DEVELOPMENT AND PERFORMANCE EVALUATION OF A DEPODDING MACHINE FOR FRESH MELON PODS

Abstract

The aim of this study was to develop a new melon depodding technique that would remove the drudgery, time consuming and seed wasteful fermentation process associated with the traditional melon depodding techniques. A depodding machine for fresh melon pods was designed, fabricated and evaluated. Operating components of the fresh melon depodding machine are the hopper, rotor shaft, concave screen, hammers, rotor disk and electric motor. During evaluation two operational factors were varied; screen size (S) at four levels (i.e. 15, 20, 25 and 30 mm) and operating speed (P) at three levels (i.e. 650, 850 and 1200 rpm). The statistical design was 4x3x3 factorial experimental design replicated thrice and 36 experimental runs were made. Statistical software SPSS 18 was used to carry out statistical analysis of variance (ANOVA) and Duncan’s New Multiple Range Test (DNMRT) on the evaluation data of the fresh melon depodding machine. However, results of the (ANOVA) and (DNMRT) of the machine showed that the two operational factors (i.e. screen sizes and operating speeds) have no significant effect on the material discharge index (MDI) of the machine at P ≤ 0.05 . Also (ANOVA) and (DNMRT) results showed that only the screen size was significant on depodding performance index (DPI) and machine performance index (MPI) at P ≤ 0.05 , while the operating speed and its interactions were not significant at P ≤ 0.05. In addition, the (ANOVA) and (DNMRT) results showed that both the screen size and operating speed have significant effects on mechanical damage index (MEDI) at P ≤ 0.05 of the depodding machine. Also, the evaluation experimental data of the machine were subjected to further statistical analysis using SPSS to plot graphs that showed the interactions between the operational factors and the parameters. The graph revealed that material discharged index (MDI) has high percentage mean values (i.e. 98%) at all operating speeds and screen sizes. Also, the graphs revealed that depodding performance index (DPI) and machine performance index (MPI) were generally high (i.e. 97%) at lower operating speeds (i.e. 650 and 850 rpm), with higher screen sizes (i.e. 25 and 30 mm). However, the mechanical damaged index (MEDI) graphs showed low percentage of (MEDI) (i.e. 1.3 %) at lower operating speeds (i.e. 650 and 850 rpm), with higher screen sizes (i.e. 25 and 30 mm). The throughput (Ct) of the depodded machine was measured to be 150.15 kg/h at all operating speeds and screen sizes. Hence, the new melon processing technique for extracting and washing melon seeds from its pods is a fast and efficient technique.