Effects of four drying methods on Ganoderma lucidum volatile organic compounds analyzed via headspace solid-phase microextraction and comprehensive two-dimensional chromatography-time-of-flight mass spectrometry

The effect of four drying methods (namely, sun drying, vacuum freeze drying, vacuum drying, and hot air drying) on the fresh Ganoderma lucidum volatile organic compounds (VOCs) was studied by their separation via headspace solid-phase microextraction and identification via comprehensive two-dimensional chromatography-time-of-flight mass spectrometry. In total, 247 kinds of VOCs, mainly composed of alcohols, aldehydes, esters, ketones, and olefins, were identified. Orthogonal partial least squares discriminant analysis and displacement test combined with the variable important in the projection method revealed that VOCs' types and contents in Ganoderma lucidum were influenced by the particular drying method, which could be identified using specific organic compounds. The heating process increased the content of aldehydes, esters, and olefins and reduced alcohol and ketones' content. Since 3-propoxy-1-Propene, 2-pentyl-Furan, Acetic acid, 2-Butanone, 1-Pantano, and other VOCs did not disappear during the drying process, they can be used for the classification and identification of Ganoderma lucidum species and other edible fungi.