Influência da taxa de congelamento no comportamento físico-químico e estrutural durante a liofilização da albumina bovina

Abstract

Lyophilization (freeze-drying) is the most commonly method used to prepare dehydrated proteins, which should have the desired long-term stability at ambient temperatures. However, recent infrared spectroscopic studies have documented that the acute freezing and dehydration stresses of lyophilization can induce protein unfolding. Through Roman spectroscopy associated with thermal analysis using differential scanning calorimetry (DSC), it was studied the influence of cooling rate on the structural and phase changes during lyophilization of bovine serum albumin. It was observed that bovine serum albumin (BSA) lyophilized under slow freezing (2.5 °C/min) presented higher structure damage than the BSA lyophilized under fast freezing (30 °C/min) However, the lyophilization process using cooling rate of 30 °C/min presented fewer spectra alterations on the Amide I, III and disulfide bridges, supporting the maintenance of protein structural conformation.