Design, Construction and Evaluation of Zobo Juice Processing Device

Abstract

This study was aimed to develop a device which can process Zobo juice at an economic rate utilizing the principle of leaf extraction method. Four tanks were constructed using aluminium sheet and stainless steel. The boiling, heat exchanger, and homogenizing tanks were made of aluminium while the cold water tank was made of stainless steel. The volumes of the tanks are 9.0 m3, 9.5 m3, 9.0 m3 and 5.0 m3 for boiling tank, homogenizing tank, heat exchanger and cold water tank respectively. The Zobo calyces are boiled in the boiling tank and the product is exited into the heat exchanger where water from the cold water tank is allowed into the heat exchanger to reduce the temperature of the zobo juice after which it finally enters the homogenizing tank where other ingredients (sugar and ginger) are added. The homogenizing tank stirs its content to obtain the final product. Its performance showed that in an average of 32 minutes using 9 litres capacity of boiling tank with mean volume of 9.0 cm3, the homogenizing tank with mean volume of 9.5cm3 would produce 9 litres of Zobo juice. It takes 32 minutes total processing time per 9 litre of zobo juice. This implies that on the average, one man working at a normal rate of 8 hours 32 minutes shift could process 144 litres of zobo juice using 9 litres capacity boiling tank. The calculated volumetric flow rate was 4.69×10-6m3/s. The microbiological quality assessment from the processed zobo juice showed 1.8×104 cfu/ml of mesophilic bacteria and 2.8×103 cfu/ml of yeast/mould with complete absence of coliform cells. The results implied its safety for consumption as a beverage. The zobo-juice processing device is low cost in terms of construction, easy to construct, easy to assemble and requires very little maintenance. It eliminates the unhygienic manual method of producing zobo juice. It serves the purpose of quick production of Zobo juice in homes, hotels, bars and restaurants. The cost of production is eighteen thousand six hundred and ninety Naira 18,690:00 which is approximately $117:00 US Dollars.