Influence of Different Drying Techniques on Selected Physicochemical and Bioactive Properties of Mushroom Powders

In the present study, the effect of different drying techniques on the mushroom powders were comparatively investigated. Mushroom purees were dried by refractance window drying (RW), oven drying (OD), vacuum drying (VD) and freeze drying (FD) techniques both in their original form and as foams. For foam mat drying (FM) experiments the puree samples were foamed with carboxymethyl cellulose (CMC) and whey protein (WP) with the ratio (1:1) that formed the maximum stable foam. The dried mushrooms were ground to obtain mushroom powder. Some chemical and physical properties of the mushroom powders were determined. Total phenolics content (TPC) of the mushroom powders were determined in the ranges of 0.545-1.293 g GAE 100 g-1 dry matter (dm). The highest TPC was determined for the sample dried by VD while the lowest TPC was determined for the sample dried by FM-FD. The L*, chroma and hue angle values of the samples obtained from the FM experiments were higher than those obtained from the three different drying methods (OD, RW and VD) directly applied to the mushroom purees. It was determined that the browning index of the samples especially those subjected to FM was significantly lower than that of the other samples (OD, RW and VD). The study reveals that the FM method generally reduced the drying time in all drying techniques.