Changes in the Volatile Flavor Compounds and Quality Attributes of Tilapia Fillets Throughout the Drying Process

The rising popularity of ready-to-eat self-heating sauerkraut fish necessitates a meticulous production process to ensure high-quality products. This study investigated the impact of processing stages on the quality of ready-to-eat tilapia fillets. The results showed that lipid oxidation, protein degradation, pH levels, and TBA concentrations increased during processing. GC-IMS analysis revealed 56 volatile compounds in tilapia fillets, with distinct compositions at different processing stages. The flavor profiles of tilapia fillets underwent significant changes during blanching and rehydration. The levels of aldehydes and alcohols notably increased, with the blanching group exhibiting the highest concentration of aldehydes, particularly saturated linear aldehydes such as hexanal, nonanal, octanal, and benzaldehyde, which play key roles in enhancing fish flavor. Conversely, the proportion of ketones decreased following heat treatment, which is a crucial factor in mitigating undesirable fishy odors. Therefore, the optimal method for preparing ready-to-eat tilapia fillets was salting pretreatment (1.5% salt and 3% propylene glycol) at 4 °C for 1 h, blanching at 100 °C for 1 min, pre-freezing at -40 °C for 12 h, and vacuum freeze-drying at -40 °C under 20 Pa for 18 h. Finally, the dried fish fillets were vacuum-sealed for storage. Principal Component Analysis (PCA) revealed that the combined variance explained by the first two principal components post-dimensionality reduction was 95%, serving as a primary indicator of the volatile flavor profile of the fish. The dried fillets were thoroughly verified using sensory evaluation. This specific formulation garnered the highest scores in sensory evaluations, resulting in superior aroma, color, and texture attributes for the self-heating fish product. The findings of this study offer a foundational framework for developing ready-to-eat tilapia fillets and other convenient food products in the future.