Bambara groundnut (Vigna subterranea) is an underutilised indigenous crop, which is cultivated by subsistence farmers throughout Zimbabwe and other sub-Saharan countries. Bambara groundnut is an ideal alternative crop to improve food security in Zimbabwe because of its drought resistance, nitrogen fixation and the ability to produce a reasonable harvest when grown under low input farming and poor soils. The major limiting factor in the utilisation of bambara groundnut is the post-harvest hard-to-cook (HTC) phenomenon, which develops during storage at ambient conditions of high temperature and high relative humidity in tropical and sub-tropical regions. HTC bambara groundnuts require longer boiling time of (3-4 hours) and higher energy expenditure to become edible. Hardening of nuts also results in hard-to-mill properties, which are a concern to processors, who find it hard to elucidate proper dehulling and milling techniques.
The current research effort seeks to establish baseline information for the exploitation of bambara groundnut in semi-arid regions of Zimbabwe. This includes developing and optimising processing technologies that fit local conditions in managing HTC phenomenon in bambara groundnuts.
i. (Survey): Gathering indigenous knowledge on the utilization of legumes (cowpea, bambara groundnut and groundnut) in Zimbabwe.
ii. (Critical literature review): Assessing the hard-to-cook phenomenon in legumes: causes and technological solutions with a focus on bambara groundnut utilisation.
iii. Effect of alkaline treatments and cell wall degrading enzymes on milling properties and cooking time reduction of bambara groundnut.
iv. Optimisation by modelling the combined effect of temperature, time, alkaline treatments, enzymes, and use of firewood and water to produce ready-to-eat bambara groundnut dhal (mutakura) and flour under local conditions.