Development and Performance Evaluation of Hand Operated Screw Juicer for Small Scale Application

Abstract

Nutrients from fruits are lacking in most African diets despite their importance. This results in malnutrition and diseases. Some of the factors responsible for these dietary deficiencies are income level and technologies to address postharvest losses. A hand-operated screw juicer was developed in this technical brief to address some of the problems. The machine developed uses screw principle for fruits mastication and juice extraction. The screw juicer performance was tested based on extraction capacity, efficiency and number of runs. Bivariate linear regression was the statistical model used to understand the relationship between the explanatory variable, x (number of pass/runs) and the response variable, y (extraction capacity/efficiency). For orange, cucumber, pineapple, golden melon and watermelon, the efficiencies (%) are respectively 79.30, 48.68, 68.96, 56.41 and 56.52 at single pass. Also, the extraction capacities of the machine (L h-1) are respectively 6.38, 5.08, 9.16, 7.84 and 10.48 for the fruits. The efficiencies are higher with orange and pineapple due to fibrous nature of the fruits. Pineapple and watermelon gave higher extraction capacity due to higher water content and juicy nature, at 5 and 7 runs respectively. The model (Y = -49.29X1 + 295.71 ± 89.75) from the analysis using watermelon reveals machine extraction capacity in volume is a function of number of runs. The machine reached its highest extraction capacity of 10.48 liters in 1 hour at 7 runs. This extraction capacity makes the machine fit to meet daily dietary requirements (400 g per person, an equivalence of 380 ml) of more than 4 households if operated for one hour. The machine can be adopted for use by small scale processors as it is affordable, less stressful and easy to maintain.