Hard-to-cook phenomenon in bambara groundnut (Vigna subterranea(L.) Verdc.) processing: Options to improve its role in providing food security

Abstract

Hard-to-cook phenomenon in bambara groundnut (Vigna subterranea (L.) Verdc.) processing: Options to improve its role in providing food security Indigenous legume crops are pivotal in providing proteins and food security to sub-Saharan African rural communities, but most of these crops are underutilized because of the so-called hard-to-cook (HTC) phenomenon in combination with inadequate processing techniques. This review studies the case of bambara groundnut, which is third in importance after groundnut and cowpea and especially adapted to semi-arid areas. Published data on the HTC phenomenon implicate microstructural and compositional changes as factors leading to its development. Useful and sustainable techniques to process HTC legumes in developing countries include cooking with alkaline salts, milling, roasting, fermentation, and malting. Improvement of these processing techniques in relation to nutrient bioaccessibility, safety, and consumer acceptance of the products is urgently needed. Recommendations are to lessen the problems of food security in subSaharan African countries through, amongst other means, the optimization of bambara groundnut processing methods.

Functional Properties of Select Dry Bean Seeds and Flours

“…Seed porosity is important as it affects the size reduction and drying properties of dry beans. Packed dry bean seeds with low porosity are difficult to dry and cook due to restricted fluid flow and heat transfer (Mubaiwa, Fogliano, Chidewe, & Linnemann, 2017). Seed porosity, however, does not appear to be directly related to the seed shape.…”

Managing the hard-to-cook (HTC) phenomenon in bambara groundnut (Vigna subterranea (L.) Verdc.) processing for resource limited communities in Zimbabwe

“…Despite all these diverse dishes, the long cooking time involved in boiling bambara groundnut remains a major setback to its utilization as recounted by consumers (50-75%) as shown in Table 2.5, concurring with studies of Mwangela, Makoka [100] in Malawi and Quaye and Johnson-Kanda [94] in Ghana. Moreover, as narrated by Bressani [76] and Mubaiwa, Fogliano [70], high-energy consumption and firewood scarcity are important factors limiting bean preparation and consumption.…”

“…Despite all these possible uses and the nutritional and agronomic potential, bambara groundnut remains scientifically neglected [69]. An important reason for underutilization is the hardto-cook (HTC) phenomenon in combination with inadequate processing techniques [70]. HTC in legumes is characterized by extended cooking time (3)(4) h) [27] needed to ensure adequate softening during cooking [71], and the hard seed coat makes dehulling challenging [28].…”

“…autolysis of cytoplasmic organelles and lignification of middle lamella) and compositional changes (e.g. formation of insoluble pectate and interactions of proteins and phenolic compounds), which occur in the cotyledons and seed coats [70]. The HTC problem may not seem serious to people living in developed countries, who have energy resources and state-of-the-art techniques to utilize HTC legumes as well as access to a variety of protein-rich foods.…”

“…Thus, sustainable processing approaches that fit the local social-cultural framework in rural Zimbabwe and other sub-Saharan communities are urgently needed [14,55,78]. Processing methods for HTC legumes used in other sub-Saharan countries, such as Ghana and Nigeria, include chemical treatments (cooking aids), biological treatments (germination and fermentation), and physical treatments (milling, roasting and canning) [70].…”