Effect of varying fermentation periods on the proximate and vitamin composition of Mahogany Bean (Afzelia africana) seed flour

Mohagany bean seed (Afzelia africana) locally known as “akparata” in Nigeria among the Igbos is a food thickening agent with some nutritional values. However, the availability of these nutrients is dependent on the processing method used on the seeds. Fermentation as one of the methods of processing was used in the processing of Afzelia africana seeds. The seeds were bought, sorted and roasted for 20 – 25 minutes on gas cooker at 145oC. Then dehulled, cracked into smaller pieces and divided into four portions. One portion was not soaked while three others were fermented for 24hrs, 48hrs and 72hrs. The fermented cotyledons were dried in the oven at 60oC for 24hrs separately. All the (four samples) seeds processed were ground into flour separately using hammer mill machine and sieved using cheese cloth (0.4mm diameter) to obtain fine flour. The proximate and mineral compositions of the samples were determined using standard methods. The results showed the following ranges: moisture content (4.36% – 4.46%), ash (3.41% – 6.05%), crude fibre (1.87% – 2.29%), fat (10.21% – 22.47%), protein (14.88% – 22.33%) and carbohydrate (45.56%–62.11%). The moisture, crude fibre, ash and carbohydrate content of fermented Afzelia africana increased as fermentation period increased. The fat and protein contents of fermented Afzelia africana decreased as fermentation period increased. Fermentation does not necessarily increase protein quantity but quality due to increase in micro organisms that use protein for metabolism. The pro-vitamin A content of unfermented and fermented Afzelia africana varied from 14.88iu – 22.36iu, ascorbic acid (7.76iu – 39.48iu) and vitamin E (6.57iu– 10.66iu). The results showed that fermentation for 24hrs yielded the highest pro-vitamin A and vitamin E content. This shows that fermentation increases the quantity of the ash, crude fibre, vitamin A and E of the seeds. Keywords: Fermentation, proximate, vitamin composition, of Mahogany Bean, Afzelia Africana and seed flour