Structural and rheological properties of weakly deacetylated glucomannan gels after high-pressure treatment

Figures & data

Figure 1. FT-IR spectra of native glucomannan (lot A) (A) and weakly deacetylated (lot L) (B) glucomannan gels at 5g/100 mL of concentration at different high hydrostatic pressures 0MPa (A0 and L0); 100 MPa (A100 and L100); 200 MPa (A200 and L200); 400 MPa (A400 and L400), and 600 MPa (A600 and L600).

Table 1. Effect of high pressure on the linear viscoelastic (LVE) parameters for native (A0–A600), and slightly deacetylated (L0–L600) glucomannan (GM) gels, at 5 g/100 mL concentration, frequency: 1 Hz T = 25°C.

Sample	σmax (Pa)	γmax (%)	G* (kPa)	tanδ
A0	194 ± 19cA	4.58 ± 0.22dA	4.24 ± 0.21aA	0.361 ± 0.051aA
A100	314 ± 31abA	7.59 ± 0.32bA	4.14 ± 0.17aA	0.293 ± 0.003cB
A200	266 ± 27bA	5.94 ± 0.21cA	4.48 ± 0.16aA	0.368 ± 0.080aA
A400	362 ± 36aA	9.36 ± 0.82aA	3.89 ± 0.33aA	0.308 ± 0.004bB
A600	350 ± 35aA	8.27 ± 0.68abA	4.25 ± 0.35aA	0.319 ± 0.021aA
L0	200 ± 20abA	5.38 ± 0.61aA	3.75 ± 0.42aA	0.414 ± 0.026aA
L100	163 ± 16cB	4.21 ± 0.52bB	3.95 ± 0.48aA	0.401 ± 0.045aA
L200	200 ± 20abB	5.43 ± 0.27aA	3.68 ± 0.19aB	0.533 ± 0.094aA
L400	164 ± 16bcB	4.14 ± 0.58bB	3.99 ± 0.50aA	0.412 ± 0.052aA
L600	218 ± 22aB	5.49 ± 0.43aB	3.98 ± 0.31aA	0.286 ± 0.014bA

Values are given as mean ± expanded uncertainty limit (EUL).

a-c Different small letters indicate significant differences (p < 0.05) among different pressure levels for each Lot.

A-B Different capital letters indicate significant differences (p < 0.05) between Lots at fixed Pressure.

Figure 2. Thermal profiles of native (A, B) and weakly deacetylated (C, D) glucomannan gels at 5 g/100 mL at several high hydrostatic pressures: 0M Pa (A0 and L0), 100 MPa (A100 and L100), 200 MPa (A200 and L200), 400 MPa (A400 and L400), and 600 MPa (A600 and L600). Changes in storage modulus (G?) (A, C) and phase angle (?) (B, D).