Coupled Diffusion Model for Curing via Seepage‐Fractal Theory

ABSTRACT To address the limited applicability of traditional diffusion theories in the curing of collagen‐based foods, this study aimed to construct a multi‐factor coupled effective diffusion coefficient model suitable for pork skin (a representative of collagen‐based foods). The experiment used pork skin cured with different NaCl concentrations (2%–8%) for 24 h as the research object. Parameters such as porosity and tortuosity were measured. Combined with the verification of Fick's model, the model was derived by coupling percolation, fractal and other theories. Origin 2021 was used for data analysis, and SPSS 27 was employed for analysis of variance (ANOVA) with a significance level of p < 0.05. The results showed that the model's prediction deviations were only 0.18%–0.52% at NaCl concentrations of 2%–6%, while it failed at 8% high salt concentration due to collagen denaturation. The model simplified the measurement process, reduced the number of samples, and revealed the influence of microstructure on mass transfer. In conclusion, the model is accurate and reliable within the low‐salt range, providing theoretical support for the precise processing of collagen‐based materials in the food industry. It needs further optimization to adapt to high‐salt environments.