Microstructural characteristics of turbot (Scophthalmus maximus) muscle: effect of salting and processing

Figures & data

Figure 1. Effect of salt on WHC of turbot (mean ± SD, n = 4). *Different letters indicate significant differences (p < 0.05) between treatments.

Figure 2. Effect of salt on hardness of turbot (mean ± SD, n = 4). *Different letters indicate significant differences (p < 0.05) between treatments.

Figure 3. Effect of salt on elasticity of turbot (mean ± SD, n = 4). *Different letters indicate significant differences (p < 0.05) between treatments.

Table 1. NMR parameters obtained from different treatments with turbot.

Sample	T21 (ms)	T22 (ms)	T23 (ms)	A21(1/g)	A22(1/g)	A23(1/g)	ATotal (1/g)
Fresh turbot	2.01 ± 0.00^d	57.22 ± 0.00^a	1497.45 ± 229.15^b	113.39 ± 3.67^b	7118.99 ± 46.71^d	24.77 ± 2.11^a	7257.14 ± 45.68^d
1% Salted turbot	2.43 ± 0.20^e	65.79 ± 0.00^a	811.13 ± 0.00^a	132.07 ± 2.68^c	8103.23 ± 59.76^e	202.62 ± 0.62^e	8437.92 ± 61.57^e
5% Salted turbot	1.67 ± 0.13^c	91.32 ± 7.52^b	979.16 ± 80.64^a	118.95 ± 10.34^b	5727.56 ± 250.38^b	29.43 ± 2.80^b	5875.95 ± 241.20^b
10% Salted turbot	1.32 ± 0.00^b	95.66 ± 7.52^b	1072.27 ± 0.00^a	74.53 ± 3.63^a	5479.69 ± 27.34^a	27.84 ± 1.34^ab	5582.06 ± 26.98^a
15% Salted turbot	1.00 ± 0.00^a	100.65 ± 14.01^b	892.11 ± 70.13^a	110.81 ± 7.15^b	5823.94 ± 33.21^b	52.05 ± 0.95^d	5986.81 ± 39.72^b
20% Salted turbot	1.45 ± 0.11^b	95.66 ± 7.52^b	1025.71 ± 80.64^a	74.45 ± 9.53^a	6685.76 ± 52.25^c	34.36 ± 1.65^c	6794.57 ± 46.76^c

*Different letters in a column indicate significant differences (p < 0.05) within each treatment (ANOVA).

Each value is expressed as means ± S.D. (n = 3).

Values in the same row followed by different superscript letters are significantly different (p < 0.05).

Figure 4. T₂ relaxation spectra for turbot during different concentrations of salting.

Figure 5. Effect of salt on the longitudinal section muscle of turbot.

Table 2. Least-square means of histological variables as affected by salt concentration.

	Treatments (salt concentration, % w/w)
	Fresh	1%	5%	10%	15%	20%
Area (μm^2)	3248.6 ± 78.0^a	4418.0 ± 777.6^ab	5476.5 ± 756^b	5503.7 ± 549.9^b	4280.2 ± 87.2^a	3731.2 ± 27.4^a
Diameter (μm)	40.1 ± 0.2^a	46.4 ± 5.2^ab	54.1 ± 4.0^b	48.9 ± 1.6a^b	43.6 ± 4.1^a	40.7 ± 4.7^a
Porosity (%)	31.3 ± 1.3^a	35.4 ± 5.3^ab	43.6 ± 2.8^c	40.1 ± 1.6^bc	50.8 ± 2.6^d	46.6 ± 2.9^cd

*Different letters in a column indicate significant differences (p < 0.05) within each treatment (ANOVA).

Each value is expressed as means ± S.D. (n = 3).

Values in the same row followed by different superscript letters are significantly different (p < 0.05).

Table 3. The correlation analysis of low-field NMR, WHC, TPA, and histology microstructure data.

	The correlation between indexes
	WHC	Area	Porosity	Diameter	T21	T22	T23	A21	A22	A23	ATotal	Hardness	Elasticity
WHC	1.000	−0.151	−0.803	−0.043	0.909	−0.879	0.207	0.714	0.736	0.585	0.746	−0.859	−0.777
Area		1.000	0.142	0.644	−0.249	0.431	−0.419	−0.102	−0.512	−0.026	−0.485	−0.115	−0.104
Porosity			1.000	0.149	−0.738	0.753	−0.487	−0.291	−0.577	−0.273	−0.566	0.769	0.472
Diameter				1.000	−0.036	0.337	−0.370	0.223	−0.384	0.039	−0.354	−0.263	−0.376
T21					1.000	−0.821	0.124	0.578	0.830	0.655	0.836	−0.696	−0.612
T22						1.000	−0.422	−0.488	−0.726	−0.395	−0.719	0.712	0.566
T23							1.000	−0.148	0.021	−0.511	−0.016	−0.275	−0.054
A21								1.000	0.462	0.566	0.494	−0.646	−0.746
A22									1.000	0.747	0.999	−0.354	−0.362
A23										1.000	0.779	−0.337	−0.400
ATotal											1.000	−0.369	−0.384
Hardness												1.000	0.835
Elasticity													1.000

Figure 6. Results of the PCA—score plots in the PC1 vs. PC2 plane for all samples tested.