Abstract: In order to investigate the processing suitability of Agaricus bisporus, coarse (passing through a 60-mesh sieve) and superfine (passing through a 300-mesh sieve) powders were prepared from the mushroom after dried by hot air drying (HAD), heat pump drying (HPD) or vacuum freeze drying (VFD) and were used to evaluate the effect of different drying methods and grinding degrees on the physicochemical, nutritional and functional properties of A. bisporus. The results showed that among the three drying methods, VFD dried sample had the smallest color difference, lowest browning degree, highest rehydration and hydration capacity, highest tap density and largest dissolution of polysaccharides, soluble protein, and total triterpenoids, indicating the best overall quality. The overall quality of HAD dried sample was the worst. The dissolution of ergosterol from HPD dried sample was the highest, and its overall sensory quality was between that of VFD and HAD dried samples. Compared to coarse powder, superfine powder showed a smaller particle size, a larger tap density, better water solubility, higher dissolution of nutritional and functional components, stronger antioxidant activity, and lower water retention capacity and swelling degree. In general, VFD is the most effective in maintaining the eating quality of A. bisporus, which is more suitable for the production of high value-added products. The eating quality of HPD dried mushroom is much superior to that of HAD dried mushroom, and HPD requires low energy consumption and is a better choice for the industrial dehydration of A. bisporus. Additionally, superfine grinding can significantly decrease the particle size of A. bisporus powder and improve its water solubility, antioxidant activity and nutrient dissolubility, which can be used as a pre-treatment method for the development of functional foods based on A. bisporus.

Key words: Agaricus bisporus; vacuum freeze-drying; hot air drying; heat pump drying; superfine grinding