Abstract: Pre-packaged fish bone soup offers a novel approach for the high-value utilization of tilapia (Oreochromis niloticus) processing by-products such as fish bones. This study investigated the effects of two reheating methods (boiling and microwave) on the flavor and taste characteristics of laboratory-developed pre-packaged tilapia fish bone soup before and after frozen storage (days 0 and 15) using gas chromatography-ion mobility spectrometry (GC-IMS), an electronic nose, and an electronic tongue. The electronic nose and electronic tongue results indicated that the microwave-treated fish soup group exhibited the highest richness response values, with the strongest sensor responses observed for methyl compounds, aldehydes, alcohols/ketones, and hydrogenated compounds, confirming that its flavor characteristics were maintained at a high level. GC-IMS analysis indicated that reheating after freezing significantly reduced the contents of certain odor-active compounds in the fish soup samples. Among the reheated fresh fish soup samples, microwave reheating resulted in the most pronounced flavor profile. Specifically, the signal intensity of 3-methyl-1-butanol increased to 0.016 mg/kg, while the ethanol content decreased significantly to 1.33 mg/kg. The ester content notably increased to 0.52 mg/kg, and the acid content was significantly lower than in the boiling treatment group. In conclusion, microwave reheating is conducive to better flavor retention of tilapia fish bone soup packets. This research provides a scientific basis for the high-value utilization of tilapia processing by-products and offers theoretical insights for flavor regulation and the processing of pre-prepared soup products.

Key words: tilapia bone soup; pre-packaged soup pouches; storage; reheating; flavor; gas chromatography-ion mobility spectrometry; electronic nose; electronic tongue