Crude enzyme extracts were prepared from leaves and stems of Abrus precatorius Linn. (Fabaceae) from Cameroon under optimized conditions. Proteolytic enzymes were precipitated with ammonium sulfate at 35% (w/v) saturation and assayed for enzyme activity. The effects of temperature, pH, incubation time and substrate specificity were studied. SDS-PAGE was used to determine molecular weight of precipitated protease. Results indicated that proteolytic activity of crude extract was 35.20 U/ml compared to 51.03 U/ml of partial purified extract. The optimum enzyme activity was found to be at 40˚C, while 50% of activity was maintained at 60˚C after 60 min incubation. Partial purified crude extract exhibited two optimum pH (2.75 and 9.0). The highest enzyme activity towards Bovine Serum Albumine (25.9 U/ml) was noted. SDS-PAGE gels exhibited molecular weight between 40 -60 KDa. This result confirms that partial purified extract of A. precatorius contains proteases and could be a promising source for proteolytic enzyme extraction.

A protease from fresh leaves of Abrus precatorius was purified using two classical chromatography techniques: ion-exchange (DEAE-Sepharose) and Gel filtration (Sephadex G-75). The purified protease showed a molecular weight of ∼ 28 kDa on sodium dodecyl sulfate polyacrylamide gel electrophoresis. The optimum pH and temperature for the purified protease was 8 and 40°C, respectively. The purified protease was stable throughout a wide temperature range from 10 to 80°C and pH from 2 to 12. Protease activity was inhibited in the presence of Co, Ni, Hg, and Zn while its activity has increased in the presence of Ca and Mg. The protease was highly specific to casein when compared to its specificity for gelatin, bovine serum albumin, hemoglobin, and defatted flour of Ricinodendron heudelotii. Its V and K determined using casein as a substrate were 94.34 U/mL and 349.07 µg/mL respectively. Inhibition studies showed that this purified protease was inhibited by both phenylmethane sulfonyl fluoride and aprotinin which are recognized as competitive inhibitors of serine proteases.

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In Cameroon, pepper is consumed either fresh, in powder form, as pepper oil or as pepper sauce. The aim of this work was to propose added value of spices by formulated ready to use cubes facilitating the consumption of pepper and reducing its post-harvest losses. A survey was carried out in Ngaoundere-Cameroon to know the level of pepper consumption, and the ingredients commonly added in pepper sauces. A simplex lattrice mixture design was carried out to optimise the pepper cube formulation, which was further characterized. The sensory evaluation was done to select the best sample among those produced. From the survey, 76.92% of the population consume pepper. Onion, garlic, white pepper, and pebe were found to be the spices commonly used along with pepper sauces preparation. The pepper cubes were obtained by incorporating onion and pebe as additives into the pepper enrichment at different proportions. The pepper enrichment was formulated at the optimal condition of the basic ingredients which were 0.817, 0.133 and 0.05% respectively for pepper, white pepper and garlic. Sample 107 with the colours ranging between orange yellow and yellow, made up of 50 % pepper enrichment, 32.5% onion and 17.5% pebe was selected through sensorial analysis by the panellist as the best specimen. This retained product exhibited about 50% of DPPH scavenging activity compare to ascorbic acid taken as control.