PREPARATION OF HIGH-GRADE POWDERS FROM HONEY–GLUCOSE SYRUP FORMULATIONS BY VACUUM FOAM-DRYING METHOD

摘要

This article presents rapid and gentle-drying method for the preparation of highgrade honey powders from honey–glucose syrup formulation. The honey invertase was used as a marker of final product quality. Honey–glucose syrup ratio was 0.55:0.45 w/w; 1% whey protein isolate was added as surfactant. Drying of honey– glucose syrup formulation was carried out in the foamed state. The material was pre-foamed to an initial air volume fraction of 0.25–0.30, subsequently expanded in vacuo to 0.65–0.70. Drying trials were performed at a vacuum level of 100 mbar in a temperature range of 40–60C chosen in accordance with invertase degradation kinetic data. Powders that were vacuum foam dried at 40C and 50C showed insignificant invertase loss and thus similar quality to powders obtained by the much more time-consuming freeze-drying method. Furthermore, the powders proved very stable as no powder caking was observed after 6 months of storage at ambient conditions.