Detection and analysis of VOCs in chili pepper based on HS-SPME-GC × GC-TOFMS and HS-SPME-GC-MS techniques

Chili pepper (Capsicum annuum L.) is highly preferred by consumers owing to its distinctive flavor. Volatile organic compounds (VOCs) significantly influences the aromatic characteristics of chili peppers, thereby impacting their overall fruit quality. The study of chili pepper aroma remains at a nascent stage, with a notable gap in the literature regarding the composition and metabolic regulation of volatile flavor compounds in fresh chili peppers. This study focuses on the pepper cultivar var 'Qujiao 5' with rich fruit aroma, using headspace solid-phase microextraction full two-dimensional gas chromatography time of flight mass spectrometry (HS-SPME-GC × GC-TOFMS) and headspace solid-phase microextraction gas chromatography-mass spectrometry (HS-SPME-GC-MS) detection technology platforms to analyze the VOCs present in green ripe pepper. A total of 1,558 VOCs were successfully identified. Utilizing the HS-SPME-GC × GC-TOFMS method pinpointed 933 substances, whereas the HS-SPME-GC-MS approach detected 773 compounds. Moreover, the two methods together identified 150 substances. Through the meticulous analysis of relative odor activity values (ROAV), it was conclusively determined that Pyrazine, 2-methoxy-3-(2-methylpropyl)- and 2-Nonenal, (E)- serve as pivotal volatile flavor compounds in chili fruit. Through the analysis of sensory flavor characteristics of chili peppers, it was found that fresh chili peppers have the main aroma characteristics of fatty, green bell pepper, and green, while also possessing modified odors such as floral and sweet. This research undertook a thorough comparative analysis of two different detection methods. It also meticulously examined the compositional and sensory attributes of the pepper VOCs, providing an essential reference for subsequent studies on the development of pepper fruit flavor quality.