Identification of Volatile Odor Compounds in Extracts of Four Types of Herbaceous Plant Spices via GC × GC–O-TOF MS

Abstract

To conduct an in-depth exploration of the unique flavors of herbal spices, four spice extracts—sour horn, alfalfa, chicory, and fenugreek—were selected for this study. All four extracts have a long history of use in traditional food applications. In this study, volatile compounds and key odor-active components in the four herbal spice extracts were analyzed using sensory evaluation, electronic nose (E-nose), solid-phase microextraction (SPME), and comprehensive two-dimensional gas chromatography-olfactometry-time-of-flight mass spectrometry (GC×GC-O-TOF MS). The results indicated that the sour horn, alfalfa, chicory, and fenugreek extracts all exhibited flavor profiles characterized by sourness, sweetness, and medicinal notes. A total of 116 volatile odor compounds were identified in the sour horn extract (SHE), 181 in the alfalfa extract (AE), 224 in the chicory extract (CE), and 119 in the fenugreek extract (FE). Across all four herbal spice extracts, 59 odor-active components were collectively detected. Furthermore, the number of substances with rOAV ≥ 1 was determined to be 11 in the SHE, 16 in the AE, 27 in the CE, and 18 in the FE, respectively. This study investigated the odor components of four herbal spices, which will facilitate further in-depth research on spice extracts in the future.