摘要:

The solid-state stability of aspartame hemihydrate (APM) sweetener during thermal treatment is important information for the food industry. The present study uses the novel technique of Fourier transform infrared microspectroscopy equipped with differential scanning calorimetry (FT-IR/DSC microscopic system) to accelerate and determine simultaneously the thermaldependent impurity formation of solid-state APM. The results indicate a dramatic change in IR spectra from 50, 110 or 153°C, which was respectively attributed to the onset temperature of water evaporation, dehydration and cyclization processes. It is suggested that the processes of dehydration and intramolecular cyclization occurred in the solid-state APM during the heating process. As an impurity, 3-carboxymethyl-6-benzyl-2,5-diketopiperazine (DKP) degraded from solid state APM via intramolecular cyclization and liberation of methanol. This was evidenced by this novel FT-IR/DSC microscopic system in a one-step procedure.

ISSN:0265-203X    

DOI:10.1080/026520300420385

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

A survey was carried out to investigate the prevalence of nicarbazin residues in eggs in Northern Ireland. Nicarbazin, in the form of 4,4′-dinitrocarbanilide (DNC), was detected in 39 of the 190 eggs analysed. An experiment was designed to establish the relationship between nicarbazin-contaminated feed and nicarbazin residues in eggs. The concentrations of both the DNC and 4,6-dimethyl-2-hydroxypyrimidine (DHP) components of the drug in eggs were proportional to feed levels. The maximum feed nicarbazin concentration of 12.1mg/kg (8.6 mg/kg DNC and 3.5mg/kg DHP) gave rise to mean maximum whole egg concentrations of 631 μg/kg DNC and 51.8 μg/kg DHP. After withdrawal of the experimental diet, DNC was undetectable in eggs after 12 days and DHP after 3 days. Feed contaminated with nicarbazin at concentrations greater than about 2mg/kg gave rise to egg DNC residues at concentrations greater than the Differential Action L imit (DAL) set by the UK (100 μg/kg). DNC was contained almost entirely in the yolk of the egg, whereas DHP was distributed between albumen and yolk in a ratio of approximately 3:1.

ISSN:0265-203X    

DOI:10.1080/026520300420394

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

ISSN:0265-203X    

DOI:10.1080/026520300420402

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Market basket food samples from six Canadian cities collected from 1992 to 1996 were analysed for pesticide residues. One hundred and thirty-six composites were prepared for each city, representing 99% of the Canadian diet. Residues were found most frequently in peanut butter and butter. DDE, malathion and captan occurred most frequently, while the fungicides chlorothalonil, dicloran and captan were present in the highest concentrations. Processed commodities contained fewer residues and at lower concentrations than the raw products. No residues were detected in either milk or soy-based infant formula. Of the infant foods sampled, fruit contained both the greatest number and highest concentrations of pesticides.

ISSN:0265-203X    

DOI:10.1080/026520300420411

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Field trials were carried out to study the persistence of acephate and buprofezin on olives. Two cultivars, pizz'e carroga and pendolino, with very large and small fruits respectively were used. After treatment, no difference was found between the two pesticide deposits on the olives. The disappearance rates, calculated as pseudo first order kinetics, were similar for both pesticides (on average 12 days). Methamidophos, the acephate metabolite, was always present on all olives, and in some pendolino samples it showed higher residues than the maximum residue limit (MRL). During washing, the first step of olive processing, the residue level of both pesticides on the olives did not decrease. After processing of the olives into oil, no residues of acephate or methamidophos were found in the olive oil, while the residues of buprofezin were on average four times higher than on olives.

ISSN:0265-203X    

DOI:10.1080/026520300420420

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

ISSN:0265-203X    

DOI:10.1080/026520300420439

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

ISSN:0265-203X    

DOI:10.1080/026520300420448

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

During June to September 1999, 31 samples of raw milk were obtained from individual farms and 70 samples of ultrahigh-temperature-treated (UHT) milk (18 samples of whole milk, 22 of semi-skimmed and 30 samples of skimmed milk) were collected in supermarkets in Lisbon, Portugal. The total number of samples analysed was 101. The incidence of aflatoxin M1(AFM1

ISSN:0265-203X    

DOI:10.1080/026520300420457

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Eighty-one samples of corn products were acquired from markets and supermarkets in the city of Campinas, SP, Brazil, and were analysed for fumonsins B1and B2(FB1and FB2). Forty samples (49%) were positive for FB1

ISSN:0265-203X    

DOI:10.1080/026520300420466

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

The levels of bisphenol-F-diglycidyl ether (BFDGE) were quantified as part of a European survey on the migration of residues of epoxy resins into oil from canned fish. The contents of BFDGE in cans, lids and fish collected from all 15 Member States of the European Union and Switzerland were analysed in 382 samples. Cans and lids were separately extracted with acetonitrile. The extraction from fish was carried out with hexane followed by re-extraction with acetonitrile. The analysis was performed by reverse phase HPL C with fluorescence detection. BFDGE could be detected in 12% of the fish, 24% of the cans and 18% of the lids. Only 3% of the fish contained BFDGE in concentrations considerably above 1mg/kg. In addition to the presented data, a comparison was made with the levels of BADGE (bisphenol-A-diglycidyl ether)analysed in the same products in the context of a previous study.

ISSN:0265-203X    

DOI:10.1080/026520300420475

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor