Characterization and techno-functional properties of Tenebrio molitor larvae protein concentrate

Global population growth and an alarming rate of global warming conditions have driven the need for protein from alternative non-conventional sources, namely, insect proteins, through a sustainable approach. The protein concentrate of Tenebrio molitor larvae was examined for its suitability and applicability as a food ingredient. Protein was extracted through the acid-alkali method with similar to 79% of extraction efficiency. The protein-bound polyphenols were extracted and quantified, and the anti-oxidant potential of protein-bound polyphenols and protein concentrate was assessed. The colour parameters of protein concentrate showed brighter colour (L*, 57.3) than the whole insect powder (L*, 39.0). The surface hydrophobicity of protein concentrate increased to 650, and an increase in the total and free sulfhydryl content (15.39 and 9.158 mu mol/g, respectively) was also observed compared to the whole insect powder. Significantly higher protein solubility was observed at pH 2 (72.3%) and pH 11 (66.4%), as compared to near the pI (6.9% at pH 5 and 30.15% at pH 4). Several prominent proteins, including 86 and 56 kDa early-staged encapsulation-inducing proteins, cuticle proteins, and structural proteins were identified in protein concentrate. The techno-functional properties revealed that mealworm protein concentrate was superior to whole insect powder and comparable to whey protein isolate. These findings confirmed the excellent functional properties of mealworm protein concentrate, which can be further explored as a novel food ingredient.