DEVELOPMENT AND PERFORMANCE EVALUATION OF A GROUNDNUT CAKE EXTRUDING MACHINE

Abstract

ABSTRACT Manual production of groundnut cake involves a great deal of drudgery and time consumption in addition to the low consumer acceptance as a snack due to its unhygienic mode of production. In this study, a groundnut cake extruding machine was developed to mechanize the process and its extrudate properties evaluated. The effect of extrusion and process variables: feed moisture content, screw speed and die shape on the system parameters (extruder efficiency and specific mechanical energy) and the extrudate properties of the groundnut cake (expansion ratio, bulk density and specific length) were determined. The factors were varied at screw speeds (7, 9 and 11 rpm), moisture content (5.04 %, 7.04 % and 10.65 %) and die shape (square, inverted and circular). Data obtained were analyzed statistically using Design expert 11.1.2.0 statistical package to determine the response model and analysis of variance (ANOVA). It was observed that varying the screw speed and moisture content affected the length, bulk density, extruding time, extrusion capacity and expansion ratio but did not significantly affect the specific length, weight and diameter of the groundnut cake. Response variables predicted with model equations under optimum conditions were in general agreement with experimental data. Optimization of the independent factors produced the best response of 98.511 mm Length, 16.8 g weight, 12.867 mm Diameter, 1.161 g/ml Bulk density, 473.791s Extruding time, 0.257 Kg/min Extrusion Capacity, 1.537 mm Expansion ratio and 8.821 mm Specific length of dependent factors respectively. The developed groundnut cake extruder has an extruding efficiency of 93.5 % and extrusion capacity of 12.30 Kg/h.