African yam bean: optimization of thermal treatment for degradation of antinutrients in the seeds

B.Sc. Margaret Serwaa Darko, BSc

Master's thesis

Abstract:

African yam bean is a neglected and underutilised leguminous plant known for its adaptability to diverse agroecological zones in West and East Africa and its rich protein content which could help alleviate the issue of malnutrition and add to food security in Africa. There is however a decline in the use of the crop due to several reasons, like the presence of antinutrients. The seeds are traditionally used as a pulse, and the tubers are also consumed. The purpose of this project was to assess the effect of soaking and the ratio of water to seed during cooking on the antinutrient content of the African Yam Beans and their functional properties. The seeds were subjected to different treatments by soaking for 24 hours, cooked in different ratios of water, and processed by grinding, finally, the content of antinutrients (tannins, saponins, and phytate) was also determined spectrophotometrically. Functional properties (water absorption capacity, oil absorption capacity, water solubility index, foaming capacity, and emulsifying capacity) were determined by standard methods. The results depicted differences in the antinutrient contents of the seeds based on the different treatments the seeds were subjected to. The content of antinutrients decreased as the ratio of water used to cook the seeds also increased, with the lowest antinutrient content observed as 2.8 ± 0.05 mg/g, tannin concentration, 1.2 ± 0.07 mg/g, Saponin concentration and 2.7 ± 0.05 mg/g phytate concentration, there was however no significant difference in the functional properties of the seeds when the seeds were subjected to different treatments. These findings implied that soaking African Yam Bean seeds before cooking in a ratio of 7 times water to seeds is enough to reduce the quantity of antinutrients in the seeds to make them safe enough for food consumption, the functional properties of the seed are also not affected which makes the seeds subjected to this treatment good for industrial use

Keywords

Sphenostylis stenocarpa, antinutrients, seeds, cooking time, African neglected crop

Language used: English

Date on which the thesis was submitted / produced: 28. 4. 2024

Thesis defence

• Date of defence: 3. 6. 2024
• Supervisor: Ing. Olga Leuner, Ph.D.
• Reader: Jan Kubeš, Ph.D.

Czech University of Life Sciences Prague

Faculty of Tropical AgriSciences

Master programme:
Tropical Crop Management and Ecology