Extraction Of Shea Butter And Preparation Of Cocoa Butter Equivalent

Cocoa butter is an important raw material for chocolate and related candy industry.It can meet the hardness,brightness and melting characteristics of the product.However,due to the high price and insufficient supply of cocoa butter,there has been a lot of research to replace cocoa butter for a long time.Shea butter is a pure natural,non-toxic and non-irritating lipid extracted from African Shea butter.It has high similarity in composition with cocoa butter,and has the characteristics of wide source and low price.Stearin extracted from shea butter can prolong the shelf life and enhance the heat resistance of chocolate products.The high content of antioxidants in shea butter can reduce the acidity of products and improve the stability of products.China also approved shea butter as a new food raw material in June 2017.In order to explore the feasibility of preparing cocoa butter-like oil from Shea butter,the physicochemical properties of shea butter kernels were determined,the extraction technology of shea butter and its sequestration technology were optimized,the physicochemical properties and crystallization characteristics of fractionated shea stearin were studied,The crystallization state of fractionated shea stearin and cocoa butter mixture was discussed,and the compatible formula of the mixture was obtained.Finally,the cocoa butter-like base oil with suitable processing characteristics was determined by optimizing the emulsifier formula.The frosting degree of chocolate prepared by different formulations was compared through accelerated frosting experiment,and the reasons for the frosting of chocolate were preliminarily analyzed.The main research contents and results are as follows:1.The effects of microwave time,liquid-material ratio,extraction time and extraction temperature on the yield of shea butter were studied by single factor and orthogonal experiments.The results showed that the optimum technological parameters were microwave time 120 s,liquid-to-material ratio 10:1(ml/g),extraction time 60 min,extraction temperature 70?.Under these conditions,the yield of shea butter was 47.73%,and the extraction rate was 96.04%.The results showed that the optimum conditions could be used as extraction parameters of shea butter.2.The effects of extraction temperature,liquid-to-material ratio and extraction time on the comprehensive score of fractionated shea stearin were studied by single factor and orthogonal experiments,and the physical and chemical properties of butter were compared with those of natural cocoa butter.The results showed that the optimum technological parameters were extraction temperature 10 ?,liquid-to-material ratio 4:1(m L/g)and extraction time 10 h.Under these conditions,the comprehensive score of butter extraction from shea butter was 45.263,and the solid fat content of butter extraction from shea butter and cocoa butter had the same change trend with temperature.XRD diffraction results show that there are a few crystals of the dominant Beta-type in segregated lipids and cocoa butters,The fractionated shea stearin showed a strong absorption peak at 35.13?,showing good single crystal characteristics,but the absorption peak was wider and less sharp than natural cocoa butter.3.In order to obtain a cocoa-like base oil with good compatibility,fractionated shea stearin was physically mixed with natural cocoa butter in different proportions.The compatibility of these binary systems was studied by thermodynamic method,isothermal curve,isothermal curve and deviation curve.The results showed that there was only slight monotectic or eutectic phenomena in all binary systems of fractionated shea stearin and cocoa butter at different melting points.When the mixing ratio of shea butter and cocoa butter was 5:95,10:90 and 20:80,the peak temperature and enthalpy of melting and crystallization of mixed oil were similar to those of natural cocoa butter,indicating that when the content of fractionated shea stearin was 5%-20%,the mixed oil phase was similar to that of natural cocoa butter.The compatibility of cocoa butter-like base oil is the best when the proportion of fractionated shea stearin is 20%.It can be used as cocoa butter-like base oil.4.In order to obtain high-quality cocoa-like base oil for chocolate,the compound emulsifier was screened.On the basis of the selected base oil,the optimum ratio of emulsifier to base oil and its dosage were selected by taking the rate of viscosity change,crystal growth rate,the difference of solid fat content at 30-35?and the ratio of beta crystal form as evaluation indexes.The results showed that soybean lecithin,tween 60 and polyglycerol ricinol ester(all 1%)had the best effect on promoting the formation of beta crystalline form in the base oil,and the proportion of beta crystalline form was 77.65%,79.67% and 79.27% respectively.Regression design experiments showed that the optimum proportion of soybean lecithin:tween 60:polyglycerol ricinolate = 1:1:1,and the optimum amount of compound emulsifier was1.5%.5.To evaluate the effect of base oil in chocolate products,compare the physical and chemical properties of chocolate prepared with compound emulsifier + pure cocoa butter,base oil and compound emulsifier + base oil,and use atomic force microscope,DSC XRD diffraction method was used to determine the changes of physical and chemical properties of chocolate during storage and to analyze the reasons for its blooming.The results showed that the chocolate prepared by compounding emulsifier + base oil had smooth surface,bright and bright color,pure flavor,complete shape,silky smoothness and the slowest frosting.When the storage time was 75 days,the surface had frost.The complex emulsifier + pure cocoa butter chocolate,the surface is slightly rough,the taste is fine,the color is general and the frost is the fastest,when the storage time is 45 days,the surface begins to have a slight frost;The chocolate prepared from the base oil has a general color,a slightly rough surface,and is fine and generally has a slight frost on the surface when the storage time is 60 days.Therefore,the chocolate prepared by the compound emulsifier + base oil has better sensory and storage stability than the chocolate prepared by the other two formulations.The slowest reason for chocolate frosting prepared by compounding emulsifier + base oil is that it contains higher content of symmetrical monounsaturated triacylglycerol(St OSt)and compound emulsifier,which can promote chocolate beta(V)Crystal form formation,which is beneficial to improve the heat resistance and frost resistance of chocolate.The frosting of the three kinds of chocolates is related to the migration of triglycerides from the base oil to the surface through tiny capillary holes in the chocolate and the transformation of part of the metastable form of beta(V)into the stable form of beta(VI).