| Corn is the main careal crop in China,the production ranks second in the world. It is a staple food,at the same time,it is also an essential raw stuff in many industries such as bioengineering,medicine,chemical industry etc. Corn processing industry plays an important role in the national economy.But now they mainly process and make use of corn starch and its ramification,the corn spermoderm and corn protein which have special bioactivity and physiological function are wasted,and their economic benefits and social benefits are not played out, corn resources are wasted.With the discovery of important impact of dietary fiber on abnormal metabolism of human body,dietary fiber science have been the hot research.Compared to other grain spermoderms such as rice spermoderm,wheat spermoderm etc.Corn spermoderm not only contains rich dietary fiber,but also the fiber structure is good.So it is a good source of dietary fibre. But the palate of raw corn spermoderm is rough and nedible, so it is only used as feed and no significant function to prostate health. For this reason, it is necessary to study out a better way to degradate corn spermoderm by separation recombination technology for improving its physicochemical properties and the machining quality.The degradation is one of the research contents of functional food raw material.To degrease and remove impurity on corn spermoderm through supercritical CO2 fluid extraction, the study use some advanced technology to degradeate corn spermoderm,including twin-screw extrusion technology,ultrasonic wave technology,cellulose and cellulose under ultrasonic wave technology. It gain an optimal degradation conditions to yield high quality dietary fiber.The study not only improve the utility value of corn and economic efficiency of corn processing enterprise,bue also the result lay a theoretical foundation for related fields.The results are mainly as follow:1.The corn spermoderm was degradated by twin-screw extrusion machine.The study was made by using the defatted corn spermoderm as raw material.The optimal extrusion technology was determined by 3-variable,3-level response surface methodology on the basis of single factor experiment,the moisture content,extrusion temperature and corn spermoderm granularity were response factors and soluble dietary fiber yield was response value.The result indicate that when moisture content is 138%,extrusion temperature is 169℃, corn spermoderm granularity is 0.175mm,the content of soluble dietary fiber is 10.75%.2.The ultrasonic wave degradation conditions of corn spermoderm fiber was optimized by response surface analysis.The study was made by using the twin-screw extrusion corn spermoderm as raw material.The optimal degradation technology was determined by 3-variable,3-level response surface methodology on the basis of single factor experiment,ultrasonic time, corn spermoderm granularity and ultrasonic power were response factors and soluble dietary fiber yield was response value.The result indicate that when ultrasonic time is 68min,corn spermoderm granularity is 80,ultrasonic power is 378W,the content of soluble dietary fiber is 12.77%.3.The corn spermoderm after twin-screw extrusion was degradated by cellulase.The optimal degradation technology was determined by 3-variable,3-level response surface methodology on the basis of single factor experiment and placket-burman design,the cellulase dosage,pH value and enzymolysis temperature were response factors and soluble dietary fiber yield was response value.The result indicate that when cellulase dosage is 0.76%,pH value is 5,enzymolysis temperature is 42℃, the content of soluble dietary fiber is 13.40%.4.The corn spermoderm was degradated through cellulase assisted by ultrasonic wave. The study was made by using the twin-screw extrusion corn spermoderm as raw material.The optimal degradation technology was determined by 3-variable,3-level response surface methodology on the basis of single factor experiment,the cellulase dosage,ultrasonic power and ultrasonic time were response factors and soluble dietary fiber yield was response value.The result indicate that when cellulase dosage is 0.57%,ultrasonic power is 300W,ultrasonic time is 1.5h,the content of soluble dietary fiber is 16.10%.5.The defatted corn spermoderm was degradated refer to the technological parameter which is optimized by response surface analysis,so as to produce high quality dietery fiber,the physicochemical properties of materials were studied detailedly by variance analysis and multiple comparison, it turned out that the expansibility is 15.66ml/g; The water-holding capacity is 10.07g/g; The water retention capacity is 6.88g/g; The gerase holding capacity is5.05g/g.The comprehensive properties are about 2.14 times to raw corn spermoderm. It can be used for processing high-fiber functional food.
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