Optimizing Tenebrio molitor powder as ingredient in breadmaking: Impact of enzymatic hydrolysis on dough techno-functional properties and bread quality

Edible insects have garnered significant attention due to their potential to provide high-quality proteins, nevertheless, despite the appealing composition, their large-scale utilization still needs improving. In this study, a two-step enzymatic treatment with Alcalase® and Flavourzyme® was set up to improve protein bio-accessibility and digestibility of Tenebrio molitor powder (TMP) and a first comprehensive analysis of its impact on bread's nutritional and technological properties was performed. An integrated approach, including the combination of electrophoretic and chromatographic techniques was used to monitor the proteolysis extent. During the treatment, peptide concentration changed in the first few hours of treatments (increasing significantly from 145 to 439 mg/g). A modification of the protein profile was also observed, whereas a 7-fold increase of free amino acids was found by the end of the hydrolysis. The treatment also affected TMP emulsifying capacity, foaming activity, as well as other techno-functional properties. Since these changes led to hypothesizing a positive influence on leavened products volume and nutritional quality, breads fortified with TMP were produced using mixture-process experimental design. Substitution reduced bread dough viscosity, nevertheless, fortified breads had higher protein, lipid, and ash contents than the control, meeting EU nutritional claim requirements for protein content. The use of enzymatic treated TMP provided a higher content of proline and arginine, and a different volatile organic profile, with higher concentrations of amino acids catabolism products (2-methylbutanal, 3-methylbutanal, and 2-pentylfuran). The fortification also impacted bread visual-textural features (hardness, color) in a more pronounced manner as the inclusion rate increased.