Processing technology, antioxidant ability and flavor characteristics of hybrid crucian carp soup

• Optimal cooking gave WR2 soup superior sensory quality and balanced flavor. • WR2 soup showed the strongest antioxidant and lipase inhibition among tested fish. • 201 proteins and 61 volatiles reveal rich nutrition and unique flavor profile. Crucian carp ( Carassius auratus ) soup is a traditional Chinese functional food known for health benefits. Hefang crucian carp 2 (WR2) is a newly bred hybrid with enhanced nutritional value. In this study, WR2 soup processing was optimized using single-factor and response surface methods. The best conditions—a 1:5.46 solid-to-liquid ratio, 1.12 h boiling time, and 0.71% salt—produced superior sensory quality. Compared with soups from hybrid crucian carp ( Carassius carassius ) × common carp ( Cyprinus carpio ) (CC), Micropterus salmoides (LMB) and Megalobrama amblycephala (BSB), WR2 soup exhibits the highest DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging activity, hydroxyl radical scavenging activity, total reducing power and ABTS 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radical scavenging activity. Proteomic analysis identified 201 proteins mainly related to metabolism and immune function, highlighting its nutritional potential. Additionally, 61 volatile compounds, including aldehydes, ketones and alcohols create a complex fragrance with fresh fruity notes and rich milk flavors coexisting, contributed to its rich, distinctive flavor. These results demonstrate that WR2 fish soup inherits the traditional health benefits of crucian carp while offering superior nutritional and functional characteristics, supporting its development as a high-value product in the aquatic food industry.