Effects of multi-frequency ultrasound-assisted immersion freezing processing on myofibrillar protein structure and lipid oxidation of large yellow croaker (Larimichthys crocea) during long-time frozen storage

Abstract

In this study, large yellow croaker (Larimichthys crocea) was frozen using multi-frequency ultrasound-assisted freezing (MUIF) with different powers (160 W, 175 W, and 190 W, respectively) and stored at -18 °C for ten months. The effect of different ultrasound powers on the myofibrillar protein (MP) structures and lipid oxidation of large yellow croaker was investigated. The results showed that MUIF significantly slowed down the oxidation of MP by inhibiting carbonyl formation and maintaining high sulfhydryl contents. These treatments also held a high activity of Ca²⁺-ATPase in the MP. MUIF maintained a higher ratio of α-helix to β-sheet during frozen storage, thereby protecting the secondary structure of the tissue and stabilizing the tertiary structure. In addition, MUIF inhibited the production of thiobarbituric acid reactive substances value and the loss of unsaturated fatty acid content, indicating that MUIF could better inhibit lipid oxidation of large yellow croaker during long-time frozen storage.

Keywords: Frozen storage; Large yellow croaker; Lipid oxidation; Multi-frequency ultrasound; Myofibrillar protein.

Fig. 1

Schematic of the ultrasound-assisted immersion freezing apparatus.

Fig. 2

Average (±standard deviation) of total sulfhydryl contents (A), carbonyl content (B) and Ca²⁺-ATPase activity (C) of large yellow croaker samples during frozen storage (IF: immersion freezing; UIF: ultrasound-assisted immersion freezing at different ultrasound powers). Letters are used “a” to “e” significance differences between the samples (p < 0.05, n = 3). (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)

Fig. 3

Freezing curves of large yellow croaker with different freezing treatments (Ma et al., 2022). (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)

Fig. 4

Secondary structure (A, B), fluorescence intensity (FI, C, D) of large yellow croaker samples during frozen storage (IF: immersion freezing; UIF: ultrasound-assisted immersion freezing at different ultrasound powers). (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)

Fig. 5

Average TBARS of myofibrillar proteins of large yellow croaker muscles during frozen storage (IF: immersion freezing; UIF: ultrasound-assisted immersion freezing at different ultrasound powers). Letters are used “a” to “c” significance differences between the samples (p < 0.05, n = 3). (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)

Fig. 6

Schematic mechanism of the effects of the MUIF on lipid and protein of large yellow croaker during frozen storage. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)