Effect of Different Drying Processes on the Quality of Edible Bird's Nest

In this experiment, the effects of hot air drying, microwave drying, vacuum freeze drying and supercritical CO₂ drying on the quality of edible bird's nests were investigated by comparing and analyzing the sensory quality, drying rate, rise times, color, whole texture, microstructure and nutrient composition. The results showed that the rise rate (42.71±0.09) and color (79.16±0.35) of supercritical CO₂-dried edible bird's nests were significantly higher than those of vacuum freeze-dried, microwave-dried and hot air-dried edible bird's nests (P<0.05). In terms of holomorphic structure, supercritical CO₂-dried edible bird's nests showed significantly higher gelling (0.0127±0.0024) and cohesion (0.4330±0.0580) (P<0.05) than hot air-dried, microwave-dried and vacuum freeze-dried samples, but the elasticity of the samples was not significantly different between the four drying processes (P>0.05). The samples dried by supercritical CO₂ and vacuum freeze-drying were found to have large and many cavities by scanning electron microscopy (SEM), while the cavities of the samples dried by microwave and hot air were smaller and had a tight structure. The total sugar content of the supercritical CO₂ and vacuum freeze-drying samples were significantly higher than that of the hot-air and microwave drying samples, and the Lysine, Aspartic acid, Alanine and Methionine in the supercritical CO₂-drying samples were significantly higher (P<0.05) than those of the other three dried processes. The quality of edible bird's nest varied greatly between different drying methods and supercritical CO₂-drying was the best drying process for edible bird's nest.