Exploring the quality change mechanism of tea polyphenol-assisted cured grass carp from perspectives of physicochemical and flavor

Figures & data

Figure 1. Effects of tea polyphenols assisted pickling on water and NaCl content of grass carp.

Table 1. Effects of tea polyphenols assisted pickling on the pH value of grass carp.

Pickling time/min	C	E1	E2
10	6.88 ± 0.03^aA	6.72 ± 0.01^aB	6.64 ± 0.02^bcC
20	6.87 ± 0.03^aA	6.69 ± 0.01^cB	6.68 ± 0.02^aB
30	6.88 ± 0.04^aA	6.72 ± 0.02^aB	6.69 ± 0.01^aB
40	6.89 ± 0.06^aB	6.69 ± 0.01^bcB	6.67 ± 0.01^abB
50	6.88 ± 0.07^aA	6.66 ± 0.01^dB	6.62 ± 0.02^cB
60	6.85 ± 0.06^aA	6.71 ± 0.01^abB	6.64 ± 0.01^bcB

Different lower case letters indicate significant differences between data in the same column (p < 0.05) and different capital letters indicate significant differences between data in the same row (p < 0.05). The same as below.

Table 2. Effects of tea polyphenols assisted pickling on the color of grass carp.

color	pickling time/min	C	E1	E2
L*	10	41.83 ± 0.60^bB	43.27 ± 0.15^bA	43.10 ± 0.70^bcA
	20	45.50 ± 1.71^aA	45.63 ± 1.56^aA	42.13 ± 0.76^cdB
	30	45.20 ± 0.95^aA	44.03 ± 0.38^bA	43.97 ± 1.18^abA
	40	41.90 ± 1.15^bAB	43.77 ± 1.07^bA	41.10 ± 0.61^deB
	50	41.77 ± 1.37^bB	44.47 ± 0.67^abA	44.67 ± 0.76^aA
	60	41.33 ± 1.67^bA	41.57 ± 0.35^cA	40.13 ± 0.32^eA
a*	10	−2.60 ± 0.10^aA	−2.47 ± 0.21^aA	−2.50 ± 0.17^aA
	20	−2.83 ± 0.06^abA	−2.73 ± 0.25^aA	−2.53 ± 0.21^aA
	30	−2.77 ± 0.06^abB	−2.63 ± 0.12^aAB	−2.27 ± 0.32^aA
	40	−3.10 ± 0.46^bA	−2.90 ± 0.44^aA	−2.37 ± 0.23^aA
	50	−3.17 ± 0.25^bB	−2.83 ± 0.31^aAB	−2.43 ± 0.21^aA
	60	−2.77 ± 0.06^abB	−2.57 ± 0.15^aA	−2.47 ± 0.06^aA
b*	10	−0.73 ± 0.15^aA	−0.87 ± 0.21^aA	−0.83 ± 0.15^aA
	20	−0.80 ± 0.35^aA	−1.40 ± 0.10^bB	−0.90 ± 0.20^aA
	30	−1.13 ± 0.12^aA	−1.50 ± 0.26^bcA	−1.23 ± 0.15^bA
	40	−1.80 ± 0.26^bAB	−1.83 ± 0.21^cB	−1.40 ± 0.10^bA
	50	−1.73 ± 0.21^bA	−1.63 ± 0.15^bcA	−1.47 ± 0.21^bA
	60	−1.93 ± 0.12^bB	−1.47 ± 0.06^bA	−1.30 ± 0.20^bA

Different lower case letters indicate significant differences between data in the same column (p < 0.05) and different capital letters indicate significant differences between data in the same row (p < 0.05).

Table 3. Effects of tea polyphenols assisted pickling on the texture of grass carp.

	picking time/min	C	E1	E2
Hardness	10	1920.12 ± 145.74^bC	2149.78 ± 73.03^cB	2506.84 ± 40.79^bA
	20	1410.61 ± 78.43^cdB	2564.43 ± 71.33^bA	2435.14 ± 145.63^bA
	30	1780.73 ± 126.91^bcB	2671.07 ± 87.17^abA	2391.22 ± 144.06^bA
	40	1293.25 ± 97.46^dC	2817.79 ± 72.57^aA	2140.40 ± 105.82^cB
	50	2493.63 ± 100.00^aB	1730.82 ± 93.10^dC	2796.11 ± 42.54^aA
	60	2571.63 ± 99.03^aA	2170.77 ± 74.68^cB	2953.97 ± 43.04^aA
Springness	10	0.92 ± 0.02^aA	0.74 ± 0.01^aB	0.49 ± 0.00^abC
	20	0.88 ± 0.01^bA	0.62 ± 0.01^bB	0.50 ± 0.01^aC
	30	0.88 ± 0.01^bA	0.55 ± 0.01^cB	0.48 ± 0.02^abC
	40	0.89 ± 0.02^bA	0.46 ± 0.00^fB	0.45 ± 0.01^dB
	50	0.88 ± 0.00^bA	0.51 ± 0.02^dB	0.47 ± 0.01^bcC
	60	0.88 ± 0.00^bA	0.49 ± 0.00^eB	0.47 ± 0.00^cC
Cohesiveness	10	0.52 ± 0.01^bAB	0.53 ± 0.01^aA	0.51 ± 0.01^aB
	20	0.54 ± 0.01^aA	0.52 ± 0.01^aB	0.51 ± 0.02^abB
	30	0.52 ± 0.02^bA	0.46 ± 0.01^cB	0.50 ± 0.00^abcA
	40	0.52 ± 0.00^bA	0.50 ± 0.01^bB	0.48 ± 0.01^cdB
	50	0.50 ± 0.01^aA	0.49 ± 0.01^bAB	0.48 ± 0.01^dAB
	60	0.46 ± 0.01^aB	0.49 ± 0.01^bA	0.49 ± 0.00^bcA
Chewiness	10	695.01 ± 19.17^bcB	731.02 ± 16.53^bcAB	751.9 ± 21.84^aA
	20	635.21 ± 20.30^cB	737.159 ± 5.21^bcA	756.04 ± 39.92^aA
	30	790.34 ± 53.70^aA	758.33 ± 23.49^abA	798.66 ± 43.21^aA
	40	759.01 ± 33.07^abA	711.83 ± 18.75^cA	742.02 ± 17.11^aA
	50	758.96 ± 39.98^abA	727.87 ± 21.12^bcA	771.77 ± 38.19^aA
	60	731.11 ± 29.32^abA	777.481 ± 11.23^aA	774.26 ± 38.86^aA

Different lower case letters indicate significant differences between data in the same column (p < 0.05) and different capital letters indicate significant differences between data in the same row (p < 0.05).

Table 4. Changes in the composition and content of free amino acids during curing in group C.

		Contents (mg/100g)
Types	Threshold (mg/100g)	0min	10min	20min	30min	40min	50min	60min
Asp*	3	0.66 ± 0.02^b	1.13 ± 0.11^a	1.27 ± 0.19^a	1.15 ± 0.10^a	1.15 ± 0.13^a	1.14 ± 0.12^a	1.07 ± 0.04^a
Thr*	260	19.04 ± 0.08^a	15.60 ± 1.21^b	16.73 ± 0.40^b	16.78 ± 0.77^b	16.75 ± 1.46^b	17.24 ± 1.02^b	17.13 ± 1.32^b
Ser*	150	6.91 ± 0.19^b	7.07 ± 0.21^b	7.43 ± 0.36^ab	7.76 ± 0.32^ab	7.20 ± 1.06^ab	6.81 ± 0.69^b	9.11 ± 1.79^a
Glu*	30	1.75 ± 0.05^c	1.82 ± 0.03^d	2.57 ± 0.12^c	2.78 ± 0.06^c	3.02 ± 0.14^bc	3.31 ± 0.15^ab	3.77 ± 0.58^a
Gly*	130	113.76 ± 4.58^ab	105.48 ± 5.97^b	109.72 ± 3.76^ab	115.20 ± 1.51^a	117.04 ± 4.49^a	116.41 ± 3.70^a	115.02 ± 3.84^a
Ala*	60	33.35 ± 1.55^b	33.30 ± 3.40^b	33.15 ± 2.68^b	37.56 ± 2.92^ab	37.07 ± 3.32^ab	42.44 ± 3.99^a	43.03 ± 4.75^a
Cys	ND	1.64 ± 0.12^a	1.59 ± 0.11^a	1.38 ± 0.38^a	0.60 ± 0.05^b	0.62 ± 0.14^b	0.63 ± 0.14^b	0.74 ± 0.14^b
Val^▲	40	10.98 ± 0.28^a	6.38 ± 0.05^a	6.05 ± 0.55^a	4.50 ± 0.34^b	4.19 ± 0.21^b	4.53 ± 0.38^b	4.68 ± 0.17^b
Met^▲	30	2.45 ± 0.09^a	2.07 ± 0.03^c	2.35 ± 0.17^c	1.20 ± 0.19^d	3.13 ± 0.44^ab	3.00 ± 0.17^b	3.65 ± 0.43^a
Ile^▲	90	7.69 ± 0.28^a	4.85 ± 0.13^b	4.82 ± 0.68^b	4.90 ± 0.38^b	4.69 ± 0.31^b	4.70 ± 0.49^b	4.60 ± 0.45^b
Leu^▲	190	11.13 ± 0.63^a	6.40 ± 0.26^b	6.50 ± 0.78^b	7.12 ± 0.52^b	6.61 ± 0.33^b	7.12 ± 0.41^b	6.73 ± 0.22^b
Tyr^▲	ND	10.17 ± 0.74^a	9.81 ± 1.61^a	8.33 ± 0.53^b	2.58 ± 0.17^c	2.79 ± 0.65^c	2.55 ± 0.38^c	2.27 ± 0.41^c
Phe^▲	90	5.14 ± 0.15^a	3.42 ± 1.48^a	2.34 ± 0.38^b	4.09 ± 0.16^a	3.99 ± 0.29^a	4.30 ± 0.11^a	4.44 ± 0.26^a
Lys^▲	50	15.93 ± 0.81^a	13.52 ± 1.41^ab	13.25 ± 1.54^b	14.76 ± 0.70^ab	15.14 ± 0.43^a	14.31 ± 0.35^ab	14.35 ± 0.05^ab
His^▲	20	301.67 ± 3.29^b	329.59 ± 8.29^ab	343.38 ± 7.89^a	310.53 ± 7.93^bc	304.77 ± 13.76^c	325.53 ± 6.28^ab	310.67 ± 10.81^bc
Arg^▲	50	5.72 ± 0.35^a	4.47 ± 0.23^c	4.86 ± 0.22^bc	5.43 ± 0.28^a	4.84 ± 0.41^bc	5.15 ± 0.20^ab	4.90 ± 0.20^abc
Pro*	300	33.95 ± 1.06^a	15.45 ± 0.91^b	18.09 ± 0.89^a	16.96 ± 0.27^a	17.68 ± 0.40^a	13.42 ± 0.75^c	13.25 ± 1.24^c
TFAA		581.93 ± 10.01^a	561.90 ± 8.37^bc	582.22 ± 4.39^a	553.90 ± 11.62^bc	550.68 ± 7.49^c	569.94 ± 6.40^ab	561.07 ± 9.53^bc

Different letters in the same row indicate significant differences (p < 0.05). *denotes sweet amino acids; ^▲denotes bitter amino acids; ND denotes threshold not found. TFAA denotes total free amino acids.

Table 5. Changes in the composition and content of free amino acids during curing in group E₁.

		Contents (mg/100g)
Types	Threshold (mg/100g)	0min	10min	20min	30min	40min	50min	60min
Asp*	3	0.66 ± 0.02^c	1.43 ± 0.06^a	1.14 ± 0.09^b	1.21 ± 0.19^ab	1.23 ± 0.09^ab	1.22 ± 0.23^ab	1.21 ± 0.05^ab
Thr*	260	19.04 ± 0.08^a	12.34 ± 0.56^b	11.85 ± 1.27^b	11.22 ± 0.65^b	12.35 ± 0.52^b	11.25 ± 0.40^b	11.85 ± 1.26^b
Ser*	150	6.91 ± 0.19^a	5.58 ± 0.25^ab	5.05 ± 0.60^b	5.52 ± 0.25^ab	5.87 ± 0.14^a	5.36 ± 0.60^ab	5.06 ± 0.19^b
Glu*	30	1.75 ± 0.05^b	2.66 ± 0.35^a	2.94 ± 0.37^a	2.85 ± 0.15^a	3.21 ± 0.07^a	3.13 ± 0.24^a	3.22 ± 0.65^a
Gly*	130	113.76 ± 4.58^b	129.29 ± 7.21^ab	135.38 ± 3.73^a	138.16 ± 2.15^a	134.08 ± 7.54^a	122.05 ± 5.09^bc	114.62 ± 1.00^c
Ala*	60	33.35 ± 1.55^b	38.38 ± 4.18^a	37.89 ± 2.82^a	38.83 ± 5.21^a	35.11 ± 1.52^b	35.58 ± 3.82^b	34.54 ± 3.80^b
Cys	ND	1.64 ± 0.12^a	0.67 ± 0.08^a	0.51 ± 0.07^bc	0.41 ± 0.12^c	0.65 ± 0.04^a	0.47 ± 0.05^bc	0.59 ± 0.03^ab
Val^▲	40	10.98 ± 0.28^a	5.58 ± 0.61^b	5.34 ± 0.29^b	4.89 ± 0.71^b	5.18 ± 0.76^b	5.00 ± 0.37^b	5.63 ± 0.36^b
Met^▲	30	2.45 ± 0.09^b	2.93 ± 0.61^a	3.18 ± 0.88^a	2.59 ± 0.13^b	3.38 ± 0.26^a	2.67 ± 0.13^b	2.48 ± 0.18^b
Ile^▲	90	7.69 ± 0.28^a	5.83 ± 0.61^a	5.74 ± 0.57^a	4.80 ± 0.14^b	4.90 ± 0.25^b	5.29 ± 0.34^ab	5.71 ± 0.19^a
Leu^▲	190	11.13 ± 0.63^a	10.14 ± 0.56^a	9.81 ± 0.94^a	6.95 ± 0.11^c	8.81 ± 1.70^ab	7.37 ± 0.29^bc	9.48 ± 0.37^a
Tyr^▲	ND	10.17 ± 0.74^a	2.53 ± 0.38^b	2.72 ± 0.28^b	2.21 ± 0.57^b	2.61 ± 0.26^b	2.69 ± 0.25^b	2.83 ± 0.32^b
Phe^▲	90	5.14 ± 0.15^a	5.04 ± 0.47^b	4.68 ± 0.15^b	4.52 ± 0.48^b	4.83 ± 0.55^b	4.32 ± 0.29^b	4.67 ± 0.41^b
Lys^▲	50	15.93 ± 0.81^a	13.95 ± 2.41^b	13.34 ± 1.52^b	12.32 ± 0.85^b	12.20 ± 2.14^b	13.24 ± 2.76^b	12.64 ± 1.85^b
His^▲	20	301.67 ± 3.29^b	314.37 ± 5.47^a	268.72 ± 23.01^b	225.97 ± 19.58^c	243.89 ± 11.78^bc	254.19 ± 3.01^b	242.57 ± 9.46^bc
Arg^▲	50	5.72 ± 0.35^a	3.83 ± 0.43^ab	4.04 ± 0.73^ab	3.69 ± 0.28^b	4.84 ± 0.49^a	4.85 ± 0.89^a	3.37 ± 0.28^b
Pro*	300	33.95 ± 1.06^a	21.17 ± 1.60^b	22.44 ± 0.92^b	23.88 ± 0.96^b	20.91 ± 3.56^c	24.68 ± 3.48^c	23.60 ± 2.82^c
TFAA		581.93 ± 10.01^a	575.71 ± 11.11^a	534.77 ± 33.82^ab	490.01 ± 13.64^bc	504.06 ± 11.05^bc	503.36 ± 18.77^bc	487.42 ± 38.32^c

Different letters in the same row indicate significant differences (p < 0.05). *denotes sweet amino acids; ^▲denotes bitter amino acids; ND denotes threshold not found. TFAA denotes total free amino acids.

Table 6. Changes in the composition and content of free amino acids during curing in group E₂.

		Contents (mg/100g)
Types	Threshold (mg/100g)	0min	10min	20min	30min	40min	50min	60min
Asp*	3	0.66 ± 0.02^c	1.09 ± 0.14^ab	1.24 ± 0.14^a	1.00 ± 0.13^ab	0.91 ± 0.20^b	0.79 ± 0.09^b	0.90 ± 0.28^b
Thr*	260	19.04 ± 0.08^a	13.50 ± 1.28^ab	14.23 ± 0.57^a	12.93 ± 0.81^ab	14.47 ± 1.10^a	12.35 ± 0.45^b	11.74 ± 1.06^b
Ser*	150	6.91 ± 0.19^a	4.97 ± 0.07^b	4.77 ± 0.34^b	4.56 ± 0.22^b	4.52 ± 0.11^b	4.70 ± 0.22^b	4.82 ± 0.49^b
Glu*	30	1.75 ± 0.05^a	1.52 ± 0.09^ab	1.19 ± 0.09^b	1.19 ± 0.28^b	1.71 ± 0.40^a	1.41 ± 0.29^ab	1.38 ± 0.39^ab
Gly*	130	113.76 ± 4.58^c	202.47 ± 4.15^a	201.15 ± 4.93^a	191.32 ± 2.06^ab	192.37 ± 7.47^ab	178.94 ± 12.44^b	181.50 ± 8.90^b
Ala*	60	33.35 ± 1.55^b	38.81 ± 2.10^a	36.36 ± 3.10^ab	36.54 ± 2.15^ab	32.36 ± 1.33^bc	29.10 ± 3.53^c	29.38 ± 3.10^c
Cys	ND	1.64 ± 0.12^a	1.32 ± 0.37^ab	1.27 ± 0.07^ab	1.34 ± 0.25^ab	1.58 ± 0.39^a	1.44 ± 0.13^ab	0.96 ± 0.18^b
Val^▲	40	10.98 ± 0.28^a	3.50 ± 0.24^a	3.47 ± 0.06^ab	3.32 ± 0.13^ab	3.55 ± 0.32^a	3.46 ± 0.23^ab	3.07 ± 0.06^b
Met^▲	30	2.45 ± 0.09^a	1.42 ± 0.20^b	1.68 ± 0.04^b	1.71 ± 0.13^b	1.40 ± 0.19^b	1.69 ± 0.14^b	1.34 ± 0.40^b
Ile^▲	90	7.69 ± 0.28^a	2.48 ± 0.30^b	2.55 ± 0.06^b	2.27 ± 0.11^b	2.55 ± 0.21^b	2.47 ± 0.33^b	2.17 ± 0.08^b
Leu^▲	190	11.13 ± 0.63^a	5.81 ± 0.64^ab	5.97 ± 0.08^a	5.30 ± 0.58^ab	5.89 ± 0.45^ab	5.08 ± 0.44^ab	4.99 ± 0.41^b
Tyr^▲	ND	10.17 ± 0.74^a	1.84 ± 0.37^a	1.34 ± 0.22^ab	1.52 ± 0.41^ab	0.97 ± 0.11^b	1.55 ± 0.38^ab	1.35 ± 0.28^ab
Phe^▲	90	5.14 ± 0.15^a	2.67 ± 0.03^b	2.63 ± 0.06^b	2.67 ± 0.27^b	2.61 ± 0.10^b	2.71 ± 0.28^b	2.47 ± 0.08^b
Lys^▲	50	15.93 ± 0.81^a	8.17 ± 0.78^a	8.26 ± 0.18^ab	8.74 ± 1.05^ab	8.59 ± 0.45^ab	9.50 ± 0.49^a	8.97 ± 0.28^ab
His^▲	20	301.67 ± 3.29^a	265.53 ± 19.21^ab	263.26 ± 16.37^ab	272.86 ± 13.41^ab	246.15 ± 23.60^ab	280.23 ± 9.75^a	241.96 ± 21.96^b
Arg^▲	50	5.72 ± 0.35^a	1.93 ± 0.20^ab	1.61 ± 0.12^c	1.53 ± 0.12^c	1.73 ± 0.08^bc	2.04 ± 0.08^a	1.62 ± 0.20^c
Pro*	300	33.95 ± 1.06^a	22.00 ± 2.13^ab	22.26 ± 1.17^ab	20.42 ± 0.33^b	20.63 ± 1.37^b	24.38 ± 2.84^a	20.30 ± 0.67^b
TFAA		581.93 ± 10.01^a	579.05 ± 16.76^a	573.26 ± 11.44^a	569.23 ± 17.35^a	541.99 ± 26.07^ab	561.82 ± 22.80^a	518.86 ± 7.74^b

Different letters in the same row indicate significant differences (p < 0.05). *denotes sweet amino acids; ^▲denotes bitter amino acids; ND denotes threshold not found. TFAA denotes total free amino acids.

Table 7. Effects of tea polyphenols assisted pickling on the taste activity values of fresh and sweet amino acids in grass carp cured products.

		TAV
	Pickling time/min	Asp	Thr	Ser	Glu	Gly	Pro
C	0	0.22 ± 0.01^b	0.07 ± 0.00^a	0.05 ± 0.00^a	0.06 ± 0.00^d	0.87 ± 0.04^a	0.11 ± 0.00^a
	10	0.38 ± 0.04^a	0.06 ± 0.00^a	0.05 ± 0.00^a	0.06 ± 0.00^d	0.81 ± 0.04^b	0.05 ± 0.00^c
	20	0.42 ± 0.06^a	0.06 ± 0.00^a	0.05 ± 0.00^a	0.09 ± 0.00^c	0.84 ± 0.03^ab	0.06 ± 0.00^b
	30	0.38 ± 0.03^a	0.06 ± 0.00^a	0.05 ± 0.00^a	0.09 ± 0.00^c	0.89 ± 0.01^a	0.06 ± 0.00^b
	40	0.38 ± 0.03^a	0.06 ± 0.00^a	0.05 ± 0.00^a	0.10 ± 0.00^bc	0.9 ± 0.04^a	0.06 ± 0.00^b
	50	0.38 ± 0.04^a	0.05 ± 0.02^a	0.05 ± 0.00^a	0.11 ± 0.00^ab	0.89 ± 0.03^a	0.04 ± 0.00^c
	60	0.35 ± 0.01^a	0.07 ± 0.01^a	0.06 ± 0.02^b	0.13 ± 0.02^a	0.88 ± 0.03^a	0.04 ± 0.00^c
E1	0	0.22 ± 0.01^c	0.07 ± 0.00^a	0.05 ± 0.00^a	0.06 ± 0.00^a	0.87 ± 0.04^c	0.11 ± 0.00^a
	10	0.48 ± 0.02^a	0.05 ± 0.00^b	0.04 ± 0.00^b	0.09 ± 0.01^b	0.99 ± 0.06^ab	0.11 ± 0.00^b
	20	0.38 ± 0.03^b	0.05 ± 0.00^bc	0.04 ± 0.00^c	0.10 ± 0.01^b	1.04 ± 0.03^a	0.07 ± 0.01^b
	30	0.40 ± 0.07^ab	0.04 ± 0.00^bc	0.04 ± 0.00^b	0.09 ± 0.00^b	1.06 ± 0.02^a	0.08 ± 0.00^b
	40	0.41 ± 0.03^ab	0.05 ± 0.00^b	0.04 ± 0.00^b	0.11 ± 0.00^b	1.03 ± 0.06^a	0.08 ± 0.00^b
	50	0.40 ± 0.07^ab	0.04 ± 0.00^c	0.03 ± 0.00^c	0.10 ± 0.00^b	0.92 ± 0.06^bc	0.07 ± 0.01^b
	60	0.40 ± 0.02^ab	0.05 ± 0.00^bc	0.03 ± 0.00^c	0.11 ± 0.02^b	0.88 ± 0.01^c	0.08 ± 0.01^b
E2	0	0.22 ± 0.01^c	0.07 ± 0.00^a	0.05 ± 0.00^a	0.06 ± 0.00^a	0.87 ± 0.04^c	0.11 ± 0.00^a
	10	0.36 ± 0.05^ab	0.05 ± 0.00^bc	0.03 ± 0.00^a	0.05 ± 0.00^ab	1.56 ± 0.04^a	0.08 ± 0.00^bc
	20	0.41 ± 0.05^a	0.05 ± 0.00^bc	0.03 ± 0.00^a	0.04 ± 0.00^b	1.55 ± 0.04^a	0.07 ± 0.00^bc
	30	0.34 ± 0.05^ab	0.05 ± 0.00^bc	0.03 ± 0.00^a	0.04 ± 0.00^ab	1.47 ± 0.02^ab	0.07 ± 0.00^bc
	40	0.30 ± 0.06^bc	0.06 ± 0.00^bc	0.03 ± 0.00^a	0.06 ± 0.02^ab	1.48 ± 0.06^ab	0.07 ± 0.0^c
	50	0.27 ± 0.03^bc	0.05 ± 0.00^bc	0.04 ± 0.00^a	0.05 ± 0.01^ab	1.38 ± 0.09^b	0.08 ± 0.01^b
	60	0.30 ± 0.09^bc	0.05 ± 0.00^c	0.03 ± 0.00^a	0.05 ± 0.01^ab	1.40 ± 0.06^b	0.07 ± 0.00^bc

Different lower case letters indicate significant differences between data in the same column (p < 0.05).

Table 8. Effects of tea polyphenols assisted pickling on the nucleotide compounds in grass carp cured products.

		Contents (mg/100g)						TAV
	pickling time/min	IMP	ATP	ADP	AMP	Hx	HxR	IMP	AMP
C	10	106.63 ± 7.42^a	3.47 ± 0.27^a	9.35 ± 0.18^a	1.87 ± 0.12^a	1.11 ± 0.05^c	11.58 ± 1.82^d	4.27 ± 0.30^a	0.019 ± 0.00^a
	20	101.36 ± 5.25^ab	3.35 ± 0.32^a	9.10 ± 0.10^ab	1.72 ± 0.29^a	1.18 ± 0.10^c	13.04 ± 1.54^cd	4.05 ± 0.21^ab	0.017 ± 0.00^a
	30	94.16 ± 0.51^bc	2.64 ± 0.06^b	8.89 ± 0.09^b	1.66 ± 0.14^ab	1.39 ± 0.03^b	14.85 ± 0.96^c	3.99 ± 0.29^ab	0.017 ± 0.00^ab
	40	92.12 ± 1.02^bc	2.44 ± 0.24^b	8.19 ± 0.36^c	1.63 ± 0.06^ab	1.47 ± 0.11^b	15.76 ± 1.12^bc	3.77 ± 0.08^b	0.016 ± 0.00^ab
	50	92.82 ± 2.75^bc	2.79 ± 0.07^b	8.02 ± 0.02^c	1.38 ± 0.10^bc	1.67 ± 0.06^a	17.99 ± 1.12^ab	3.80 ± 0.26^ab	0.014 ± 0.00^bc
	60	87.55 ± 4.71^c	2.69 ± 0.16^b	8.31 ± 0.14^c	1.34 ± 0.06^c	1.74 ± 0.09^a	19.79 ± 1.63^a	3.79 ± 0.06^ab	0.013 ± 0.00^c
E1	10	108.33 ± 4.59^a	3.88 ± 0.21^a	9.36 ± 0.24^a	1.95 ± 0.19^a	1.15 ± 0.08^b	11.80 ± 0.99^c	4.33 ± 0.18^a	0.020 ± 0.00^a
	20	100.12 ± 6.70^b	3.63 ± 0.43^a	9.26 ± 0.33^a	1.84 ± 0.16^ab	1.14 ± 0.06^b	13.11 ± 0.87^bc	4.00 ± 0.28^b	0.018 ± 0.00^ab
	30	97.48 ± 0.32^bc	2.97 ± 0.04^b	9.40 ± 0.25^a	1.58 ± 0.01^c	1.12 ± 0.12^b	14.12 ± 0.09^ab	3.90 ± 0.01^bc	0.016 ± 0.00^c
	40	95.74 ± 2.08^bc	3.58 ± 0.15^a	9.23 ± 0.11^ab	1.58 ± 0.08^c	1.22 ± 0.11^b	14.29 ± 0.43^ab	3.82 ± 0.08^bc	0.016 ± 0.00^c
	50	93.12 ± 3.65^bc	2.09 ± 0.31^c	8.93 ± 0.16^ab	1.71 ± 0.02^bc	1.51 ± 0.05^a	13.88 ± 0.51^ab	3.72 ± 0.15^bc	0.017 ± 0.00^bc
	60	89.72 ± 1.2^c	2.43 ± 0.32^c	8.76 ± 0.32^b	1.78 ± 0.04^abc	1,61 ± 0.09^a	15.31 ± 1.53^a	3.59 ± 0.05^c	0.018 ± 0.00^abc
E2	10	102.54 ± 4.75^a	3.58 ± 0.18^a	9.63 ± 0.41^a	1.62 ± 0.04^ab	1.04 ± 0.08^d	13.33 ± 0.95^b	4.10 ± 0.19^a	0.016 ± 0.00^ab
	20	95.57 ± 4.76^ab	3.47 ± 0.03^a	8.91 ± 0.29^b	1.59 ± 0.15^ab	1.23 ± 0.09^c	13.38 ± 1.14^b	3.82 ± 0.19^ab	0.016 ± 0.00^ab
	30	95.46 ± 4.42^ab	3.07 ± 0.27^b	9.10 ± 0.18^b	1.65 ± 0.04^a	1.31 ± 0.08^c	14.97 ± 0.53^ab	3.82 ± 0.18^ab	0.016 ± 0.00^a
	40	92.36 ± 4.25^b	2.95 ± 0.28^b	8.25 ± 0.08^c	1.50 ± 0.03^b	1.33 ± 0.06^c	15.99 ± 0.75^ab	3.69 ± 0.17^ab	0.015 ± 0.00^b
	50	94.15 ± 5.02^ab	2.93 ± 0.17^b	8.36 ± 0.39^c	1.57 ± 0.02^ab	1.49 ± 0.07^b	14.71 ± 2.83^ab	3.77 ± 0.20^ab	0.016 ± 0.00^ab
	60	91.20 ± 5.58^b	2.81 ± 0.19^b	8.69 ± 0.06^bc	1.26 ± 0.02^c	1.82 ± 0.03^a	16.82 ± 2.56^a	3.65 ± 0.22^b	0.013 ± 0.00^c

Different lower case letters indicate significant differences between data in the same column (p < 0.05).

Figure 2. Effects of tea polyphenols assisted pickling on EUC of grass carp Different lower case letters indicate significant differences between data in the same column (p < 0.05).

Figure 3. Effects of tea polyphenols assisted pickling on TAV of grass carp Different lower case letters indicate significant differences between data in the same column (p < 0.05).