Protein quality and physical characteristic of wood grasshopper (Melanoplus cinereus) hydrolysate flour

Abstract

Indonesia is a tropical country with high biodiversity including insects. Insects are referred to as a good source of protein to overcome various nutritional problems. Wood grasshoppers (Melanoplus cinereus) have been consumed for a long time as a source of protein with limited digestibility due to its high chitin content. In this research, wood grasshoppers flour was added with bromelain enzyme with various concentrations 0%, 4%, 5%, 6% (w/v) to produce hydrolyzed flour in order to improve its protein quality. The manufacture of wood grasshoppers hydrolyzate flour was carried out by first dissolving the flour with water, then adjusting it at pH 7. Then, various concentrations of the bromelain enzyme and inucbated 7 hrs at 55°C. The final product obtained was the hydrolyzed flour in freeze-dried form. These flour were analyzed for their proximate analysis, protein quality (soluble protein, protein digestibility, amino acids total), antioxidant activity and physical properties (pH, color quantification). All these results were compared to obtain the best flour quality. The protein digestibility and color quality improved by the increasing bromelain concentration. However, soluble protein, amino acid total, and pH of wood grasshopper’s hydrolysate flour decreased. Variation of bromelain concentration gave a significant difference on water content, carbohydrates, fats, protein, protein soluble, protein digestibility, antioxidant activity, redness and yellowness. Nonetheless ash content, pH and lightness of these flour were comparable. In conclusion, the best protein digestibility of wood grasshopper’s hydrolysate flour was 6% of bromelain concentration, which was 51.33%.