Physicochemical, biochemical, and functional characterization of improved cassava varieties resistant to cassava brown streak disease

Abstract

Improved cassava varieties resistant to the Cassava Brown Streak Disease (CBSD) have been released in the eastern Democratic Republic of the Congo (DRC) and subsequently introduced into other agro-ecological zones of the country and across sub-Saharan Africa. However, information regarding their food quality attributes remain limited. This study evaluated the physicochemical, biochemical, and functional characteristics of four improved CBSD-resistant varieties (Mundola, Bukenge, Sikirou, and Mulezi) and two local checks (Nambiyombiyo and Ngorodima) grown in DRC, using standard analytical procedures. Significant varietal differences were observed for most traits ( p  < 0.001); CBSD-resistant cassava varieties exhibiting distinct combinations of food-safety, starch-composition, and functional traits, some of which compare favourably with locally preferred varieties while others reveal clear breeding trade-offs. For instance, the improved varieties generally contained lower hydrogen cyanide (HCN) levels than local checks, with Sikirou recording the lowest concentration. They also exhibited higher carbohydrate and starch contents, with Mulezi showing the highest values. In contrast, the local varieties had higher total sugar contents and better ash content, water absorption capacity, and gelation properties. Among the improved varieties, Mulezi and Sikirou encompassed desirable technological and nutritional characteristics, including high starch content and comparatively low HCN, making them promising candidates for processing and value addition. However, the superior functional attributes of the local checks highlight the need to incorporate these traits into future cassava breeding programmes. Further multi-location evaluation of processing performance, consumer acceptability, and effective detoxification practices is recommended to support the wider adoption of these improved varieties.