SOME PHYSICAL PROPERTIES OF TWO AFRICAN YAM BEAN (SPHENOSTYLIS STENOCARPA) ACCESSIONS AND THEIR INTERRELATIONS WITH MOISTURE CONTENT

Abstract

The study was undertaken with the objective of determining the size and shape, density, porosity, weight, andvolume of two African yam bean accessions (TSs 137 and TSs 138) at four moisture content levels of 4, 8, 12, and 16% wetbasis which are useful in the design of harvesting, processing, handling, and storage equipment. The axial dimensions,equivalent diameter, individual grain weight, and volume were found to increase as moisture content increased between 4 and16% w.b. for the two accessions. With increase in moisture content there was a decrease from 42.67 to 40.96% for porosity,0.76 to 0.741g/cm3 for bulk density, and 1.326 to 1.255 g/cm3 for true density for TSs 137 while for TSs 138, the decrease wasfrom 45.05 to 43.84%, 0.731 to 0.711 g/cm3, and 1.33 to 1.266 g/cm3, respectively. Sphericity increased between 4 and 8%MC and then decreased between 8 to 16% MC for the two accessions. The effect of moisture content was highly significanton these properties (p < 0.05) and the accessions found not to be statistically different only in terms of sphericity. Thefrequency distributions for size and shape measurement parameters generally approximated those of the normal distribution.The shape of African yam bean can be described as prolate sphere.