• vacuum impregnation;
  • infiltration;
  • jalapeño pepper;
  • mass transfer;
  • isotonic solution

ABSTRACT: The kinetics incorporation of an isotonic solution (IS) into the whole jalapeño pepper, as a function of the vacuum pressure (p1, vacuum application time (t1), and relaxation time (t2), is necessary to determining the conditions leading to the highest incorporation of IS. This study was aimed at determining the operation conditions to achieve maximum impregnation (Min) of whole jalapeño pepper tissue, and a complete infiltration (Min) of its inner void with an IS, using a vacuum pulse. Impregnation of whole jalapeño peppers was conducted using an IS (aw= 0.993 ± 0.001), a vacuum pulse, and 5 levels for each process variable (t1, t2, p1), according to a central composite design. The amounts of impregnated and infiltrated IS were measured by following changes in pepper weight. The p1, t2 had a significant effect (P < 0.01) on the rate of Mim and Min (g IS/g pepper). It was found that the structure of whole jalapeño plays an important role in the deformation-relaxation process, which also affects the impregnation and infiltration kinetics. A high level of p1 (666 mbar) and t2 (840 min) allowed to achieve the maximum values of Mim and Min (0.07 and 0.29 g IS/g pepper, respectively). These results suggest that different driving force acts in promoting the Mim and Min, during the t1 and t2. This information will be of great value in the analysis of the pickling process of whole jalapeño pepper with a hypertonic solution and a vacuum pulse.