Effect of Ultrasound and Cellulase Pre-treatment on the Water Distribution, Physical Properties, and Nutritional Components of Lentinula edodes Chips

This study aimed to understand the effect of ultrasound pre-treatment (UP), cellulase pre-treatment (CP) and their combination (UP+CP) pre-treatments on freeze-dried Lentinula edodes chips. The water distribution, microstructure, physical properties (colour, texture and shrinkage) and the main nutritional components (polysaccharides, protein and phenolic compounds) were investigated. The low-field nuclear magnetic resonance spectroscopy results showed that UP+CP improved the water mobility and level in mushroom slices. The chips subjected to UP+CP were found to have no free water. In addition, compared with other pre-treatment, UP+CP chips achieved better physical properties, which were characterized by the texture, colour and pore structures. All these attributors could contribute to a rapidly water transfer and improve the crisp characteristics. However, no significant difference was found in three pre-treatment products in polysaccharide and protein contents, though UP+CP products obtained higher phenolic content. Overall, the application of UP+CP was a potential pre-treatment approach for improving the quality of mushroom chips.