Objective Flavor and nutrition of the broth of poached croaker steaks were improved by adding NaHCO₃ in preparation.

Method Sensory qualities, broth opacity, and E-tongue detection were used as indicators in a single-factor experiment to optimize the preparation including fish frying temperature and time, simmering duration, and glucose usage for the poached steaks of large yellow croaker (Larimichthys crocea). Then, up to 0.04% of NaHCO₃ was added to achieve the optimal pH, Maillard reaction, and contents of soluble protein, amino acid (AA) nitrogen, fat, free AAs, and umami nucleotides in the broth.

Result The fish steaks were firstly fried in oil at 180°C for 120s, then poached in water containing 0.4% of glucose and 0.03% or 0% (CK) of NaHCO₃ for 2h. The soluble protein and AA nitrogen in the broth increased significantly over CK by 0.42g·100g⁻¹ and 5.49mg·100g⁻¹, respectively, and the fat decreased significantly by 0.69g·100g⁻¹ (P＜0.05) with the alkali addition; the total free AAs, including the Maillard reaction-related glutamic acid and lysine, declined significantly (P＜0.05); and the total umami nucleotides rose slightly but with significantly increased AMP and IMP (P＜0.05). The sensory score on the broth of the NaHCO₃-added fish steaks was significantly improved from the Maillard reaction-generated roast aroma.

Conclusion The addition of NaHCO₃ at 0.03% significantly promoted the protein dissolution, reduced the fat content, and enhanced the flavor through Maillard reaction and umami compounds in the poached croaker steaks. It seemed to be a plausible means to apply in a processed similar fish product.