Effect of particle size on the physicochemical and morphological properties of Hypsizygus marmoreus mushroom powder and its hot-water extracts

Abstract

Hypsizygus marmoreus, an edible mushroom with various functional properties, was prepared to obtain coarse and superfine powders. We evaluated the effect of particle size on mushroom powder quality. The water absorption index and total dietary fiber contents of superfine powders (average median diameter, 4.791 μm) were 5.79 g/g and 28.50 g/100 g, respectively, which were higher than the corresponding values of coarse powder (average median diameter, 168.085 μm). Similarly, extracts prepared from the superfine mushroom powders exhibited higher total polyphenolics contents (83.91 mgGAE/100 g), total sugar contents (5,138.50 mg/100 g), and total flavonoid contents (43.99 mgNE/100 g) compared with those prepared from coarse mushroom powders. The extraction yield and pH were higher for superfine powder concentrates than for coarse powder concentrates. According to the electronic tongue results, superfine powder extracts had high scores for umami, sourness, and sweetness, while coarse powder extracts scored high in bitterness. Furthermore, SEM images indicated that both powders differed in either the shape or size of the particles; coarse powder particles exhibited irregular shapes and high porosity, while superfine powder particles represented a uniform shape and lower porosity. Particle size reduction through superfine grinding improved the physicochemical and morphological properties of the mushroom powder samples and their hot-water extracts.