食品掺假检测方法.ppt
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1、食品掺假检测方法研究进展,张 健,一、为何要实施掺假检测二、如何实施掺假检测三、实例四、国内外仪器检测技术研究进展五、国内外软件分析技术研究进展,一、为何要实施掺假检测,生产企业:品牌保障,经济保障消费者:安全保障,经济保障监管部门:“有法必依”的保障,二、如何实施掺假检测,已知掺假物的检测 常规检测可操作(如:三聚氰胺、合成色素、瘦肉精等)常规检测无法操作(如:食品中原来就有的成分)未知掺假物的检测 常规检测无法操作,解决办法:只有靠先进的分析仪器,对食品中多种成分进行准确定量,并在此基础上结合化学计量学建模判别,才可能彻底解决食品掺假检测问题。,实例,ANOVA,PCA,Six princ
2、ipal components with eigenvalues higher than 1(Kaisers rule)that accounted for only 70.7%of the total variance,were considered significant.,Principal components 1(PC1)and 2(PC2)accounted for 24.1%and 18.1%,respectively,of the total variability.Cabernet Sauvignon wines can be described as rich in v19
3、,v26,v6,v9 andv7,Merlot wines were associated with the attributes v20,v10,v3,v24,v16,v2 and v25,and Cabernet Gernischt wines associated with higher contents of v28,v17,v5 and v11.,SLDA,The results have shown that with only 11(v2,v3,v6,v7,v11,v17,v18,v24,v25,v27 and v28)of the 19 initial variables,it
4、 is possible to differentiate the wines obtained from the three different grape varieties.,Only the two first discriminant functions are statistically significant(Wilks lambda values),explaining 100%of variability(71.6%and 28.4%,respectively).The coefficients of the variables in the two first discri
5、minant functions(Table 2)reveal which variables have a greater influence on those.,The recognition ability,according to the a posteriori probabilitieswas of 100%for all the considered classes.The prediction ability(Table 3)was 100%for Cabernet Sauvignon and Cabernet Gernischtwines,but only 92.31%for
6、 Merlot wines.,Three groups representing each variety of wine can be clearly observed.,Identification of discriminant volatile compounds,Applicability test,Conclusion,例子的启示,1、食品掺假鉴别不容易2、食品掺假鉴别必需要测定一些特征性成分(如:挥发性成分、矿物质成分、酚类物质、同位素比例、波谱吸收、DNA、蛋白质谱等)3、食品掺假鉴别常需要适当的化学计量学方法配合建模。,三、特征性成分检测技术研究进展,1、Spectrosco
7、pic techniques2、Chromatographic techniques3、Electronic nose4、DNA-based technology5、Immunological technology6、Thermal techniques,1、Spectroscopic techniques(1)MIR and NIR spectroscopy(2)Raman spectroscopy(3)NMR spectroscopy(4)SNIF-NMR and IRMS(5)Fluorescent and UVvis spectroscopy,(1)MIR and NIR spectr
8、oscopyMIR:4000400 cm-1,molecular bonds NIR:140004000 cm-1,complex structural information Common merit:rapid,non-destructive,be appropriate for different state,employed chemometric analysis,(2)Raman spectroscopy特点:对于碳碳双键,碳碳或碳氮三键敏感,对水不敏感,对无机物有高度的选择性。报道不多,例子:植物油和蜂蜜掺假,(3)NMR spectroscopy13C NMR 鉴定脂肪酸组成,
9、区分奶牛奶和水牛奶。1H NMR 区分不同品种咖啡。应用较少,设备昂贵,操作复杂。,(4)SNIF-NMR and IRMSIRMS:同位素比质谱仪,可以进行少量样品的同位素测定和区分,精确测量同位素含量;SNIF-NMR:点特异性天然同位素分馏核磁共振技术,可以确定同位素在分子中的具体位置。它们是目前国际上通用的2 种同位素比值检测技术,这2 种技术的联合使用可以获得多元素多方位的信息,从而解决更复杂的掺假问题。,原理与应用:原理:在人工、天然和生物合成过程中,产物分子具有特殊的同位素比例,即所谓的“同位素签字”。生命科学中常用的有:13C/12C、18O/16O、2H/1H、15N/14N
10、,已成功应用于多种食品掺假检测,被认为是可信度最高的检测方法之一。,13C/12C:Dependent on Plants physiologyC3 plants:cereals and most fruits,use the Calvine-Benson pathway to fix CO2 C4 plants:maize(corn)and sugar cane,use the Hatche-Slack pathwayC3 plants fix CO2 and incorporate less 13C than C4 plants.,13C/12C:用于检测是否外加糖。添加蔗糖、玉米糖化液、
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- 食品 掺假 检测 方法
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