Extraction Of Corn Protien And Its Processing Features, Application

Corn gluten meal and corn germ, which are rich in protein, oils and carbohydrates,are the main by-products in the corn starch plant. Corn gluten meal contain about60%ofprotein consisted of zein and maize gluten. Corn germ contains about20%of protein and40%of oils. Zein is not soluble in water, but it can be soluble in60%-95%of alcoholsolution. The extraction of zein and germ protein from corn gluten meals and corn germ，their processing features and application in the dough’s quality improvement wasinvestigated in the thesis.The extraction conditions of zein were optimized as follows: ethanol concentration70%, time of ultrasonic treatment for120min, solid-liquid ratio1g/12mL, pH as11. Someprocessing and functional properties of zein were studied. The results showed that thefilm-processing ability of zein was perfect. The mechanical properties of zein films weremeasured with TA-XT2i Texture analyzer. The Tensile strength, elasticity and toughnesswas respectively493.0g、3.12mm and261.34g.s. The water-binding capacity of zein waslarger than wheat gluten flour. Emulsification and emulsion stability of zein and wheatgluten were almost the same.Zein was added to wheat flour to prepare the noodle for the tension test using Textureanalyzer. The results showed that stretching length and break work of the noodles addedzein was better than the blank group. The ductility and chewiness was improvedsignificantly. Similarly, the elastic and chewiness was improved according to the sensorytasting. The score of the noodles added zein was higher than the blank group. The textshowed that it was feasible to add zein to the noodles for increasing texture.Extraction ofprotein from corn germ by AOT/isooctane reverse micelle system and its processingfeatures were studied in this article. The effects of dosage of cellulase enzyme, AOT massconcentration, KCl concentration, pH and W0on the forward extraction rate and extractiontime, KCl concentration, pH on the backward extraction rate was investigated. Theoptimum forward extraction conditions were determined as follows: dosage of cellulaseenzyme4000IU/g corn germ, AOT mass concentration3g/50mL isooctane, pH as6, KClconcentration0.1mol/L, W0as25. The optimum backward extraction conditions wereoptimized as follows: KCl concentration0.5mol/L, pH as10.5, extraction time for40min.Some processing features of corn germ protein were studied. The result showed that oil absorbency (2.9mL/g), emulsification (54.5%, emulsion stability (86.5%) and foamstability (58.3%) was good. But the absorbent and foaming capacity was slightly poorerthan rice protein. The nutritive value of corn germ was higher. And the processing featureswere perfect. Therefore the protein in corn germ can be used in food industry.Corn germ protein polypeptides (CGPP) were prepared by alkaline proteases: papain(1:1) complex enzymatic hydrolysis. The Box-Behnken design response-surface method isadopted, with reducibility of polypeptides of corn germ protein for optimizing index. Theconditions of enzymatic hydrolysis were optimized on the basis of single factorexperiment. And the optimum enzymolysis conditions of the corn germ protein weredetermined: protease dosage9200IU/g, substrate concentration11%and hydrolysis time188min. The reducibility of polypeptides of corn germ protein was0.229under theoptimal conditions. Polypeptide of corn germ protein was added to the noodles to forpreventing browning test. The results showed that polypeptides of corn germ protein caneffectively prevent browning in the storage of fresh noodles. When the additive amountwas30%, the browning prevention effect was the same as ascorbic acid. TPA test resultsshowed that adding30%of the polypeptides of corn germ protein into the noodles canimprove its hardness, flexibility and chewiness...