Some physical properties of acha as affected by moisture content

Abstract

Mechanization of acha processing has been limited by dearth of data on engineering properties to aid design of equipment for its postharvest operation. Therefore, this study was undertaken to determine the particle size, bulk density and porosity of acha as influenced by moisture content. Particle size was determined by the method of sieve analysis.  The fineness modulus obtained from the analysis was used in calculating the average particle size of acha grains.  Bulk density was determined from the mass of a known volume of samples, while a porosity measuring apparatus was used for measuring the porosity of acha grains at four levels of moisture content and five levels of bulk density.  The results showed that acha grains increased in size from 1.745 mm to 2.366 mm in the moisture content range of 11.46 to 17.46% wet basis. A regression analysis of average grain size on moisture content showed a positive linear relationship (r = 0.887).  Similarly bulk density increased with moisture content and showed a positive linear dependency on moisture content (r = 0.997). Grain porosity was also affected individually and jointly by moisture content and bulk density. A multiple linear regression analysis however showed a negative correlation of porosity with moisture content and bulk density (r = -0.991). Moisture content and bulk density of acha are therefore important factors to consider when designing facilities for its handling, processing and storage.