The Studies On Extraction, Properties And Lipid-lowering Activity Of Oat Protein

Oats was both a diet and traditional grains crops with high nutritional value andlipid-lowering effect. The oat β-glucan has been widely known for its lipid-loweringactivity,but function of other ingredients such as protein was still lack of systemresearch.Thereore,39samples of2010from the six oats major production areas werecollected to analyse the difference of nutritional quality in different samples. We optimizedthe alkali extraction and acid precipitation method of protein, then analysised the compositionof amino acids and nutritional quality of different protein varieties.And in the last, four oatsprotein were selected to study the cholesterol-lowering properties in this paper.The quality analysis results showed that there was a different variation in the mainnutritional quality indexes of the varieties The CV(>15%) of crude fat, β-glucan, content ofprotein and amylose was bigger than that in total starch and ash content(<8%). The clusteranalysis suggested that the classifications were significant associated with theirorigins(production areas). DingYou series which from Gansu province were clustered into thesame group for its stable quality while it was helpful for promoting planted.The paper adopted single factor experiments and the quadratic orthogonal rotationcombination design to optimize the factors of traditional alkali extraction and acidprecipitation method in oat protein extraction from the whole oat flour. According to varianceanalysis and response surface analysis, the optimum conditions for oat protein extractionwere chosen as follows: pH11,35℃,1.2h, and the ratio of material to solvent:1:20(m:V),therefore, the extraction rate of oat protein was64.47±2.89%with the protein content of80.21%(dry basis). It also showed the pH was the main factor in the extraction, temperatureseond.The content of essential amino acids reached33.14%of the total amino acids,which wasclose to the WHO/FAO assessment pattern of ideal protein(36%).The first limiting aminoacid in oat protein was lysine, followed by threonine and sulfur-containing amino acids(methionine+cysteine). Gel electrophoresis experiment showed the major molecular weightdistribution regions were20.1~24KDa and31~37KDa,which were globulins. Compared thenutrition evaluation of oat protein, Gansu and Ningxia had the obvious superiority in crudeprotein, lysine content and nutrition index (NI), but comprehensive nutrition of protein indifferent areas had no significant difference (p>0.05). In order to study the cholesterol-lowing properties of oats protein,Yanke1, Baiyan1,S109and DingYou1, the four oats protein and their flour were offered to the modeledhyperlipidemia Wistar male rats. After30days, it was found that each group could reduce theblood fat, meanwhile, it also could improve the liver function. Generally, the lipid-loweringeffect of oats protein was better than their flour. Especislly protein of Ding You1, which hadhigh arginine (Arg) and sulphur amino acids content and high Arg/Lys ratio, restrained theTC and LDL-C with the inhibition rate of38.55%and56.37%, and the alanine transaminase(ALT) decreased significantly by28.10%(p <0.01), the histopathological examination alsorevealed the liver lesions were the lightest. In addition, the cholesterol in the feces of ratsshowed the metabolic pathway of samples was not promote the excretion.We inferred theefficacy of protein in relation to the Arg sulphur amino acids content and Arg/Lys ratio.