Table 2: Characterization of compounds from acidified methanolic extracts of rice during grain development by LC-ESI-QTOF-MS/MS in negative mode.

No. tR (min) [M-H]-m/z MS/MSm/z Formula Error(ppm) Tentative identification Rice variety and Stage found
19 8.65 359.0743 a C18H16O8 8.16 5,2',3'-Trihydroxy-3,6,7-trimethoxyflavone W: S2
21 8.97 439.1918[M + Cl]- 403.22,359.19,329.18, 297.15,186.12,127.05 C23H32O6 -5.71 1-alpha-O-Methylquassin W: S4-S5
25 9.38 176.0369 134.02 C6H11NO3S 10.09 N-Formylmethionine W: S4
28 9.73 325.0497[M +Cl]- 289.07,245.07 C15H14O6 -3.92 Catechin* R: S2-S3
2 2.99 104.0348 74.02 C3H7NO3 4.97 D-Serine B: S1-S3
3 3.01 225.0599 179.05,161.04 C6H12O6 1.73 Hexose B: S1-S3,S5
15 7.22 147.0317 129.01,85.02 C5H8O5 -12.18 (S)-2-Hydroxyglutarate B: S1
17 8.04 164.0733 a C9H11NO2 -9.68 Phenylalanine B: S2
20 8.84 465.1006[M + 16] 285.048,329.08 C21H21O11 -19.85 Cyanidin glucoside* B: S4-S5
8.85 447.089[M-H]- 284.03,256.03
24 9.36 479.1143[M +16]- 355.06,299.05,284.03, 149.02 C22 H23O11 10.85 Peonidin glucoside* B: S4-S5
30 11.68 463.083[M-H]- 301.03,257.04,109.02 C21H20O12 11.23 Tricetin-7-glucoside B: S5
5 3.16 171.0081 78.95 C3H9O6P -9.95 Glycerol-3-phosphate R: S2,S4,S5;B: S1,S3,S5
26 9.5 153.0183 109.02 C7H6O4 6.7 Protocatechuic acid R: S4-S5;B: S2-S5
31 12.78 167.035 108.022 C8H8O4 -0.11 Vanillic acid R: S2-S5,B: S2-S5
32 13.37 195.0292 136.01,108.02 C9H8O5 3.57 (2E)-3-(2,4,5-Trihydroxyphenyl)acrylic acid R: S5;B: S2-S5
1 2.88 194.9476 176.93,96.96 Unidentified W: S1,S3,S5;R: S1,S2,S4; B: S1-S4
4 3.03 132.0298 88.03 C4H7NO4 3.27 D-Aspartic acid W: S1-S5;R: S1-S4; B: S3-S5
6 3.25 377.0864[M + Cl]- 341,10,179.05,89.05 C12H22O11 -2.09 Sucrose W: S5;R: S1-S5;B: S1
7 3.25 215.0343[M + Cl]- 179.05,89.05 -7.02 Glucose W: S5;R: S1-S5;B: S1
8 3.42 134.049 107.03,65.01 C5H5N5 -13.19 Adenine W: S1,S3,S5;R: S1-S3; B: S1-S4
9 3.55 359.0768 305.08,215.83 C18H16O8 1.23 5,8,4'-Trihydroxy-3,6,7-trimethoxyflavone W: S1,S3,S4;R: S1-S5; B: S1-S5
10 3.7 391.1037[M + Cl]- 355.14,193.08 C13H24O11 -6.23 D-Pinitol hexose isomer W: S1-S3,S5;R: S1-S5; B: S1-S5
11 3.75 110.9767 79.96 CH4O4S -8.46 Monomethyl sulfate W: S1-S5;R: S5;B: S1-S5
12 3.98 229.0482 170.89,78.95 C13H10O4 10.62 4-Hydroxyphenyl-4-hydroxybenzoate W: S1-S5;R: S1-S5; B: S1,S2, S4,S5
13 4.78 391.1027[M+Cl]- 355.12,193.07,89.02 C13H24O11 -3.67 D-Pinitol hexose isomer W: S2-S3,S5;R: S3,S5; B: S1-S5
14 5.18 279.0369 243.06,200.05,111.02, 110.02 C14H12O4 15.09 3,3',4,5'-Tetrahydroxy-trans-stilbene W: S1-S4; R: S1-S3; B: S1-S5
16 8.04 323.0557 164.07 C18H12O6 1.27 Neobanol W: S2,S4;R: S3,S5;B: S1-S3
18 8.05 205.0371 143.03,111.08,87.00, 67.01 C7H10O7 -8.41 2-Methylcitric acid W: S3; R: S3-S5;B: S4
22 9.13 236.0535 176.03,162.01,134.02 C7H15N32S2 -0.88 Cysteinyl-N-(2-sulfanylethyl)glycinamide W: S2-S4,R: S5,B:S4
27 9.73 219.0526 169.04,115.03,73.02 C8H12O7 -7.18 1-Hydroxypentane-1,2,5-tricarboxylate W: S1-S5;R: S1-S5; B: S1.S2,S4,S5
29 11.01 137.0228 93.0343 C7H6O3 11.72 p-hydroxybenzoic acid W: S2;R: S1-S5;B: S1,S4-S5

W = White Rice, R = Red Rice, B = Black Rice, S = Stage, a = Fragmentation was not achieved