Study On Aqueous Enzymatic For Extracting Corn Germ Oil And Comprehensive Utilization

Aqueous enzymatic extraction is a new method which free oil can be obtained through enzymatic hydrolysis and centrifugation without material drying. The conventional methods of separating oil and protein are mechanical expression and solvent extraction. Although high amounts of oil can be extracted by these methods, the protein in the residue is denatured which leads to the residue being less useful. The objective of this dissertation was to develop the technology of aqueous enzymatic extraction of corn germ oil and study the methods of protein extraction. Main result and conclusion are as follows:1 Under the laboratory condition the optimum parameters are as follows: The raw material and liquid rate is 1:0.78, the size of corn germ is 105 mesh and cellulose's amount of influx is 6936u/ g, the reaction time is 4.3 h. The protease's amount of influx is 1670u/ g, reaction time is 2.8h. Under these conditions, the oil extraction rate is 75.38%.2 The optimum parameters of proteins extraction as follows: pH was 10.85, temperature was 52.5℃, reaction time was 1.86h, the raw material and liquid rate was 1:9.27;the deposit pH is 4.2.The proteins extraction rate was 76.54% under these conditions.3 The oil quality of aqueous enzymatic extraction is better than conventional methods from physicochemical property, and is as the same as conventional methods on the content of fatty acid, although on the content of Vitamin E is lower than solvent extraction, oxidation resistance is higher than mechanical expression.4 The mathematical model of aqueous enzymatic extracting oil is Y=0.59794X2-2.11569X1×X6-0.00320X22+1.25456X5+0.99979X12+0.00212X3-0.86843X62+6.7858X6+0.00023X4.The extraction rate is mainly influenced by the volume of the corn germ and the cellulose's recruitment. Then the extraction rate correlated positively with the cellulose's recruitment, the cellulose's reaction time and the protease's recruitment. And when the volume of the corn germ is below the 186 mesh, which is correlated positively with the extraction rate, if not, the volume of the corn grain is negatively correlated with the extraction rate.