Table 2.

Relative contribution (%) and structural indices calculated from spectral data of main C structures over chemical shift regions (ppm) of ¹³C CPMAS-NMR spectra of HA-LIG and HA-CYN.

	Carboxyl-C	Phenol-C	Aryl-C	O-Alkyl-C	Methoxyl-C	Alkyl-C	Structural indexes
	190–160	160–145	145–110	110–60	60–45	45–0	HB/HIa	A/OAb	ARMc	LigRd
HA-LIG	6.1	9.6	33.0	12.8	9.8	28.7	2.49	2.27	1.02	1.06
HA-CYN	10.9	5.7	20.0	27.5	13.8	22.2	0.92	0.81	0.52	2.43

^aHB/HI = hydrophobicity index = [Σ (0–45) + (110–160)/ Σ (45–60) + (60–110) + (160–190)].

^bA/OA = alkyl/O-alkyl ratio (0–45)/(60–10).

^cARM = aromaticity index [(110–160)/Σ (0–45) + (60–110)].

^dLigR = Lignin ratio (45–60)/(140–160).