Blanching is a critical step in the industrial production of frozen vegetables, primarily intended to inactivate enzymes and preserve quality during storage. Residual enzyme activity can cause undesirable changes in texture, flavor, and appearance. However, excessive blanching may also impair product quality. Therefore, understanding enzyme inactivation and its relation to quality deterioration under specific blanching conditions is essential. This study developed models for the inactivation of selected enzymes during blanching of green beans prior to freezing. Additionally, if combined a heat-transfer the model can link the enzyme activity to texture development. Model validation was fitted using literature data and validated by new blanching experiments, measuring the activities of pectin methylesterase (PME), lipoxygenase (LOX), and peroxidase (POD). Furthermore, it is shown that POD inactivation functions as a practical time–temperature integrator for blanching intensity, but LOX is even a more sensitive indicator of overall quality. Nevertheless, the equivalent-blanching-time correlated to POD activity, texture loss, and leaching metrics, suggesting it is a practical tool for blanching optimization. • Development of predictive model for enzyme activity/inactivation during blanching. • PME activity and beta-elimination determine texture development during blanching. • POD enzyme is validated as time–temperature integrator, indicating blanching intensity. • Effective time is a practical quantitative indicator for blanching intensity.
Sman et al. (Fri,) studied this question.