.

ABSTRACT
Flours are susceptible to rapid moisture uptake, caking up and discoloration consequently leading to mould growth when exposed to humid conditions in tropical and sub-topical zones of the world. This study therefore was designed to determine the shelf lives of flours from four indigenous crops (rice, maize, soy bean and bambara nut) stored under controlled accelerated ambient storage conditions (27±1°C, 92 % RH). Moisture and colour changes in the flours were monitored at three and seven day interval, respectively for six weeks. The water vapour permeability coefficient (
) of the low density polyethylene (LDPE) bags used was determined as
was 1.708 × 10-14 g.mm/day/mmHg. In terms of colour stability, redness (a*) changed more rapidly across all flour samples while Lightness (L*) was the most stable. Stability of L* values was least for rice flour while maize flour the greatest L* stability. Soy bean flour had the highest rate of moisture gain followed by bambara nut, maize and rice flour. The estimated shelf life based on 12% and 15% targeted moisture content was 1112 and 1528 days, 9 and 98 days, 160 and 244 days, 225 and 339 days for rice, maize, soy bean and bambara nut flours respectively.
Keywords: Accelerated Shelf lives, Moisture Sorption Isotherm, Cereals, and Legumes.