title: Thermal aggregation behaviour of soy protein: characteristics of different polypeptides and sub-units.
abstract: BACKGROUND
  Due to the differences in structure and composition of glycinin and β-conglycinin, they exhibit different characteristics during heat treatment. In present study, the thermal aggregation behaviour of glycinin, β-conglycinin and their isolated sub-units was investigated at pH 7.0.
  
  
  RESULTS
  Acidic polypeptides, basic polypeptides, αα' and β sub-units of soy protein were denatured during the isolation process. The degree of aggregation of protein fractions after heat treatment was in the order: denatured basic polypeptides > native glycinin > denatured β sub-unit > native β-conglycinin > denatured acidic polypeptides > denatured αα' sub-units. Glycinin, β-conglycinin, acidic polypeptides and αα'/β sub-units exhibited different changing trends of surface hydrophobicity with increasing temperature. The αα' sub-units showed higher ability to suppress thermal aggregation of basic polypeptides than β sub-units during heat treatment. The β sub-units were shown to form soluble aggregates with glycinin after heating.
  
  
  CONCLUSIONS
  The interaction mechanism of αα' and β sub-units heated with basic polypeptides was proposed. For the β sub-units-basic polypeptides mixed system, more hydrophobic chains were binding together and buried inside during heat treatment, which resulted in lower surface hydrophobicity. The αα' sub-units-basic polypeptides mixed system was considered to be a stable system with higher surface hydrophobicity after being heated.
authors: Research and Development Center of Food Proteins, Department of Food Science and Technology, South China University of Technology, Guangzhou, 510640, P.R. China.
authors: Xiu-Ting
authors: XT
authors: He
authors: Research and Development Center of Food Proteins, Department of Food Science and Technology, South China University of Technology, Guangzhou, 510640, P.R. China.|Hainan Key Laboratory of Banana Genetic Improvement, Haikou Experimental Station, Chinese Academy of Tropical Agricultural Sciences, Haikou, 570102, P.R. China.
authors: De-Bao
authors: DB
authors: Yuan
authors: Research and Development Center of Food Proteins, Department of Food Science and Technology, South China University of Technology, Guangzhou, 510640, P.R. China.
authors: Jin-Mei
authors: JM
authors: Wang
authors: Research and Development Center of Food Proteins, Department of Food Science and Technology, South China University of Technology, Guangzhou, 510640, P.R. China.|State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, Guangzhou, 510640, P.R. China.
authors: Xiao-Quan
authors: XQ
authors: Yang
mesh_terms: D004591:Electrophoresis, Polyacrylamide Gel; D019649:Food Industry; D005916:Globulins / Q000737:chemistry; D006358:Hot Temperature; D006801:Humans; D010455:Peptides / Q000737:chemistry*; D017510:Protein Folding; D030262:Soybean Proteins / Q000737:chemistry*; D013329:Structure-Activity Relationship
chemical_list: D005916:Globulins; D010455:Peptides; D030262:Soybean Proteins; C011474:glycinin
keywords: polypeptides of glycinin; soy protein; sub-units of β-conglycinin; surface hydrophobicity; thermal aggregation mechanism