REGULATION OF STRUCTURAL AND MECHANICAL PROPERTIES OF SHIITAKE MUSHROOM SUSPENSION AS AN OBJECT OF DRYING

Abstract

The article considers whether a shiitake basidiomycete can be processed into powder. This mushroom is a source of valuable nutrients: it contains, on a dry basis, 18.76% of protein, 74.5% of carbohydrates, 1% of lipids, and 5.73% of ash. It has been determined that to obtain a uniform mushroom suspension, it is advisable to use the mechanisms of discrete-pulse energy input, which is an effective tool to influence the high-strength structural elements of heterogeneous systems of different nature. It has been determined that the mechanostructural properties of a mushroom suspension as an object of spray drying need to be changed. Studies of the microstructure have shown that in a suspension obtained from a whole fruiting body, particles of the insoluble fractions of a shiitake mushroom aggregate into chaotic clusters. These are spatial associates up to 3–4 mm in size, with individual hyphae of their caps or their fragments that are significantly shorter (10–15 μm) than the hyphae of the stems (50–5000 µm). The three-cycle processing of the suspension obtained from a whole mushroom by discrete-pulse energy input led to a decrease in the average particle size by 2.3 times. The same processing of the mushroom suspension obtained from the shiitake caps made it possible to reduce the average particle size by 20 times (to δmax≤100–150 μm). Microstructural analysis of the powder obtained from the whole fruiting body of the mushroom has shown that while the size of the particles generally ranges 4–120 µm, the bulk of them (80–85%) are quite large agglomerates, 40–120 µm in size. The powder obtained from the caps of the mushroom had smaller particles (ranging 4–60 µm), mostly round-shaped, and 75–80% of these particles were 4–20 µm in size. This improved its drying conditions and increased the yield from the spray dryer up to 92% (while the yield of powder prepared from the whole shiitake mushroom was less than 50%). The complex of studies carried out has shown the advantages of obtaining a mushroom suspension from the caps of shiitake mushrooms. The use of mechanisms of discrete-pulse energy input allows a 6-fold increase in the bioavailable health-improving polysaccharide complex contained in the powder from shiitake caps, as compared with the powder obtained from mushroom’s whole fresh fruiting body.