Table 2.
The total volatile basic nitrogen (TVB-N), thiobarbituric acid reactive substances (TBARS), carbonyl content, and total sulfhydryl content results of frozen large yellow croaker under different methods.
| Treatment | TVB-N | TBARS | Carbonyl content | Total sulfhydryl content |
|---|---|---|---|---|
| (mg N/100 g) | (10−2 mg/MDA kg) | (μmol/g protein) | (μmol/g protein) | |
| FS | 9.81 ± 0.03f | 11.67 ± 0.06 g | 2.22 ± 0.07 g | 72.02 ± 0.44a |
| IF | 10.81 ± 0.08a | 14.70 ± 0.30a | 3.01 ± 0.02a | 56.19 ± 2.58f |
| SUAF-20 | 10.62 ± 0.04b | 13.63 ± 0.35b | 2.91 ± 0.05b | 59.72 ± 1.05e |
| SUAF-28 | 10.51 ± 0.05c | 13.30 ± 0.10c | 2.88 ± 0.05b | 60.62 ± 1.36e |
| SUAF-40 | 10.47 ± 0.06c | 13.10 ± 0.17 cd | 2.83 ± 0.04bc | 61.64 ± 0.49de |
| DUAF-20/28 | 10.34 ± 0.03d | 12.83 ± 0.12de | 2.76 ± 0.06 cd | 63.15 ± 0.95 cd |
| DUAF-20/40 | 10.32 ± 0.03d | 12.73 ± 0.06e | 2.72 ± 0.03de | 64.03 ± 0.28c |
| DUAF-28/40 | 10.28 ± 0.03d | 12.37 ± 0.06f | 2.67 ± 0.04e | 64.92 ± 0.20c |
| MUAF-20/28/40 | 10.09 ± 0.05e | 12.07 ± 0.15f | 2.42 ± 0.06f | 67.13 ± 1.04b |
The methods include immersion freezing (IF), single-frequency UAF (SUAF) at 20 kHz, 28 kHz and 40 kHz, dual-frequency UAF (DUAF) at 20/28 kHz, 20/40 kHz and 28/40 kHz, multi-frequency UAF (MUAF) at 20/28/40 kHz. The letter from “a” to “g” are used to describe the significance of differences between the samples (p < 0.05).