Proximate and Anti-nutrient Contents of Kersting’s Groundnut (Macrotyloma geocarpum) Subjected to Different Fermentation Methods

Aim: The study aimed to ascertain the effect of different fermentation methods and time on the proximate and reduced the anti-nutrient contents Kersting’s groundnut (Macrotyloma geocarpum).

Design of the Study: A comparative effect of different fermentation methods on the proximate and anti-nutrient content was evaluated.

Place and Duration of Study: Department of Microbiology and Central Science Laboratory, Federal University of Technology, Akure, Nigeria, between March 2013 and June 2014.

Methodology: The seeds were de-husked and sorted to remove extraneous matters. Liquid and solid fermentation were carried out using standard analytical methods. The proximate and anti-nutrients (trypsin inhibitor, tannin, oxalate, phytate) of the fermenting samples were analysed every 24 h during fermentation.

Results: Proximate analysis revealed that moisture content significantly (P=0.05) decreased from 6.25±0.14% to 4.69±0.06% and 4.89±0.02% after 24 h of liquid and solid fermentation respectively. Liquid fermentation significantly (P=0.05) increased the protein content of the groundnut from 18.11±0.50% to 21.10±0.49% and 22.47±0.48% after 24 h and 48 h respectively. No significant difference (P=0.05) was observed after 72 h of fermentation. While solid fermentation significantly (P=0.05) increased protein content from 18.11±0.50% to 19.08±0.01% after 72 h. Both fermentation methods significantly (P=0.05) reduced crude fibre and increased fat content respectively. Soluble carbohydrate decreased significantly (P=0.05) from 63.72±0.39% to 58.17±0.87% after 48 h of liquid fermentation. Anti-nutrient (trypsin inhibitor, tannin, oxalate and phytate) contents decreased significantly (P=0.05) more in liquid state fermentation than in solid state fermentation. Trypsin inhibitor unit significantly (P=0.05) reduced from 72.18±0.00 mg/g to 12.28±0.38 mg/g and 24.17±0.01 mg/g after 24 h of liquid and solid fermentation respectively. However, a significant (P=0.05) increase was observed in trypsin inhibitor content after 48 h of both fermentation methods.

Conclusion: The research has revealed that 24 and 72 h liquid and solid fermentation of Kersting’s groundnut significantly (P=0.05) enhanced the proximate content. The anti-nutrient contents also reduced significantly (P=0.05) in liquid fermentation.