| According to previous research in the laboratory,camphor seed kernel oil(CCSKO),soybean oil and flaxseed oil were used as raw materials to synthesize new medium and long carbon chain triacylglycerides(MLCT)through lipase catalysis.The results showed that the functional oil had a low melting point and was suitable for human absorption.The ratio of medium chain fatty acid(MCFA)to long chain fatty acid(LCFA)was 3:1,and the ratio of linolenic acid(9.86±0.54%)to linoleic acid(5.22±0.12%)was 2:1.C57BL/6 mice were fed with CCSKO and MLCT oil instead of fat in high fat(HF)diet,respectively,to observe the anti-obesity effect of MLCT oil.The results showed that MLCT group and CCSKO group had less body weight gain and body fat deposition than that of HF group.Furthermore,the MLCT group exhibited lower levels of serum triacylglycerols(TG)and total cholesterol(TC),and liver TG and TC,as well as a higher high/low-density lipoprotein cholesterol ratio(HDL-C/LDL-C)than those in the CCSKO group.Mice fed MLCT fat showed a healthier state of being.The study has shown that MLCT was more effective in improving blood lipids and hepatic lipid than CCSKO,and in the prevention of obesity.In view of the high price of Novozyme 435 lipase as catalyst used in the production of MLCT lipids,and the immature production technology of domestic manufacturers at present,it is urgent to find a substitute lipase for MLCT lipids production.In this study,after analyzing the advantages and disadvantages of various catalysts,considering the strong alkalicity and more binding sites of organic base TBD,a magnetic solid organic base catalyst(γ-Fe2O3@SiO2@TBD)was prepared.The catalyst was easy to separate,and the maximum base load of 1.23mmol/g was determined when the ratio of TBD to magnetic carrier was 8.Then,the active components were successfully loaded on the magnetic carrier by Fourier Transform Infrared(FIR),elemental analysis,thermogravimetric analysis,nitrogen adsorption and desorption determination,scanning electron microscopy(SEM)and other characterization methods.Meanwhile,the loading of the active components did not change the structure of the carrier,and the morphology of the carrier was well preserved.The catalyst was used to catalyze transesterification of camphor seed kernel oil,soybean oil and flaxseed oil.The optimum reaction conditions were determined as follows:reaction temperature 60℃,catalyst amount 8wt.%,reaction time 4h,the transesterification rate reached 43%.After the reaction,the catalyst was cleaned and dried with petroleum ether,and then activated with methanol solution of NaOH.After repeated use for 5 times,the catalytic activity did not decrease significantly,which proved that the catalyst had good stability.Then,the transesterification products catalyzed by chemical catalyst and enzyme-catalyzed transesterification products were characterized.After the transesterification products were deacidified by alkali refining,the acid value of the transesterification products were reduced to less than 0.4mg(KOH)/g,which fully met the market standard of edible oil.Melting point is also significantly reduced,suitable for human use.After methyl esterification,the fatty acid composition of the products was analyzed by gas chromatography.The results showed that the fatty acid composition of the chemically catalyzed transesterification products and the enzyme-catalyzed transesterification products were not significantly different,and the fatty acids at the Sn-1,3 and Sn-2 sites were not significantly different,indicating that the catalyst and enzyme had no specificity for the transesterification reaction sites.Compared with the traditional equivalent carbon number method,the composition of complex triglycerides can not be clearly characterized.In this study,triglyceride compositions of transesterification products with two different catalytic methods were determined by UPLC-QTOF-MS.Results more than 50 MLCT configuration triglycerides were found in the two transesterification products successfully,among which MLCT triglycerides accounted for 59.93～74.17%in the enzyme-catalyzed transesterification products and 38.59%～53.99%in the chemically catalyzed transesterification products.In conclusion,the γ-Fe2O3@SiO2@TBD catalyst prepared in this study was successfully prepared,which can replace the expensive lipase to synthesize MLCT lipids with the effect of preventing obesity. |
