Characterization of Rutin-rich Bread Made with 'Manten-Kirari', a Trace-rutinosidase Variety of Tartary Buckwheat (Fagopyrum tataricum Gaertn.)

The rutin content of dough made with 'Manten-Kirari', a new Tartary buckwheat variety with trace-rutinosidase activity and minimal bitterness, was assessed in a time course study of rutin hydrolysis in doughs with various water contents and blending ratios of Tartary buckwheat flour. In the normal rutinosidase variety, 'Hokkai T8', the majority of rutin was hydrolyzed within 30 min of water addition, whereas about 90% of rutin remained in 'Manten-Kirari'. We also investigated the residual rutin ratio in white bread, butter enriched roll, pound cake and galette. With 'Hokkai T8', rutin was hydrolyzed almost completely in all foods tested, whereas 88.5%, 49.8%, 31.0% and 26.2% of rutin remained in 'Manten-Kirari'-containing pound cake, white bread, butter enriched roll and galette, respectively. Also, 'Hokkai T8' bread exhibited strong bitterness, whereas 'Manten-Kirari' foods showed minimal bitterness. These results indicate that 'Manten-Kirari' is a promising material for the production of rutin-rich food products without bitterness.