Biochemical and functional properties of proteins from red kidney, navy and adzuki beans

Abstract

Chemical composition and functional properties of proteins extracted from adzuki, navy and red kidney beans were investigated. Protein contents were 17.33, 18.15 and 19.91% for red kidney, navy and adzuki beans, respectively. Red kidney bean exhibited the highest carbohydrates content, while the highest fat, ash and crude fibre content was found in navy bean. The highest trypsin inhibitory activity was found in adzuki bean. Globulin polypeptides (molecular weight ranges 45-55 kDa) were the major polypeptides in both whole protein and protein isolate. Protein isolate from all seeds contained at least one major glycopeptide, while more than two major glycopeptides were observed in the whole proteins. The minimum protein solubility of isolated proteins from all seeds was at around pH of 4-5. High foamability and foam stability were obtained in red kidney and navy beans when compared with those of adzuki bean. The highest oil absorption was found in adzuki bean, while no significant differences for water absorption between adzuki and red kidney beans was observed (p>0.05). Red kidney bean showed lower emulsifying activity as well as stability when compared with the other two beans.