Preparation Of Corn Protein Concentrates And Zeaxanthin From Corn Gluten Meal

Corn gluten meal was a by-product of wet milling process of producing corn starch and has a high content of protein and pigments. But the shortcomings of CGM including deep color, odor, slightly water solubility, poor digestion, make corn gluten meal rarely used in the food industry.The research aim to systematically study corn protein and zeaxanthin of corn gluten meal.Corn protein concentrates(CPC) were prepared continuously by CGM. The CPC was treated by Jet-cooking and critic acid. And the CPC was used to make a gluten-free bread by adding hydroxy propyl methyl cellulose(HPMC). In addition, zeaxanthin was extracted from CGM by emzyme-assisted and Organic solvent extraction. Finally, the Zeaxanthin-SSPS was prepared by the pigment extracted from corn gluten meal. The main results are as follows:(1) Corn protein concentrates(CPC) were prepared continuously from corn gluten meal(CGM) by sub-critical fluid and ultra-filtration membrane. Through the process of concentration, the protein content of products could reach 82%. And the CPC was incubated with 0.2 M citric acid and treated by jet cooking device at 140℃ for 90 s. The results show that when the p H value was below 4.0 and above 7.0, the solubility of JC-CPC was enhanced. The foaming capacity and the foaming stability of JC-CPC were improved significantly. After digestion, the nitrogen release and the degree of hydrolysis of JC-CPC was higher than the CPC and HT-CPC. Due to the effect of Jet-cooking,JC-CPC exhibits excellent functional properties, and in vitro digestibility properties.(2) The experiments of the application of CPC in baking products show that CPC do not have the similar properties of the gluten dough, and CPC dough without any additive could not form the network structure in the dough. After adding HPMC, the Farinographical properties of dough was improved obviously. The formation time of dough decreased,while the stability time of dough increased. In addition, CPC bread have a similar texture properties of gluten and wheat bread. Furthermore, the addition of HPMC did not affect the secondary structure of proteins in the dough. The addition of CPC in the bread not only has the effect of solid filler in the dough and bread, but also has a nutritional function for human beings.(3) Zeaxanthin was extracted from corn gluten meal by the method of the alkaline protease enzymolysis and organic solvent extraction. And this method may increase the extraction ratio and purity of zeaxanthin. In addition, Zeaxanthin-SSPS particle was prepared by SSPS and zeaxanthin extracts which extracted by ethyl alcohol. FTIR and XRD spectra shows that there is a certain interaction between SSPS and zeaxanthin. Stability experiments show that, when the mass ratio of SSPS and zeaxanthin was 1:1 and 1:0.5,Zeaxanthin-SSPS particle has a good temperature stability and salt ion tolerance ability in the condition of low p H value. In vitro antioxidant activity experiments show that, the particle exhibits a excellent antioxidant activity for a long time.