Study On The Production Of Cocoa Butter Equivalent By Fractionation And Enzymatic Interesterification Of Palm Oil

The price of cocoa butter is very high because of its limitation of planting andspecial function. The cocoa butter as the raw material product is expensive. So manyscientific researchers devote themselves to the study of cocoa butter alternatives. Inthis paper, the research was studied on the production of cocoa butter equivalents.First, the influence of melting point and yield was studied by dry fractionation ofpalm oil. Next, the fatty acid structures and compositions of the productiontriacylglycerol were analyzed in order to compare with cocoa butter. After that, theproduction of cocoa butter equivalents by enzymatic interesterification was furtherstudied. Then, using liquid-liquid extraction and short-range molecular distillationmethod to take off the free fatty acid, which were produced from the enzymatic esterexchange reaction. Finally, the physical and chemical properties of the productionswere analyzed.The influence of melting point and yield of palm oil by fractionation was studiedduring different phases of cooling. The optimized conditions were getted by theanalysis of stirring rate, crystallization temperature, cooling rate and crystallizationtime. The results by response surface methodology showed that it is very importantfor the influence of melting point and yield by dry fractionation to controlcrystallization temperature. Crystal can form obvious nucleus at16.83℃.At the sametime, grease would not directly solidify because the cooling rate was reduced so slowduring dry fractionation. The cooling rate was1.31℃/h.At the end of13.39hcrystallization time, solid fat and liquid oil were obtained by fractionation. The fattyacid structures and compositions were analyzed in combination with thin-layerchromatography and gas chromatography. The type of fatty acid is similar with cocoabutter. The major difference on the composition of fatty acid is content ofhexadecanoic acid. And Sn-2position fatty acid was analyzed. The Sn-2position fattyacid, which is given priority to oleic acid, consists with cocoa butter. So the solid lipidis suitable for modification using Sn-1,3position lipase.The effect of palm oil with Lipozyme TL IM catalyzed interesterification was discussed by orthogonal experiments. Factors included the water activity, the massratio of POMF to StA, the amount of enzyme, the reaction temperature, the reactiontime and the shaking speed. Under the water activity0.43and the shaking speed150r/min circumstances, the optimum condition showed that the enzyme dose＞thereaction temperature＞the substrate mass ratio＞the reaction time. The optimumconditions were as follows: enzyme dose12%, reaction temperature60℃, substratemass ratio of POMF to StA1:1.8, and reaction time10h. Under the optimal conditions,the ester exchange rate was75.52%and acyl transfer rate was13.96%.In the case of six extractions, the ethanol aqueous solution83%, the mass ratio1:1.5g/g and the extraction time45min was selected. Based on deacidification rateand yield index by the regression analysis, the orthogonal experiments results showedthat the extraction time＞the ethanol aqueous solution＞the mass ratio. The optimumconditions were as follows: the extraction time50min, the ethanol aqueous solution83%, the mass ratio1:1.75g/g. Under this circumstance, the deacidification rate was96.60%and yield was40.69%. In the study of molecular distillation acid, thedistillation temperature210℃, the blanking rate2.0mL/min and the scrapingmembrane speed was selected. The deacidification rate as the index, through theresponse surface analysis shows that blanking rate was the greatest influence ondeacidification rate, the effects of distillation temperature is minor, and the scrapingmembrane speed has no obvious significance. After analyzing by the response surfaceinteraction, the optimum condition showed that the deacidification rate was97.31%,and deacidification rate was97.11%after test.Finally, the productions were analyzed by nuclear magnetic resonance anddifferential scanning calorimetry. And the indicators were preliminarily measured.There was a resemblance on the physical and chemical properties between theproductions and cocoa butter.