Abstract

Ginger juice obtained from mechanical expression of fresh ginger rhizomes offers a value-added ginger product which increases market opportunity for farmers. In this study, the performance of a developed motorized ginger juice expression machine was evaluated to determine the effects of moisture content of ginger and screw shaft speed on the expression efficiency, juice yield, expression loss and throughput capacity. Three levels of moisture content (84, 79 and 72%) (wet basis) and three levels of screw shaft speed (420, 472 and 660 rpm) at two replications were used for the study. A 3 × 3 factorial experiment in a completely randomized experimental design was used. Data for the performance evaluation were subjected to analysis of variance for test of significance of the experimental factors and their interactions. The result showed that mean expression efficiency decreased with increase in screw shaft speed and with decrease in moisture content for the speed and moisture content range studied. The highest expression efficiency of 91.62% and juice yield of 61.28% were obtained at screw shaft speed of 420 rpm and at 72% moisture content (wb). The mean juice yield decreased with an increase in screw shaft speed and with a decrease in moisture content of ginger considered. The lowest expression loss of 11.69% was obtained at 472 rpm and 72% moisture content. The machine had highest throughput capacity of 9.47 kg/h at 420 rpm. Analysis of variance (ANOVA) results showed no significant effect of moisture content levels considered, speed and their interactions on all the performance indicators of the machine at P<0.05.

Key words: Expression, moisture content, ginger juice, expression efficiency, expression loss, juice yield.