The bromelain fraction precipitated by 30–70% (v/v) ethanol
was lyophilized in order to maintain the enzyme stability in the
long-term. It was observed that after the lyophilization process, a
loss of 48.6% of the initial enzyme activity occurred (Fig. 2). During
lyophilization, the water around a protein is extracted into a matrix
of ice crystals and the presumed hydration layer would be interrupted. So the hydration, under the same environment, would
cease to exist in solution and during lyophilization, the passage of
the water from solid to gas states could denature some proteins
sensitive to the process, especially enzymes [38].