Table 3.

Description of FTIR peaks.

Peak cm−1	Functional Group/Vibration Mode
750	Aromatic protons
927	C–O–C vibration modes of α-1,4 glycosidic linkage
1040/1162	Carbonyl (C=O) group, C–O stretching alcohols (primary, secondary and tertiary), carboxylic acids, esters, and ethers
1020/1079 1116/1156	C–O/C stretching in exo/endo-cyclic bonds and C–O–H/C deformation modes of oligo/polysaccharides and absorption bands for carbohydrates
1383/1456	The spectral bands for C–O–H stretching in pyranose and C–H deformation in esters
1621/1637	Aromatic C=C/C–OH stretching in exocyclic bond
2923	Glucoside ring due to the stretching vibration of O–H [44]
3420	O–H, as also the H-bonded alcohols and phenols, carboxylic acid