DSC study of hydration and water-holding behaviour of cultured in vitro mycelium and naturally grown fruiting bodies of freeze-dried Boletus badius, Agaricus bisporus and Cantharellus cibarius

The aim of the study was to calculate the content of non-freezing water (NFW) as well as amount of water associated with the evaporation process (Nev) in the chosen species of fungi. The study focused on lyophilized in vitro mycelium and commonly cultivated mushrooms Agaricus bisporus, Boletus badius and Cantharellus cibarius. Both NFW and Nev were examined by means of differential scanning calorimetry (DSC). The above-mentioned types of water are important components of the state diagram that is a kind of functional graph helping in identifying food stability during storage and selecting suitable conditions of temperature and moisture content for processing. The content of non-freezing water in all examined samples ranged between 0.19 and 0.31 g g−1. The estimated amount of water associated with the evaporation process was found to be between 0.05 and 0.13 g g−1. The obtained results were variable and highly dependent on fungus species, origin (in vitro mycelium vs cultivated) and content of accumulated metals. The influence of these factors is discussed. In order to determine statistical significance, selected samples were measured at least 5 times; the relative standard of deviation (%RSD) did not exceed 4.45 of measured enthalpies. In the group of mycelium from in vitro cultures, the DSC method was used for the first time. The publication also compared the NFW and Nev values with those obtained for naturally grown fruiting bodies of the same species.