Use of Ultrasonic Treatment Combined with Tumbling Curing to Improve Quality Characteristics of Low-Salt Pre-prepared Sea Bass

In this study, the effects of different curing methods (static treatment, ultrasonic treatment, ultrasonic treatment combined with tumbling, vacuum tumbling and atmospheric pressure tumbling) on the textural properties, water retention and flavor quality of low-salt pre-prepared sea bass were investigated using texture analysis, scanning electron microscopy (SEM), liquid chromatography (LC) and gas chromatography-mass spectrometry (GC-MS). The results showed that tumbling alone and combined with ultrasonic treatment both significantly increased the marinade absorption rate and the mass transfer rate of sodium ion (P < 0.05), and the marinade absorption rate was 15.07% in the atmospheric pressure tumbling group, which was accompanied by reduced hardness and chewiness of fish meat. Organoleptic analysis showed that the fish treated by ultrasonic-assisted tumbling and tumbling was soft in texture, uniformly salty, and had less odor. In addition, both tumbling treatments significantly increased the total free amino acid content (P < 0.05), and the total free amino acid content was 7.395 mg/g in the atmospheric pressure tumbling group, which was about 1.24 times higher than that of the static treatment. A total of 65 volatile flavor compounds were detected across all treatment groups, among which, the contents of alcohols, esters and aromatic compounds were significantly higher (P < 0.05) in the tumbling treatment and ultrasonic-assisted tumbling groups than in the other treatment groups, suggesting that tumbling, irrespective of whether combined with ultrasonic or not, contributed to the formation of flavor substances. However, single tumbling marination showed poor water retention and water-holding capacity, and excessive tumbling might have adverse effects on fish texture. Therefore, ultrasonic-assisted tumbling was more suitable for the intensive processing of sea bass.