## 3 Results and Discussion
### Basic Properties of Cookies
The discussed parameter of the samples ranged from 8.80 (for the Po6 sample) to 9.59 (for the Po2 sample), however, no significant (_p_ < 0.05) differences were noted between the results. [PERSON] et al. [22] reported that using dried _C. militaria_ in amounts of 1%, 3%, and 5% instead of wheat flour, the supplemented cookies had similar diameter, thickness, and spread ratio compared with the control cookies, but the weights of cookies with 3% or 5% mushrooms were significantly lower than the control cookies. [PERSON] et al. [6] write that the addition of _Calocye indica_ in an amount of 5-20% to the cookies had no significant effect on the weight. However, it was found that with the increase in the mushroom powder content, the thickness increased significantly, while opposite tendencies were observed for the diameter and spread factor. The addition of _A. bisporus_ to barley flour cookies in an amount from 10% to 50% resulted in significant increases in diameter and weight of samples, with 20% or more addition of mushroom flour producing a decrease in the thickness value and spread ratio; however, no significant difference was found for these two parameters (_p_ < 0.05) [72]. The results regarding water activity (a\({}_{\mathrm{w}}\)) are presented in Table 6. This parameter corresponded to moisture content (Table 1). The highest a\({}_{\mathrm{w}}\) values were noted for the control sample (a\({}_{\mathrm{w}}\) = 0.513) and cookies with 2% _A. bisporus_ (a\({}_{\mathrm{w}}\) = 0.482), and the lowest for cookies with 4% _P. ostreatus_ powder (a\({}_{\mathrm{w}}\) = 0.404); however, an increasing tendency was observed for cookies with 4% and 6% mushroom. Water activity and moisture content are crucial in the determination of the quality, acceptability, and storage stability of bakery products with high content of sugar and fat. Typical cookies have low water activity and low final moisture content (1-5%), which guarantees a long shelf life [27; 104]. Food with a\({}_{\mathrm{w}}\) below 0.6 is considered microbiologically stable. However, a drop in a\({}_{\mathrm{w}}\) below 0.2 results in accelerated fat oxidation reactions [104]. [PERSON] et al. [72] reported that cookies based on barley flour were characterized by comparatively low a\({}_{\mathrm{w}}\) value (0.402) and moisture content (3.81%), while cookies in which 10% to 50% of barley flour was replaced with _A. bisporus_ powder were characterized by significantly higher water activity and moisture content. Substitution of wheat flour with _C. militaria_ powder from 1% to 5% resulted in a slight increase in moisture content, from 6.45% for control cookies to 6.70% for cookies with 5% _C. militaria_ flour, but no significant differences were found for this parameter [22]. In turn, [PERSON] et al. [6] reported that wheat cookies supplemented with _C. indica_ (from 5% to 20%) had moisture content ranging from 5.5% to 4.8%, with the highest moisture content in control cookies (5.5%). The hardness of the control samples was 569.78 g (Table 6). In turn, the value of this parameter for cookies enriched with mushrooms ranged from 564.94 g for cookies with the addition of 2% button mushroom lyophiliste to 894.01 g for cookies with the addition of 6% _P. ostreatus_ powder. Replacing 4% or 6% base flour with mushroom lyophiliste resulted in an increase in the hardness of the cookies, but significantly (_p_ < 0.05) higher values compared with the control sample were recorded only for cookies with 6% addition of mushroom lyophilistes. The influence of the addition of mushroom flours to base flours on the hardness of cookies has been analyzed by other researchers. [PERSON] et al. [72] reported that a decrease was recorded in the hardness of barley cookies enriched with _A. bisporus_ lyophiliste in an amount of 10-50%.