Abstract:
In Tanzania, chronic malnutrition rates remain high, with 32 percent of children under the age
of 5 being stunted. The high cost of dietary protein sources is a contributing factor to the
deterioration of the nutritional status of most children. Edible insects are suggested to provide
an alternative source of protein in enriching the nutritional composition of foods. However,
there is limited knowledge on the potential use of long-horned grasshopper (Ruspolia
differens) to enhance the nutritional properties of extruded composite flour. This study
intended to develop an extruded composite flour enriched with the long-horned grasshopper
and further evaluate its proximate composition, mineral properties, antinutritional
composition, functional properties, sensory acceptability, and shelf-life stability. Four samples
of composite flour were formulated and processed using a twin-screw extruder to produce
extruded composite flour (ECF) with a mixing (%wt.) ratios of 100:0 (ECF 0), 95:5 (ECF 5), 85:15
(ECF 15), 75:25 (ECF 25) for composite flour (cassava, millet, sorghum) and edible long-horned
grasshopper pellets, respectively. Feed moisture content and barrel temperature were
adjusted from 15 to 16% and 128 to 142
0
C for Zone I, and 105 to 114
0
C for Zone II, respectively.
The findings show that the inclusion of long-horned grasshopper meal in the extruded
composite flour significantly increased the moisture, crude fibre, crude ash, crude protein, and
crude fat and mineral contents of Fe and Zn while significantly decreasing the carbohydrate
contents at (p<0.001), and Mg contents at (p=0.0089). The phytate contents between ECF 0
and extruded composite flour treatments enriched with long-horned grasshopper did not
differ significantly (p<0.141). All treatments showed a significant higher tannin content ECF 5
(0.007 mg CE/g), ECF 15 (0.012 mg CE/g) and ECF 25 (0.011 mg CE/g) when compared to values
in control (0.004 mg CE/g). There was a significant difference at a 5% confidence level on the
sensory properties between ECF 0 and ECF 15 and ECF 25; the latter two treatments had higher
scores for colour and a lower score for aroma and taste attributes, respectively ECF 0. In
addition, treatments (ECF 5, ECF 15, ECF 25) showed significantly higher peroxide values (3.52
to 5.32 mEq/Kg) than those in the control sample (2.80 to 3.33 mEq/Kg). In conclusion, the
inclusion of edible long-horned grasshopper in the composite flour, significantly improved the
quantity of crude protein, crude fat, and energy with an adequately appropriate amount of Zn
and Fe to meet the needs of fast-growing infants and young children. Moreover, the functional
