Free Phenolic Acids in Shanxi Aged Vinegar: Changes During Aging and Synergistic Antioxidant Activities

Figures & data

FIGURE 1 The production flow chart of SAV.

FIGURE 2 The chromatogram of FPAs in 5 year SAV.

FIGURE 3 The content of TFPAs and FPAs in SAV.

TABLE 1 The chromatogram of FPAs extracted from 5 year SAV

Comparison with standard (without dihydro ferulic acid standard)				Accurate molecular weight
Rt (min)	Compound	[M-H]-	Fragments	Detected [M-H]-	Theoretical [M-H]-	Error (ppm)
2.346	Protocatechuic acid	153.0	109.0	153.01854	153.01875	1.62
3.719	p-Hydroxybenzoic acid	137.0	93.1	137.02387	137.02369	1.30
4.054	Salicylic acid	137.0	93.1	137.02387	137.02369	1.30
7.069	Dihydro sinapic acid	225.1	181.0, 151.0, 125.0	225.07702	225.07630	3.20
7.455	p-Coumaric acid	163.0	145.8, 135.0, 119.0	163.03957	163.03952	0.28
7. 835	Sinapic acid	223.1	178.9, 164.1, 123.0	223.06131	223.06065	2.96
7.940	Dihydro ferulic acid	195.1	151.0, 136.0, 123.1	195.06587	195.06574	0.67
8.292	Ferulic acid	193.1	177.9, 149.0, 134.0	193.05000	193.05009	0.46

TABLE 2 The antiradical activity of FPAs (ppm)

FPAs	Protocatechuic acid	Dihydro ferulic acid	Ferulic acid	Sinapic acid	p-Coumaric acid	p-Hydroxybenzoic acid
	(0.512 ± 0.012)	(0.510 ± 0.014)	(0.501 ± 0.005)	(0.392 ± 0.022)	(0.390 ± 0.020)	(0.060 ± 0.001)
Protocatechuic acid (0.512 ± 0.012)	–	–	–	–	–	–
Dihydro ferulic acid (0.510 ± 0.014)	0.487 ± 0.010^*－	–	–	–	–	–
Ferulic acid (0.501 ± 0.005)	0.441 ± 0.003^**－	0.469 ± 0.009^**－	–	–	–	–
Sinapic acid (0.392 ± 0.022)	0.422 ± 0.011^*－	0.435 ± 0.009	0.455 ± 0.008	–	–	–
p-Coumaric acid (0.390 ± 0.020)	0.295 ± 0.007^**－	0.354 ± 0.002^**－	0.384 ± 0.011^**－	0.342 ± 0.003^**－	–	–
p-Hydroxybenzoic acid (0.060 ± 0.001)	0.266 ± 0.009^**－	0.287 ± 0.001	0.356 ± 0.007^**+	0.225 ± 0.002	0.313 ± 0.008^**+	–
Salicylic acid (0.001 ± 0.000)	0.265 ± 0.004^*+	0.288 ± 0.001^**+	0.348 ± 0.002^**+	0.236 ± 0.004^**+	0.276 ± 0.005^**+	0.022 ± 0.001^**－

Number in the bracket is the antiradical activity of FPAs. Intersections represent the antiradical activity of the equal mixture of two FPAs;

^－:Half of the total antiradical activity of two FPAs more than the mixture of two FPAs;

⁺:Half of the total antiradical activity of two FPAs less than the mixture of two FPAs;

*:one-sided t-test, p < 0.05;

**:one-sided t-test, p < 0.01.

TABLE 3 The reducing power of FPAs (ppm)

FPAs	Protocatechuic acid	Dihydro ferulic acid	Ferulic acid	Sinapic acid	p-Coumaric acid	p-Hydroxybenzoic acid
	(1.256 ± 0.025)	(0.941 ± 0.001)	(0.761 ± 0.016)	(0.610 ± 0.032)	(0.758 ± 0.038)	(0.451 ± 0.017)
Protocatechuic acid (1.256 ± 0.025)	–	–	–	–	–	–
Dihydro ferulic acid (0.941 ± 0.001)	1.138 ± 0.017^*+	–	–	–	–	–
Ferulic acid (0.761 ± 0.016)	1.038 ± 0.010	0.916 ± 0.003^**+	–	–	–	–
Sinapic acid (0.610 ± 0.032)	1.017 ± 0.009^**+	0.857 ± 0.017^**+	0.681 ± 0.010	–	–	–
p-Coumaric acid (0.758 ± 0.038)	1.039 ± 0.005	0.850 ± 0.003	0.812 ± 0.005^*+	0.787 ± 0.012^*+	–	–
p-Hydroxybenzoic acid (0.451 ± 0.017)	0.718 ± 0.001^**－	0.607 ± 0.026^**－	0.585 ± 0.009	0.543 ± 0.009	0.576 ± 0.027	–
Salicylic acid (0.359 ± 0.013)	0.718 ± 0.010^**－	0.615 ± 0.007^**－	0.587 ± 0.005^*+	0.534 ± 0.003^*+	0.539 ± 0.007	0.428 ± 0.001^*+

Number in the bracket is the reducing power of FPAs. Intersections represent the reducing power of the equal mixture of two FPAs;

^－:Half of the total reducing power of two FPAs more than the mixture of two FPAs;

⁺:Half of the total reducing power of two FPAs less than the mixture of two FPAs;

*:one-sided t-test, p < 0.05;

**:one-sided t-test, p < 0.01.