Comparative Analysis of Volatile Organic Compounds in Freshwater-Cultured and Saline–Alkaline Selectively Bred Tilapia Using Electronic Nose, GC-IMS, and HS-SPME-GC-MS

Tilapia is a cornerstone species in global aquaculture, yet the impact of saline-alkaline adaptive breeding on its flavor-related volatile organic compounds (VOCs) remains unclear. Herein, we compared VOCs in freshwater-cultured tilapia (FW) and 7th-generation tilapia subjected to long-term selective breeding for saline-alkaline tolerance (SAWG7) using an electronic nose (E-nose), gas chromatography-ion mobility spectrometry (GC-IMS), and headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS). The aim was to identify flavor differentiation and assess the effect of saline-alkaline acclimation. E-nose analysis revealed distinct odor profiles, with SAWG7 showing higher sensor responses for aldehydes, ketones, and alcohols. GC-IMS detected 32 VOCs, highlighting significant increases in alcohols, aldehydes, and heterocyclics in SAWG7. GC-MS identified 43 VOCs, with orthogonal partial least-squares discriminant analysis (OPLS-DA) confirming 18 discriminant compounds, including elevated ketones (2-undecanone), aldehydes ((E)-2-octenal), alcohols (2,7-Octadien-1-ol), and furans (2-ethyl-Furan) in SAWG7, linked to lipid oxidation under saline-alkaline stress. These findings demonstrate that long-term saline-alkaline breeding achieves a potentially more diverse VOC profile in tilapia by altering its volatile profiles. The study provides insights for optimizing aquaculture practices to improve product quality in marginal environments.