Effects Of Enzymatic Interesterification On The Physio-chemical Properties Of Palm-based Oils And Its Potential Application In Margarine

"Eat less oil,eat better oil"has become the consensus of academia and the public,providing special oils and fats with excellent processing characteristics to food industry has become a major demand for people's healthy diet.Interesterification is an important method for the modification of special oil for food.Enzymatic catalytic interesterification,as a safe and efficient second-generation technology,is more environmentally friendly,has milder reaction conditions,and has low requirements on raw materials,which has revolutionary significance on the interesterification of fats.This study used Lipozyme TL IM~?lipase to catalyze palm oil-based interesterification to prepare margarine base oil.The main research is as follows:(1)The effects of different oil ratios,reaction time and reaction temperature on the physicochemical properties of enzymatically catalyzed mixed systems of palm stearin(PST)and palm olein(POL)were studied.The study found that when the ratio of PST to POL is different,the interesterification rate under the same calculation conditions is different.The interesterification rate increases with the increase of reaction time and reaction temperature.Among them,when the reaction time is 46 min and the reaction temperature is 80?,the interesterification rate reaches the maximum.(2)PST,POL and Palm Kernel Oil(PKO)are used as raw materials to compare the physicochemical properties of Enzymatic Interesterification(EIE)in a pilot plant with Packed Bed Reactor(PBR)and Chemical Interesterification(CIE)products.The solid fat content(SFC),viscosity and hardness of the EIE sample are lower than those of the CIE sample,which is consistent with the result that the rheological properties show lower consistency;the temperature of the crystallization starting point of the EIE sample is higher than the CIE sample,and the crystallization rate of EIE sample is faster at10?;the crystallization kinetics Avrami constant K of EIE sample is larger and the n value is smaller;the crystal size of EIE sample is smaller.(3)EIE and CIE samples were stored at constant temperature and fluctuating temperature,observed the change of physicochemical properties of all samples and oxidation stability of EIE sample.The SFC and crystal form of all samples stored at a constant temperature were more stable,the SFC of samples under fluctuating temperature decreased significantly after 1 week and then increased slowly;the??crystal form of CIE and EIE samples stored under fluctuating temperature is easy to change to?crystal form(especially EIE samples);the hardness increased with stored time increase,except the hardness of CIE samples stored under fluctuating temperature which were decreased;the microscopic crystal morphology of fats has no obvious change with the stored time increase,and all the fat are fine needle crystals.Enzymatic interesterification and fractional distillation will reduce the oxidation stability of samples.(4)Margarine were prepared by adding 0.1,0.3,0.5,0.7%(the total weight of margarine)of lecithin into EIE oil phase.The properties of pure oil phase,margarine,cake batter and cake were studied respectively.The addition of lecithin to the oil phase can increase the crystal size,make the fat thicker,and inhibit the conversion of??to?crystal form.The SFC value and hardness increase while the amount of lecithin added in margarine increase,but the whipping properties become worse,which reduces the density of the cake batter.The whipping properties of 0.1%lecithin margarine are the best,the volume of the cake with 0.1%lecithin is fluffy and the texture is also good.