Volatile Odor Compounds by HS-SPME-GC-MS and Nutritional Composition of Hybrid Sturgeon (Acipenser baerii ♀ × Acipenser schrenckii ♂) Back Muscle: Freshwater vs. Seawater Cultivation

While the sturgeon farming industry is renowned for its valuable caviar, sturgeon muscle tissue remains an underutilized byproduct. The present investigation evaluated the physiological profiles and meat quality attributes of hybrid sturgeon (<i>Acipenser baerii</i> ♀ × <i>Acipenser schrenckii</i> ♂) cultivated in freshwater (FW) and seawater (SW) in terms of conventional nutritional components, color, amino acid, texture, fatty acid, as well as volatile flavor substances. Results revealed that the SW group demonstrated significantly higher muscle whiteness and hardness. The SW group showed significantly higher contents of crude protein, eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA), n-3 polyunsaturated fatty acids (<i>p</i> < 0.01). Although there was no significant difference in the total hydrolyzed amino acids between the SW and FW groups (<i>p</i> > 0.05), the SW group exhibited significantly higher levels of umami free amino acids, such as glutamic acid and aspartic acid (<i>p</i> < 0.01). Flavor profiling indicated that the SW group exhibited lower levels of several off-flavor compounds, including 1-octen-3-ol, (E,E)-2,4-decadienal, and 3,5-octadien-2-one. Notably, the contents of geosmin (GSM) and 2-methylisoborneol (2-MIB), responsible for earthy off-flavors, were significantly lower in the SW group (<i>p</i> < 0.05). Overall, seawater-cultured hybrid sturgeons offer superior nutritional value and sensory characteristics compared to their freshwater counterparts. These findings provide important scientific insights for enhancing the value-added processing of sturgeon products and the sustainable development of the aquaculture industry.