Canning Quality of New Grain Runner Bean Lines Developed in Kenya

Canned beans are becoming a major form of dry bean consumption especially in urban areas of East and Central Africa for its convenience, distinctive flavor and excellent consumer value. Grain quality traits related to end-user preferences are of utmost importance for success of new grain runner bean varieties. The Legume Breeding Research and Seed Programme at the University of Nairobi recently developed several grain-type runner beanlines with different seed colours and superior agronomic traits. However, their potential for use by the processing industry is not known. The objective of this study was to evaluate the canning quality of the new breeding lines and to identify the lines that combine most of the canning quality traits. Forty-three advanced lines, three checks and one reference variety (TruFood RB) grown at Ol-Joro-Orok and Kabete Field Stations were evaluated for canning quality. The beans were soaked, blanched, canned in brine and incubated for seven days, and subsequently evaluated for canning quality attributes including hydration coefficient (HC), washed drained weight (WDWT), percentage washed drained weight (PWDWT) and texture. Physical properties (size, shape, uniformity) and visual appearance properties (splits, clumping and brine clarity) were determined subjectively using seven point hedonic scale. Results showed significant (P<0.05) differences for all traits evaluated. Thirty-five lines grown across sites met the industrial canning standards. Among the best performers at Kabete were KAB-RB13-327-92/1, KAB-RB13-326-207/1B and KAB-RB13-326-207/1B. However, the best performers among lines grown at Ol-Joro-Orok were KAB-RB13-471-117/1, SUB-OL-RB13-275-248/3 and KAB-RB13-310-161/5 suggesting a genotype x environment interaction for canning traits. The new grain runner bean lines will reduce scarcity of raw materials required by processing industries and increase the diversity of processed runner bean products.