A Comparison of the Nutrient and Antinutrient Composition of Industrially Processed Zimbabwean Jatropha curcas and Glycine max Meals

Abstract

In a study to compare the nutritive and Anti-nutritional Factors (ANFs) composition of industrially processed shelled Jatropha curcas (Physic nut) kernels and soyabean (Glycine max) seed; samples of industrially processed Soyabean Meal (SBM) generated from the traditional industrial hexane extraction method were used. Samples of J. curcas Meal (JCM) were derived from double solvent extraction of shelled J. curcas kernels in a hexane-ethanol extraction system followed wet extrusion (126°C, 2 atmospheres, 10 min contact time) and then re-extraction with hexane. The re-extracted JCM was then heated with pressurized steam at 121°C for 30 min before dried samples were used in the laboratory analyses. Significant differences (p<0.05) in both the nutrient and ANFs existed between the seed meals. The JCM had a significantly higher (p<0.05) Crude Protein (CP) with 577.00 g kg-1 DM versus 470.80 g kg-1 DM in SBM. Similarly JCM had a higher (p<0.05) ash, calcium and phosphorus content with 119.7, 12.4 and 22.26 g kg-1 DM, respectively versus the 73.8, 3.43 and 7.31 g kg-1 DM, respectively in SBM. The SBM and JCM registered statistically similar levels of Acid Detergent Fibre (ADF); however JCM had a significantly higher (p<0.05) Neutral Detergent Fibre content (NDF) at 177.30 g kg-1 DM with the SBM having 125.60 g kg-1 DM Neutral Detergent Fibre. The JCM had a residual Phorbol Esters (PEs) concentration of 0.8 mg g-1 that was equivalent to a decrease of 87.69% from the 6.5 mg g-1 PEs content in raw shelled Jatropha curcas kernels. The SBM registered 19.40 TUI mg-1 as trypsin inhibitor activity while the JCM did not show any such activity. Both meals did not cause agglutination and haemolysis of erythrocytes indicating that lectins and saponins were completely inactivated during the industrial processing of each meal.