title: Effect of pre-harvest sprouting on physicochemical changes of proteins in wheat.
abstract: BACKGROUND
  High moisture before harvest can cause sprouting of the wheat kernel, which is termed pre-harvest sprouting (PHS). The aim of this study was to examine the variation in physicochemical properties of proteins in PHS-damaged (sprouted) hard red and white spring wheat genotypes. Specifically, protein content, enzyme activity and degradation of proteins were evaluated in sound and PHS-damaged wheat.
  
  
  RESULTS
  Protein contents of sprouted wheat samples were lower than that of non-sprouted samples; however, their differences were not significantly (P > 0.05) correlated with sprouting score. Sodium dodecyl sulfate (SDS) buffer extractable proteins (EXP) and unextractable proteins (UNP) were analyzed by high-performance size exclusion chromatography. PHS damage elevated endoprotease activity and consequently increased the degradation of polymeric UNP and free asparagine concentration in wheat samples. Free asparagine is known to be a precursor for formation of carcinogenic acrylamide during high heat treatment, such as baking bread. Free asparagine content had significant correlations (P < 0.01) with sprouting score, endoprotease activity and protein degradation.
  
  
  CONCLUSIONS
  Genotypes with higher endoprotease activity tend to exhibit a larger degree of degradation of UNP and higher free asparagine concentration in sprouted wheat samples.
authors.affiliation: Department of Plant Sciences, North Dakota State University, Fargo, ND, 58108-6050, USA.
authors.forename: Senay
authors.initials: S
authors.lastname: Simsek
authors.forename: Jae-Bom
authors.initials: JB
authors.lastname: Ohm
authors.forename: Haiyan
authors.initials: H
authors.lastname: Lu
authors.forename: Mory
authors.initials: M
authors.lastname: Rugg
authors.forename: William
authors.initials: W
authors.lastname: Berzonsky
authors.forename: Mohammed S
authors.initials: MS
authors.lastname: Alamri
authors.forename: Mohamed
authors.initials: M
authors.lastname: Mergoum
mesh_terms: D020106:Acrylamide / Q000737:chemistry; D001216:Asparagine / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D001939:Bread; D003296:Cooking; D004032:Diet; D005838:Genotype; D018525:Germination; D006358:Hot Temperature; D006801:Humans; D010447:Peptide Hydrolases / Q000235:genetics* / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D012639:Seeds / Q000254:growth & development / Q000378:metabolism*; D014908:Triticum / Q000737:chemistry / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D014867:Water
chemical_list: D010940:Plant Proteins; D014867:Water; D020106:Acrylamide; D001216:Asparagine; D010447:Peptide Hydrolases
keywords: free asparagine; pre-harvest sprouting; spring wheat; wheat proteins