Table 3.
Retention time (Rt), wavelengths of maximum absorption in the visible region (λmax), mass spectral data, tentative identification, and quantification (μg/g dry matter) of free and bound phenolic compounds present in raw lentils and lentil sprouts.
| Compounds |
Rt
(min) |
λmax
(nm) |
Molecular ion [M-H] − (m/z) |
MS2
(m/z) |
Concentration (μg/g) | |||
| Free phenolics | Bound phenolics | |||||||
| Raw lentil | Lentil sprout | Raw lentil | Lentil sprout | |||||
| Hydroxybenzoic acids | ||||||||
| p -Hydroxybenzoic-hexoside | 5.48 | 255 | 299 | – | 8.14 ± 4.16 | 3.34 ± 0.20 | 34.32 ± 6.84 | 27.06 ± 1.58 |
| Protocatechuic acid | 6.70 | 257, 294 | 153 | – | 23.22 ± 2.52 | 4.36 ± 0.60*** | 26.34 ± 3.00 | 21.48 ± 10.92 |
| Total | 31.36 ± 6.68 | 7.70 ± 0.80** | 60.66 ± 9.84 | 48.54 ± 12.50 | ||||
| Hydroxycinnamic acids | ||||||||
| trans-p-Coumaric derivative | 10.04 | 309 | 417 | – | 18.94 ± 2.08 | 5.16 ± 1.08*** | nd | nd |
| p-Coumaroyl malic acid | 12.46 | 308 | 278 | 163 | 9.50 ± 1.06 | 11.10 ± 2.88 | nd | nd |
| p-Coumaroyl glycolic acid | 12.80 | 314 | 220 | 163 | 12.48 ± 2.32 | 13.68 ± 2.16 | nd | nd |
| p-Coumaric acid derivative | 13.10 | 312 | – | 163 | 13.08 ± 0.78 | nd*** | nd | nd |
| trans-p-Coumaric acid | 18.20 | 314 | 163 | – | 12.72 ± 0.00 | 8.78 ± 1.46** | 2.58 ± 0.00 | 2.64 ± 0.62 |
| trans-Ferulic acid | 20.4 | 322 | 193 | – | nd | nd | 3.18 ± 0.34 | 3.16 ± 1.04 |
| Total | 66.72 ± 6.24 | 38.72 ± 7.58** | 5.76 ± 0.34 | 5.80 ± 1.66 | ||||
| Catechins and procyanidins | ||||||||
| (+)-Catechin | 10.90 | 280 | 289 | 245, 203, 161 | 262.98 ± 37.20 | 150.06 ± 14.08** | 78.74 ± 14.54 | 27.94 ± 5.22*** |
| (+)-Catechin 3-O-hexoside | 9.02 | 280 | 451 | 289 | 298.58 ± 15.76 | 206.32 ± 5.26*** | nd | nd |
| Dimer prodelphinidin | 7.76 | 276 | 593 | 447, 441, 423, 305, 289 | 120.20 ± 2.54 | nd*** | nd | nd |
| Dimer procyanidin | 10.40 | 279 | 577 | 289 | 52.68 ± 0.02 | 23.86 ± 2.00*** | nd | nd |
| Total | 734.44 ± 55.52 | 380.24 ± 19.34 *** | 78.74 ± 14.54 | 27.94 ± 5.22*** | ||||
| Flavonols and flavanone | ||||||||
| Kaempferol glucuronide dihexoside | 10.12 | 346 | 785 | 285 | nd | 2.56 ± 0.60** | nd | nd |
| Kaempferol dirutinoside | 14.05 | 346 | 901 | 755, 593, 285 | 408.60 ± 3.72 | 305.74 ± 10.04*** | 22.70 ± 4.72 | 8.44 ± 0.46** |
| Kaempferol rutinoside hexoside (I) | 15.00 | 345 | 755 | 593, 285 | 15.02 ± 0.26 | 8.92 ± 1.26** | 1.82 ± 0.12 | 1.90 ± 0.36 |
| Kaempferol rutinoside hexoside (II) | 17.04 | 346 | 755 | 593, 285 | nd | 7.10 ± 0.24*** | nd | nd |
| Kaempferol rutinoside rhamnoside (I) | 18.30 | 346 | 739 | 593, 285 | 12.68 ± 0.04 | 16.10 ± 1.00** | 0.82 ± 0.06 | 1.24 ± 0.26 |
| Kaempferol rutinoside rhamnoside (II) | 19.14 | 346 | 739 | 593, 285 | nd | 11.32 ± 3.08** | nd | nd |
| Quercetin 3-glucoside | 20.1 | 356 | 463 | 301 | 3.30 ± 0.26 | 3.02 ± 0.32 | nd | nd |
| Kaempferol glucuronide | 25.40 | 346 | 461 | 285 | 11.22 ± 2.48 | 14.10 ± 1.24 | nd | nd |
| Kaempferol rhamnoside | 34.10 | 346 | 431 | 285 | 10.52 ± 2.06 | 69.00 ± 8.54*** | 4.84 ± 0.46 | 8.76 ± 1.36*** |
| Eriodyctyol hexoside | 16.30 | 288, 338 (sh) | 449 | 287 | 8.92 ± 1.26 | 18.78 ± 0.96*** | nd | nd |
| Total | 470.26 ± 10.08 | 456.64 ± 27.28 | 30.18 ± 5.36 | 20.34 ± 2.44* | ||||
| Total phenolic compounds | 1302.78 ± 78.52 | 883.30 ± 55.00 ** | 175.34 ± 30.08 | 102.62 ± 21.82 * | ||||
Results are reported as mean ± SD (n = 3). Mean values followed by superscript asterisks significantly differ (raw vs. sprouted lentils) when subjected to T-test (* p < 0.05, ** p < 0.01, *** p < 0.001). nd: nondetected.