气质联用法测定生食水产品中的挥发性N-亚硝胺

利用二氯甲烷提取腌制生食水产品中的挥发性N-亚硝胺,即:N-二甲基亚硝胺(NDMA)、N-二乙基亚硝胺(NDEA)、N-亚硝基吡咯烷(NPYR)、N-二丙基亚硝胺(NDPA).利用气质联用仪采用选择离子法(SIM)进行定性定量检测.结果表明,该检测方法前处理简单快捷,易于操作,线性相关系数分别可达0.999 1、0.999 1、0.999 0、0.999 5;线性范围分别可达0～250 μg/mL;方法重现性良好,其RSD可达1.49%～1.94%;回收率可达90%～105%;灵敏度高,检测限分别为0.04,0.025,0.05,0.01 μg/kg.     

Volatile N-nitrosamines in sausage products

The authors studied the content of volatile N-nitrosamines (NA) in the most common sausage products. It was established that the total content of NA in sausage products is not high and ranges from trace amounts up to 10 micrograms/kg product. The allowable doses of nitrite in the sausage manufacture being low, no relationship was discovered between the content of NA and residual nitrite in meat products.     

Content of N-nitrosamines in Soviet food products

The author presents the results of the analysis of N-nitrosamine (NA) content in animal and vegetable products from various regions of the country. The causes of NA formation from their precursors during technological treatment and possible ways of its prevention have been discussed.     

Absence of volatile N-nitrosamines in cooked nitrite-free cured muscle foods

Nitrite-free cured pork systems were prepared using the preformed cooked cured-meat pigment (CCMP) and sodium ascorbate. Absence of volatile N-nitrosamines in cooked nitrite-free systems was confirmed using a gas chromatography-thermal energy analyzer (GC-TEA) methodology. Similar results were obtained when cod, cod surimi or mixtures containing pork with 15 or 50% cod or cod surimi were used. However, counterpart samples cured with sodium nitrite (156 ppm) and sodium ascorbate (550 ppm) produced N-nitrosodimethylamine at 1·0 ppb levels or less. Results demonstrate that nitrite-free curing of meat and meat/fish systems containing the preformed CCMP is successful in yielding products devoid of volatile N-nitrosamines.     

Determination of N-nitrosamines in food products intended for long term storage

The content of carcinogenous N-nitrosoamines (N-nitrosodimethylamine, N-nitrosodiethylamine, N-nitrosopiperidine) was determined fluorimetrically (as NBD-amines) in preserved products, food concentrates, dried fruit and mushrooms. No N-nitrosoamines were found in the concentrates and dried products. The content of N-nitrosamines did not exceed 3 g/kg. In some samples its content reached 19 microgram/kg.     

The preferential formation of volatile N-nitrosamines in the fat of fried bacon

Whole bacon rashers and the separated lean and fat components were fried in an electrically heated pan and the residues in the pan and the trapped cooking vapours analysed for N-nitrosopyrrolidine and N-nitrosodimethylamine. The fat produced 12 times more N-nitrosopyrrolidine and six times more N-nitrosodimethylamine than the lean. In all cases the largest proportions of both nitrosamines were recovered from the cooking vapours. Prolonged heating of lean did not increase amounts of the nitrosamines. The importance of the non-polar lipid phase of the adipose tissue in nitrosamine formation was demonstrated by heating fat and lean components of bacon in a non-polar heating medium when high levels of nitrosamines were produced from the lean as well as the fat.     

N-nitrosamines and nitrites in meat and meat products]

Content of N-nitrosamines and nitrites in meat and meat products of Russian manufacture made on traditional and recently developed techniques was measured. The influence of conditions and duration of storage of meat products on changes in N-nitrosamines and nitrites was investigated. It is established that in observance of instruction of entering nitrites during manufacture their residual amounts in a ready product do not exceed hygienic levels accepted in Russian Federation. N-nitrosamines (N-nitrosodimethylamine and N-nitrosodiethylamine) were found in amounts from 0.1 up to 30 ppb. The least amount of N-nitrosamines was in canned meat (up to 0.7 ppb) and fresh meat (up to 0.4 ppb), greatest--in smoked products from pork. 8.6% tested samples of meat products contained N-nitrosamines in amounts exceeding the hygienic levels. The reasons of high contents of N-nitrosamines was infringement of conditions and terms of storage of ready meat products.     

畜禽肉和鱼肉对南极磷虾凝胶制品挥发性风味成分的影响

利用顶空固相微萃取-气相色谱-质谱联用(HS-SPME-GC-MS)技术分析南极磷虾凝胶制品和分别添加畜禽肉(鸡肉、猪肉、牛肉)、鱼肉(白姑鱼、鳙鱼)后南极磷虾凝胶制品挥发性风味成分,结合感觉阈值,利用气味活度法(OAV)确定特征风味物质。研究结果表明:南极磷虾凝胶制品中挥发性风味物质浓度仅为421.32μg/100 g,共确定11种特征风味物质;而添加畜禽肉和鱼肉的制品中挥发性风味物质浓度明显增加,分别为1 378.51、1 026.73、2 291.20、1 192.37、1 199.93μg/100 g,且特征风味物质分别为20、18、23、15、16种。因此磷虾制品中添加畜禽肉和鱼肉能一定程度提高制品的挥发性风味品质,且添加鸡肉和牛肉的制品其挥发性风味品质优于添加猪肉的制品,添加白姑鱼的制品其挥发性风味品质优于添加鳙鱼的制品。     

A risk-based sampling plan for monitoring of histamine in fish products

In 2008, the French Institute for Public Health Surveillance reported an increase in the number of histamine food poisoning outbreaks and cases in France. The aim of this study was to propose a new monitoring plan for characterizing consumers' exposure to histamine through fishery products. As fish products of concern are numerous, we proposed that the number of samples allocated for a fish category be chosen based on the risk associated with the category. Point risk estimates of histamine poisoning were assessed with the Risk Ranger tool. Fresh fish with high histidine content was found to contribute most to the number of cases. The (estimated) risks associated with the consumption of canned and deep-frozen fish appear marginal as compared with the risk associated with fresh fish with high histidine concentrations. Accordingly, we recommend excluding canned and deep-frozen fish from the monitoring plan, although these risk estimates can be biased. Within a category, samples were proportional to the relative food consumption of the different fishes. The spatial and seasonal consumption patterns were also taken into account for the design of the new monitoring plan. By testing appropriate numbers of samples from categories of fish products of concern, this plan will permit investigation of trends or comparison of product categories presenting risks of histamine poisoning.     

The effect of food products on the endogenous formation of N-nitrosamines in rats

Data have been presented on carcinogenic N-nitrosoamines (NA) synthesis from precursors in the gastric juice and in the stomach of rats. It is shown that vegetable juices and milk produce an inhibitory effect with respect to NA synthesis in vitro and in vivo, however, food products with high content of fat intensify amine nitrosation.     

Novel volatile thermal degradation products of thiamine

Thirteen compounds (nine thiophenes, two alicyclic sulphur compounds and two aliphatic hydroxyketones) are reported as novel thermal degradation products of thiamine. Most possessed meaty and/or onion-like aromas.     

Application of modified atmosphere packaging on aquacultured fish and fish products: A review

The aquaculture industry has undergone a rapid and continuous growth during the last decade due to increased demands in seafood consumption and reduced pelagic fish production. The aquaculture sector can provide products with a consistent flow and quality standards to cover the market's needs. The modified atmosphere packaging (MAP) technique has evolved over the last two decades and many reports indicate its beneficial effect on many quality parameters during fish and shellfish preservation. The use of MAP can clearly offer an advantage to the safer distribution of quality aquacultured fishery products. This article summarizes most of the experimental data of packaging techniques applied (MAP, VP, various pretreatments and packaging materials) on aquacultured fish and fish products to provide a clear view of the potential for a future commercial use.     

Optical fibre-based micro-analyser for indirect measurements of volatile amines levels in fish

An analytical method based on optical fibre (OF) detection has been developed and validated for monitoring of trimethylamine (TMA) and dimethylamine (DMA) in fish handling environments and for non invasive assessment of fish quality.     

Patterns in volatile components over heated fish powders

Freeze dried powders of herring and blue whiting filets were heated for 0.5–4 h at 40 to 140 °C. The volatile components over the powders were analysed by solid phase micro extraction and gas chromatography–mass spectrometry.Principal component analysis was performed on the chromatographic areas. The patterns over the heated samples showed evolution with temperature exposure along one gradient, indicating that heating at high temperature over a short time interval can produce a similar pattern as heating at a lower temperature for a longer time interval.The response to heating was similar for both herring and blue whiting powders, and a common model based on partial least squares regression was developed for prediction of the temperature exposure. Chemical markers for evaluation of the temperature exposure in a heated fish powder were found. The best markers were pyridines, pyrazines, aromatic hydrocarbons, amides and selected volatile sulfur compounds.     

Performance evaluation of a fluorescamine-HPLC method for determination of histamine in fish and fish products

A method for the quantification of histamine in fish and fish products using tandem solid-phase extraction and fluorescence derivatization with fluorescamine was previously developed. In this study, we improved this analytical method to develop an official test method for quantification of histamine in fish and fish products, and performed a single laboratory study to validate it. Recovery tests of histamine from fillet (Thunnus obesus), and two fish products (fish sauce and salted and dried whole big-eye sardine) that were spiked at the level of 25 and 50 μg/g for T. obesus, and 50 and 100 μg/g for the two fish products, were carried out. The recoveries of histamine from the three samples tested were 88.8-99.6% with good repeatability (1.3-2.1%) and reproducibility (2.1-4.7%). Therefore, this method is acceptable for the quantification of histamine in fish and fish products. Moreover, surveillance of histamine content in food on the market was conducted using this method, and high levels of histamine were detected in some fish products.