Proximate Composition, Functional Properties, and Mineral Composition of Whole Meal, Defatted, and Protein Hydrolysates from Edible Grasshopper

Abstract

Edible insects are a unique food ingredient with great potential to contribute to global food security and provide an interesting food alternative. This study aims to determine whole meal, defatted, and protein hydrolysates from edible grasshoppers. Edible grasshoppers were harvested, sorted, degutted, washed with boiling water for 20 min, oven dried and milled into whole grasshopper protein meal (WGM). The WGM was defatted using acetone to obtain defatted grasshopper protein meal (DGM). Grasshopper protein hydrolysate (GHM) was produced by hydrolyzing DGM with pepsin and pancreatin enzymes to mimic the gastrointestinal tract (GIT) digestion of proteins in humans. The grasshopper samples were evaluated for proximate composition, functional properties, and mineral composition using standard methods. The proximate results revealed that moisture, fat, crude protein, fibre, ash and carbohydrate ranged from 7.33-15.54 %, 0.15-17.55 %, 37.45-87.54 %, 6.34-6.43 %, 0.23-2.76 % and 4.75- 23.27%, respectively. The functional results showed oil absorption capacity ranged between (131.32-212.43 %), water absorption capacity (201.00-237 %), gelation concentration (11.00-23 %), foaming capacity (324.00-367 %), foaming stability (65.00-87.00 %), emulsification capacity (35.43-42.54 m2/g), emulsion stability (67.54-81.43 %) and invitro protein digestibility (67.54-86.54 %). Also, the mineral results revealed that sodium ranged between (43.43-301 %), calcium (1.43-15.43 %), potassium (241.54-2143.53 %) and phosphorus (0.98-7.43 %) showed a significant difference (p<0.05). The different samples of the studied grasshoppers were high in proteins, essential macromolecules and minerals needed for optimal human health. The study concludes that with observed functional attributes and nutrient values, grasshopper protein could be promoted as a human food ingredient for manufacturing diversified food products. Further studies should be carried out through bioassay-guided HPLC purification to elucidate the structural composition and sequences of the active components of grasshopper proteins showing the observed bioactivities.