Functional and Microbial Quality of Extruded Snack from Blends of Dehulled Rice, Whole Grain Rice Husk, Date Palm Fruit and Defatted Groundnut Cake Flours
Keywords:
Dehulled, Whole Grain, Twin-Screw Extruder, Husk, Defatted Groundnut Cake, Bulk Density, Expansion Ratio, Water Absorption Index, Viscosity, Wettability, ColiformAbstract
Nine extruded snacks were produced from blends of dehulled (polished) rice, whole rice grain Rice husk flour groundnut cake and dried date palm flours. The flours were blended in ratio of 3:1: 1. at variable fed moistures of 11,12 and 13 %. All Samples having code with letter A contained 60% polished rice flour, 20% defatted groundnut cake and 20% date fruit at 11,12 and 13 % fed moisture content. Sample coded with B contain 60% polished rice flour, 20% defatted groundnut cake, 20% date fruit 11,12 and 13% moisture while samples coded with C contain 11,12 and 13 fed moisture content. The extrusion was carried out using a twin-screw extruder, at screw speed of 140 rpm, temperature of 900C and nuzzle diameter of 2mm. The bulk density ranged from 0.5875 g/ml to 0.9085 g/ml for sample BBA and BBB respectively and the expansion ratio varied from 0.8250 g/ml (AAB) to 0.9300 gl/ml (BBA) The water absorption index (WAI) ranged from 1.000gH20/g observed in sample AAC to 2.90g H20/g in sample BBA. Lowest water solubility index was recorded in sample AAC (1.180 g/100 ml to 1.420 (BBB). The wettability of the extruded snacks ranged from 15:05(CCC) to 29:23 secs (AAA) while the viscosity varied from 0.00466 (CCB) to 0.00914 (AAA) mpas. Microbial analysis of the snacks after five weeks was studied using morphological and biochemical tests. Molds were isolated in some of the samples and total aerobic plate count (TAPC) ranged from cfu/g to 3.0X102 cfu/g. (BBB). No coliform was isolated in any of the samples.