The protection effect of trehalose on the multinuclear microcapsules based on gelatin and high methyl pectin coacervate during freeze-drying

Drying of coacervates can cause various stresses which may lead to the damage of the outer layer membrane, aggregation, and poor rehydration properties. Gelatin/pectin coacervates prepared with addition of trehalose as cryoprotectant were subjected to freeze-drying. The addition of trehalose (15%) improved wettability, bulk density and encapsulation efficiency. Fourier transform infrared (FTIR) results revealed the formation of a hydrogen bond between coacervates and trehalose. Trehalose increased the degradation temperature of coacervates from 200-250 degrees C to 300-350 degrees C. Scanning electron microscopy analysis showed that samples with (10% and 15%) trehalose had a spherical shape. The trehalose added microcapsules improved the rehydration state and maintained the integrity of multinuclear wall and spherical shape. The retention and stability of cinnamaldehyde stored at 45 degrees C were enhanced by trehalose addition. The amount of trehalose, the interaction between coacervates and trehalose are the main reasons to affect thermal stability, rehydration properties, particle size and the protection degree of core material.