Energy-driven structural and thermal transitions induced by high-energy ball milling in Sphenarium purpurascens and Nauphoeta cinerea flours

Abstract

High-energy ball milling (HEBM) is increasingly used to modify complex biopolymeric materials; however, quantitative energy-based descriptions of structural transitions in insect flours remain limited. This study investigated the energy-dependent structural and thermal evolution of grasshopper ( Sphenarium purpurascens ) and cockroach ( Nauphoeta cinerea ) flours subjected to planetary milling under controlled conditions. The specific supplied energy ( E _supp ) was calculated using the Burgio et al. kinematic model for planetary ball milling, enabling the processing intensity to be interpreted quantitatively in terms of mechanical energy input rather than operational time alone. Multiscale characterization integrating scanning electron microscopy (SEM), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), differential thermal analysis (DTA), and Fourier transform infrared spectroscopy (FTIR) revealed progressive morphological fragmentation, thermal destabilization, and molecular rearrangement within the protein–chitin matrix. Species-dependent energy thresholds were identified: N. cinerea exhibited the onset of critical structural and thermal transitions at approximately 64.8 kJ g ⁻¹ , whereas S. purpurascens required approximately 97.3 kJ g ⁻¹ under identical milling conditions. These findings indicate that mechanical resilience in insect flours is influenced by matrix organization and can be interpreted in relation to the supplied mechanical energy, expressed as E _supp . This study provides an energy-based approach to support the interpretation of structural transformations in heterogeneous biopolymeric systems subjected to planetary ball milling.