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

ABSTRACT

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⁻¹ and the appearance near 1548 cm⁻¹ 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.

KEYWORDS:

• Blanching
• Cordyceps militaris
• Fourier transform infrared
• gas chromatography–mass spectrometry
• volatile compounds

Additional information

Funding

We acknowledge the financial support from National Key R&D Program of China (Contract No. 2017YFD0400901), Jiangsu Province (China) Agricultural Innovation Project (Contract No. CX(17)2017), Jiangsu Province (China) “Collaborative Innovation Center for Food Safety and Quality Control” Industry Development Program, Jiangsu Province (China) Infrastructure Project (Contract No. BM2014051) all of which enabled us to perform this study.