Effects of Dry-, Wet- and Freeze-grinding Pretreatment Methods on the Physicochemical Properties of Maitake Mushroom (Grifola frondosa) Superfine Powders

摘要

The dendritic caps and stipes of maitake mushrooms (Grifola frondosa) were pretreated by dry-, wet-, or freeze-grinding followed by jet milling to produce superfine powders. The effects of the pretreatment grinding conditions on the physicochemical properties of these powders were investigated. Compared to the dry and wet processes, the freeze-grinding pretreatment effectively reduced particle sizes (cap, 6.75 μm; stipe, 5.76 &mum) and produced narrow and uniform particle size distributions. For cap or stipe, For the same material (cap or stipe), powders from the freeze-grinding pretreatment exhibited higher values of specific surface area, bulk density, water holding capacity, but worse color values than the dry- and wet-ground powders. For the same grinding pretreatment method, cap powders exhibited higher values for the water solubility index and mobility than stipe powders. For the same environmental humidity, the Halsey model showed the best goodness-of-fit for the moisture sorption isotherms of the superfine powders.