The Production Of Transesterification Product From Mutton Tallow And Flaxseed Oil By Lipase

Structured lipids(SL)are special lipids which are obtained by reorganizing or modifying the fatty acid on natural lipid,and have lots of special effects and nutritional value.ln this study,through single factor experiments and response surface methodoloy,the preparation process of new transesterification product was studied by sheep oil and flaxseed oil in the present of immobilizedlipases(Novozym435)whose catalytic was better.Fatty acid composition,physical-chemical properties,rheological characteristics and volatile flavor compounds of the raw oils and transesterification product were also studied.The results were as follows:(1)Sheep oil was main saturated fatty acids and long-chain unsaturated fatty acids,while stearic acid,palmitic acid,oleic acid was respectively 37.08%,20.11%and 33.05%.Flaxseed oil was main unsaturated fatty acids,while linolenic acid,linoleic acid was respectively 68.51%and 18.89%.The fatty acid types of transesterification product was numerous,eicosatrienoic acid,stearic acid,palmitic acid was respectively 41.64%,24.65%and 18.31%.(2)Single factor experiment was used to study substrate weight ratio,enzyme load,reaction time and reaction temperature on transesterification.On this basis,response surface methodoloy was designed to optimize preparation process of the product.The results showed that the optimal technology was substrate weight ratio 3,enzyme load 9%,reaction time 24h and reaction temperature 65℃.Under the best condition,the average content of eicosatrienoic acid in the transesterification product was 35.1%.(3)The rheological characteristics of raw oils and transesterification product were also studied.The result showed that the sheep oil was typical pseudoplastic non-Newtonian fluid,and when shear rate increased,the viscosity of flaxseed oil and transesterification product decreased gradually and then stabilized at a constant temperature,indicating that this two kinds of oils were gradually converted to Newtonian fluid from non-Newtonian fluid.According to the nearly linear relationship of shear stress and shear rate,flaxseed oil and transesterification product showed to be Newtonian fluid under a wide range of shear rate.(4)The volatile compounds in this three kinds of oils were determined through solid-phase microextraction and gas chromatography-mass spectrometry.The results showed that there are 32 kinds of main volatile flavor compounds in the sheep oil,including alkanes,alcohols,aldehydes,ketones,acids and esters,and 29 kinds of main volatile flavor compounds was identified in the flaxseed oil,including alkanes,alcohols,aldehydes,ketones and heterocycles,while there were 35 kinds of volatile flavor compounds identified in the transesterification product,including alkanes,alcohols,aldehydes,ketones,acids,esters and amines.(5)The physical-chemical properties indicators of raw oils and transesterification product were as follows:The acid value of sheep oil,flaxseed oil and transesterification product was respectively 1.26mg/g,0.78mg/g and 0.85mg/g.And the POV of sheep oil,flaxseed oil and transesterification product was respectively0.08mmol/g,2.73mmol/g,1.13mmol/g.And the saponification value of sheep oil,flaxseed oil and transesterification product was respectively 129.2mg/g,227.3mg/g and 183.6mg/g.