Effect of Particle Size on in Vitro Intestinal Digestion of Emulsion-Filled Gels: Mathematical Analysis Based on the Gallagher–Corrigan Model

Free fatty acid (FFA) release from the in vitro digestion of an emulsion-filled gel using three different particle size distributions and its modeling using the Weibull function and Gallagher–Corrigan model were investigated. To produce the emulsion-filled gel, an oil/water mix was prepared and blended with sodium alginate to finally produce small calcium alginate gel cubes. Three different particle size area distributions were generated by comminuting the cubes applying 5, 10, and 15 cycles of compression/shearing. The particles were intestinally in vitro digested, and the fraction of FFA released was calculated and analyzed using the Weibull function and Gallagher–Corrigan model. The FFA release showed a sigmoidal behavior for the three particle distributions; the Weibull function did not show a good fit. The Gallagher–Corrigan model presented a good fit to the FFA data, reinforced with a random error distribution. The model parameters were able to explain the kinetic processes related to both surface emulsion release and emulsion release by matrix dissolution. In addition, some parameters were linearly correlated (R2 > 0.99) with particle size, which established a relationship between particle size and the kinetics of release attained during the first stage of the digestion curve.