ABSTRACT
Mango fruit (Mangifera indica) is very
rich in fibre and vitamin C which are the required nutrients for good
health and easy digestion of food in human body system. However, the
fruit is highly perishable in its natural state after harvest due to the
chemical deterioration and environmental effects. Due to the perishable
nature, abundant wastage during the production season and relative
scarcity during the off season were recorded by farmers. Processing the
fruit into the form that can easily be stored, preserved, packaged,
transported or consumed is crucial to having the product all the year
round. Besides, mango juice can be consumed freshly, processed into dry
powder, mixed or blended with other juice to make fruit jams, or
evaporated to concentrates. These products have a lot of potential in
food and beverage industries for export and foreign exchange earnings.
Therefore, a small scale machine to process mango fruits to high quality
juice is highly essential to reduce the postharvest loss and then add
value to the commodity.
To achieve this purpose, an
abrasion-macerating device (AMD) was designed, fabricated and tested for
small scale mango juice extraction. Design considerations focused on
the techno-economic status of the micro and small scale fruit juice
processors who are the intended users of the machine. The major
components of the machine included hopper, perforated drum, screw
conveyor, juice outlet, waste outlet, frame, electric motor and motor
stand. Other components included screw shaft, the juice collector, top
cover and the transmission system. In operation, the screw conveyor
conveys and presses the mango fruits against the perforated roughened
drum. The abrasion/tearing process of the screw on the flesh of the
fruit and further pressing against the drum squeeze enough juice out of
the fruit. The juice extracted is drained through the perforated mesh of
the juice channel into the juice outlet from where it is collected
while the residual waste is collected at the waste outlet. The machine
was tested using freshly harvested mango fruits and results obtained
showed the juice recovery rate, extraction efficiency and extraction
loss of 68%, 66% and 32%, respectively with an actual capacity of
72.3Kg/hr. These values of juice yield, extraction efficiency and low
level of extraction loss indicate satisfactory performance of the
machine. Powered by a 2.0 hp single-phase electric motor, the machine
has a production cost of ?80,000 with the construction materials being
locally available at affordable costs. A cottage mango juice extraction
plant based on this technology can provide employment for at least three
to four persons at the same time providing fresh juice at low costs and
residual waste as an ingredient for livestock feed manufacturing.