| Corn germ and corn bran is a byproduct of corn processing industry,which is rich in corngerm oil,protein and dietary fiber. It is worthy of great efforts to develop. In this thesis,wedesign corn germ three recycling process route. First, germ oil extracted from the germ, andthen to the discharge of waste defatted germ as raw materials extraction of corn proteins,Finally, the use of quadratic residue as raw materials to preparation of dietary fiber. Takeconcept of circular economy for the depth of high-value use of the corn germ. Optimization ofthe process of extraction germ oil, protein and dietary fiber,the comparative analysis of thepros and cons of the different extraction methods. Were characterized on the extraction of theproduct,To study the relationship between the extraction process and product nutritional valuefrom the perspective of the chemical composition. To guide process improvement, to improvethe quality of extract. This article also covers the biochemical means to change the structureand molecular weight distribution of dietary fiber,upgrade Indicators of its physiologicalfunction, depth useing objectives to achieve of the preparation of high-value products withcheap resources (including waste).In this thesis,firstly take corn germ as raw material after drying broken,using Soxhletextraction,ultrasonic assisted extraction,supercritical carbon dioxide extraction and aqueousenzymatic extraction to extract corn germ oil,the oil was standard by the single factorexperiment extraction process were optimized. Soxhlet extraction parameters: corn germ，crushed to40mesh (the other three methods to select the degree of fragmentation),the choiceof the boiling point of30~60℃petroleum ether extract of solid to liquid ratio1:6，60℃reflux6h; parameters of ultrasonic extraction conditions: use the boiling point of30~60℃petroleum ether extract,temperature22℃(room temperature can be),power180W,time50minsolid-liquid ratio of1:6; supercritical CO2extract the optimal parameters: the proportion of12.5%by adding anti-caking agent,pressure25KPa temperature of45℃,3h; AqueousEnzymatic Extraction of the best technology: cellulase+α-amylase enzyme,theenzyme2%,the optimal pH5.0and With citric acid-sodium citrate buffer solution,thesolid-liquid ratio of1:7. Shaking4h, and then centrifuge,the supernatant petroleum ether. The optimum oil rate: Soxhlet extraction of49.66%,49.13%ultrasound to break supercritical47.40%,24.63%aqueous enzymatic.Under the optimum conditions for the four extraction methods to extract corn germ oilfor analysis and testing results show that: the physical and chemical indicators of the fourextraction methods from the germ oil to meet the national standards.Supercritical CO2extraction from the oil extraction rate and operating safety and environmental protectionconsidering the more desirable; less impurities and health hazards point of view,aqueousenzymatic extract acid number too large Soxhlet method extracts the peroxide value is toohigh,are not desirable; from the perspective of the chemical composition of the four oil thereis no significant difference; consider nutritional value,high-quality germ oil obtained byaqueous enzymatic. The four extraction methods have advantages and disadvantages，considering the supercritical CO2method dominant.Followed, the single factor experiment to optimize the conditions for extracting proteinfrom defatted corn germ. The results showed that albumin protein optimum extractionconditions for the temperature of50℃,the solvent7mL/g,the time for30min. Globulinprotein best extraction conditions for the temperature of40℃,the amount of solvent6mL/g,extraction time40min. Zein protein extraction conditions were a temperature of50℃,theamount of solvent7mL/g, time40min. Glutelin protein extraction conditions were60℃temperature,the amount of solvent6mL/g,ime40min.Finally，by chemical and enzymatic extraction of corn dietary fiber,the results show:purity of the enzymatic extraction of the insoluble dietary fiber. And then use the of xylanaseand cellulose to modified extracted insoluble dietary fiber, obtained the optimal reactionconditions for xylanase biological modification by single factor: the pH value of5.0,theamount of enzyme0.2ml/g,reaction temperature of55℃,the reaction time was50min. Underthis condition,the water holding capacity of the modified product is up to5.70g/g， and theexpanding force of3.03ml/g,holding the oil force of3.67g/g. Respectively65.70%,14.93%and81.68%high than the raw materials. Biological modification of cellulase reactionconditions: pH value of6.0,the enzyme dosage of0.1ml/g,reaction temperature of45℃,the reaction time of2h. Modified products under this condition, water holding capacity of5.83g/g, the expansive force of2.73ml/g, holding oil force of2.72g/g. Respectively increased by69.48%,3.70%and34.65%than the raw materials. |
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