Effect of different heat processing methods on the proximate composition of <i>Piliostegma reticulatum</i> seed meal

Abstract

Plants (legumes) are important sources of dietary protein for both human and animals, but the presence of antinutritive factors affect the nutritional quality of the legumes. Unless these factors are destroyed by processing methods, they can exert adverse physiological effects when ingested by animals. To improve the nutritional quality of legumes for animal feed, it is important to establish a processing method that  will remove or reduce these antinutritive factors The objectives of this study is to determine the  processing method suitable for processing P. reticulatum seed for animal feed formulation. The proximate composition of the raw and differently heat processed P.reticulatum seed were investigated using  Association of Officials Analytical Chemists (AOAC, 1990). Complete randomized experimental design  with triplicates replications was applied. The raw seed revealed the following result moisture (7.27%),  crude protein (34.20%), crude fire (6.05%), ether extract (5.51%), ash (7.21%), nitrogen free extract  (47.03); the result of 30 minutes boiled seed was moisture (7.26%), crude protein (36.01%), crude fibre (4.71%), ether extracts (7.10%), ash (8.09%) and nitrogen free extracts (44.08%); 60 minutes boiled seed indicated the following results moisture (6.25%), crude protein (31.54%), crude fibre (3.33%), ether extract (8.22%),ash (14.01%) and nitrogen free extract (42.90%); traditionally boiled seed results were moisture (7.07%), crude protein (28.48%), crude fibre (3.07%), ether extracts (12.89%), ash (11.76%) and nitrogen free extracts (43.78%); 40 minutes toasted seed results were moisture (1.91%), crude protein (31.94%), crude fibre (5.29%), ether extracts (11.21%), ash (13.02%) and nitrogen free extracts (38.62%); The results of 80 minutes toasted seed were moisture (5.16%), crude protein  (20.96%), crude fibre (5.24%), ether extracts (9.04%), ash (8.74%) and nitrogen free extracts  (55.69%); 120 minutes toasted seed results were: moisture (10.24%), crude protein (24.12%), crude fibre (3.42%), ether extracts (9.03%), ash (11.27%) and nitrogen free extracts (52.16%) and the traditionally roasted seed record the following results moisture (3.20%), crude protein (31.37%), crude fibre (2.60%), ether extracts (8.15%), ash (12.91%) and nitrogen free extracts (44.20%). In the  proximate analysis, T2 (30 minutes boiled seed) had the highest crude protein content (36.01%), disadvantaged when compared with T3 (60 minutes boiled seed), T5 (40 minutes toasted seed) and T8 (traditionally roasted seed) in the other parameters. Among these treatments (T3, T5 and T8), T3 has an advantage over the others in terms of moderate crude protein (CP) and nitrogen free extract and also had the highest ash content. T1 (raw seed), although has high (34.20%), but recorded the highest crude fiblre and the lowest ash content. Thus from this finding of this study, T3 appeared to be the best in terms of proximate composition for animal feed formulation.

Keyword : Piliostigma reticulatum, seed, heat processing, proximate composition.