Study On Fast Determination Of Trans Fatty Acids In Diary Food And Its Reduction Technology

The research on fast determination of trans fatty acids(TFA)in diary food by GC and the reduction of TFA in diary food are two parts of this thesis.Firstly,four kinds of cis fatty acids and eleven kinds of trans fatty acids have been chosen to be standard solution,besides five different kinds of diary foods have been chosen to be samples.The analysis of normalization method and internal standard methed should be used to determine the quantity of TFA.The preparation of fatty acid methyl ester(FAME)should esterified by KOH-CH₃OH.The key point in the first part is to optimize the temperature program in GC.We have two optimum design at last:1,100℃isothermal for 5 min;increased to 150℃at 3℃/min,isothermal for 3 min;then increased to 190℃at 1℃/min,isothermal for 2 min;finally increased to 220℃at 3℃/min, isothermal for 10 min.2,150℃isothermal for 15 min;then increased to 190℃at 1℃/min,isothermal for 3 min;finally increased to 220℃at 3 ℃/min,isothermal for 5 min.We also come to the conclusion that the 18C TFAs have been enrichment in the diary foods.In the second part, two different samples have reacted together through two method which are chemical interesterification(CIE)and enzymatic interesterification (EIE)to come to a conclusion that the EIE is better.Then we have determine the optimum condition for EIE that is:added lipase quantity: 10 IUN/g;temperature of reaction:70℃;time of reaction:4h.Finally, compared with five diffirent quantity ratio(9:1,8:2,7:3,6:4,5:5)through optimum EIE condition,we have determined that the TFA's content in new product have obviousely decreased by 40%-50%by GC,and the new product in ratio(7:3)is the optimum condition.