Influence of Different Cowpea ( Vigna unguiculata (L.) Walp.) Genotypes from Burkina Faso on Proteases Inhibition

Cowpea is an important protein crop widespread in Africa. The purpose of this research was to determine the content of trypsin and chymotrypsin inhibitors in different genotypes of cowpea seeds. Trypsin percentage inhibition showed about 13.5-fold variation (5.12% ± 1.47 to 70.52% ± 6.58) between the cowpea genotypes respectively for KVx 421-2J and Kondèsyoungo local. The chymotrypsin inhibitory activity varies among cowpea genotypes from 21.19 to 76.94%. The highest percent inhibitory activity was exhibited by KVx 396-4-5-2D on chymotrypsin. This study also showed significant correlations between type of cowpea genotype and trypsin inhibition potential and also between colour and chymotrypsin inhibition potential of cowpea seeds. Kondèsyoungo local, a landraceae genotype exhibited the high potential to inhibit the trypsin enzyme. Coloured seeds of cowpea genotypes possess higher percentage inhibition of chymotrypsin than the colourless ones (p < 0.05). The calculated mean of trypsin and chymotrypsin inhibition activities showed that Labagela local genotype possess the highest inhibition activity of both protease enzymes. The PCA components analysis and the dendrogram performed basis on the protease inhibitory activities divided the thirty-one genotypes of cowpea used in this study into three classes. The results presented in this work can contribute greatly to the planning of a cowpea breeding program aimed at reducing the content of proteases inhibitors in order to improve the nutritional value of seeds or to increase PI content for tolerance to stored grain pests