Table 1.
Resonance assignments with chemical shifts of constituents identified molasses and sugarcane juice (methanol-d4) 600 MHz with concentration of metabolites represented in µg/mg (n = 2).
| Class | Metabolite | δ1H (ppm) and Multiplicity | Assignments | Molasses | Sugarcane |
|---|---|---|---|---|---|
| Amino acids | Valine | 1.00 (d, J = 7.1 Hz) | CH3-4,5 | 0.87 | 0.61 |
| Alanine | 1.41 (d, J = 7.2 Hz); 3.23 (d, J = 1.7 Hz) | CH3-3; CH-2 | 1.67 | 1.0 | |
| Aspartate | 2.89 (dd, J = 16.9, 3.4 Hz); 2.63 (dd, J = 17.1, 9.5 Hz) | CH2-3 | - | 6.44 | |
| Organic acids | Lactic acid | 1.33 (d, J = 6.9 Hz) | CH3-3 | 1.54 | - |
| Malic acid | 2.28 (dd, J = 13.5, 1.7 Hz) | CH2-3 | - | 3.45 | |
| Formic acid | 8.31 (s) | HCOOH | 0.94 | 0.4 | |
| Sugars | β-Glucose | 4.42 (d, J = 7.8 Hz); 3.11 (d, J = 1.8 Hz); 3.36 (m); 3.22 (d, J = 2.0 Hz); 3.24 (m) | CH-1; CH-2; CH-3; CH-4; CH-5 | 57.1 | 11.2 |
| α-Glucose | 5.12 (d, J = 3.7 Hz); 3.61 (d, J = 2.9 Hz) | CH-1; CH-5 | 51.1 | 10.2 | |
| Fructose | 4.04 (d, J = 8.3 Hz); 3.56 (m) | CH-5 (α-Fructofuranose); CH2-6 (β-Fructofuranose) |
+ | + | |
| Sucrose | 5.39 (d, J = 3.8 Hz); 4.11 (d, J = 8.3 Hz) | CH-1 (glucose)CH-3 (fructose) | 126 | 67 | |
| Phenolic acids | Gentisic acid | 7.35 (d, J = 3.6 Hz); 6.75 (dd, J = 8.5, 2.3 Hz); 6.67 (d, J = 2.3 Hz) | CH-3; CH-5; CH-6 | 10.6 | 6.5 |
| Fatty acids | Fatty acids | 2.27 (m); 1.60 (m); 1.29 (m); 1.32 (m) | H-2; H-3; (CH2-)n ω-2; (CH2-)n ω-1 | + | + |
| Flavones | Luteolin | 6.73 (d, J = 2.3 Hz); 6.75 (d, J = 2.3 Hz) | CH-6; CH-8 | 8.5 | 6.2 |
| Apigenin | 7.41 (d, J = 8.5 Hz); 7.80 (d, J = 9.5 Hz); 6.66 (d, J = 2.3 Hz) | CH-3’ & 5’; CH-2’ & 6’; CH-6 | 11.2 | - |
s: singlet; d: doublet; dd: double doublet; t: triplet; m: multiplet; +: present; -: absent.