Abstract:
The development of small-scale extruder machines has become increasingly important
due to the growing demand for efficient food processing technologies. This
study focuses on the design and fabrication of a screw-type extruder machine and
the assessment of its performance using jackfruit seed flour as the primary raw
material for the production of extruded snacks. Among existing designs, screwtype
mechanisms were chosen over piston-type mechanisms due to their simpler
operation and continuous processing capability. The fabricated machine consists
of essential components, comprising the feeder, barrel, screw, heating system, and
die, all mounted on a single integrated frame. The performance of the machine was
evaluated at different moisture contents, while the quality of the extruded snacks
assessed through physicochemical and sensory analysis. Quality parameters measured
as expansion ratio, density, water absorption, and water solubility index.
Results showed that for the density, expansion ratio, Water Absorption Index
(WAI), and Water Solubility Index (WSI) were 1.11± 0.08 g cm-3, 1.33 ± 0.02%,
3.58 ± 0.04 g g-1, and 22.85 ± 0.07% respectively. Regression analysis revealed
that the temperature had the statistically significant effect on the expansion ratio
(P < 0.001). Sensory evaluations were carried out for two treatments by a panel
comprising 30 untrained panelists. According to the Friedman nonparametric
test, sensory evaluation results for treatment two has the highest preference in
terms of color (4.50), aroma (4.25), texture (4.50), flavor (4.50), mouthfeel (4.50),
appearance (4.50) and overall acceptability (4.50). In treatment number two, the
formulation was composed of 30 g jackfruit seed flour, 49 g wheat flour, 20 g powdered
sugar, and 1 g salt. Commercially imported extruders normally cost more
than LKR 100,000, whereas the estimated total cost of the small-scale extruder
was approximately LKR 13,000. The study concludes by recommending future
research on incorporating a vacuum chamber within the barrel to further enhance
product quality.
