EFFECT OF MOISTURE CONTENT ON SOME PHYSICAL PROPERTIES OF COWPEA (Vigna unguiculata)

Abstract

The effect of moisture content on the physical properties of three of the most popular Nigerian cowpea varieties namely Ife 98-12, IT90K-277-2 and Ife Brown was determined with a view to obtain data useful for the design of handling and processing equipment for the crop. Physical properties such as linear dimensions, geometric mean diameter, sphericity, aspect ratio, bulk density, true density, projected area, porosity and 1000 grain mass were studied in the moisture range of 8 to 18% w.b. which covers the moisture range from harvesting to storage. The length of the grains ranged from 9.36 to 9.74mm, 7.70 to 8.49mm and 8.01 to 8.49mm for the three varieties respectively. The width ranged from 6.34 to 6.53mm, 6.08 to 6.45mm and 6.01 to 6.46mm while the thickness ranged from 5.24 to 5.33mm, 5.00 to 5.24mm and 4.42 to 4.75mm respectively for the three varieties. The results show that variety and moisture content had significant effects (p≤ 0.05) on all the physical properties studied except aspect ratio on which the effect of moisture content was not significant. Regression equations that could be used to express the relationships existing between the physical properties and grain moisture content were established.