Physicochemical characteristics, protein hydrolysis, and textual properties of surimi during fermentation with Actinomucor elegans

Figures & data

Table 1. Changes in basic components, texture profile, and color properties of surimi at different stages of fermentation.

Fermentation stages		Surimi curd	Surimi pehtze	Salted surimi	Ripened surimi
Basic components (%)	Crude fat	2.81 ± 0.05^a	2.70 ± 0.08^a	2.20 ± 0.04^c	2.57 ± 0.07^b
	Protein	16.03 ± 0.19^a	15.65 ± 0.11^b	14.51 ± 0.13^c	14.21 ± 0.13^d
	Ash	2.50 ± 0.31^a	4.02 ± 0.12^b	14.81 ± 0.13^c	10.33 ± 0.20^d
	NaCl	0.49 ± 0.01^d	2.10 ± 0.20^c	12.93 ± 0.12^a	8.58 ± 0.27^b
	Water content	74.71 ± 0.71^a	70.90 ± 1.10^b	62.11 ± 2.78^c	68.09 ± 0.31^d
Texture profile	Hardness (g)	1426.0 ± 28.5^a	768.2 ± 21.3^b	1277.9 ± 43.7^c	80.2 ± 17.2^d
	Adhesiveness (g×s)	–2.45 ± 0.11^a	–27.34 ± 1.61^b	–39.41 ± 3.51^c	–22.60 ± 2.82^d
	Springiness	0.82 ± 0.01^a	0.52 ± 0.05^b	0.61 ± 0.02^c	0.49 ± 0.04^b
	Cohesiveness	0.34 ± 0.01^a	0.21 ± 0.01^b	0.38 ± 0.02^c	0.26 ± 0.07^d
Color properties	L*	65.08 ± 0.58^a	63.58 ± 0.34^b	64.40 ± 0.86^ab	55.48 ± 1.06^c
	a*	–2.38 ± 0.09^a	–1.41 ± 0.16^b	0.78 ± 0.50^c	4.45 ± 0.43^d
	b*	3.33 ± 0.47^a	6.30 ± 0.72^b	10.77 ± 1.22^c	18.59 ± 0.81^d

^a–dMeans with different superscript letters in the same row indicate significant differences (p < 0.05).

Table 2. Physiochemical properties and protease activity of surimi at different stages of fermentation.

Fermentation stages	Surimi curd	Surimi pehtze	Salted surimi	Ripened surimi
pH	6.82 ± 0.07^a	6.21 ± 0.13^b	6.29 ± 0.07^b	4.62 ± 0.04^c
Total acidity (%)	0.09 ± 0.02^a	0.40 ± 0.05^b	0.21 ± 0.01^c	0.64 ± 0.10^d
TCA-N content (g/100 g)	0.08 ± 0.02^a	0.68 ± 0.03^b	0.49 ± 0.04^c	0.97 ± 0.03^d
Protease activity (U/g)	0.97 ± 0.04^a	69.34 ± 4.92^b	7.45 ± 1.12^c	32.08 ± 0.35^d

Data were expressed as means ± standard deviation (n = 3).

^a–dMeans with different superscript letters in the same row indicate significant differences (p < 0.05).

Figure 1. SDS-PAGE patterns of surimi protein at different stages of fermentation. MHC: myosin heavy chain; M: molecular weight marker; (a) surimi curd; (b) surimi pehtze; (c) salted surimi; (d) ripened surimi.

Figure 2. Changes in free amino acids contents of surimi at different stages of fermentation. Different letters at the tops of the bars indicate significant differences (p < 0.05).

Figure 3. SEM images of surimi at different stages of fermentation. (a) surimi curd; (b) surimi pehtze; (c) salted surimi; (d) ripened surimi.

Figure 4. Changes in aerobic plate count, bacterial endospores, lactic acid bacteria, and enterobacteriaceae of surimi at different stages of fermentation. Different letters at the tops of the bars indicate significant differences (p < 0.05).

Table 3. Sensory scores of surimi with different ripening time.

	Ripening time (d)
	0	15	30	45	60
Taste	6.76 ± 0.52^c	7.01 ± 0.51^b	7.50 ± 1.02^ab	7.90 ± 0.52^a	7.92 ± 0.45^a
Flavor	7.13 ± 0.62^c	7.31 ± 0.82^c	7.86 ± 0.52^b	8.13 ± 0.88^a	8.15 ± 0.98^a
Texture	7.15 ± 0.45^d	7.58 ± 1.27^c	7.85 ± 1.00^b	8.13 ± 1.05^ab	7.95 ± 1.12^a
Overall acceptability	7.20 ± 1.02^d	7.55 ± 0.98^c	7.88 ± 0.52^b	7.92 ± 0.50^b	8.25 ± 0.28^a

Data were expressed as means ± standard deviation (n = 3, textural properties; n = 15, acceptance scores).

^a–dMeans with different superscript letters in the same row indicate significant differences (p < 0.05).