Sustainable Protein-Enriched Biscuits: Effects of Mealworm Protein Powder on the Properties of Wheat Flour and Biscuit Quality

Mealworm (Tenebrio molitor, LINNAEUS, 1758) is a protein-rich edible insect. In this study, low-gluten wheat flour was formulated with mealworm protein powder at various concentrations (0%, 5%, 10%, 15%, and 20%) to investigate its influence on the pasting, farinographic, and extensographic properties of low-gluten wheat flour, as well as the changes in the overall quality of the resulting biscuits (soda crackers and cookies). The viscosity of the composite flour decreased with an increasing substitution level of mealworm protein powder, and the setback significantly decreased from 69.31 ± 0.16 RVU (M0) to 19.00 ± 0.71 RVU (M20), indicating enhanced resistance to starch retrogradation. Farinographic and extensographic analyses revealed that the addition of mealworm protein powder reduced dough water absorption, significantly prolonged dough development time and stability time, and enhanced overall dough stability. However, extensibility gradually decreased, with a further reduction observed as the proofing time increased. Concurrently, the baking expansion ratio and hardness of the biscuits decreased. Specifically, for soda crackers, the baking expansion ratio decreased from 198.96 ± 3.88% (M0) to 135.74 ± 1.28% (M20), and hardness dropped from 26.40 ± 1.53 N (M0) to 6.32 ± 0.08 N (M20). For cookies, the baking expansion ratio and hardness decreased from 93.77 ± 0.72% (M0) to 86.06 ± 1.08% (M20) and from 1.76 ± 0.06 N (M0) to 1.10 ± 0.16 N (M20), respectively. The impact of mealworm protein powder (5–20%) was relatively minor in cookies but more pronounced in soda crackers, likely due to differences in formulation and processing methods. Additionally, the crunchiness of soda crackers was 3.42 times greater than that of cookies, whereas resilience was only 0.15 times that of cookies under controlled conditions. Pearson correlation analysis and principal component analysis (PCA) further elucidated the relationships between the dough properties and final product quality. Furthermore, the substitution of mealworm protein powder affected the sensory properties of the product but significantly enhanced its nutritional value, confirming the feasibility of replacing low-gluten wheat flour with mealworm protein powder and offering a theoretical foundation for its development and application in diverse biscuit formulations.