Development of high-protein biscuits by the enrichment with mopane worm (Gonimbrasia belina) flour.

Abstract

Mopane worm (Imbrasia belina) has high protein content, unsaturated fatty acids and minerals. This study was carried out to determine the influence of incorporating mopane worm flour on the nutritional quality and technological and sensory properties of wheat flour biscuits. Wheat flour was partially replaced with 5%, 10%, 15%, 20%, 25% and 30% of mopane worm flour. The protein, fat and ash content of mopane worm flour was higher than wheat flour. Biscuits enriched with mopane protein flour had significantly higher protein, fat and ash content than the control biscuits. There was no significant difference (p > 0.05) between the moisture of control and biscuits added with 5% to 20% mopane worm flour. Nevertheless, the moisture of biscuits added with 20% to 30% mopane worm flour significantly increased, ranging from 3.92% to 3.99%. The incorporation of mopane worm flour increased the amounts of leucine, phenylalanine and lysine in biscuits. Results obtained for colour analysis showed that there was a decrease in L* (56.41-41.10), a*(13.00-8.47) and b* (31.35-24.17) values of biscuits with the addition of mopane worm flour. Nevertheless, the diameter, thickness and weight of enriched biscuits decreased. Spread ratio (2.70-5.87) and hardness (26.83-37.17 g) of enriched biscuits increased. Sensory scores showed that the panellists accepted biscuits enriched with 5% to 15% mopane worm flour. The results of this study show that mopane worm flour improved the nutritional quality of biscuits, and its usage in bakery products should be encouraged.