Physical, nutritional, functional and rehydration properties of palm beetle (Oryctes rhynoceros) larvae as affected by drying and roasting

Abstract

Abstract The effects of sun-drying, oven-drying and roasting on physical, chemical, functional and rehydration properties of palm beetle (Oryctes rhinoceros L.) larvae were investigated. Average weight (18.64g), length (67.74mm), breadth (22.56mm), and thickness (19.12mm) of live larvae reduced to 2.85-3.86mm, 36.78-38.24mm, 20.10-21.05mm and 16.50-18.88mm, respectively, with degutting, drying and roasting. Generally, lightness (49.93) and yellowness (11.68) of live larvae reduced to 28.89 and 5.60, when sun-dried. Crude protein, ash, fat and crude fibre contents of processed larvae varied from 65.46–69.99, 9.75–10.27. 13.79–21.01 and 0.55-1.23g/100g, respectively. Potassium, magnesium and sodium contents of processed larvae varied from 212.6–379.1, 58.76–184.6, and 104.65–170.75mg/100g, respectively. Sun-dried larvae showed higher amino acids contents than oven-dried and roasted larvae. However, the processed beetle larvae were rich in leucine, lysine, phenylalanine, aspartic acid, glutamic acid, isoleucine, leucine, threonine, valine, arginine, histidine and tyrosine. The water and absorption, OAC, loose and packed bulk density and dispersibility varied between 1.77–2.03, 1.20–1.33, 0.38-0.41g/mL, 0.56-0.60g/mL, 15.15-24.67sec and 18.77-26.00sec, respectively. Moisture contents of rehydrated sun-dried larvae were higher than oven-dried and roasted larvae between 15-45oC.