Extraction and physicochemical characterization of [i]Tenebrio molitor[/i] proteins
Résumé
This study focused on the extraction and physicochemical characterization of proteins from larvae and larvae meal of Tenebrio molitor. The larvae were subjected to a protein extraction process which involved a thermo-me- chanical pre-treatment to produce the larvae meal. Soluble proteins from larvae and from larvae meal were sub- sequently extracted by solubilisation at an alkaline pH. The products obtained were then characterized and compared. The larvae and larvae meal were rich in protein (65.6% and 71.6% respectively) and displayed good essential amino acid (EAA) profiles. They contained all EAA and in sufficient quantities to meet the dietary re- quirements of both humans and salmon, except for a deficiency in methionine. The EAA profile of the larvae mealwas also comparable to those of fish and soya meals used for feed. At pH 10 and 45 °C, the protein extraction yield of larvae (59.9%) was two-fold that of larvae meal (26.4%). The soluble proteins had protein contents on dry matter of 84% and 80% from larvae and larvae meal respectively. Molecular weights ranged from ≤14 to 100 kDabut the two soluble proteins differed. The soluble proteins had a solubility which was highly pH-dependent, with a low solubility at pH 3 to 5. Their surface charge depended on both the pH (in particular) and the NaCl concentration.The surface hydrophobicity at pH 7 of soluble proteinsfrom larvae(670.3) washigherthan that of soluble proteins from larvae meal (102.5). These soluble proteins lowered the water surface tension to 42 mN/m and 32 mN/m for the soluble proteins from larvae and from larvae meal respectively