgkg-1for kidney. The cadmium level in blood samples was always below 6 μgl-1. The cadmium concentrations in muscle, liver and kidney were found to be related to the life span of the specimens and increased with age. Females exhibited higher levels than males, but this difference was significant only in the case of muscle tissue. The geographical origin was recognized as the main factor influencing the cadmium content of the equine specimens analysed. The differences between horses coming from the three main breeding countries considered in this study (Poland, Lithuania, Hungary) were marked and statistically significant. The average intake of cadmium from equine meat was estimated for the general population and for population groups resident in areas with high consumption of this food item. While the cadmium intake from equine meat for the average consumer accounts for about 1% of the total cadmium intake estimated for Italy, in the latter case the enhanced consumption of equine muscle is often accompanied with the consumption of substantial quantities of equine liver and this may lead to high cadmium intakes.

ISSN:0265-203X    

DOI:10.1080/02652030050083204

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Three types of commercial sweet corn hybrids [sugary (su1), shrunken or ‘supersweet’ (sh2) and sugary enhancer (se1)] were silk channel inoculated in 1996 and 1997 with a macroconidial suspension of Fusarium graminearum to determine how early the mycotoxin deoxynivalenol accumulates in kernels. Disease symptoms rapidly developed on all hybrids and were apparent 4 days after inoculation. Symptoms stabilized by 28 days after inoculation. Toxin levels were greater than 1 μg/g in kernels as early as 2 weeks after silk emergence and rapidly increased to extremely high levels. Susceptibility in all hybrids decreased as the silk dried out. Deoxynivalenol concentrations were correlated to disease severity. There was some indication that the sh2 genotype was more susceptible than the su1 or se1 genotypes. These results suggest that improvement needs to be made in sweet corn with respect to resistance to gibberella ear rot.

ISSN:0265-203X    

DOI:10.1080/02652030050083213

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

The advent of the functional barrier concept in food packaging has brought with it a requirement for fast tests of permeation through potential barrier materials. In such tests it would be convenient for both foodstuffs and materials below the functional barrier (sub-barrier materials) to be represented by standard simulants. By means of inverse gas chromatography, liquid paraffin spiked with appropriate permeants was considered as a potential simulant of sub-barrier materials based on polypropylene (PP) or similar polyolefins. Experiments were performed to characterize the kinetics of the permeation of low molecular weight model permeants (octene, toluene and isopropanol) from liquid paraffin, through a surrogate potential functional barrier (25 μm-thick oriented PP) into the food simulants olive oil and 3% (w/v) acetic acid. These permeation results were interpreted in terms of three permeation kinetic models regarding the solubility of a particular model permeant in the post-barrier medium (i.e. the food simulant). The results obtained justify the development and evaluation of liquid sub-barrier simulants that would allow flexible yet rigorous testing of new laminated multilayer packaging materials.

ISSN:0265-203X    

DOI:10.1080/02652030050083222

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

The retention of alpha-tocopherol (vitamin E) in lowdensity polyethylene (LDPE) film was investigated when in contact with different food-simulating liquids. Variations of the aqueous food simulants approved by the EU for testing of interactions between packaging materials and food, and an alternative fatty food simulant (95% aqueous ethanol) were used to study the influence of trace metals and acids, as well as variation in pH and ethanol concentration, on the stability of α-tocopherol in the L DPE film. The presence of trace metals in aqueous media accelerated loss of α-tocopherol from the film, while the addition of citric or ascorbic acid counteracted this loss. In contact with aqueous ethanol at a concentration of 50% or higher, the loss of α-tocopherol from the film was total. However, with solutions containing less than 50% ethanol, the antioxidant was almost completely retained in the film, unless the temperature was increased from 6 to 40°C. For contact with solutions containing ethanol or trace metals, an increase in temperature resulted in a greater loss α-tocopherol from the LDPE film.

ISSN:0265-203X    

DOI:10.1080/02652030050083231

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor