Research Article
Infrared and Terahertz Spectra of Pu’er White Tea with Different Degrees of Oxidation
Table 1
Attribution of absorption peak of white tea [
31–
33].
| | Absorption peak | Characteristic vibration |
| | 3400~3300 cm-1 | O-H and N-H stretching vibrations of proteins and polysaccharides | | Near 2929 cm-1 | Antisymmetric stretching vibration of fatty saturated hydrocarbon chain methylene-CH2 | | Near 2871 cm-1 | C-H antisymmetric and symmetric stretching vibration | | Near 1698 cm-1 | C=O stretching vibration on the benzene ring of catechin gallate | | Near 1654 cm-1 | The stretching vibration of C=O | | Near 1544 cm-1 | C=C skeleton vibration on benzene ring | | Near 1455 cm-1 | -OH in-plane bending vibration | | Near 1376 cm-1 | C-H symmetric bending vibration of methyl groups in phenolic substances | | Near 1240 cm-1 | Stretching vibration of phenolic C-O | | Near 1145 cm-1 | C-O-C asymmetric stretching vibration | | Near 1041 cm-1 | C-O-C symmetric stretching vibration | | Near 827 cm-1 | =C-H stretching vibration on 1,3-disubstituted benzene | | Near 763 cm-1 | =C-H stretching vibration on 1,2-disubstituted benzene | | Near 613 cm-1 | Stretching vibration produced by substituting -H with benzene |
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