Comparative analysis of drying methods on in vitro protein digestibility of house cricket (Acheta domesticus)

nsects can be considered high-quality protein sources for human diet; however, processing methods can influence protein digestibility, which is a critical factor for their nutritional value. This study evaluates the effect of different blanching and drying techniques on the protein digestibility of house cricket (Acheta domesticus) in vitro. Samples were water blanched (60 oC for 90 s; 100 oC for 60 s) or steam blanched (60 s, 90 s) using a non-pressurized domestic steam cooker operating at approximately 100 oC, before drying in a conventional dryer (at 85 oC and 100 oC), freeze-dryer, or microwave-vacuum dryer. Protein content was determined using the Kjeldahl method (kp = 5.33), and digestibility was assessed through in vitro gastrointestinal simulation according to the INFOGEST protocol. A total of 21 samples were processed. Results indicated no statistically significant differences in protein digestibility across drying methods (p > 0.05), suggesting that drying technique selection can be based on industrial feasibility, energy efficiency, and cost, without compromising nutritional quality. Blanching method and duration also had no significant impact on protein digestibility, raising questions about the necessity of this pre-treatment step. This study further highlights the importance of using accurate nitrogen-to-protein conversion factors, as conventional calculations (kp = 6.25) may overestimate protein content in insects due to chitin interference. By applying a corrected factor (kp = 5.33), more precise protein values were obtained. These findings contribute to optimizing insect processing for food applications, supporting sustainability and efficiency in edible insect production. The research aligns with broader efforts to improve alternative protein quality and develop evidence-based food labelling standards.