Nutritional Characteristic And Polyphenol Isolation Purification And Antioxidant Activity Of Quinoa

Quinoa was native to the Andes mountains,had the rich nutritional value and biological active substances.In recent years,quinoa planting area increased rapidly and has also started to grow in the Inner Mongolia region.However,the research of nutrients and bioactive substances for the Inner Mongolia region introduction quinoa were lack.To systematically analysis and evaluate the quinoa nutritional characteristic and the isolation,purification,structure and antioxidant activity of polyphenol,using quinoa which grown in Inner Mongolia as raw material.The main nutritional composition were systematically analyzed and evaluated,the extraction of polyphenol compounds were optimized by response surface method.And then the polyphenol components and antioxidant activity were detected after purification.The main research results were as follow:The contents of protein,fat,starch,ash and crude fibre in quinoa were 13.1%,7.7%,49.0%,2.2%and 2.0%,respectively.Quinoa contained seven essential amino acids among seventeen common amino acids and rich in lysine.According to the amino acid score and chemical score,its first limited amino acid was Met+Cys.Quinoa contained 13 kinds of fatty acid and rich in unsaturated fatty acid.The unsaturated fatty acid was accounting for 85.25%and mainly included linoleic acid(55.01%),oleic acid(21.14%)and a-linolenic acid(7.27%).The palmitic acid was the main saturated acid,accounting for 7.92%of the total fatty acids.It was also rich in mineral and vitamin,especially potassium(7597.1 mg/kg),calcium(280.2 mg/kg),magnesium(2045.8 mg/kg),phosphorus(2579.3 mg/kg),iron(49.6 mg/g),VB1(0.40 mg/100g)and VB2(0.39 mg/100g).Experimental factors and their levels were determined by single factor test,with yield as test index to extract polyphenols.Subsequently,the response surface method was performed to optimize the conditions for quinoa polyphenols extraction.The results indicated the optimum conditions were obtained as follows:ethanol concentration was 49%,material liquid ratio was 1:26(g/mL),extraction temperature was 73 ?,extraction time was 62 min.Under these conditions,the best yield of quinoa polyphenols was 226.77 mg/100g.Quinoa polyphenol compounds was separated and purified.Quinoa polyphenol(QP)had many polyphenols and flavonoids after purification by macroreticular resin AB-8.The clearing of ·OH(23.25%)and DPPH·(52.09%)and reducing power(1.05)of QP was higher than quinoa crude polyphenol(QCP).There was collecting 7 components after purification by Sephadex LH-20.The antioxidant activity of all quinoa polyphenol components(QPC)were lower than gallic acid,and QPC5 had the highest antioxidant activity of all.The clearing of ·OH and DPPH· and reducing power of QPC5 were 62.92%?69.59%and 2.68,respectively.Analysis of the constituent of QPC5 was studied.Identified by UV-Vis,IR and HPLC,the QPC5 had many polyphenols and flavonoids and was constituted by p-coumaric acid,isoferulic acid,rutin and 2 kinds unknown compounds.