Comparative Study of Raw and Dehydrated Boletus edulis Mushrooms by Hot Air and Centrifugal Vacuum Processes: Functional Properties and Fatty Acid and Aroma Profiles

Abstract

A study on Boletus edulis mushrooms subjected to either hot air drying (HAD) or centrifugal vacuum drying (CVD) was performed to evaluate and compare their functional properties, fatty acids, and aroma compounds. Better flowability and a higher rehydration ratio were observed for HAD powders, while enhanced indices of water solubility, emulsifying activity, and stability were noticed for CVD ones. The composition of 21 identified fatty acids varied between raw and dried samples, the most relevant being the decrease of oleic acid and the increase of linoleic acid during drying. The PUFAs/SFAs ratio was >3.3 in all samples, thus meeting the requirements for healthy lipids. Of the 15 aroma compounds identified in raw mushrooms, only hexanal, 1-octen-3-ol, and (Z)-2-octen-1-ol were also found in dried samples, to different extents; 1-octen-3-ol was the major volatile constituent in all samples. Low amounts of new alcohols, aldehydes and ketones, D-limonene, and caryophyllene were detected in HAD powders, while dimethyl disulfide and 2-n-pentyl-furan were detected in CVD ones. The drying of mushrooms resulted in a total loss of 2-methyl-2-butenal, (E)-2-octenal, and 1-octen-3-one. These findings become important milestones for food manufacturers and researchers in selecting the desired drying technique of B. edulis based on the powder/emulsifying properties and preservation of fatty acids and aroma molecules.