Research On The Refining Technology Of Milk Thistle Seed Oil

In this study, with the mechanical compression milk thistle seed oil as raw materials.The test materals were from Shaanxi Weinan Fat Factory .We systematically studied the acid of alkali refining and activated clay bleaching and steam distillation deodorization process conditions by multi-factor orthogonal test respectively. First of all, through determine the various physical and chemical properties of milk thistle seed crude oil, understanding of the nature of crude oil, Meanwhile, determine the method of crude oil deacidification: By aqueous solution of sodium hydroxide direct alkali refining on milk thistle seed crude oil, To optimize the various process parameters deacidification on the impact of alkali refining, Optimized the best parameters of deacidification process conditions. Then, activated clay to bleaching the oil after alkali refining, by orthogonal test Optimized the best bleaching conditions, deacidification by alkali refining, bleaching by activated clay after the oil has a better appearance. Then again, by steam distillation, steam at high temperature to remove the odor material and part of the free fatty acid. Finally, to test the physical and chemical properties of refined oil with the national standard for the control, to ensure the high quality refinement and good taste of cooking oil. Meanwhile, use high performance liquid chromatography to detective the content of milk thistle silymarin in the milk thistle oil ,to clarify its role in health care. The main results are as follows:(1)Aqueous solution of sodium hydroxide for direct use of alkali refining deacidification,Through orthogonal test,impact of each single factor on the effect acidity:ultra-alkali capacity、sodium hydroxide concentration、alkali refining time、alkali refining temperature.The optimal tested deacidification conditions are:ultra-alkali capacity of 0.15%,sodium hydroxide concentration of 10%, smelting base temperature of 60℃for 25min,In this condition,acidity can be reduced to 1.131 mgKOH / g oil. phospholipid content from 0.982mg / g down to 0.251mg / g.(2)With different amounts of activated clay for bleaching of deacidification oil.Through orthogonal test,the impact of single factors on decolorization were:add the amount of clay,bleaching time, bleaching temperature and stirring rate.The optimum test conditions for decolorization:4% activated clay, bleaching for 25min ,bleaching temperature 100℃with Stirring rate 90r/min,make best decolorization effect.After bleaching the color of oil is: Y10.1 R1.0(3)Deodorized by steam distillation method.Use of electric heating units, the voltage control 100～120V.Distillation 2h,relatively low acid value oil, deodorization results are satisfactory,acid value dropped to 0.215mgKOH / g oil. Peroxide value 1.479mmol/kg(4)Milk thistle seed oil analyzed the physical and chemical properties,the indicators have reached the desired results.Oil transparent and light color and low odor,quality has improved significantly, meet the standards of edible vegetable oil.HPLC be used to determined the silymarin content of milk thistle seed of crude oil and refined oil .Measurement results are as follows:Per gram of crude oil contains silymarin 0.279mg, per gram of refined oil contains silymarin 0.247mg,Loss rate of 11.47%. the nutritional value of Milk Thistle seed oil affected small.