Design & construction of a motorized tomato pulp and seed extraction machine.

Abstract

Tomato (Lycopersicon esculentum) is one of the significant fruit/vegetable crop popularly consumed almost in every country of the world. They are consumed fresh in combination with salads or used in cooking as a recipe. Therefore, the commercial value of the tomato lies in its processing. Tomatoes are important for health and rich in several good compounds. They give protection and reduces the risk of contracting chronic degenerative diseases. For example, nutritional values like lycopene, a food component known to reduce the incidence of prostate cancer, heart and age related diseases, and also provide good quantities of vitamins A, C and E. Therefore, the commercial value of the tomato lies in its processing. Tomato processing in Uganda is still a minor activity due to lack of funds and appropriate technology in spite of its high economic potential in the country. Local farmers extract seeds from tomato by use of hands is associated with contamination, injuries and drudgery. For easy separation, the pulp is left to ferment for at least 1-2 days and this puts pulp to wastage and produces large effluent during the washing process. The large and small industrial units engaged in processing tomatoes in various forms use a temperature gradient of 65 0 C to 700 C to isolate Pulp from the. peel destroying the seed and thus sacrificing the quality of the pulp. The motorized tomato pulp and seed extractor therefore separates the pulp, peels and seeds in a single process to present, the above challenges. Conceptualization of the. machine involved two units; the squeezing unit and the rubbing unit. Different components of the machine were designed basing On the physical, mechanical and chemical properties of the tomato. the components include; the feed hopp.er¾ screw conveyor. shaft, rubbing unit; pulp collection chamber, main frame. From the designs, the squeezing, conveying and the rubbing unit operate at a speed of 700rpm with a total maximum transmitted power requirement After fabrication, the performance and economic analysis of the machine were performed in terms of extraction efficiency and extraction loss, resulted into 88% extraction efficiency and 6.6% losses in peels and other areas. Machines total cost; Ugx.604500, cost of extraction; Ugx 2056.8, Breakeven units; 39.5kg of pulp, monthly income; Ugx. 436728 and pay back-period of 1.4 years.