Textural and physicochemical properties of surimi gels prepared with potassium and calcium chloride as substitutes for sodium chloride

Figures & data

Table 1. Salt substitutes (%) in surimi gels with, respectively, equivalent ionic strength (IS).

	Sodium chloride		Potassium chloride		Calcium chloride
Treatment	IS	%	IS	%	IS	%
A1	0.51	3.00
A2	0.34	2.00
A3	0.17	1.00
B1			0.51	3.82
B2			0.34	2.55
B3			0.17	1.27
C1					0.51	1.89
C2					0.34	1.27
C3					0.17	0.63

Table 2. Texture profile analysis (TPA) of surimi gels.

Treatment	Hardness (N)	Springiness	Gumminess	Chewiness (N*mm)			Resilience
A1	2742.37 ± 99.12^ab	0.93 ± 0.02^a	2069.24 ± 95.86^ab		1935.93 ± 81.63^ab	0.43 ± 0.01^ac
A2	2853.66 ± 111.03^ab	0.94 ± 0.01^a	2112.28 ± 80.37^ab		1961.55 ± 60.23^ab	0.42 ± 0.01^b
A3	3184.90 ± 281.85^b	0.93 ± 0.01^a	2278.92 ± 190.11^b		2126.81 ± 154.32^b	0.39 ± 0.01^a
B1	2722.09 ± 61.71^ab	0.93 ± 0.01^a	1976.03 ± 48.59^a		1829.92 ± 42.68^a	0.40 ± 0.01^ac
B2	2900.67 ± 148.03^ab	0.93 ± 0.01^a	2094.85 ± 98.42^ab		1951.66 ± 89.82^ab	0.40 ± 0.01^ac
B3	2900.45 ± 429.18^ab	0.92 ± 0.01^a	2149.72 ± 244.52^ab		1921.42 ± 321.39^ab	0.41 ± 0.02^ac
C1	3838.67 ± 522.56^c	0.89 ± 0.01^b	2726.10 ± 325.20^c		2421.81 ± 280.02^c	0.33 ± 0.01^d
C2	3931.39 ± 226.43^c	0.89 ± 0.01^b	2331.17 ± 128.55^b		2077.29 ± 116.35^ab	0.28 ± 0.02^e
C3	1273.47 ± 127.07^d	0.89 ± 0.02^b	517.03 ± 25.36^d		466.70 ± 29.92^d	0.14 ± 0.01^f

Values are mean±standard error (SD). Different parameter superscripts (a–f) in the same row indicate significant differences (p < 0.05) according to Duncan’s test. A1, A2, and A3; B1, B2, and B3; C1, C2, and C3 were the surimi gels prepared with sodium, potassium, and calcium chloride corresponding to ionic strength of 0.51, 0.34, and 0.17, respectively.

Figure 1. WHC of surimi gels with the addition of salt treatments. A1, A2, and A3; B1, B2, and B3; and C1, C2, and C3 were the surimi gels prepared with sodium, potassium, and calcium chloride corresponding to ionic strength of 0.51, 0.34, and 0.17, respectively. Bars on each column indicate standard deviation (SD). Different letters on the top of SD bars indicate significant differences (Duncan’s test, p < 0.05).

Figure 2. Breaking force, distance to rupture (a), and gel strength (b) of surimi gels with the addition of salt treatments. A1, A2, and A3; B1, B2, and B3; and C1, C2, and C3 were the surimi gels prepared with sodium, potassium, and calcium chloride corresponding to ionic strength of 0.51, 0.34, and 0.17, respectively. Bars on each column indicate standard deviation (SD). Different letters on the top of SD bars indicate significant differences (Duncan’s test, p < 0.05).

Figure 3. Rheological properties of surimi gel with the addition of salt treatments. A1, A2, and A3; B1, B2, and B3; and C1, C2, and C3 were the surimi gels prepared with sodium, potassium, and calcium chloride corresponding to ionic strength of 0.51, 0.34, and 0.17, respectively. (a) frequency sweep; (b) temperature sweep.

Figure 4. Chemical interactions of surimi gels with the addition of salt treatments. A1, A2, and A3; B1, B2, and B3; C1, C2, and C3 were the surimi gels prepared with sodium, potassium, and calcium chloride corresponding to ionic strength of 0.51, 0.34, and 0.17, respectively. Bars on each column indicate standard deviation (SD). Different letters on the top of SD bars indicate significant differences (Duncan’s test, p < 0.05). (a) nonspecific associations; (b) ionic bonds; (c) hydrogen bonds; and (d) hydrophobic interactions.

Figure 5. Sulfhydryl groups’ contents of surimi gels with the addition of salt treatments. A1, A2, and A3; B1, an d B2, B3; and C1, C2, and C3 were the surimi gels prepared with sodium, potassium, and calcium chloride corresponding to ionic strength of 0.51, 0.34, and 0.17, respectively. Bars on each column indicate standard deviation (SD). Different letters on the top of SD bars indicate significant differences (Duncan’s test, p < 0.05).

Figure 6. Solubility of surimi gels with the addition of salt treatments. A1, A2, and A3; B1, B2, and B3; an d C1, C2, and C3 were the surimi gels prepared with sodium, potassium, and calcium chloride corresponding to ionic strength of 0.51, 0.34, and 0.17, respectively. Bars on each column indicate standard deviation (SD). Different letters on the top of SD bars indicate significant differences (Duncan’s test, p < 0.05).

Figure 7. Scanning electronic microscopy (SEM) of surimi gels with the addition of salt treatments. Bar represents 10 μm. A1, A2, and A3; C1, C2, and C3 were the surimi gels prepared with sodium and calcium chloride corresponding to ionic strength of 0.51, 0.34, and 0.17, respectively (magnification, 10,000×). C3a and C3b were graphs of C3 with magnification for 20,000× and 40,000×, respectively.

Table 3. Correlation coefficient between gel properties and chemical interactions of surimi gels.

	Nonspecific associations	Hydrogen bonds	Ionic bonds	Hydrophobic interactions	SH group content	Solubility
Breaking force	−0.27	−0.10	0.57	−0.14	−0.15	−0.32
Distance to rupture	0.16	0.50	0.07	−0.51	0.47	−0.81**
Gel strength	0.09	0.38	0.26	−0.55	0.37	−0.79*
Hardness	−0.17	−0.61	0.09	0.40	−0.47	0.78*
Springiness	0.93**	−0.39	−0.49	−0.55	0.85**	0.10
Gumminess	0.13	−0.78*	−0.15	0.17	−0.23	0.86**
Chewiness	0.20	−0.80*	−0.17	0.13	−0.17	0.85**
Resilience	0.73*	−0.69	−0.53	−0.32	0.48	0.54
WHC	0.09	0.38	0.26	−0.55	−0.37	−0.34

* p < 0.05; ** p < 0.01