Table 2.
Main components of RSE across three batches.
| Analyte | Unit | Mean ± SD | CV (%) |
|---|---|---|---|
| Total phenolic content | mg GAE L−1 | 94.9 ± 3.6 | 3.8 |
| Total flavonoid content | mg QE L−1 | 25.3 ± 0.2 | 0.8 |
| Soluble sugars | g glucose equivalents L−1 | 1.74 ± 0.08 | 4.6 |
| pH | — | 5.63 ± 0.09 | 1.6 |
| Vanillic acid | mg L−1 | 8.28 ± 0.46 | 5.6 |
| p-Coumaric acid | mg L−1 | 6.47 ± 0.28 | 4.3 |
| Ferulic acid | mg L−1 | 5.85 ± 0.29 | 5.0 |
| Syringic acid | mg L−1 | 5.08 ± 0.25 | 4.9 |
| Protocatechuic acid | mg L−1 | 3.63 ± 0.10 | 2.8 |
| Caffeic acid | mg L−1 | 2.88 ± 0.14 | 4.9 |
| Quercetin | mg L−1 | 2.06 ± 0.11 | 5.3 |
| Rutin | mg L−1 | 3.53 ± 0.19 | 5.4 |
Values are presented as mean ± SD from three independently prepared RSE batches. RSE, rice-straw extract; SD, standard deviation; GAE, gallic acid equivalents; QE, quercetin equivalents; CV, coefficient of variation; UHPLC–MS/MS, ultra-high-performance liquid chromatography–tandem mass spectrometry. Total phenolic and flavonoid contents are expressed relative to gallic acid and quercetin standards, respectively, and do not represent the summed concentrations of individual compounds. Individual phenolic compounds were quantified separately by UHPLC–MS/MS and are reported in mg L−1. All values refer to the undiluted RSE stock and are not expressed per gram of dry straw or as concentrations in the final diluted treatment solutions.