摘要:

Potassium sorbate can undergo oxidation to form carbonyl moieties and cause browning. This investigation studied the fate of the compounds produced by auto-oxidation of potassium sorbate and measured the browning in the presence of amines. Experimental plans in which four factors were combined (temperature, oxygen, amine and light) led to the observation that the interaction between oxygen and high temperature (75°C) favoured browning, independently of the presence of amine. At 4°C, the amine seemed to cause a decrease in the proportion of carbonyl-containing compounds which would appear to participate in carbonylamine reactions. At 75°C, the amine forms adducts with the potassium sorbate. In parallel, high temperature favours auto-oxidation reactions that produce carbonyls. GC/MS and NMR analysis of the reaction products of potassium sorbate/amine mixtures led to the identification of cyclic products.

ISSN:0265-203X    

DOI:10.1080/02652030050207729

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

A simple, rapid and inexpensive method has been developed for the determination of benzo[a

ISSN:0265-203X    

DOI:10.1080/02652030050207738

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

New controlled release water-soluble formulations of sorbic (2,4-hexadienoic) acid were prepared and their inhibitory activity on mycelium growth of Fusarium oxysporum f.sp.radicis-cucumerinumwas evaluated. The new products are epoxidized polymers of polyvinylpyrrolidone (PVP) containing covalently bonded sorbic acid (polymeric esters of sorbic acid) and complexes of PVP with hydrogen bonded sorbic acid, characterized by controlled release of sorbic acid. It was shown that the polymeric complexes of sorbic acid with PVP were more effective fungicidal agents than sorbic acid polymeric esters. In all cases the activity of polymeric derivatives (esters and complexes) was increased by lowering the molecular weight of the polymeric carriers. Controlled release formulations of these polymeric derivatives are new promising products due to their low toxicity, wide range of efficient concentrations for application and ability to regulate lyophilicity. Our data contribute to the understanding of the action mechanism of various polymeric sorbic acid formulations and can result in products which are particularly suitable for food and feed protection applications.

ISSN:0265-203X    

DOI:10.1080/02652030010002289

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

The EC official method of total SO2analysis in grape juice was modified in 1990. The main improvements concerned the amount and concentration of H3PO4used during the distillation to recover the combined SO2and the standardization of the distillation time at 15min. This comparative study evaluated the total SO2level of 12 grape juices determined by five methods, including distillation, iodimetric and enzymatic-based methods. Attention was focused on the total SO2legal limit of 10mg/l fixed in Europe for grape juice. Analysis of variance disclosed a significant difference among the total SO2content in grape juices determined by five methods. Each analytical method showed limits in relation of their ability to release the combined SO2. In particular, the SO2bonded to phenolic compounds is partially released at low pH in the acidified juice leading to higher results.

ISSN:0265-203X    

DOI:10.1080/02652030050207756

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

The theoretical risk of exceeding the Acceptable Daily Intake (ADI) for sulphites has mostly been examined on the basis of a worst-case scenario. In order to examine the real situation the determination of residue sulphite levels in ready-to-consume foods is required. The aim of this paper is to assess the actual sulphite content of diets obtained from a combination of realistic meals high in sulphite-containing foods. Food products available in Italy containing added sulphites were identified. Overall, 211 samples of foods and beverages (including 85 samples of wine) were collected. The determination of sulphite residues was carried out on the foods which were prepared according to normal domestic practice. It was shown that the diets obtained from these foods would lead to an intake of 23mg/day in children and 50mg/day in adults (both slightly above the ADI for respectively a 30kg child and a 60kg adult). Among all sulphite-containing foods, the highest contributors to the intake were dried fruit and wine, both ingested without further treatment. The analysis of specific consumption data confirmed the existence of a risk of exceeding the ADI related to sulphite residue levels in wine.

ISSN:0265-203X    

DOI:10.1080/02652030010014402

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Incurred penicillin G, oxytetracycline, enrofloxacin and ciprofloxacin residues in bovine and porcine muscle and kidney samples were analysed by microbiological and chemical methods, the former usingBacillus subtilisBGA as a test organism on agar media of pH 6, pH 7.2 and pH 8 and the latter using liquid chromatography. Least squares fits between the logarithms of the chemically obtained concentrations of the antimicrobials and the widths of the inhibition zones were used to estimate the inhibition zone widths corresponding to the maximum residue limit concentrations.In vitrosensitivities were determined with standard antimicrobial solutions. The results indicate that ifB. subtilisBGA is used as a test organism, muscle tissue cannot be used as test material for screening oxytetracycline, enrofloxacin and ciprofloxacin residues on the plates used in this study, while penicillin G can be screened from muscle tissue. Because of the numerous factors causing or increasing variation in the analysis, the inhibition zone caused by a given antibiotic concentration cannot be predicted precisely. Therefore, a positive agar diffusion test needs to be confirmed chemically. If a kidney sample gives a positive agar diffusion test result, the antimicrobial concentration in a muscle sample from the same carcass should be checked chemically.

ISSN:0265-203X    

DOI:10.1080/02652030050207774

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

ISSN:0265-203X    

DOI:10.1080/0265203001001325

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Total mercury concentrations were measured in the muscle of different kinds of fish: megrim (Lepidorhombus boscii), common sole (Solea vulgaris), striped mullet (Mullus barbatus), anglerfish (Lophius piscatorius), and black-bellied angler (Lophius budegassa), caught in the South Adriatic Sea (South Italy). The highest total mercury levels were found in anglerfish (0.61-2.22 mg/kg wet wt, mean 1:26±0.58), followed by black-bellied angler (0.22±1.62 mg/kg wet wt, 0.68±0.36), megrim (0.05±0.92 mg/kg wet wt, 0.39±0.30), striped mullet (0.10±0.63 mg/kg wet wt, 0.31±0.13) and common sole (0.05±0.44 mg/kg wet wt, 0.19 ±0.15). According to current regulations, 62.5% of anglerfish (Lophius piscatorius) and 23% of black-bellied angler (Lophius budegassa) samples showed concentrations exceeding the peak value of 1 mg/kg, while only 25% of samples of megrim (Lepidorhombus boscii), and 8.3% of striped mullet (Mullus barbatus), exceeded the peak value fixed at 0.5mg/kg. Correlations between total mercury concentration and specimen weight were evident in all the species examined.

ISSN:0265-203X    

DOI:10.1080/02652030050207792

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

ISSN:0265-203X    

DOI:10.1080/02652030010002081

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

High doses of T-2 toxin are known to decrease protein synthesis and mono-oxygenase activities in rat liver. The purpose of this study was to investigate whether exposure at a low dose could alter the normal metabolism of the xenobiotic by the liver. Three doses of T-2 toxin, dissolved in olive oil, were orally and daily administered to New Zealand white rabbits for five days. At 0.5mg/kg, three of the five animals died, whereas only a weak decrease in body weight gain and moderate signs of toxicity occurred in rabbits receiving 0.25mg/kg/day, and the body weight increased without signs of toxicity at 0.1mg/kg/day. At 0.25mg/kg/day, total liver microsomal P450 content, and the activities of aminopyrine and benzphetamineN-demethylases, pentoxyresorufinO-depentylase, glutathioneS-transferases accepting 1-chloro-2,4-dinitrobenzene and 1,2-dichloro-4-nitrobenzene as substrates, were decreased. By contrast, ethylmorphine and erythromycinN-demethylases, ethoxyresorufin and methoxyresorufinO-dealkylases, aniline hydroxylase, and UDP-glucuronyltransferase acceptingp-nitrophenol as substrate, were unaffected. The expression of P450 1A1, 1A2, 2A1, and 2B4, but not P450 2C3 and 3A6, were also decreased, whereas microsomal conjugated dienes, fluorescent substances, and malondialdehyde contents were increased. At 0.1mg/kg/day, neither significant effects on drug metabolizing enzymes nor microsomal oxidative damages were obtained. Taken together, these results suggest that a short exposure time to the mycotoxin would not be associated with significant changes in the normal metabolism of xenobiotics by the liver.

ISSN:0265-203X    

DOI:10.1080/02652030050207819

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor