摘要
目前，全社会已广泛关注到了地沟油带来的危害。为加强监管、保障食品安全，建立简单、快速、有效的地沟油的鉴别检测方法就显得十分重要。
本文分析、对比了正常食用油与地沟油的理化特点，初步建立了快速鉴别检测地沟油的方法，具体如下：
1、检测了正常食用油、问题油样和地沟油的感官性质、水分、过氧化值、羰基值、皂化值、酸价等指标，通过分析、对比检测结果，发现地沟油与食用植物油在气滋味、过氧化值和酸价等指标上有较大差异，可以根据这些指标对正常食用油、粗制地沟油进行初步鉴别判断。
2、酸价快速检测试纸的初步验证、优化。参照文献制作了以玻璃板为载体的微型薄层色谱。利用制作好的硅胶板可在15s内测定食用油的酸价范围，检测时只需取0.1mL油样滴在硅胶板上，快速显色后与标准比色板对比即可得出酸价范围，从而初步判断油质的好坏，但是只有当地沟油或问题油样的酸价大于3.95mgKOH/g时，才可被鉴定出来，并且酸价差距不大的油样颜色对比不明显，容易造成误判。本研究试图从显色条件、显色剂、粘合剂、显色载体上进行优化，以此来解决此方法的局限性，但是效果不理想。
3、过氧化值快速检测试剂盒的试制。根据氧化还原的原理试制试剂盒，通过显色剂的选择、显色时间的确定等条件试验，最终确定过氧化值试剂盒以2mL的样品瓶做载体、自制亚甲基蓝溶液为指示剂、采用针管注射进样、适宜显色时间为10min.此试剂盒达到了快速、直观检测过氧化值的效果，能较好的区分地沟油和正常食用油。此方法与国标中滴定法检测过氧化值的方法相比，具有简单方便、快速、经济等特点；与酸价快速检测方法相比，具有灵敏、准确、颜色稳定等特点；可用来进行问题油样以及地沟油的快速初筛定性。
4、核磁共振技术测定甘油三酯的含量。通过核磁共振技术考察了甘油三酯的弛豫面积与含量的相关性，利用核磁共振技术检测了不同油样中甘油三酯的含量，并进行了分析、对比。结果表明，甘油三酯驰豫面积与其含量有相关性，相关性方程为y=7056.4x+342.05,相关系数为R2=0.9997.市售品牌油样甘油三酯的含量都在97.00%以上；粗制潲水油的甘油三酯含量很低，只有61.07%;但精炼地沟油的甘油三酯含量超过了95.00%,达到正常油脂的标准，久置油样低于正常油脂的标准。由此可知，正常食用油与粗制地沟油在甘油三酯含量上有较大差异，精炼后的地沟油甘油三酯含量可达到正常油脂的标准，久置油样属于问题油样。
该法不需溶剂、可进行无损检测，相比利用核磁共振测定固体脂肪含量来鉴别地沟油而言，更加简单快速，并且受温度影响较小，但目前优化的核磁共振参数只适用于粗制地沟油的快速鉴别检测。
关键词：地沟油；鉴别检测；优化；试剂盒；核磁共振
Abstract
At present, the harm of cooking oil has avidly commanded wholesociety's attention.In order to develop the supervision and to ensure foodsafety, it is very important to establish a simple, rapid, accurate andsuitable detection of illegal cooking oil.
This paper analyzed the different physical and chemical characteristicsof cooking oil and illegal cooking oil,and a rapid detection method ofillegal cooking oil was preliminarily established, the results are as follows:
1 .The sensory properties,moisture, peroxide value and carbonyl value,saponification value, acid value and other indicators of cooking oil,problems oil and illegal cooking oil are detected.Through the analysis andthe test results,there are differences between cooking oil and illegalcooking oil in the smell,taste, peroxide value and acid value.According tothese indicators,normal cooking oil and crude illegal cooking oil can bepreliminarily judged
2 .The rapid detection and optimization of test paper of acid value.
According to the literatures,micro thin layer chromatography with silicagel plate as the carrier was made.The silica gel plate can measure acidvalue range of illegal cooking oil in 15 seconds.Through the silica gel platecolor, we can preliminary judge the oily. Only 0.1 ml sample oil on silicagel plate, acid value range are obtained after the comparison betweensample oil color and standard colorimetric board.But this method onlywhen problems oil and illegal cooking oil acid value is greater than 3.95 mgKOH/g,can be identified, what's more, the contrast of sample color acidvalue with little difference is not obvious,which is easy to causemiscarriage.This study attempts to optimize color conditions,chromogenicagent, adhesive,chromogenic medium,so that we can solve the limitation ofthis method, but not succeed.
3 .The trial production of rapidly detection of peroxide value.
According to the principle of oxidation reduction, test kits were made.
Through the choice of chromogenic agent and chromogenic time,2 mlsample bottles as the carrier of the peroxide value kit is determined.Thenwith self-made methylene blue as the indicator, with the help of the needleinjection, the results shows that the appropriate color for is 10 minutes.
This kit achieved rapid and intuitive testing the effect of peroxide value, itcan better to distinguish illegal cooking oil and normal cooking oil.Thismethod, compared with national standard test method, is more simple,convenient, rapid and economic.Compared with the acid value,this rapiddetection methods,has the characteristics of sensitive,accurate and stablecolor. This can applied to field and laboratory detection of illegal cookingoil,problems oilat the beginning of the rapid screening of qualitative.
4 .Nuclear magnetic resonance （NMR） technique for determining thecontent of triglycerides.By magnetic resonance imaging the correlation ofthe relaxation area and content of triglycerides was investigated.By usingnuclear magnetic resonance （NMR） technology the content of triglyceride indifferent sample was detected.Next through analyzing and comparingdifferent oil.Results showed that the size of triglyceride relaxed area wascorrelated with its content, the correlation equation was y=7056.4x+342.OS,the correlation coefficient for RZ一0.9997.The commercial brandsample triglyceride content of 97% or more.Crude oil pigwash triglyceridecontent is very low, only 61.07%.But refined cooking oil,the content oftriglyceride reached 96.55%,reached the standard of normal oil,but thestandard sample is below. Accordingly, normal cooking oil and crude oil hasgreat differences in triglyceride levels,illegal cooking oil after refiningtriglycerides,its content can reach the standard of normal grease.Themethod down't need solvent, nondestructive testing can be performed,compared to solid fat content measured by NMR to identify cooking oil, theeasier and faster, and is less affected by temperature, but the currentoptimized nuclear magnetic resonance （NMR） is only applicable to crudeillegal cooking oil for quick detection.
Key Words:illegal cooking oil;discrimination;optimization;reagent box;nuclear magnetic resonance （NMR）
目录
摘要
Abstract
第1章 绪论
1.1 地沟油
1.2 国内外研究现状
1.2.1 感官检测
1.2.2 常规油脂理化指标检测
1.2.3 电导率测定法
1.2.4 胆固醇含量测定法
1.2.5 脂肪酸相对不饱和度（U/S值）测定法
1.2.6 测真菌毒素法
1.2.7 挥发性成分测定法
1.2.8 快速检测试纸法
1.2.9 色谱检测技术
1.2.10 核磁共振鉴别法
1.2.11 质谱法
1.2.12 光谱检测技术
1.2.13 油脂内源性指标作为地沟油特征指标的研究方向
1.3 地沟油检测方法研究的应用前景和学术价值
1.4 研究范围与内容
第2章 不同油样的感官鉴评与理化指标检测
2.1 前言
2.2 材料与方法
2.2.1 材料与设备
2.2.2 试验方法
2.3 结果与讨论
2.3.1 感官检测
2.3.2 常规理化指标的检测
2.4 本章小结
第3章 地沟油快速检测方法的研究
3.1 前言
3.2 材料与方法
3.2.1 材料与设备
3.2.2 试验方法
3.3 结果与讨论
3.3.1 酸价的快速检测试纸验证结果
3.3.2 过氧化值快速测定结果
3.4 本章小结
第4章 低场核磁共振快速检测甘油三酯含量
4.1 前言
4.2 材料与方法
4.2.1 材料与设备
4.2.2 试验方法
4.3 结果与讨论
4.3.1 分析油样的核磁图谱
4.3.2 甘油三酯含量与核磁共振参数的相关性分析
4.4 本章小结
结论
参考文献
致谢
