title: Optimisation of antioxidant peptide preparation from corn gluten meal.
abstract: BACKGROUND
  Corn gluten meal, containing approximately 600 g kg(-1) protein, is a main by-product of corn wet milling. The annual output of corn gluten meal in China is over 840 000 tons. However, it is difficult to utilise corn gluten meal in the food industry because of its low water solubility and amino acid imbalance. In the present study, corn gluten meal was hydrolysed by different proteases to produce hydrolysates with antioxidant activity in order to increase its value. The hydrolysis conditions were optimised by multiple linear regression and response surface methodology. Furthermore, the amino acid sequence of one corn peptide was determined.
  
  
  RESULTS
  The optimal conditions for alkaline protease hydrolysis were a pH of 9.5, an enzyme/substrate (E/S) ratio of 8 g per 100 g, a liquid/solid ratio of 25 mL g(-1) and a time of 75 min, while the optimal conditions for flavourzyme hydrolysis were a pH of 7, an E/S ratio of 4.2 g per 100 g and a time of 66 min. After gel filtration chromatography, fraction F2 exhibited the highest antioxidant activities. The amino acid sequence of a purified peptide in fraction F2 was determined as Gly-His-Lys-Pro-Ser (507.2 Da).
  
  
  CONCLUSIONS
  The results indicate that corn gluten meal hydrolysates and/or its isolated peptides are potent antioxidants.
authors.affiliation: Department of Food Science and Engineering, Jilin University, Changchun, China.
authors.forename: Hong
authors.initials: H
authors.lastname: Zhuang
authors.forename: Ning
authors.initials: N
authors.lastname: Tang
authors.forename: Shu-ting
authors.initials: ST
authors.lastname: Dong
authors.forename: Bin
authors.initials: B
authors.lastname: Sun
authors.forename: Jing-bo
authors.initials: JB
authors.lastname: Liu
mesh_terms: D000595:Amino Acid Sequence; D000975:Antioxidants / Q000302:isolation & purification* / Q000494:pharmacology; D002681:China; D002850:Chromatography, Gel; D005983:Glutens / Q000737:chemistry* / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D007502:Iron Chelating Agents / Q000737:chemistry; D010447:Peptide Hydrolases / Q000378:metabolism; D010455:Peptides / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D010940:Plant Proteins / Q000737:chemistry / Q000378:metabolism; D012639:Seeds / Q000737:chemistry; D003313:Zea mays / Q000737:chemistry*
chemical_list: D000975:Antioxidants; D007502:Iron Chelating Agents; D010455:Peptides; D010940:Plant Proteins; D005983:Glutens; D010447:Peptide Hydrolases
keywords: amino acid sequence; antioxidant peptide; corn gluten meal; optimisation