Optimization of ratio of silkworm pupae powder to broken rice flour and of barrel temperature to develop high protein breakfast cereal using response surface methodology

The effects were investigated of the ratio of silkworm pupae powder to broken rice flour (10:90, 20:80, 30:70 or 40:60, respectively) and of barrel temperature (140°C or 150°C) on the chemical and physical properties and on sensory evaluation of breakfast cereal. An increase in the silkworm pupae powder resulted in increased values for a* and b*, bulk density, hardness, crispness and the protein and fat contents of extrudates, while there were decreases in the values for L*, the sectional expansion index and moisture content. The sensory evaluation showed that all treatments had overall liking scores of 6.02–6.66. The study clearly showed that a feed composition with a ratio of 35–40% silkworm pupae powder to 60–65% broken rice flour and with an extrusion temperature of 140–150°C provided optimal extrusion conditions to produce a breakfast cereal with a high protein content (30.96–33.56 g/100g) and an overall liking score of more than 6.0, which was considered acceptable. In addition, the developed product could help to improve the nutritional value as an effective solution to protein-deficient diets and to reduce global warming and increase food security in the future.