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Characterising Bambara Groundnut Landraces: Nutritional and proximate composition

No changes made on the images.  Photo by Wibowo Djatmiko

CC BY-SA 2.0 DEED license

Bambara groundnut (BGN) is a highly nutritious but often overlooked legume (a plant in the bean family) grown in some parts of Africa. Farmers value it due to its ability to survive in poor soils, low water requirements, and its tolerance for hot and dry conditions. A recent NRF-funded research study examined the nutritional make-up of 70 different types of BGN (known as landraces) from South Africa to find those with the best nutrient content for improving diets and food security.

By fully measuring the nutrients in each BGN landrace, the researchers sought to identify varieties with the greatest health benefits so they could be promoted for wider cultivation to help fight malnutrition.

Seeds were collected from farmers in Limpopo and grouped according to the colour and pattern of their seed coats. Then 70 landraces were grown under controlled conditions at Stellenbosch University over two planting seasons. After harvesting, the seeds were dried, shelled, and ground into powder.

The nutrient analysis  revealed :

  1. Carbohydrates in the form of sugars, amino acids, and fatty acids
  2. Macro and Micro Minerals
  3. Proximate composition –included crude protein, fat, fibre, moisture, ash  and minerals.

Statistical comparisons were done using principal component analysis (PCA), which shows similarities and differences in nutrient profiles between landraces. The findings were as follows:

  • Sugars:

Sucrose (table sugar) made up 91% of total sugars, followed by myo-inositol and D-glucose. Landrace BGN 23 had the highest sucrose and glucose levels which contributed to sweetness.

  • Amino acids:

All essential amino acids were present. Lysine was the most common, and tryptophan the least. Landrace BGN 57 had high levels of lysine, histidine, and methionine.

  • Proximate composition:

Average crude protein was 19.20%, with BGN 16 highest at 36.87%. Average fat was 6.34% and gross energy averaged 17.63 MJ/kg. Fibre content (neutral detergent fibre – NDF, and acid detergent fibre – ADF) varied widely, showing differences in digestibility and energy value.

  • Fatty acids:

Linoleic acid (41%) and oleic acid (21%) were the most common unsaturated fats. Landrace BGN 13 had very high linoleic acid content, similar to soybeans.

  • Minerals:

Potassium, iron, and sodium were most abundant. Landrace BGN 55 had the highest overall mineral content, especially of potassium, phosphorus, and zinc.

The research confirmed that BGN is a nutrient-rich crop that provides good plant-based protein, healthy fats, and key minerals such as iron and potassium. Some landraces had notably superior nutrient profiles, which made them strong candidates for targeted breeding and farming. In particular, BGN 13, 16, 23, 55, and 57 should be prioritised for cultivation. Promoting BGN could improve food security and dietary quality, especially in resource-limited areas of Africa.

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