The analysis of trans fatty acid profiles in deep frying palm oil and chicken fillets with an improved gas chromatography method

An improved gas chromatography method for the simultaneous separation of 52 fatty acids (FAs) has been developed. For both oleic acid and linoleic acid, a good resolution was achieved for their positional and geometrical (cis/trans) isomers. This method was validated to be precise, accurate and sensitive. With this method, the FAs profiles in palm oil and chicken fillets were analyzed. In general, small changes were observed in the composition of FAs and formation of trans isomers after 8 h frying at the temperature lower than 200 °C. However, with extreme deep-frying process, the thermal degradation and TFAs formation in frying oil increased in direct proportion to frying temperature and time. Moreover, the FAs composition of fried chicken fillets was found to be mostly in correspondence with that of the frying oil, which might be due to the oil absorption or interaction between the frying oils and frying materials.     

《食品营养强化剂使用标准》实施跟踪评价

目的调查食品企业对GB 14880—2012《食品营养强化剂使用标准》的满意度及标准实施对企业的影响。方法 2014年通过问卷调查的方式在全国25个省针对强化食品生产企业相关人员开展调查,共回收有效问卷686份,采用描述性分析、卡方检验等进行统计学分析。结果 686位受访者对标准知晓率为87.61%(601/686),以5分为满分,对标准可操作性平均得分为4.325分;合理性平均得分为4.293分;92.15%(552/599)食品企业为新标准实施采取了相应措施,新标准实施对食品企业起到了正向的推动作用,同时增加了检验成本。结论食品企业对GB 14880—2012《食品营养强化剂使用标准》的知晓率及满意度较高,标准实施推动了食品企业的正向发展,同时带来了一定执行成本。     

我国食品生产经营规范类标准现况分析

原卫生部(现国家卫生与人口计划生育委员会)于2012年底全面启动了食品标准的清理工作,共搜集到食品标准约5 000项,其中食品生产经营规范类标准398项。此次清理过程反映出我国食品标准存在内容界定不清、部分标准内容之间重复交叉、食品安全国家标准体系亟需建立完善等诸多问题,本文对食品生产经营规范类标准进行了汇总、整理和分析,并提出了存在的问题和建议,为食品标准清理及整合工作提供参考。     

Development of novel functional ingredients: Need for testing systems and solutions with Caenorhabditis elegans

BackgroundNutrition is increasingly understood as a means of maintaining health and well-being and the market for functional foods keeps growing in double-digits. Functional nutrition is seen by many as the interphase between food and pharmaceuticals. In fact, players from both sides are increasingly making moves in the form of strategic alliances, M&A operations and co-investments which are bringing the two realms closer together.Food regulations to prove safety of novel ingredients or to support health claims are every day more stringent and the general public is also increasingly informed about the science, risks and benefits of what they eat. All this presents a magnificent opportunity for innovation and differentiation in the food industry, but also demands more investment, effort and rigour in its R&D.In programmes that also resemble pharmaceutical discovery and development, having high-throughput, appropriate models for screening, functional and mechanistic testing of novel ingredients will be crucial for success.Scope and approachThe most widespread in vitro and in vivo testing systems used in food and pharma, from cell cultures to rats, were assessed with regard to the most relevant aspects for novel functional ingredient discovery and development.Key findings and conclusionsAmongst all the testing and screening systems analysed, the nematode Caenorhabditis elegans seems to be the one offering the most advantages for early preclinical studies due to its time and cost efficiency, high degree of similarity with human genetics and metabolism, ease of handling, scalability and regulatory status.     

食品微生物学检验方法标准体系跟踪评价

目的通过对现行食品微生物学检验方法 GB 4789标准体系开展跟踪评价,为完善食品微生物学检验方法标准体系提供建设性意见。方法采用问卷调查的方式在中西部19个省和直辖市开展研究,调查对象主要包括政府检验机构、企业检验部门和第三方实验室的相关检验人员。通过国家食品安全风险评估中心网站数据录入系统进行数据在线录入和填报,数据采用SPSS 22.0和Microsoft Excel 2013进行统计分析。结果本次调查共收回有效问卷1 056份,政府和企业的检验人员为调查主体。来自不同机构的调查对象对标准的整体评价均在4分以上(5分为满分),企业检验部门的评分高于政府检验机构,差异有统计学意义(P0.05)。93.8%(991/1 056)的调查对象认为现行标准体系可以完全满足或基本满足工作需求。在标准体系的完善方面,50.7%(535/1 056)的调查对象认为最为需要修订的是样品前处理方法;不同机构对于需要增加的检验项目建议不同,差异有统计学意义(P0.05);92.4%(976/1 056)的调查对象认为有必要增加快速检验方法。结论 GB 4789食品微生物学检验标准体系使用率高,整体评价好。建议国家管理部门明确微生物快速检验方法在食品安全国家标准体系中的定位,为其发展提供指导性意见。     

免疫亲和柱结合超高效液相色谱-串联质谱法测定牛奶中的16种真菌毒素比较研究

目的 通过比较5种不同商品化多合一免疫亲和柱的可检测目标毒素种类、回收率和稳定性,筛选性能最优的免疫亲和柱,建立免疫亲和前处理-超高效液相色谱-串联质谱法(ultraperformanceliquid chromatography-tandem mass spectrometry, UPLC-MS/MS)测定牛奶中16种真菌毒的方法。方法 牛奶样品分别经5种不同多毒素免疫亲和柱进行净化富集,用优化后的UPLC-MS/MS,在多反应监测模式下测定,同位素内标法定量,筛选覆盖牛奶中真菌毒素污染种类全面、回收率和稳定性最佳的免疫亲和柱,并进行免疫亲和柱性能评价和方法学验证,最终将方法应用于实际样品检测。结果 免疫亲和柱A对牛奶中16种真菌毒素在低、中、高3个添加水平均具有良好的准确度和精密度,加标回收率在83.6%～126.8%之间,相对标准偏差为0.2%～18.4%。柱A内各毒素残留水平低于仪器检出限,柱容量在21.8～1317.5 ng之间。使用免疫亲和柱A富集净化样品,各目标毒素在线性范围内线性良好,相关系数均大于0.99,定量限为0.0010～0.2000ng/g。应用该方法对牛奶质...     

Highly efficient synthesis of(R)-1,3-butanediol via anti-Prelog reduction of 4-hydroxy-2-butanone with absolute stereoselectivity by a newly isolated Pichia kudriavzevii

(R)-1,3-butanediol is an important pharmaceutical intermediate, and the synthesis of(R)-1,3-butanediol using green biological methods has recently been of interest for industrial application. Here, a novel strain QC-1 that efficiently transforms 4-hydroxy-2-butanone to(R)-1,3-butanediol was isolated from soil samples. Based on morphological, physiological, and biochemical tests and 5.8 S-internal transcribed spacer sequencing, the strain was identified as Pichia kudriavzevii QC-1. The reaction conditions were optimized to 35 ℃, pH 8.0, rotation speed 200 rpm, and 6:5 mass ratio of glucose to 4-hydroxy-2-butanone. Evaluation of the effects of 4-hydroxy-2-butanone concentrations on yield and cell survival rate showed that 85.60 g·L~(-1) product accumulated, with an enantiomeric excess of more than 99%, when 30 g·L~(-1)4-hydroxy-2-butanone was added at 0, 10, and 30 h in a 3-L bioreactor. Thus, strain QC-1 showed excellent catalytic activity and stereoselectivity for the synthesis of(R)-1,3-butanediol from 4-hydroxy-2-butanone.     

基于微生物分型的归因方法对我国归因研究的启示

食源性疾病是全球重要的公共卫生问题,尤其以微生物危害因素中致病菌导致的危害最为严重,在基于风险的食品安全管理体系下,识别优先管控的危害因素极其重要的食物来源是防控食源性疾病的前提和关键。结合微生物分型和统计建模的归因方法是国际通用的以确定不同食物来源对食源性疾病相对贡献的技术方法,目前欧美等国已经建立了频率匹配和群体遗传学两大类基于微生物分型的归因方法模型,并将其结果转化为食品安全风险管控措施制定的科学依据,而我国目前正处于食源性疾病归因方法研究的初步探索阶段。本文系统梳理了目前国际广泛应用的归因方法的方法原理和模型,结合我国食源性疾病归因研究基础和现状,提出“建方法、合数据、搭平台、强交流”四个我国下阶段食源性疾病归因体系建设的工作方向,其中研发本土化微生物分型归因模型方法是解决我国确证管控核心和防控我国食源性疾病面临的挑战,最终实现食品安全和保障人民生命健康。     

程序升温大体积进样在HRGC-HRMS法测定食品中PCDD/F的应用

目的通过优化程序升温蒸发进样口的相关参数,建立测定食品中多氯代二苯并二噁英和多氯代二苯并呋喃(PCDD/Fs)的程序升温大体积进样高分辨气相色谱-高分辨质谱(HRGC-HRMS)方法。方法食品样品提取、净化分离和浓缩按《GB/T 5009.205-2007食品中二噁英及其类似物毒性当量的测定》规定进行,待测试样进样15μL,应用HRGC-HRMS结合同位素稀释技术测定其中PCDD/Fs。结果最佳条件为进样口初始温度115℃,蒸发相温度140℃,蒸发相吹扫流速为5 mL。大体积进样所获得的待测物峰面积及S/N存在显著增加(P0.05)。结论程序升温大体积进样方式能显著提高食品基质中PCDD/Fs的检测能力,有助于保证食品安全风险评估结果的准确可靠。     

微胶囊化功能性番茄红素产品的高效液相色谱测定法改进

采用高效液相色谱法测定微胶囊化功能性番茄红素产品中的番茄红素(片剂、胶囊或软胶囊)。样品用二甲基亚砜溶解破膜,以1%BHT-二氯甲烷提取释放出的番茄红素,用HPLC检测番茄红素的含量。方法线性范围为0 70μg/mL,r=0.9996,最低检出浓度为0.30μg/mL,加标回收率为90%107%,相对标准偏差为小于10%。本方法简便,耗时短,试剂消耗少,且结果准确可靠,对功能性食品中微胶囊化番茄红素的测定提供了一种较好的解决方法。