Table 3. Tentative phenolic phytochemicals discovered in the free fractions of white, brown and black rice by UHPLC-Q-TOF-MS2.
| S.No | Sample Name | RT (min) | Peak Area | Charge /Adduct | Precursor mass | Found at mass | Molecular Formula | Tentative Phenolic compound |
|---|---|---|---|---|---|---|---|---|
| 1 | WR(white rice) | Nd | Nd | [M‒H]‒ | Nd | Nd | C15H14O7 | Epigallocatechin |
| BR(Brown rice) | Nd | Nd | [M‒H]‒ | Nd | Nd | |||
| BLK(Black rice) | 5.49 | 780000 | [M‒H]‒ | 305.041 | 305.038 | |||
| 2 | WR(white rice) | Nd | Nd | [M+H]+ | Nd | Nd | C7H6O4 | Gentisic acid |
| BR(Brown rice) | Nd | Nd | [M+H]+ | Nd | Nd | |||
| BLK(Black rice) | 5.49 | 1000000 | [M+H]+ | 153.019 | 153.019 | |||
| 3 | WR(white rice) | Nd | Nd | [M‒H]‒ | Nd | Nd | C17H26O4 | 6-Gingerol |
| BR(Brown rice) | 4.61 | 12000 | [M‒H]‒ | 293.177 | 293.176 | |||
| BLK(Black rice) | Nd | Nd | [M‒H]‒ | Nd | Nd | |||
| 4 | WR(white rice) | Nd | Nd | [M+H]+ | Nd | Nd | C8H8O4 | Vanillic acid |
| BR(Brown rice) | 11.71 | 7000 | [M+H]+ | 167.032 | 167.033 | |||
| BLK(Black rice) | 11.73 | 120000 | [M+H]+ | 167.032 | 167.035 | |||
| 5 | WR(white rice) | Nd | Nd | [M+H]+ | Nd | Nd | C15H12O7 | Dihydroquercetin |
| BR(Brown rice) | Nd | Nd | [M+H]+ | Nd | Nd | |||
| BLK(Black rice) | 16.83 | 380000 | [M+H]+ | 303.049 | 303.051 | |||
| 6 | WR(white rice) | Nd | Nd | [M+H]+ | Nd | Nd | C13H16O9 | Protocatechuic acid 4-O-glucoside |
| BR(Brown rice) | Nd | Nd | [M+H]+ | Nd | Nd | |||
| BLK(Black rice) | 1.24 | 140000 | [M+H]+ | 315.071 | 315.072 | |||
| 7 | WR(white rice) | Nd | Nd | [M+H]+ | Nd | Nd | C15H18O9 | Caffeic acid 4-O-glucuronide |
| BR(Brown rice) | Nd | Nd | [M+H]+ | Nd | Nd | |||
| BLK(Black rice) | 8.54 | 98000 | [M+H]+ | 355.067 | 355.067 | |||
| 8 | WR(white rice) | Nd | Nd | [M‒H]‒ | Nd | Nd | C16H20O10 | Dihydroferulic acid 4-O-glucuronide |
| BR(Brown rice) | 14.80 | 8600 | [M‒H]‒ | 371.097 | 371.097 | |||
| BLK(Black rice) | 14.81 | 140000 | [M‒H]‒ | 371.097 | 371.098 | |||
| 9 | WR(white rice) | Nd | Nd | [M‒H]‒ | Nd | Nd | C9H8O2 | Cinnamic acid |
| BR(Brown rice) | 4.03 | 7800 | [M‒H]‒ | 147.046 | 147.0455 | |||
| BLK(Black rice) | 4.01 | 32000 | [M‒H]‒ | 147.046 | 147.0456 | |||
| 10 | WR(white rice) | Nd | Nd | [M‒H]‒ | Nd | Nd | C9H10O3 | Methoxyphenylacetic acid |
| BR(Brown rice) | 15.28 | 5800 | [M‒H]‒ | 165.057 | 165.0558 | |||
| BLK(Black rice) | 15.29 | 49000 | [M‒H]‒ | 165.057 | 165.056 |
Nd-Not determined, RT-Retention time.