Effect of different hot air drying process on flavor compounds and Maillard reaction products of Boletus edulis by HS-SPME/GC-MS coupled with multivariate analysis

The heat treatment has significant effect on the sensory and flavor quality of Boletus edulis product. We evaluated the sensory properties and volatile flavor compounds (VFCs) of six dried Boletus edulis products subjected to different heat treatment temperatures, as well as the correlation of VFCs with Maillard reaction products. The color of the dried samples turned brown as the drying temperature increased, and the content of seventeen free amino acids (FAAs) and five monosaccharides decreased simultaneously. When compared to vacuum drying methods, the content of Arg and Glu reduced significantly, reaching its lowest point at 100°C. Sixty VFCs were identified by HS-SPME/GC-MS, and the contents of aldehydes, ketones, sulfur-containing compounds, nitrogen-containing compounds increased with heat treatments. Furthermore, the content changes of 17 FAAs, 5 monosaccharides and VFCs related to Maillard reaction were further analyzed, which allowed us to speculate on the formation mechanism of VFCs through the Maillard reaction at high drying temperatures. These findings not only provide valuable insights into understanding the sensory and flavor characteristics of Boletus edulis products, but also offer theoretical support for the dehydration of Boletus edulis and other similar heat sensitive edible mushroom products.