聚乙烯塑料包装材料中4种抗氧化剂向脂肪食品模拟物迁移的研究

本文基于超高效液相色谱建立了一种脂肪食品模拟物异辛烷中抗氧化剂叔丁基对羟基茴香醚(BHA)、2,6-二叔丁基对甲酚(BHT)、四[甲基-β-(3,5-二叔丁基-4-羟基苯基)丙酸酯]季戊四醇酯(Irganox1010)以及β-(4-羟基-3,5-二叔丁基苯基)丙酸正十八酯(Irganox1076)的提取检测方法,加标回收率在78.0%～108.7%之间,相对标准偏差(RSD)在4.0%～13.7%之间。研究了聚乙烯(PE)膜中抗氧化剂向异辛烷的迁移,讨论了温度及时间对迁移的影响,并根据迁移数据进行了初步的数学模型的建立,对实验值与数值模拟结果计算值作了对比分析。     

超高效液相色谱/静电场轨道阱高分辨质谱法同时测定塑料食品接触材料中光稳定剂和抗氧化剂的特定迁移量

建立了超高效液相色谱/静电场轨道阱高分辨质谱同时测定塑料食品接触材料中多种光稳定剂和抗氧化剂特定迁移量的方法。采用30 g/L乙酸、体积分数分别为10%、20%、50%的乙醇和油类模拟物(异辛烷)这5种食品模拟物对塑料食品接触材料进行处理,对处理液进行超高效液相色谱/静电场轨道阱高分辨质谱分析,外标法定量。该方法测定的40种目标化合物在相应的范围内均具有良好的线性关系,相关系数均大于0.998,定量限为0.01~1.00μg/L。考察了上述5种食品模拟物中光稳定剂和抗氧化剂的特定迁移量,平均加标回收率为81.46%~94.53%,相对标准偏差为3.25%~9.99%。应用该方法对市售塑料食品接触材料进行了测定,结果在部分样品中检出了不同含量的光稳定剂和抗氧化剂。该方法灵敏度高,定量限低,满足塑料食品接触材料中光稳定剂和抗氧化剂特定迁移量的检测要求。     

食品接触聚丙烯塑料中抗氧化剂迁移模型研究

在聚丙烯(PP)树脂中加入不同浓度梯度的抗氧化剂2,6-二叔丁基对甲酚(BHT)、四(3,5-二叔丁基-4-羟基)苯丙酸季戊四醇酯(抗氧化剂1010),通过双螺杆塑料挤出机在190℃混合挤出造粒并热压成膜,自制了食品包装用PP塑料膜(膜厚0.1 mm)。通过高效液相色谱仪(HPLC)配二极管阵列(PDA)检测器(检测波长为282 nm)测定PP样品中的两种抗氧化剂在食品模拟液(95%乙醇溶液)中的迁移量,其中BHT迁移出,而抗氧化剂1010未迁移出。在实验数据基础上,利用软件对迁移数据进行迁移模型拟合,建立了抗氧化剂BHT的Weibull迁移模型和Piringer迁移模型,比较了所建立的两种模型的适用性,结果表明, Weibull模型对实际测试结果的拟合优度( R2)能达到0.99以上,Weibull模型比Piringer模型更接近于实际迁移结果,同时,Weibull模型和Piringer模型的参数间存在一定的数学关系,符合关系式τ≈12.2(L2/D)。     

气相色谱-质谱联用法测定食品包装材料中4种苯酚类抗氧剂迁移量

建立了气相色谱-质谱联用(GC-MS)测定食品包装材料中2,6-二甲基苯酚、对叔丁基苯酚、2,6-二叔丁基对甲酚和叔丁基-4-羟基苯甲醚迁移量的方法。采用水、4%(体积分数)乙酸、50%(体积分数)乙醇和异辛烷作为食品模拟物,样品经食品模拟物浸泡:水基模拟物浸泡液经乙酸乙酯液液萃取后测定,异辛烷浸泡液则直接测定。采用DB-1701色谱柱(30 m×0.25 mm×0.25μm)进行分离,选择离子模式进行检测,外标法定量。结果表明,在优化实验条件下,4种苯酚类抗氧剂在0.1~10 mg/L质量浓度范围内线性良好,相关系数(r)均大于0.999,方法检出限(LOD)均为0.01 mg/L,定量下限(LOQ)均为0.03 mg/L。在0.1、1.0、10.0 mg/L 3个加标水平下,方法的回收率为91.5%~110%,相对标准偏差(RSD,n=5)为1.9%~9.3%。该法准确、可靠、灵敏度高,适用于食品包装材料中4种苯酚类抗氧剂迁移量的测定。     

超高效液相色谱-串联质谱法同时测定食品接触材料及制品中9种抗氧化剂迁移量

为了评估食品接触材料及制品中抗氧化剂的迁移风险,采用超高效液相色谱-串联质谱法(UPLC-MS/MS)建立了同时测定食品接触材料及制品中9种抗氧化剂迁移量的方法。采用C18色谱柱对迁移实验后的食品模拟物中9种抗氧化剂进行分离,1 mmol/L氟化铵和甲醇为流动相洗脱,采用电喷雾离子源(ESI),多反应监测(MRM)正负离子模式进行扫描。结果表明,9种抗氧化剂的色谱分离效果良好,并在0.3~6 mg/L质量浓度范围内与其峰面积均呈良好的线性关系,检出限为0.1 mg/L。加标回收率为93.9%~106%,相对标准偏差(RSD)为0.80%~9.3%。该方法快速高效、线性范围好,适用于塑料食品接触材料及制品中9种抗氧化剂迁移量的检测。     

高效液相色谱法同时测定食品接触材料中抗氧化剂和紫外吸收剂的迁移量

采用高效液相色谱技术,建立了食品接触材料中多种抗氧化剂和紫外吸收剂迁移水平的检测方法。该方法测定的23种目标化合物具有较好的线性关系,相关系数（r²）≥ 0.9998,检出限和定量限分别在0.01到0.22 mg/L之间和0.03到0.85 mg/L之间。依据欧盟指令（EU）No. 10/2011,考察了5种食品模拟物30 g/L乙酸、10%（v/v）乙醇、20%（v/v）乙醇、50%（v/v）乙醇和油类模拟物（异辛烷）中抗氧化剂和紫外吸收剂的迁移量。该方法回收率在92.8%~117.7%之间,相对标准偏差在0.95%~9.72%之间。探讨了不同实验条件对抗氧化剂和紫外吸收剂回收率的影响。结果表明,该方法准确、稳定,完全满足欧盟指令（EU）No 10/2011和GB 9685-2008对食品接触材料及制品中抗氧化剂和紫外吸收剂特定迁移量（SML）的限量要求,并利用该方法测定了30批次食品接触材料中抗氧化剂和紫外吸收剂的迁移水平。     

超高效液相色谱-质谱法测定油脂中的10种抗氧化剂

对油脂中的没食子酸丙酯(PG),没食子酸辛酯(OG)、2,4,5-三羟基苯丁酮(THBP)、叔丁基对苯二酚(TBHQ)、叔丁基对羟基茴香醚(BHA)、2,6-二叔丁基对甲酚(BHT)、没食子酸十二酯(DG)、正二氢愈创酸(NDGA)、2,6-二叔丁基-4-羟甲基苯酚(HMBP)和没食子酸异戊酯(IAG)10种抗氧化剂进行了超高效液相色谱-质谱法(UPLC/MS)测定的系统研究,建立了一种简单、快速、准确测定油脂中10种抗氧化剂的测定方法。对样品中提取溶剂和提取时间的选择以及相关线性、精密度、回收率作了考察和实验。结果表明,本方法能有效提取油脂样品中的这10种抗氧化剂,并对其进行UPLC/MS分离和测定。10种抗氧化剂的平均回收率为92.56%～102.5%(n=6),相对标准偏差为0.68%～5.12%(n=6),检出限为2～10μg/L。     

液相色谱-串联质谱法测定食品中甜味剂和抗氧化剂

建立了液相色谱-四级杆飞行时间串联质谱联用技术同时测定4种甜味剂(安赛蜜、糖精钠、甜蜜素、阿斯巴甜)及2种抗氧化剂(叔丁基对苯二酚、丁基羟基茴香醚)的方法.试验采用Extend-C18色谱柱分离与ESI(-)检测,以乙腈-1 mmol/L乙酸铵为流动相梯度洗脱,在6 min内实现6种目标物的快速分离,检测限为0.250 0~5.00 0 ng/m L,日间精密度小于10.71%(n=3),液态样品平均回收率为83.24%~118.3%.方法准确、灵敏,可快速检测食品中的甜味剂和抗氧化剂.     

高效液相色谱测定食品中的7种抗氧化剂

建立了高效液相色谱同时定量测定食品中叔丁基对羟基茴香醚、2,6-二叔丁基对甲酚、特丁基对苯二酚、没食子酸丙酯、没食子酸辛酯、没食子酸异戊酯和没食子酸月桂酯7种抗氧化剂的分析方法.液态油脂样品经甲醇反复提取后氮气吹干,5 mL甲醇定容;固体样品使用正己烷提取,再用乙腈反萃取多次,氮气吹干,5 mL甲醇定容.提取液经Eclipse XDB-C18色谱柱(250 mm x4.6 mm,5μm)分离,以1.5％乙酸-甲醇为流动相,梯度洗脱.用二极管阵列检测器(PDA)进行检测,结合保留时间和紫外光谱进行定性分析,定量检测波长280 nm.7种抗氧化剂在1～100 mg/L范围内具有较好的线性关系,相关系数r2＞0.999,定量下限(LOQ,S/N=10)为1.0～1.5 mg/kg;空白样品的加标回收率为79％～ 101％,相对标准偏差均低于7％.将该方法应用于食品中抗氧化剂的检测,从成品植物油、坚果等食品中检出抗氧化剂的残留.该方法准确快速、灵敏度高,满足食品中添加剂的检测要求.     

离子液体双水相萃取-高效液相色谱法测定香精香料中的抗氧化剂

建立了香精香料中没食子酸丙酯(PG)、特丁基对苯二酚(TBHQ)、叔丁基对羟基茴香醚(BHA)和2,6-二叔丁基对甲酚(BHT)四种抗氧化剂的高效液相色谱检测方法。香精香料样品经离子液体双水相前处理,用高效液相色谱-二极管阵列检测法(HPLC-DAD)测定。结果表明,在0.5～100μg/mL浓度范围内,四种抗氧化剂的色谱峰面积均与其浓度呈线性关系,相关系数r≥0.9990,检出限分别为3.0、7.1、5.1和9.7ng/mL,回收率为85%～97%,相对标准偏差为1.2%～6.7%。     

Bioavailability of silicon from food and food supplements

The bioavailability of silicon from three different silicon sources was studied. A diet rich in silicon, a tablet containing a dry extract of horsetail and a solution of silicon in a choline-glycerol matrix were compared. Blood and urine of one healthy test person were sampled to monitor the silicon uptake. The silicon content of blood and serum samples was determined by graphite furnace atomic absorption spectrometry. Strongly diverging results were obtained for the three different silicon sources. Neither an increase in urinary silicon excretion nor in serum silicon content was observed when feeding the silicon rich diet. Urinary silicon excretion did significantly (P < 0.05) rise during supplementation with tablets containing dry extract of horsetail. Intake of a solution of silicon in a choline-glycerol matrix resulted in a significantly (P < 0.05) increased urinary silicon excretion and serum silicon content. From these results it can be concluded that speciation (chemical form, matrix) strongly influences the bioavailability of silicon. Received: 3 August 1998 / Revised: 25 September 1998 / Accepted: 30 September 1998     

Determination of methylcellulose and hydroxypropyl methylcellulose food gums in food and food products: collaborative study

A collaborative study was performed to determine the reproducibility of a method for the determination of methylcellulose (MC) and hydroxypropyl methylcellulose (HPMC) in food. These widely used food gums possess unusual solubility characteristics and cannot accurately be determined by existing dietary fiber methods. The new method uses the enzyme-digestion procedure of AOAC Official Method 991.43. Digestate solutions must be refrigerated to fully hydrate MC or HPMC. The chilled solutions are filtered and analyzed by size-exclusion liquid chromatography. Collaborating laboratories received 28 samples containing MC or HPMC in the range of 0-100%. The sample set included blind duplicates of 5 food matrixes (bread, milk, fish, potato, and powdered juice drink). Cochran and Grubbs tests were used to eliminate outliers. For food samples containing MC, values for within-laboratory precision, repeatability relative standard deviation (RSDr), ranged from 4.2 to 16%, and values for among-laboratories precision, reproducibility relative standard deviation (RSDR), ranged from 11 to 20%. For HPMC samples, RSDr values ranged from 6.4 to 27%, and RSDR values ranged from 17 to 39%. Recoveries of MC and HPMC from the food matrixes ranged from 78 to 101%. These results show acceptable precision and reproducibility for the determination of MC and HPMC, for which no Official AOAC Methods exist. It is recommended that this method be adopted as AOAC Official First Action.     

New food control system in Japan and food analysis at NFRI

In Japan, there was a drastic change in food control system, which was brought about by problems with BSE. Food Safety Basic Law was newly enacted and Food Hygiene Law, Japanese Agricultural Standards Law and so on were revised. Food Safety Commission was newly established for risk assessment, and Ministry of Agriculture, Forestry and Fisheries and Ministry of Health, Labor and Welfare were reorganized on food safety. National Food Research Institute (NFRI) works for improvement of technology for food analysis, development of technology to ensure food safety and so on. Objects of food analysis are inorganic elements, acrylamide, mycotoxins, functional components, genetically modified organisms, varieties of rice and so on. Proficiency testing schemes (PTs) were introduced to NFRI for reliability of food analysis. Certified reference materials (CRMs) of food related materials prepared in Japan, and PTs provided by Japanese organization were limited. It is requested for Japanese organizations to prepare new CRMs and provide many kinds of PTs for solution of peculiar problems.     

Application of differential scanning calorimetry in food research and food quality assurance

Differential scanning calorimetry (DSC) is the most widely used thermal analytical technique in food research and it has a great utility in quality assurance of food. Proteins are the most studied food components by thermal analysis including studies on conformation changes of food proteins as affected by various environmental factors, thermal denaturation of tissue proteins, food enzymes and enzyme preparations for the food industry, as well as effects of various additives on their thermal properties. Freezing-induced denaturation of food proteins and the effect of cryoprotectants are also monitored by DSC. Polymer characterization based on DSC of polysaccharides, gelatinization behaviour of starches and interaction of starch with other food components can be determined, and phase transitions during baking processes can be studied by DSC. Studies on crystallization and melting behaviour of fats observed by DSC indicate changes in lipid composition or help characterizing products. Thermal oxidative decomposition of edible oils examined by DSC can be used for predicting oil stability. Using DSC in the freezing range has a great potential for measuring and modelling frozen food thermal properties, and to estimate the state of water in foods and food ingredients. Research in food microbiology utilizes DSC in better understanding thermoadaptive mechanisms or heat killing of food-borne microorganisms. Isothermic microcalorimetric techniques provide informative data regarding microbial growth and microbial metabolism.     

The potentiality of NMR-based metabolomics in food science and food authentication assessment

In the last years, there was an increasing interest on nuclear magnetic resonance (NMR) spectroscopy, whose applications experienced an exponential growth in several research fields, particularly in food science. NMR was initially developed as the elective technique for structure elucidation of single molecules and nowadays is playing a dominant role in complex mixtures investigations. In the era of the “omics” techniques, NMR was rapidly enrolled as one of the most powerful methods to approach metabolomics studies. Its use in analytical routines, characterized by rapid and reproducible measurements, would provide the identification of a wide range of chemical compounds simultaneously, disclosing sophisticated frauds or addressing the geographical origin, as well as revealing potential markers for other authentication purposes. The great economic value of high-quality or guaranteed foods demands highly detailed characterization to protect both consumers and producers from frauds. The present scenario suggests metabolomics as the privileged approach of modern analytical studies for the next decades. The large potentiality of high-resolution NMR techniques is here presented through specific applications and using different approaches focused on the authentication process of some foods, like tomato paste, saffron, honey, roasted coffee, and balsamic and traditional balsamic vinegar of Modena, with a particular focus on geographical origin characterization, ageing determination, and fraud detection.     

Economics of food irradiation

The number of products being radiation processed worldwide is constantly increasing and today includes such diverse items as medical disposables, fruits and vegetables, spices, meats, seafoods and waste products. This range of products to be processed has resulted in a wide range of irradiator designs and capital and operating cost requirements.This paper discusses the economics of low dose food irradiation applications and the effects of various parameters on unit processing costs. It provides a model for calculating specific unit processing costs by correlating known capital costs with annual operating costs and annual throughputs. It is intended to provide the reader with a general knowledge of how unit processing costs are derived.     

Determining nanomaterials in food

Nanotechnology has emerged as one of the most innovative technologies and has the potential to improve food quality and safety. However, there are a few studies demonstrating that nanomaterials (NMs) are not inherently benign.This review highlights some current applications of NMs in food, food additives and food-contact materials, and reviews analytical approaches suitable to address food-safety issues related to nanotechnology.We start with a preliminary discussion on the current regulatory situation with respect to nanotechnology in relation to foods. We cover sample preparation, imaging techniques (e.g., electron microscopy, scanning electron microscopy and X-ray microscopy), separation methods (e.g., field-flow fractionation and chromatographic techniques) and detection or characterization techniques (e.g., light scattering, Raman spectroscopy and mass spectrometry). We also show the first applications of the analysis of NMs in food matrices.     

Analysis of irradiated food

Foods, e.g. chicken, shrimps, frog legs, spices, different dried vegetables, potatoes and fruits are legally irradiated in many countries and are probably also exported into countries, which do not permit irradiation of any food. Therefore all countries need analytical methods to determine whether food has been irradiated or not. Up to now, two physical (ESR-spectroscopy and thermoluminescence) and two chemical methods (o-tyrosine and volatile compounds) are available for routine analysis. Several results of the application of these four mentioned methods on different foods are presented and a short outlook on other methods (chemiluminescence, DNA-changes, biological assays, viscometric method and photostimulated luminescence) will be given.     

Development of food products

Food production entails a series of steps and operations that convert raw biomass into final products suitable for human consumption. Along the production chain, an enormous amount of side stream is generated. On one side, these represent a burden for the producers due to related disposal issues. On the other hand, many side streams are recognised as a valuable mass containing broad variety of health beneficial and functional ingredients. Besides being a valuable source for extraction of single compounds, direct conversion of side streams into products would save huge amount of effort and resources. Selection of the side stream and processing technology have direct impact on important quality attributes, process efficiency and sustainability. This review summarises studies performed within the last 3 years, focusing on possibilities of various sources, such as fruits, vegetables, dairy, meat, fish, coffee production, as well as new alternative ingredients insects, algae, grass and microorganisms. Finally, consumer perception and legal status are shortly addressed.