The stability of fruit bromelain (FBM) in pineapple pulp was studied within a high-pressure domain of 0.1–600 MPa/30–70 °C/1 s-30 min. The pulse effect was quantified as a function of pressure, temperature, pressure build-up and decompression time. A maximum of 60% reduction in FBM activity was obtained after a single pulse of 600 MPa/70 °C. Upon applying nth order model, the obtained reaction order (n) for thermal (0.1 MPa/30–70 °C) and high-pressure (100–600 MPa/30–70 °C) inactivation were 1.1 and 1.2, respectively. The inactivation rate constant (k) for FBM ranged from 1.2 to 45.0 × 10− 3 Un-1·min− 1. The activation energy was nonlinearly dependent on pressure (P, MPa); whereas, the activation volume was linearly related to temperature (T, K). The nonlinear dependence of k on P and T was modeled by an empirical equation. The D-values obtained from the empirical model appeared to be more realistic than those from the log-linear kinetics.
Industrial relevance.
Pineapple fruit bromelain (FBM) has numerous health benefits and therapeutic effect. It is a protease enzyme that helps in digestion. Processing of pineapple pulp needs an attention towards retaining the maximum FBM activity in it. The detail kinetic study of FBM within a broad range of pressure–temperature-time domain will help in designing a high-pressure process for the pineapple pulp with respect to its bromelain stability.