Gelatine-based foams produced by enzymatic foaming: formulation–structure relationships affecting expansion and stability

foam formation and fixation at 37 °C. A systematic parametric study was conducted to elucidate the effect of gelatine, hydrogen peroxide, catalase, and glutaraldehyde concentrations on foam expansion and 24 h volume retention. Statistical analysis (one-way ANOVA with Tukey's post hoc test) showed that foam behaviour reflects the interplay among enzymatic gas generation, interfacial stabilisation by gelatine, and matrix stiffening through covalent cross-linking. Excessive gas generation or cross-link density reduced structural integrity, whereas intermediate formulation ranges produced foams with improved expansion-stability balance. A practical formulation window was identified (2.0-3.0 wt% gelatine, 3.0-4.0 wt% hydrogen peroxide, 0.2 wt% catalase, and 2.5-3.0 wt% glutaraldehyde), providing a favourable compromise between high expansion and sustained volume retention over 24 h. These results provide formulation-level design guidance for enzymatically generated biomedical foams and support their potential as flexible, absorbent wound-dressing materials.