Abstract

The effects of soaking on moisture - dependent mechanical properties of some selected grains essential to design of an automatic continuous grain drinks processing machine was studied. Three grain types were used for the study, they are white maize, white sorghum and large seeded soya beans. The  white maize and white guinea corn were soaked for  36 h, while large seeded soya beans was soaked for 12 h in accordance to standard procedure (Gaffa et al., 2003; Gbabo et al., 2012). The result obtained showed that moisture content level of the grains increased with increased in soaking time from 12.4 to 20.5% M.C. for corn when soaked for 36 h, 11.3 to 20.6% M.C for sorghum when soaked for 36 h and 10.9 to 20.5% M.C for soya beans when soaked for 12 h. Soya beans had the highest decreases in rupture force with increase in moisture content level (10.9 to 20.5%) from 197.47  to 89.47 N (54.69% decrease), while corn had the least decreases with increase in moisture content level (12.4 to 20.5%) from 266.67 to 170.23 N (36.17% decrease). Also soya beans had the highest increases in rupture energy with increase in moisture content level (10.9 to 20.5%) from 27.79 to 81.95 N mm (194.89% increase), while corn had the least increase with increase in moisture level (12.4 to 20.5%) from 42.626 to 49.40 N mm (15.89% increase). In addition the expected quantity of drink to be produce from the machine under 8 h operational hours per day were 274.4 L from 34.3 kg of soya beans, 520 L from 65 kg of sorghum and 411.2 L from 51.4 kg of corn .  The result thus, obtained will assist in designing of the machine and also ensured its maximum performance.

Key words: Soaking, moisture, mechanical, properties, rapture, force, energy and grain drink.