测定食用油的保质期

好像是用热稳定仪，有国际标准

Official methods for measuring oxidative stability of Mineral
oils and derivates
British Standard
IP 306/89
Oxidation stability of straight mineral oil
IP 280/89
Oxidation stability of inhibited mineral turbine oils
International Electrotechnical Commission (CH)
IEC 474
Test Method for Oxidation Stability of Inhibited Mineral Insulating Oils.
IEC 1125 - CEI 1125
Unused hydrocarbon-based insulating liquids - Test methods for evluating the oxidation stability
ASTM - American Society for Testing Materials
ASTM D 525-88
Standard test method for oxidation stability of Gasoline (induction period method with pressure bomb)
ASTM D 2274-74
Standard Test method for Oxidation Stability of distillate fuel oil (accelerated method)
ASTM D 2440-93
Standard Test Method for Oxidation Stability of Mineral Insulating Oil
ISO - International Organization for Standardization
ISO 6249 (1984)
Petroleum products - Gas turbine fuels. Determination of thermal oxidation stability. JFTOT method
ISO 7536
Petroleum products - Determination of oxidation stability of gasoline - Induction period method
ISO 7624
Petroleum products and lubricants - Inhibited mineral turbine oils - Determination of oxidation stability

用热稳定的方法测定变质后的电导率，

能说的详细些吗？原理，什么样的仪器？

油脂样品在恒温下，向油脂中恒定速率通干燥空气，油脂中易氧化的物质被氧化成小分子易挥发的酸，挥发的酸被空气带入盛水的电导率测量池中，在线测量测量池中的电导率，记录电导率对反应时间的氧化曲线，对曲线求二阶导数，从而测出样品的诱导时间。在不同温度下测定样品的诱导时间，通过经验公式，可外推样品在不同温度下的诱导时间即在此温度下的使用或贮存时间。

那光催化呢，它的原理是什么？使用光作为介质，将油脂氧化不也可以吗？

国家现在有相应的标准吗？

我正想知道

我也想知道啊