## 3 Results and Discussion
### Colour Characteristics, pH, and Mould and Yeast Count in Edible Mushrooms  
The colour characteristics and pH of the edible mushrooms are given in Table 1. Comparing the colour parameters of thermally treated and ultrasonicated unfermented mushrooms of the same species, thermally treated _B. edulis_ samples, showed higher redness (a*) and yellowness (b*) than those of ultrasonicated samples (13.9% and 8.8% higher, respectively). However, higher coordinates of lightness (L*) were found for the ultrasonicated _B. edulis_ and _R. caperata_ samples than for thermally treated samples (1.92% and 15.5% higher, respectively). Ultrasonicated _Cantharellus_ and _R. caperata_ samples showed higher a* and b* coordinates than those of thermally treated samples of the same species (a*- 53.9% and 40.6% higher, respectively; b*--30.6% and 29.3% higher, respectively). There were no significant differences in the pH of thermally treated and ultrasonicated unfermented mushrooms of the same species; the highest pH was found in _Cantharellus_ mushrooms (on average, 18.5% higher than in _B. edulis_ and _R. caperata_). Comparing the colour coordinates of thermally treated and ultrasonicated fermented mushrooms, ultrasonicated fermented _B. edulis_ and _R. caperata_ showed higher L*, and ultrasonicated fermented _Cantharellus_ and _R. caperata_ showed higher a* and b* coordinates than those of thermally treated and fermented samples of the same species (L*--3.13% and 7.20%, a*--11.3% and 4.26%, b*--4.39% and 3.71% higher, respectively). While comparing the pH of thermally treated and ultrasonicated fermented samples, a significantly lower pH was found in  
Figure 4: Images of edible mushrooms fermented for 7 days with _L. uvarum_ LUHS245 (BE—_Boletus edulis_; Ca—_Cantharellus_; Ro—_Rozites capenta_). thermally treated and fermented _R. capenta_ samples than in ultrasonicated and fermented ones. However, no significant differences were established between other mushroom samples. Multivariate analysis of variance showed that mushroom species, thermal treatment and/or ultrasonication, and the interaction of these factors had a significant effect on the samples' colour coordinates and pH (\(p\leq 0.0001\)). In comparing the mould and yeast count in thermally treated and ultrasonicated unfermed mushrooms of the same species, a significantly lower mould and yeast count was found in thermally treated unfermed _R. capenta_ samples; however, no significant differences were established between thermally treated and ultrasonicated fermented mushroom samples of the same species. When comparing thermally treated and ultrasonicated mushrooms with fresh samples, a lower mould and yeast count were established in treated samples in all cases, and a significant moderate positive correlation (r = 0.6430, \(p\) = 0.0001) was found between the samples' pH and mould and yeast count. The colour of mushrooms is one of the most important indicators of their quality, affecting consumers' purchase intentions. The darkening of the mushroom surface is mainly related to microbial contamination, enzymatic activity, or mechanical injuries [26]. Lactic acid fermentation influences the colour of mushrooms, and this is mainly related to pre-treatment procedures such as blanching [6]. According to [PERSON] et al. [27], the stabilisation of the L* value and the reduction in the a* value could be observed during the LAB fermentation of mushrooms, while the b* value increases at every stage of this technological process (washing, blanching, and fermentation). [PERSON] et al.