Modeling the inactivation of Aspergillus niger spores in a model parenteral emulsion by high hydrostatic pressure and its effect on the emulsion droplet size

A predictive model based on the Box–Behnken design was developed to determine the effect of high hydrostatic pressure (HHP), temperature, and cycles (each holding time of 10 min) on the inactivation of Aspergillus niger spores and in the droplet size of a model emulsion. The obtained model presented goodness of fit to the data with a high correlation coefficient (R² = 0.91) and adjusted correlation coefficient value ((Formula presented.) 0.88), with no significant lack-of-fit test (p = 0.6031). The canonical analysis provides the conditions (37.29 °C, 263.33 MPa, and, 1.88 cycles) to reduce 5.0 Log₁₀ CFU/mL of A. nigger. Under such conditions, emulsions exhibited a monomodal distribution of droplet size. However, as temperature and pressure increased, both the PDI, D_3,2, and D_4,3 values increased (p ≤ 0.05). In conclusion, the proposed model has the potential to predict the reduction of A. niger spores by HHP without causing emulsion destabilization.