Study on Preparation and Property of Protein from Cottonseed Meal
|Course||Of Food Science|
|Keywords||Cottonseed meal Protein concentrate Protein isolate Physical and Chemical Properties Functional properties Enzymatic Modification|
Ours is the first major cotton producing country, cottonseed is rich in resources, and are widely distributed. Byproduct of oil extraction - high protein content of cottonseed meal, low prices, is an urgent need of an important protein resource development and utilization. Meal gossypol toxicity limits, low utilization, previous studies have focused on gossypol detoxification keeping animals, relatively little preparation and properties of cottonseed meal protein. In this paper in order to pre-pressing extraction of high temperature cottonseed meal as raw materials, system production of cottonseed meal protein, including the preparation of protein concentrates and protein isolate extraction and protein physicochemical functional properties of a more comprehensive study to depth development and cottonseed meal resources to provide a more effective way. First, the use of enzymes combined with alcohol wash prepared cottonseed protein concentrate. Optional ViscozymeL, glucoamylase cottonseed meal role, then ethanol solution bath. Studies have shown that, in to add glucoamylase 1600 U / g ViscozymeL 0.60 fbg / g liquid ratio 10,50 ℃ 140 min, and then 70% ethanol solution, liquid material washed 2 times more than 7,60 ℃ alcohol , every 45 min, cottonseed protein concentrate protein content of 64.39%. Secondly, protein extraction and separation of alkali extraction and acid precipitation. By univariate and response surface optimization to determine the best extraction process: the pH11 liquid ratio 16.5, extraction temperature 60 ℃, extraction time 105 min, 67.27% take rate in this condition alkali mention. By acid precipitation and freeze-dried extract rate of 56.02%, 86.16% protein content. The alkali extraction residue with alkaline protease further hydrolysis, extraction rate of 24.42%, protein content of 62.12%. Two-step addition cottonseed protein extraction rate of 91.69%. Again, the high temperature Cottonseed protein isolate physical and chemical functional properties have been measured, and compared with the nature of the protein extracted from the low temperature meal, in order to study the influence of high temperature on the protein in the oil extraction process. The results showed that the cottonseed meal protein amino acid composition and reasonable, the FAO / WHO under the recommended intake of 2-5 year-old children can meet other essential amino acids except Lys content slightly lower, after high temperature Lys, Leu, Thr content are reduced. Low temperature meal with albumin, globulin mainly affected by high-temperature high-temperature meal by globulin, gluten-based. Low temperature meal protein, high-temperature and high-meal protein carbonyl content increases, the enhancement of surface hydrophobicity. The high and low temperature meal extract protein denaturation temperature were 87.27 ℃, 92.73 ℃. SDS-PAGE and cottonseed meal protein with eight bands known molecular weight of 59.7 kDa and 53.6 kDa. Purchased cottonseed meal protein isolate functional properties than the functional properties of soy protein isolate. By environmental factors such as pH, salt concentration, temperature influence, a certain concentration of salt ions can improve protein function in nature, especially in the low temperature meal extract protein foamability improved significantly. Cottonseed protein in Oil Extraction leaching process, affected by high temperature, partially denatured, resulting in a protein extraction rate has declined in nutritional value and functional properties. Finally, the use of the trypsin enzymatic modification of high temperature Mianpo protein isolate. Found that increased protein solubility after hydrolysis under neutral conditions, DH3.47 solubility of 88.10%, amounted 92.40% DH11.34, compared to the enzymatic hydrolysis before solubility increase of 67.70%; DH6.37 when Preferably, the emulsifying activity than the original increase of 87.30%; foaming capacity gradually increases with increasing the degree of hydrolysis also DH11.35 hours foamability is preferably 170%, a 120% increase in foam stability is also better. Visible, moderate enzymatic cottonseed meal protein functional properties can be significantly improved.