乳制品中脂溶性维生素检测的前处理方法研究进展

脂溶性维生素是维持身体健康所必需的一类有机化合物,对人体生长发育、新陈代谢有极其重要的作用,如果长期缺乏或过量某种脂溶性维生素,就会引起生理机能障碍或某种疾病。脂溶性维生素品种丰富、结构类似;稳定性差,在光、氧、酸、碱等条件下易降解;不同类型脂溶性维生素极性不同、且在食品基质中含量差异大,因此多目标物高效前处理、有效分离、降低基体干扰等关键技术是脂溶性维生素准确定量面临的挑战。本文综述了液液萃取、固相萃取等传统及新型QuEChERS萃取、超临界流体萃取等提取与净化技术在乳制品及婴幼儿配方奶粉中脂溶性维生素的分析应用,分析了液相色谱、液相色谱串联质谱、超临界流体色谱以及酶联免疫等检测技术的特点,并展望了其发展趋势。     

Rapid determination of total fats and fat-soluble vitamins in Parmigiano cheese and salami by SFE

Supercritical fluid extraction (SFE) was used to determine total fat and fat-soluble vitamins in Parmigiano cheese and salami. Extracts were obtained quickly and effectively to gravimetrically determine total fat. The results were compared with traditional methods and the quantity extracted and collected by supercritical carbon dioxide (SC-CO₂) was statistically equivalent to the Soxhlet extraction. In addition, the use of SFE as a preparative analysis was tested to determine in a rapid and simultaneous way the fat-soluble vitamin extracted by SFE and subsequently determined by HPLC. The extractability of vitamins by SFE was comparable to the official methods. α-tocopherol was higher probably because SC-CO₂ extraction is necessarily conducted in the absence of light and oxygen, and lower temperature than traditional methods. RSD% was lower than 20% for total fat determination, while it was sometimes higher for fat-soluble vitamins determination.     

Determination of fat-soluble vitamins and carotenoids in food additives using high-performance liquid chromatography

Wide diversity of fat-soluble vitamins and carotenoids, their ability for isomerization and oxidation under action of a range of physical and chemical factors stimulates the development of modern selective methods for determination of individual compound contents of these substantial micronutrients. It is important to determine separately the geometric cis- and trans-isomers, which exhibit different vitamin and antioxidant activity. Use of high performance liquid chromatography in combination with various methods of sample pre-treatment for this purpose makes possible to determine simultaneously in automatic run the fat-soluble vitamins A, E, D, K and carotenoids as well as their isomers with high sensitivity and selectivity. The adequate estimation of vitamin value of foods and food additives is thus achieved.     

婴幼儿断乳配方食品的研究

根据(GB10769-89),运用线性规划法设计了婴幼儿断乳配方食品;利用挤压熟化技术加工了该配方食品,其中应用微胶囊技术制备的粉末油脂,有效地解决了VA、VD的添加和营养油氧化酸败的问题。     

Association between vitamin deficiency and metabolic disorders related to obesity

Inappropriate food behavior contributes to obesity and leads to vitamin deficiency. This review discusses the nutritional status of water- and fat-soluble vitamins in obese subjects. We verified that most vitamins are deficient in obese individuals, especially the fat-soluble vitamins, folic acid, vitamin B₁₂ and vitamin C. However, some vitamins have been less evaluated in cases of obesity. The adipose tissue is considered a metabolic and endocrine organ, which in excess leads to changes in body homeostasis, as well as vitamin deficiency which can aggravate the pathological state. Therefore, the evaluation of vitamin status is of fundamental importance in obese individuals.     

Third EU MAT intercomparison on methods for the determination of vitamins B-1, B-2 and B-6 in food

An intercomparison study on the determination of vitamin B-1, B-2 and B-6 was performed as part of the EU MAT project involving 16 laboratories. Each laboratory was requested to analyse three different food samples (lyophilized pig's liver, mixed vegetables and wholemeal flour, respectively) using their ‘in-house’ method as well as an ‘optimal extraction protocol’ and using a common batch of takadiastase enzyme. High-performance liquid chromatography (both normal-phase and reversed-phase HPLC), microbiological assay and chemical methods were used.For vitamins B-1 and B-2 the agreement between laboratories (using their ‘in-house’ methods) was generally good (vitamin B-1: CV_w < 5%, CV_b = 16–28%; vitamin B-2: CV_w < 8%; CV_b = 12–40%, respectively, where CV_w is the within laboratory coefficient of variation and CV_b is the between-laboratory coefficient of variation) with no apparent differences between the ‘in-house’ and ‘optimal’ extraction protocols. For vitamin B-1 microbiological results tended to be higher (e.g. ca 20–50%) than HPLC results. Some further improvement could result from optimalization (i.e. lowering) of the sample-enzyme ratio.Enzyme efficiency needs to be checked with each new batch of enzyme.For vitamin B-6 results were much more at variance (CV_w = 6–13%, CV_b = 36–63%), especially with the pig's liver. Some discrepancy was found between laboratories using dilute mineralic acid for extraction without enzyme treatment and those using trichloroacetic acid (TCA) and/or included takadiastase treatment. It is concluded that for vitamin B-6 further standardization and method improvement is needed in order to obtain acceptable variation between laboratories. In particular, B-6 vitamer interconversion during extraction and peak interference needs further study.     

加压毛细管电色谱-紫外法检测复方维生素片中4 种脂溶性维生素

采用反相加压毛细管电色谱-紫外检测,建立一种高效、简便、快速的脂溶性维生素分析方法,并用于复合维生素片中脂溶性维生素的检测。使用C18反相毛细管色谱柱,以含0.05%三氟乙酸的95%甲醇溶液（pH 3.3）为流动相进行等度洗脱,泵总流速为0.2 mL/min,分离电压为15 kV,并针对脂溶性维生素样品个体间紫外吸收波长差别较大的问题,采用波长时间程序进行检测。VA、VD3、VE、VK3四种脂溶性维生素可在5 min内实现快速分离。各组分的最低检出限（RSN=3）分别为1.5、3.0、15、1.5 μg/mL,线性关系良好,样品加标回收率在90.0%～110.0%之间,相对标准偏差为0.53%～5.46%。将所建立方法应用于维生素片样品分析,取得了良好的分析结果。该方法简单方便、重复性好、准确可靠。     

Simultaneous Determination by HPLC of Fat-Soluble Vitamins in Albacore (Thunnus alalunga)

The fat-soluble vitamins A, D and E were determined by a liquid chromatographic method. The vitamins were extracted from the tissues with chloroform and methanol, saponified and separated on a Lichrosorb normal phase column followed by UV detection. Recoveries of added vitamins in liver samples were 93.0% for vitamin A, 90.0% for vitamin D and 92.1% for vitamin E. The results from a study of fat-soluble vitamins in samples of albacore showed that the vitamin A and D were found only in fish liver and vitamin E was found in the liver and the edible muscle.     

Applicability of an in vitro model to assess the bioaccessibility of vitamins A and E from fortified commercial milk

In vitro models based on human physiology have been developed as simple, inexpensive and reproducible tools to predict the bioavailability of different food components. Our aim was to assess the applicability of an in vitro digestion model to estimate the bioaccessibility of fat-soluble vitamins contained in commercially available liquid milk. For vitamin A, the rate and degree of hydrolysis of both endogenous and synthetic ester forms varied according to the type of milk (skimmed versus whole), although the amount of free retinol transferred into micelles was equivalent. For vitamin E, there was apparently no hydrolysis of tocopheryl acetate contained in fortified whole milk, while it was incomplete in the skimmed milk. Overall, in vitro results appear consistent with in vivo observations supporting the potential applicability and predictive value of the in vitro approach to assess the bioavailability of fat-soluble vitamins from dairy matrices.     

Application of an HPLC–MS/MS method for mycotoxin analysis in commercial baby foods

This article describes the validation of an analytical method for the detection of 21 mycotoxins in baby food. The analytical method is based on the simultaneous extraction of selected mycotoxins by matrix solid-phase dispersion (MSPD) followed by liquid chromatography coupled with tandem mass spectrometry (LC–MS/MS) using a hybrid triple quadrupole-linear ion trap mass spectrometer (QTRAP®). Information Dependent Acquisition (IDA), an extra confirmation tool for samples that contain the selected mycotoxins, was used. The matrix effects were evaluated, and the corrections for the matrix effects were performed using two calibration approaches: external matrix-matched calibration and internal standard calibration. Matrix-matched calibration was ultimately used for accurate quantification, and the recoveries obtained were generally higher than 70%. The analytical method was applied to the analysis of 35 samples of commercial baby foods. No sample exceeded the maximum limit (ML) fixed by the European Union for these mycotoxins in baby food. However, this survey highlighted the occurrence of mycotoxins in cereal-based infant foods.     

复合凝聚法包埋功能性食品组分的研究进展

复合凝聚法是一种新兴的包埋技术,食品领域研究者对该技术日益关注。本文深入讨论了影响复合凝聚的 环境因素;以功能性油脂、精油、脂溶性维生素、脂溶性抗氧化物为代表组分,归纳总结了复合凝聚法包埋脂溶性 活性组分的研究进展;以益生菌、酶、水溶性维生素、甜味剂、苦味肽等为例,详细介绍了复合凝聚法包埋亲水性 活性组分的研究进展。     

A review on technological parameters and recent advances in the fortification of processed cheese

BackgroundAlthough the consumption of processed foods is growing in overseas markets, the increased awareness of consumers to health and wellbeing in recent years has led to a decline in the growth of processed food sales in the Western market. The added pressure on the food manufacturing industry to increase the perceived healthiness of processed foods has opened up new market potential in the area of fortified processed foods, such as processed cheeses.Scope and approachThis review paper provides an overview of the current methodologies into the production of a processed cheese with added health benefits, including the use of probiotics and prebiotics, vitamin and mineral fortification and the addition of plant macromolecules.Key findings and conclusionsProcessed cheeses with increased health benefits have been of great interest to manufacturers, with reduced salt and reduced fat options commercially available. Although processed cheeses fortified with vitamins, mineral, probiotics and prebiotics are not as widespread, further work in these areas has been identified as a way to produce high value processed cheese products with added health benefits.     

Simultaneous determination of the vitamins A, E, their esters and coenzyme Q10 in multivitamin dietary supplements using an RP-C30 phase

A sensitive RP-HPLC method was developed for the simultaneous quantification of the fat-soluble vitamins A, A-acetate, A-palmitate, E, E-acetate and coenzyme Q₁₀ in multivitamin dietary supplements using a C30 phase. Because of the dual-wavelength detection applied, it was possible to monitor vitamins and additionally carotenoids in one run. For identification of vitamins, mass spectra were recorded using LC-(APcI)MS. The vitamins were extracted from 10 commercial dietary supplements (seven soft gel capsules, three tablets) and quantified on the basis of extern calibration graphs. Method performance was studied by addition of vitamin-A- and -E-acetate to a blank matrix: recoveries ranged from 95.7 to 97.8%. On the basis of the amounts labeled, only two products contained substantially lower concentrations of vitamin A-acetate (34% and 46%, respectively). All other concentrations varied between 98% and 245% with respect to vitamin labeling. One product contained vitamin E as alcohol, all other formulations esterified forms of vitamins A and/or E. The presented method may be used by quality assurance laboratories for routine control of nutritional labels.     

Fortification aspects of vitamin D in dairy products: A review study

There is a higher demand for calorie-reduced foods. In the dairy industry, fat is separated to produce low-calorie products and fat-soluble vitamins such as A and D are also removed along with them. There are different factors leading to a significant decrease in people's sun exposure, which has a substantial role in isomerisation of 7-dehydrocholesterol to vitamin D. It seems logical to add vitamin D to dairy products and potentially restore their nutritional value or fortify them to improve vitamin D intakes. The main biological function of vitamin D is to control the absorption, transport and deposition of calcium and, to a lesser extent, phosphorus, which are important in bone mineralisation. Dairy products are the ideal candidates for vitamin D fortification. This article reviews the vitamin D fortification of dairy products including the concepts, fortification methods, sensory properties of final products and storage stability.     

Detection of radiolytic hydrocarbons by supercritical fluid extraction and gas chromatographic–mass spectrometric analysis of irradiated cheese

Supercritical fluid extraction (SFE) was used for the isolation of characteristic hydrocarbon patterns formed by irradiation of fat-containing foods. The proposed method has the advantage of not requiring the use of organic solvents since analyte recovery is obtained simply by thermal desorption of the solutes previously retained in an adsorbent material, packed in the trap of the SF extractor, and its subsequent GC–MS analysis. Thereby, the risks of contamination with different compounds, as well as of losses by coevaporation with the solvent, involved in the use of conventional techniques are avoided. The method is capable of verifying, in less than two hours, whether a cheese sample has been (or not) submitted to an irradiation treatment on the basis of the detection of four radiolytic markers, namely n-pentadecane, 1-tetradecene, n-heptadecane, and 1-hexadecene.     

电化学分析法检测动物源食品中氯丙嗪的3种前处理方法比较

目的对猪肉、鸡肉、牛肉、猪肝、虾肉、蜂 蜜、鱼肉、鸡蛋和牛奶共9种动物源食品中氯丙嗪电化学检测的前处理方法进行了选择和优化,方法 样品分别采用溶剂提取法、QuECHERS法（Quick、Easy、Cheap、Effective、Rugged、Safe,QuEChERS法）和固相萃取法（solid-phase extraction,SPE）进行了电化学检测比较分析。结果表明,猪肉、鸡肉、牛肉、猪肝、虾肉和蜂蜜可用溶剂提取法进行处理,氯丙嗪的加标回收率均在81.6%以上;而鱼肉和鸡蛋样品需采用QuECHERS法进行处理,回收率分别达到88.5%～95.8%和89.7%～98.2%;牛奶样品用溶剂提取法和QuECHERS 法处理时均有基质干扰,采用固相萃取法进行净化后,回收率达到80.6%～93.0%。不同类型的动物源食品由于肌肉的纤维组织、脂肪含量、水分含量、蛋白质的种类和含量等存在差别,需分别采用适宜的前处理方法才能获得满意的测定结果。结论 该研究可为不同类型动物源食品中氯丙嗪电化学检测方法的应用提供参考。     

Detection of mineral oil and paraffin in foods]

The author describes a thin-layer chromatographic method for the detection of small amounts of mineral oil and paraffin in foods. Fatty acids, glycerides, fat-soluble vitamins, sterols, and unsaturated hydrocarbons remain at the starting point. This method permits to detect as little as 0.2 mug of mineral oil or 20 mug of mineral oil/kg of food in low-fat products. 0.01% of mineral oil-like contaminants may be detected in fats.     

Application of Graphene-based Solid-Phase Extraction Coupled with Ultra High-performance Liquid Chromatography-Tandem Mass Spectrometry for Determination of Macrolides in Fish Tissues

A novel analytical protocol for the determination of five macrolides (MLs) in crucian carp tissues has been developed. Two-dimensional (2D) planar graphene powder was utilized as the solid-phase extraction (SPE) sorbent for analyte enrichment and cleanup. The target analytes were separated by ultra high-performance liquid chromatography (LC) and quantified by a triple–quadrupole linear ion trap mass spectrometer. The proposed analytical procedures were carefully optimized and validated. Average recoveries of MLs were between 81.7 and 110.5 %, which was the highest comparing with the conventional sorbents including C18 silica and multiwalled carbon nanotubes (MWCNTs). Method validation proved the feasibility of the developed nanoparticles for the quantificatation of the investigated analytes at trace levels obtaining low limit of quantitation values in the microgram per kilogram range. Good precision with coefficients of variations always lower than 10 % was obtained. The proposed method has been successfully applied to the analysis of ML in several aquaculture product samples, indicating that graphene was a potential SPE sorbent for the enrichment of trace residues in food samples.     

Stability of vitamins during the storage of liquid infant milks

The stability of the water-soluble B vitamins and the fat-soluble vitamins A and E of three liquid infant milks was followed throughout 12 months of storage at 20, 30 and 37 degrees C. Two samples were 'follow-on' milks from two different manufacturers and the other a 'junior' milk from one of these. The levels of water-soluble vitamins and vitamin E remained constant during storage at the three temperatures. In contrast, vitamin A decreased in samples from one manufacturer at all storage temperatures, and in samples from the other only at 37 degrees C. A kinetic equation was derived that made it possible to predict the influence of storage temperature on the shelf life of these kinds of products, together with the storage period during which levels of vitamin A recommended as adequate would remain.     

Screening of 23 β-lactams in foodstuffs by LC–MS/MS using an alkaline QuEChERS-like extraction

A fast and robust high performance LC–MS/MS screening method was developed for the analysis of β-lactam antibiotics in foods of animal origin: eggs, raw milk, processed dairy ingredients, infant formula, and meat- and fish-based products including baby foods. QuEChERS extraction with some adaptations enabled 23 drugs to be simultaneously monitored. Screening target concentrations were set at levels adequate to ensure compliance with current European, Chinese, US and Canadian regulations. The method was fully validated according to the European Community Reference Laboratories Residues Guidelines using 93 food samples of different composition. False-negative and false-positive rates were below 5% for all analytes. The method is adequate for use in high-routine laboratories. A 1-year study was additionally conducted to assess the stability of the 23 analytes in the working standard solution.