食品中硒的含量检测及形态分析

采用GB 5009.93—2017《食品安全国家标准食品中硒的测定》中规定的食品中硒元素含量检测方法对食品中硒元素进行含量检测,所得标准曲线方程为y=2626.595x+126.650,R²=1.000,硒元素在0~100μg/L范围内线性相关系数均为1.000,线性关系良好,并通过样品验证证明该方法准确有效。另外,该试验建立了利用高效液相色谱-电感耦合等离子色谱(HPLC-ICP-MS)联用分离检测富硒食品中硒酸根(SeO₄^2-)、亚硒酸根(SeO₃^2-)、硒代胱氨酸(SeCys₂)、硒甲基硒代半胱氨酸(MeSeCys)、硒代蛋氨酸(SeMet)5种不同硒元素形态的方法。该方法利用胃蛋白酶在0.1%盐酸体系下酶解提取食品中的硒化合物,采用Hamilton PRP X-100阴离子交换柱作为分离柱,以5 mmol/L柠檬酸、氨水调节pH 4.7为流动相,等度洗脱分离5种硒化物,再运用ICP-MS进行检测。结果表明,该方法对于5种硒元素形态分离效果较好,在900 s内可完成5种硒形态的快速准确分析,是一种有效可行的对富硒产品中硒形态的分析方法。     

食品中硒元素的形态分析研究进展

硒是人体必需的微量元素,具有显著的生理功能,这些生理功能不仅取决于硒的含量,还取决于硒的形态。膳食补硒是人们获取硒元素的主要途径,食品中硒元素的存在形态将直接影响机体补硒效果。基于此,近年来人们对食品中硒元素的形态进行了大量研究。本文从食品中硒化物的提取、硒化物的分离检测等几方面论述了近年来人们对食品中硒的形态分析状况,以期为食品中硒形态的全面分析和食源性补硒产品的开发提供理论依据。     

富硒食品的研究进展与展望

介绍了富硒食品中硒元素的优点,总结了富硒产品的分类、国内外富硒食品的研究现状以及硒元素的检测方法,并对富硒食品的前景进行了展望。     

市售富硒食品中硒形态及含量的分析

目的 研究市售富硒食品中硒元素的存在形态及含量情况,通过分析总硒、有机硒和无机硒的含量,评估富硒食品的产品质量及存在的风险。方法 改进测定富硒食品中总硒、无机硒含量的电感耦合等离子体质谱法,利用改进的方法对100批次市售富硒食品进行检测,按照相关标准分析富硒食品的质量水平。结果 优化的方法能够有效提取样品中总硒、无机硒,线性相关系数达0.9999,回收率为86%～116%,精密度为1.7%～8.4%,均能满足检验要求。有30批次富硒食品中总硒不符合GB 28050-2011《食品安全国家标准 预包装食品营养标签通则》的要求,6批次样品总硒超过GB/T 22499-2008《富硒稻谷》限量值,甚至个别批次大米的总硒超标达2倍多。此外,9批次样品的有机硒达不到DBS 42/ 002-2014《食品安全地方标准 富有机硒食品硒含量要求》的要求。结论 市售富硒食品存在总硒含量不达标、有机硒含量过低等问题,该类产品的质量不稳定,容易造成补硒不足或补硒过量。     

富硒食品中硒元素检测方法的研究进展

硒具有清除体内自由基、抗衰老、增强人体免疫力、拮抗重金属毒性及抗癌等生物功能。从来源分,富硒食品可以分为地源富硒食品(又称天然富硒食品)和外源富硒食品(也称人工富硒食品)。目前市场上常见的富硒食品有富硒大米、富硒茶、富硒酵母和富硒杂粮,主要以农产品为主,存在产品同质化倾向严重、生产技术装备落后、产品品质不高等问题。富硒食品的检测方法有原子荧光光谱法、电感耦合等离子体发射光谱法、电感耦合等离子体质谱法以及原子荧光光度法。本文就硒元素的概况、市场上常见的富硒食品以及富硒食品中硒元素的检测方法进行了介绍,并对富硒食品现有的检测方法进行了概括并分析以及对未来的检测方法进行了展望。     

电感耦合等离子体质谱法测定食品中硒元素的条件优化

目的优化电感耦合等离子体质谱法(inductively coupled plasma mass spectrometer, ICP-MS)测定食品中硒元素含量的条件,并对河北省食品中硒元素含量情况进行调查分析。方法选取8种不同基质的国家标准物质作为检测样品对实验条件进行优化,同时选择80Se作为检测目标,采用碰撞模式并加入内标和5%异丙醇的优化条件下对样品中硒元素含量进行检测。通过对比结果,分析河北省膳食样品中硒元素含量,对居民通过膳食补充硒元素给予指导。结果通过采用碰撞模式及内标添加法可以有效降低基质干扰,同时加入异丙醇可极大提高硒元素的信号强度;其在5.00~100.00μg/L范围内呈现良好的线性关系(r2=0.999),检出限为0.002mg/kg;坚果及籽类、豆类及豆制品和肉及肉制品含硒较高,坚果及籽类样品中鲍鱼果含量最高为1.472mg/kg,豆类及豆制品中黄豆含量最高为0.123mg/kg,肉及肉制品中鸭肉含量最高为0.169 mg/kg。结论在检测的6类食品中,坚果及籽类、豆类及豆制品和肉及肉制品中硒含量相对较高,缺硒人群可适量增加食用。     

微波消解-电感耦合等离子体质谱测定食品中硒的含量

建立微波消解-电感耦合等离子体质谱(ICP-MS)测定食品中硒元素的方法,样品经微渡消解后,采用Re元素为内标,用电感耦合等离子质谱测定样品硒元素的含量.用该方法对国家标准物质灌木枝叶(GBW603)和对虾(GBW08572)及国际标准物质角鲨肉(DORM-2)和龙虾肝胰脏(TORT-2)进行分析,所得结果与其参考值吻合较好,硒元素的检出限为0.18μg/L,3次测定的RSD<5%.将海带、豆芽、大蒜、洋葱在硒的溶液中培养一段时间,测定培养前后硒的变化,发现这些植物对硒均有富集作用.对市场上的一些富硒产品进行硒含量的检测,发现鸡蛋清中的硒含量为10.4mg/kg,高于鸡蛋黄中硒的含量7.4mg/kg.     

硒在“土壤-作物-食品-人体”食物链中的流动

硒是人体内不可缺少的微量营养素,参与体内多种生理和代谢过程,目前全球约5～10亿人受到缺硒相关疾病威胁。在农业-食物系统中,硒主要通过土壤进入食物链,经作物富集,再通过膳食被人体摄入吸收。利用适宜农艺措施增强作物吸收转化土壤硒的能力,可使作物可食部位有效积累有机硒。但作物富硒并不意味着硒可以全部保留至食品中,食品加工环节的影响也极为关键,各种加工条件和参数会影响最终产品的硒含量和形态,从而影响其在人体内的生物利用度。本文综述硒元素在“土壤-作物-食品-人体”食物链中的流动过程,总结各环节影响食品中硒含量、形态和人体中硒生物利用度的关键因素,建议综合考虑各环节因素,以实现从农场到餐桌硒元素的高效转化。     

食品中硒与硒形态分析方法研究进展

硒是动物和人体必需的微量营养元素,目前人体对于微量硒元素的吸收主要来自食品。硒的营养特性和毒性与摄入硒的含量和存在形态密切相关。主要综述了食品中硒含量的测定方法和食品中硒形态分析研究领域所取得的进展,以期为富硒食品深度开发利用指出分析技术发展方向。     

富硒食品的研究进展

富硒食品是膳食补硒的主要来源。硒元素作为谷胱甘肽过氧化物酶必需组成部分而在人体中发挥着保护细胞膜、抗癌、延缓衰老、预防心脑血管疾病等作用,与富硒食品特殊的保健功效紧密相关。随着对全球范围内普遍缺硒问题的认识愈来愈清晰,如何科学合理、健康安全地补硒受到了广泛的关注。因此,近年来国内外对天然或人工富硒资源中硒元素的相关研究逐渐增多。本文从天然资源中硒的形态分析、富硒组分的生物活性评价和开发、硒元素的人工转化等方面论述了富硒食品的研究开发进展,为富有机硒食品作为补硒营养源的开发提供参考。     

富硒益生菌及其发酵食品的研究进展

硒是人体必需的微量元素之一,在提高免疫力、抗氧化、抗癌等方面都有优良的功效,但无机硒存在一定的毒性,因此无法成 为理想的硒源。微生物具有富集微量元素的功能,能将无机硒转化为低毒性的有机硒,而一些益生菌本身也具有提高免疫力、抗氧化 等生物活性,并且富硒之后其抗氧化性、抗菌活性和抗癌活性等均显著提高,因此富硒益生菌应用前景广阔。该文主要从益生菌对硒 的富集与转化机制,富硒益生菌的生理活性以及富硒益生菌发酵食品方面的研究进展进行综述,为富硒益生菌的开发与富硒发酵食 品的生产应用提供理论支撑。     

Selenium losses on cooking Greek foods

The effect of various cooking practices (frying, grilling, boiling and canning) on the selenium content of selected food items has been determined. All foods examined upon cooking lost selenium and, in general, the harsher the cooking conditions the more selenium was lost. Fish lost 36–46%, meats 13–41%, cereals 20–30%, vegetables 12–37%, pulses and cereal products 5–10% selenium. It is estimated that Greeks receive 110 and c . 95 μg Se/day based on raw, and cooked plus uncooked foods, respectively. Cooking does not make a large difference to the daily selenium intake of Greeks because of their large consumption of bread.     

Harmonisation of food categorisation systems for dietary exposure assessments among European children

Within the European project called EXPOCHI (Individual Food Consumption Data and Exposure Assessment Studies for Children), 14 different European individual food consumption databases of children were used to conduct harmonised dietary exposure assessments for lead, chromium, selenium and food colours. For this, two food categorisation systems were developed to classify the food consumption data in such a way that these could be linked to occurrence data of the considered compounds. One system served for the exposure calculations of lead, chromium and selenium. The second system was developed for the exposure assessment of food colours. The food categories defined for the lead, chromium and selenium exposure calculations were used as a basis for the food colour categorisation, with adaptations to optimise the linkage with the food colour occurrence data. With this work, an initial impetus was given to make user-friendly food categorisation systems for contaminants and food colours applicable on a pan-European level. However, a set of difficulties were encountered in creating a common food categorisation system for 14 individual food consumption databases that differ in the type and number of foods coded and in level of detail provided about the consumed foods. The work done and the problems encountered in this project can be of interest for future projects in which food consumption data will be collected on a pan-European level and used for common exposure assessments.     

Harmonisation of food categorisation systems for dietary exposure assessments among European children

Within the European project called EXPOCHI (Individual Food Consumption Data and Exposure Assessment Studies for Children), 14 different European individual food consumption databases of children were used to conduct harmonised dietary exposure assessments for lead, chromium, selenium and food colours. For this, two food categorisation systems were developed to classify the food consumption data in such a way that these could be linked to occurrence data of the considered compounds. One system served for the exposure calculations of lead, chromium and selenium. The second system was developed for the exposure assessment of food colours. The food categories defined for the lead, chromium and selenium exposure calculations were used as a basis for the food colour categorisation, with adaptations to optimise the linkage with the food colour occurrence data. With this work, an initial impetus was given to make user-friendly food categorisation systems for contaminants and food colours applicable on a pan-European level. However, a set of difficulties were encountered in creating a common food categorisation system for 14 individual food consumption databases that differ in the type and number of foods coded and in level of detail provided about the consumed foods. The work done and the problems encountered in this project can be of interest for future projects in which food consumption data will be collected on a pan-European level and used for common exposure assessments.     

杏鲍菇富硒蛋白的营养结构特性及对铅毒性的缓解作用

铅主要通过饮食进入人体并在体内积累，对人体免疫和代谢等系统造成损伤，补充硒可以显著改善铅暴露对机体的危害。本研究以杏鲍菇富硒蛋白（selenium-enriched protein from Pleurotus eryngii，SePEP）为原料，通过高效液相色谱-电感耦合等离子体质谱联用技术、傅里叶变换红外光谱等测定蛋白硒形态及结构。通过细胞实验探究蛋白体外模拟消化产物对Pb2＋引起的RAW264.7细胞毒性的缓解作用。结果表明，SePEP硒含量为（360.64±3.11）mg/kg，硒形态主要包括硒代蛋氨酸（SeMet，（48.04±0.64）%（相对含量，下同））、硒代胱氨酸（SeCys2，（31.91±0.51）%）和甲基硒代半胱氨酸（MeSeCys，（14.65±0.36）%）。硒的添加显著促进了氨基酸的生成，改变了蛋白质的结构，α-螺旋结构相对含量由（20.30±0.87）%增加至（25.00±1.60）%，无规卷曲结构相对含量由（20.38±0.84）%减少至（13.85±1.66）%，总巯基与二硫键含量及表面疏水性均显著增加（P＜0.05）。添加75 μg/mL SePEP消化产物后，Pb2＋处理的RAW264.7细胞存活率由接近50%显著升高至（76.95±6.95）%，细胞培养液中乳酸脱氢酶释放量降低57.45%，并且3 种促炎细胞因子白细胞介素（interleukin，IL）-6、IL-8和肿瘤坏死因子α的释放受到显著抑制（P＜0.05），说明SePEP消化产物对Pb2＋暴露引起的RAW264.7细胞损伤有缓解作用。本实验研究成果可为研发安全、有效的改善铅毒性的功能富硒蛋白食品提供参考。     

Selenium in Foods Produced and Consumed in Greece

The total selenium within a wide variety (315 food items) of Greek foods was determined fluorimetrically. Rich selenium sources were the proteinaceous foods such as fish, meat, bread, and spaghetti. Butter, oils, vegetables, and fruits were poor sources. The selenium content of Greek foods was lower than that of many other countries and resembled more closely that of British foods. From available food consumption data and values in this study, it was estimated that the daily selenium intake of Greeks was 110 μg.     

VARIATION IN THE SELENIUM CONTENT OF INDIVIDUAL BRAZIL NUTS

Brazil nuts are high in selenium content relative to other human foods. Since the limits between human selenium essentiality and toxicity are narrow, it is important to know the variation in selenium content of individual nuts. Analysis was performed on 72 individual nuts obtained in stores as shelled nuts in bulk and shelled and unshelled nuts in packages. Their average selenium content was 14.66 ppm with a range of 0.2 to 253.0. The agronomic and health aspects of these findings are discussed.     

Trace elements in Canadian field peas: a grain safety assurance perspective

Canada is a significant exporter of field peas and, thus, issues of food safety are important in all grain and food products within the international marketplace. Environmental contaminants, such as trace elements, may be present in all foods and, as a result, international standards have been established for a number of toxic trace elements, such as cadmium, lead, mercury and arsenic, in raw food commodities and food products. The Canadian Grain Commission has undertaken a baseline study of various trace elements in Canadian peas to ensure compliance with international food safety legislation. Mean total cadmium content was found to be 0.023 mg kg^?1; arsenic and lead mean values were below the method limit of quantification of 0.050 mg kg^?1 and the total mean mercury level was below the quantification level of 0.002 mg kg^?1. All measured values in the study were below the maximum residue levels (MRLs) established by the FAO and WHO in the Codex Alimentarius. The mean total selenium content was 0.331 mg kg^?1, with 56% of the measured values exceeding the MRL established by the People's Republic of China (PRC) of 0.3 mg kg^?1. No Codex MRL has been established for selenium as it is regarded as an essential trace element for human health and the PRC is currently reviewing its MRL for selenium in light of this fact. For those parts of the world where selenium-deficiency is of nutritional concern, the higher level of selenium in Canadian peas and their products may be of nutritional benefit.