Oven-drying and decontamination effects on crude protein concentration and in vitro crude protein digestibility of yellow mealworm (Tenebrio molitor) (Coleoptera: Tenebrionidae)

• Published in: Journal of insect science (Tucson, Ariz.) Vol. 24; no. 4
• Main Authors: Gómez-Oquendo, Giovanna, Loza Puerta, Andrés, Gonzales Gutierrez, Cesar, Gómez-Bravo, Carlos A, Salazar-Cubillas, Khaterine
• Format: Journal Article
• Language: English
• Published: US Oxford University Press 01.07.2024
• Subjects: Animal Feed - analysis; Animals; Decontamination - methods; Desiccation; Dietary Proteins - analysis; Dietary Proteins - metabolism; Digestion; Hot Temperature; Insect Proteins - metabolism; Larva - growth & development; Tenebrio - chemistry; Tenebrio - metabolism; microbial contamination; drying process; pre-caecal protein digestibility; larva
• ISSN: 1536-2442; 1536-2442
• DOI: 10.1093/jisesa/ieae078

Abstract The study aims to assess the impact of oven-drying and decontamination on crude protein concentration and in vitro crude protein digestibility of yellow mealworms. Two kilograms of 12-wk-old mealworm larvae were subjected to freezing prior to the drying process. Approximately 1.5 kg of mealworm larvae were divided into 3 groups and exposed to oven-drying at temperatures of 50 °C for 36 h, 60 °C, and 70 °C for 24 h each. At intervals of 2 h, sets of 3 replicates were withdrawn to record water loss. Consistent weight stabilization was observed at 36 h for 50 °C (T50), 18 h for 60 °C (T60), and 14 h for 70 °C (T70). The remaining 0.5 kg of mealworm larvae was divided and dried under treatments T50, T60, and T70. Each treatment was then split into 2 portions, with one portion subjected to 90 °C for 15 min (denoted as T50-90, T60-90, T70-90) to eliminate microbial contamination. The 6 treatments were then used to determine concentrations of dry matter, crude ash, crude protein, pre-caecal protein digestibility, and dry matter residues after neutral detergent fiber, acid detergent fiber, and acid detergent lignin treatments. No interaction was observed between drying and decontamination treatments (P > 0.17). Pre-caecal crude protein digestibility increased with decreasing temperature (T50: 58% crude protein; T60: 51% crude protein; T70: 50% crude protein). Therefore, lower temperatures for longer times preserve crude protein digestibility. These findings are crucial for understanding how drying temperature and time impact protein bioavailability. Graphical Abstract Graphical Abstract