【商检行业标准(SN)】 食品及油脂中反式脂肪酸含量的检测 傅立叶变换红外光谱法

中华人民共和国出入境检验检疫行业标准SN/T 2326—2009
食品及油脂中反式脂肪酸含量的检测傅立叶变换红外光谱法
Determination of trans fatty acids in foodstuff and oils-FTIR method
2009-07-07发布
中华人民共和国
国家质量监督检验检疫总局
2010-01-16实施
本标准的附录A为资料性附录。
本标准由国家认证认可监督管理委员会提出并归口。本标准由中华人民共和国上海出人境检验检疫局负责起草本标准主要起草人：倪昕路、韩丽、周瑶、郭德华、朱坚。本标准系首次发布的检验检疫行业标准http：//foodmate.netSN/T2326—2009
1范围
食品及油脂中反式脂肪酸含量的检测傅立叶变换红外光谱法
SN/T2326—2009
本标准规定了食品及食用油脂中反式脂肪酸的傅立叶变换红外光谱仪检测方法。本标准适用于棕榈油、乳酪、饼干和薯条中反式脂肪酸含量的检测。2规范性引用文件
下列文件中的条款通过本标准的引用而成为本标准的条款。凡是注日期的引用文件，其随后所有的修改单（不包括勘误的内容）或修订版均不适用于本标准，然而，鼓励根据本标准达成协议的各方研究是否可使用这些文件的最新版本。凡是不注日期的引用文件，其最新版本适用于本标准。GB/T5009.6：食品中脂肪的测定GB/T5009.46乳与乳制品卫生标准的分析方法GB/T5413.3，婴幼儿配方食品和乳粉脂肪的测定3检测方法
3.1方法提要
油脂试样或试样经石油醚提取所得的脂肪直接用配有氛化三甘氨酸硫酸酯（DTGS)检测器和水平衰减全反射（HATR)附件的傅立叶变换红外光谱仪测定，根据反式脂肪酸标准曲线校正，计算样品中反式脂肪酸在总脂肪中所占的百分比含量3.2试剂和材料
除另有规定外，所有试剂均为分析纯。3.2.1石油醚（沸程30℃～60℃）3.2.2无水硫酸钠
3.2.3三油酸甘油酯标准品：纯度≥99%。3.2.4三反油酸甘油酯标准品：纯度≥98%。3.2.5标准溶液：准确称取三反油酸甘油酯Xg和三油酸甘油酯（0.3一X）g（精确至0.0001g）于5mL烧杯，其中X分别为0.0150,0.03000.0600,0.0900.0.1200.0.1500.0.1800,此混合标准液反式脂肪酸含量分别为5.00%，10.00%，20.00%，30.00%，40.00%，50.00%，60.00%。冷冻保存，有效期为6个月。
3.3仪器和设备
3.3.1傅立叶变换红外光谱仪：配有DTGS检测器和HATR附件。3.3.2分析天平：感量为0.001g及0.0001g。3.3.3恒温水浴锅。
3.4测定步骤
3.4.1非油脂样品脂肪含量的测定根据不同食品的类别，分别按GB/T5009.6、GB/T5009.46或GB/T5413.3的方法测定其脂肪含量。
3.4.2样品前处理
3.4.2.1油脂样品：可直接测定。若油脂样品呈现浑浊或絮状，则说明其中含有少量水分或杂质。可1
h
SN/T2326—2009
加人适量无水硫酸钠搅拌并离心保证获得澄清脂肪3.4.2.2可直接提取脂肪的非油脂样品：根据样品的脂肪含量，称取适量经粉碎的样品（使提取所得脂肪的量为1g～2g），用石油醚浸泡并搅拌，经滤纸过滤于烧瓶中，提取液于30℃水浴旋转蒸发至干，得到脂肪。3.4.2.3不可直接提取脂肪的非油脂样品（如乳制品等）：可用3.4.1获得的脂肪测定。3.4.3测定
3.4.3.1仪器条件
a）波数范围：1050cm-1~900cm-l；b）分辨率：4cm-1；
c）扫描次数：32次或64次。
3.4.3.2样品测定
油脂样品或由非油脂样品提取所得的脂肪置于60℃水浴保温熔融后，立即吸取少量样品直接加到ZnSe晶体上，并使其充满整条晶体，即刻采集其红外吸收光谱图，用标准曲线校正得到反式脂肪酸占脂肪的百分含量。
3.4.3.3标准曲线制作
标准溶液按3.4.3.2样品测定步骤操作。以标准溶液中三反油酸甘油酯的百分含量（%）为X轴，红外光谱图中966cm-1处反式脂肪酸特征峰（参见附录A）的峰面积为Y轴建立一元线性回归方程。4结果计算和表述
样品中反式脂肪酸的质量分数X按式（1）计算：X-cXk
式中：
X样品中反式脂肪酸的质量分数，%；一从标准曲线得到的反式脂肪酸占脂肪的质量分数，%；k
样品中脂肪所占的质量分数（若为纯油脂样品，则=1）5测定低限、测定范围、回收率和精密度5.1测定低限和测定范围
.....1)
本方法的测定低限为5%（质量分数，以脂肪计），本方法的测定范围为5%～60%（质量分数，以脂肪计）。
5.2回收率和精密度
本方法的三个水平的样品添加回收率和精密度的实验数据见表1。表1食品及油脂样品添加回收率
样品名称
棕榈油
添加水平/%
品伙伴网ht
回收率/%
75.4~83.3
90.5~98.2
98.3~102.8
100.2~117.1
99.8~~108.5
96.7104.4
精密度（RSD)/%
样品名称
添加水平/%
表1（续）
回收率/%
91.4100,0
91.1~98.7
91.2~98.9
80.6~89.7
http：//foodmate.netSN/T2326—2009
精密度（RSD)/%
SN/T2326—2009
附录A
（资料性附录）
三反油酸甘油酯标准品红外光谱图1 020
Wuxemumturstem ty
三反油酸甘油酯的红外光谱图
http://foodmate.net940
Foreword
AnnexAofthis standardis informativeannex.SN/T2326—2009
This standard was proposed by and is under the charge of the Certification and Accreditation Admin-istrationofthePeople'sRepublicofChinaThis standard wasdraftedby Shanghai Entry-Exit Inspection and QuarantineBureau.ThisstandardwasmainlydraftedbyNiXinLu,HanLi.ZhouYao,GuoDehua,ZhuJianThis standard is a professional standard for entry-exit inspection and quarantine promulgated for thefirst time.
合品成伴网ht
SN/T2326—2009
Determinationoftransfattyacids infoodstuffandoils-FTIR method
This standard specifies the Fourier transformation infrared spectrometer method for the determination of the content of trans fattyacidsThis standard is applicable for the determination of the content of trans fatty acids in palm oil.cheese,cookie and french fries samples.2Normativereferences
The following normative documents contain provisions which,through reference in this textconsti-tute provisions of this standard.For dated references,subsequent amendments to,or revisions of,any of these publications do not apply. However,parties to agreements based on this standard are en-couraged to investigate the possibility of applying the most recent editions of the normative docu-ments indicated below.For undated references,the latest edition of the normative document referredto applies.
GB/T 5009.6 Determination of fat in foodsGB/T5009.46MethodofanalysisofhygienicstandardofmilkandmilkproductsGB/T5413.3Milkpowderandformulafoodsfor infantandyoung children-Determinationoffat3Methodofdetermination
Principle
Oils orFats extracted bypetroleum etherfromsamplearedetermined by aFouriertransformation in-frared spectrometer equipped withdeuterated triglycine sulfate detector(DTGS)and horizon attenu-ation total reflection (HATR) equipment. The standard curve method is used for quantitative meas-urement.
Reagents andmaterials
Unless otherwisespecified.all thereagentsused shouldbeanalyticalgrade6免费标准下载网bzxz
全品球伴网
PetroleumEther(boilingrange30℃60℃）3.2.1
Anhydroussodiumsulfate
Standardsofglycerinetrioleate：Purity≥99%Standards of trielaidin:Purity≥98%.3.2.4
SN/T2326—2009
Mixture of the standards:Accurately weight Xg trielaidin and(0.3-X)g(accurate to0.0001g)glycerine trioleate in a5mLbeaker.theX is equal to0.0150.0.0300,0.0600.0.09000.1200,0.1500,0.180 0.The contents of trans fatty acid in these mixture of standards are 5.00%,10.00%,20.00%.30.00%,40.00%,50.00%,60.00%.Keepfreezing.Validforsixmonths.3.3Apparatus and equipments
FourierTransformationInfraredSpectrometer:EquippedwithDTGSdetectorandHATRaccessory.
Analyticbalance:withaccuracyof0.001gand0.0001g3.3.2
Thermostaticwaterbath.
3.4Procedure
Determination of fatcontentinfoodstuff3.4.1
Determine the fat in foodstuff according to GB/T5009.6.GB/T 5009.46,orGB/T 5413.3.3.4.2Samplepreparation
Oils:Detect the sample directly.Treat the melting oil sample or the extract fat sample thatappears turbid because of the presence of water with anhydrous NazSO4,then stir and centrifuge themix to get a clear sample.
Fatof foodstuffcanbeextracteddirectly:Weighsufficient sampleaccrording toits fatcontent(thefatextractedfromsampleshouldbe1g~2g),soakandstiritinpetroleumether,filterthe mix into theflask and vaporize it by rotary evaporation in constant-temperature waterat3o toget thefat for determination.3.4.2.3Fat of foodstuff can not be extracted directly(e.g.dairy product):Use the steps in 3.4.1.SN/T 2326—2009
Determination
3.4.3.1FTIR conditions
Wavelengthcoverage:1050cm-1~900cm=1;Resolution:4cm-1;
Scan times:32or 64.
Determinationof sample
Immediately transfer the sufficient fat sample or the fat extracted from sample after melting them at6oC waterbath to the horizontal ZnSe crystal. Make sample completely cover the surface of thecrystal. Collect the absorbance spectrogram by FTiR. Calculate the content of trans fatty acid fromthe standard curve.
3.4.3.3Preparationof standardcurveDetermine the standards as 3.4.3.2. Establish equation of linear regression with the concentrationsof trielaidin (X axis)and peak areas at966 cm-1(Y axis)(see annexA).Calculationsand expressions of theresult4
Calculate the content of trans fatty acids in the test sample according to formula (1) =c×k
X-thecontentoftransfattyacids inthetestsample,%;c-the content of trans fatty acids calculated from the standard curve,%;k-the ratio of fat in foodstuff(for oils,k =1).5Limitandrangeofdetermination,recoveryandprecision5.1Limitand interval of determination（1)
The limit of determination of this method for trans fatty acids is 5%(m/m,of fat). The range of de-terminationofthis method fortrans fattyacids is5%~60%(m/m.of fat).8
品伙伴网h
Recoveryandprecision
SN/T2326—2009
g recoveries of fortifying concentrations inAccording to the experimental data,the correspondingfoodstuff and oil samples are listed in table1Table 1-The corresponding recoveries of fortifying concentrations in foodstuff and oil samplessample
Palmoil
Cheese
Cookie
French fires
Fortifying level/%
合品成伴网httn·//
recovery/%
75.4~83.3
90.5~98.2
98.3~102.8
100.2~117.1
99.8~108.5
96.7~104.4
91.4~100.0
91.1~98.7
91.2~98.9
68.4~79.2
80.6~89.7
89.0~94.0
uyfoodmate.net
precision(RSD)/%
SN/T2326—2009
AnnexA
(informative)
Infrared spectrogram of standard1020
Waerunhersicem)
Figure A. 1—lnfrared spectrogram of trielaidin standardhttp://foodmate.net020
小提示：此标准内容仅展示完整标准里的部分截取内容，若需要完整标准请到上方自行免费下载完整标准文档。