Effect of blanching on volatile compounds and structural aspects of Cordyceps militaris dried by microwave-assisted pulse-spouted bed freeze-drying (MPSFD)

Effect of low temperature blanching at 50°C (for 15, 30, and 60 min) and high temperature blanching at 100°C (30, 60, and 120 s) on volatile compounds and structural properties of Cordyceps militaris dried by microwave-assisted pulse-spouted bed freeze-drying were investigated. A total of 83 volatile compounds were identified. Blanching at 100°C remarkably decreased the ketones and alcohols while contributed to the formation of alkanes. The absence at 993 cm and the appearance near 1548 cm in samples blanched at 100°C were observed, indicating blanching at high temperature would cause the loss of polysaccharides and the degradation of proteins. Principal component analysis and cluster analysis suggested that volatile compounds in untreated samples and those blanched at 50°C for 15 min were similar. In general, blanching at 50°C for 15 min is recommended regarding the retention of flavor components and structural properties of dried C. militaris.