Effects of drying methods on the quality and microstructure of Armillaria luteo-virens

Abstract

Objective: This study aimed to determine the most suitable drying method for Armillaria luteo-virens. Methods: The effects of solar drying, hot air drying, vacuum-freeze drying, vacuum drying and microwave-hot-air combined drying on the nutrition, functional components, color, rehydration ratio, shrinkage ratio, rehydration structure and microstructure of A. luteo-virens were compared. Results: The content of crude protein, crude polysaccharide and total flavonoids in vacuum-freeze drying group was the highest, and the content of total phenol was second highest and lower than the vacuum drying group. Its color difference was the smallest, with high rehydration ratio, and the shrinkage degree was small, with good internal tissue integrity. Moreover, its rehydration structure was characterized by low hardness, elasticity and chewability. Compared with hot-air drying, microwave-hot-air combined drying significantly increased the content of crude protein and crude polysaccharide of A. luteo-virens, shortened the drying time by 11%, and significantly improved the b* value; after rehydration, its hardness, elasticity, cohesion and chewability were the largest. However, the vacuum drying group was not conducive to the retention of total flavonoids, and had the worst performance in shrinkage and rehydration; the crude fiber content was the highest and the total phenol content was the lowest in the solar drying group. Conclusion: Different drying methods have significant effects on the quality of A. luteo-virens, and the overall quality of vacuum-freeze drying A. luteo-virens is optimal.

Keywords

• armillaria luteo-virens
• drying
• quality
• microstructure