Protective effects of epicatechin on the oxidation and N-nitrosamine formation of oxidatively stressed myofibrillar protein

Figures & data

Table 1. Physicochemical changes and gel property of myofibrillar protein treated with epicatechin

	Physicochemical changes				gel property
sample	Carbonyl (nmol/mg protein)	Total sulfydryl (nmol/mg protein)	Free sulfydryl (nmol/mg protein)	Surface hydrophobicity (µg BPB/mg protein)	Cooking yield (%)	water holding capacity (WHC)	whiteness
Control	1.08 ± 0.35^c	109.63 ± 5.33^a	75.78 ± 3.92^a	7.53 ± 0.63^c	85.66 ± 2.11^a	74.46 ± 3.37^a	82.99 ± 1.43^a
0mM	3.63 ± 0.58^a	102.43 ± 3.67^a	66.42 ± 2.90^b	12.24 ± 1.13^a	85.48 ± 2.08^a	64.09 ± 1.04^c	82.86 ± 0.72^a
0.1 mM	3.13 ± 0.31^a	79.78 ± 7.82^b	58.92 ± 5.01^bc	10.50 ± 0.79^b	85.20 ± 2.58^a	68.66 ± 2.78^b	81.60 ± 0.60^a
0.2 mM	2.37 ± 0.36^b	82.82 ± 8.08^b	64.21 ± 8.79^b	8.53 ± 1.00^c	83.37 ± 1.80^a	70.71 ± 2.65^ab	76.54 ± 1.70^b
0.5 mM	2.38 ± 0.32^b	81.01 ± 2.13^b	50.71 ± 2.31^cd	8.16 ± 0.91^c	84.57 ± 1.55^a	71.02 ± 2.17^ab	75.83 ± 1.73^bc
1 mM	2.06 ± 0.42^b	61.18 ± 3.33^c	47.50 ± 5.26^d	8.15 ± 0.79^c	83.60 ± 1.66^a	71.39 ± 1.29^ab	73.53 ± 1.53^c
2 mM	1.14 ± 0.18^c	45.91 ± 7.66^d	37.94 ± 2.10^e	5.40 ± 0.84^d	82.06 ± 2.57^a	71.55 ± 2.20^ab	70.87 ± 2.06^d

Values are shown as means ±standard deviations (n = 3).

^{a, b, c, d} Means in the same column with different superscripts are significantly different (p < 0.05).

Figure 1. Tryptophan fluoescence of myofibrillar protein treated with epicatechin

Figure 2. Storage modulus (G’) of myofibrillar protein treated with epicatechin

Table 2. Peaks area proportion of myofibrillar protein gels treated with epicatechin

sample	P21(%)	P22(%)	P23(%)
Control	1.57 ± 0.17 ^a	96.73 ± 0.35^a	1.94 ± 0.29^b
0 mM	1.51 ± 0.14 ^a	93.72 ± 1.05^d	3.11 ± 0.81^a
0.1 mM	1.48 ± 0.08 ^a	94.35 ± 0.64^cd	2.54 ± 0.31^ab
0.2 mM	1.49 ± 0.13 ^a	94.30 ± 0.95^cd	2.41 ± 0.07^b
0.5 mM	1.46 ± 0.09 ^a	94.61 ± 0.56^bcd	2.22 ± 0.30^b
1 mM	1.47 ± 0.10 ^a	95.22 ± 0.20^bc	2.28 ± 0.31^b
2 mM	1.57 ± 0.13 ^a	95.67 ± 1.00^ab	2.29 ± 0.21^b

Figure 3. Relaxation time T₂ of myofibrillar protein gel treated with epicatechin

Figure 4. The chromatogram of N-nitrosodiethylamine (NDEA) by HPLC

Figure 5. NDEA formation of myofibrillar protein treated with epicatechin

Table 3. Correlation coefficients between NDEA, protein oxidation variables and gel properties

	NDEA1	NDEA2	corbonyl	Free sulfydryl	Total sulfydryl	Surface hydrophobicity	Cooking yield	WHC	whiteness
NDEA1	1
NDEA2	0.496*	1
corbonyl	0.246	0.362	1
Free sulfydryl	0.660**	0.438*	−0.004	1
Total sulfydryl	−0.268	0.172	0.273	−0.558**	1
Surface hydrophobicity	0.064	0.187	0.818**	−0.309	0.551**	1
Cooking yield	−0.087	0.141	0.195	−0.206	0.478*	0.530*	1
WHC	0.501*	0.089	0.054	0.555**	−0.785**	−0.245	−0.483*	1
whiteness	−0.329	0.015	0.378	0.595**	0.879**	0.676**	0.539*	−0.721**	1

NDEA₁: 4 h at 37°C solution; NDEA₂: 1 h at 80°C solution; WHC: water holding capacity

*p < 0.05; **p < 0.01.