Abstract: Protein fractions(albumin,globulin,prolamin and glutelin)were extracted from defatted tartary buckwheat flour.The in vitro pepsin digestibility of the four fractions was different,and albumin was more susceptible to pepsin hydrolysis.The native structure of the four protein fractions could be destroyed by heat treatment,so the digestibility was all improved significantly.Adding rutin to the digestion mixture of the four fractions did not cause any decrease in vitro pepsin digestibility,but on the contrary did cause a slight increase in certain instances.Treatment with 2-mercaptoethanol 2(2-ME)only caused the higher initial proteolysis rate and did not increase the final digestibility clearly except prolamin.After pepsin digestion,the protein of unhydrolyzed albumin,globulin,prolamin and glutelin(untreated)shared some similarities.They also exhibited a minor band at 20kDa and a broad band at 14～10kDa.

Key words:  , tartary buckwheat； protein fractions； in vitro pepsin digestibility； heating； disulfide bonds； rutin；