Molecular characteristics of tara galactomannans: Effect of degradation with hydrogen peroxide

Figures & data

Table 1. Molecular weight of TG and degradation products.

Sample	Mw/10^3 (g/mol)	Mn/10^3 (g/mol)	Mw/Mn
TG	1519 ± 30	1315 ± 20	1.154 ± 0.06
^aTGH-0.4	1407 ± 20	1164 ± 35	1.209 ± 0.10
TGH-0.6	1268 ± 27	970 ± 10	1.307 ± 0.14
TGH-0.8	1289 ± 22	917 ± 25	1.328 ± 0.20
TGH-1.0	1093 ± 20	793 ± 18	1.378 ± 0.18
TGH-10	941 ± 35	646 ± 22	1.457 ± 0.21
TGH-50	335 ± 10	228 ± 15	1.470 ± 0.22
TGH-100	62.4 ± 3	37.4 ± 2	1.668 ± 0.31
^bTGH-0.4+Vc-0.2	35.1 ± 2	22.2 ± 4	1.581 ± 0.38
TGH-0.6+Vc-0.3	17.6 ± 2	12.1 ± 1	1.455 ± 0.15
TGH-0.8+Vc-0.4	16.7 ± 1	11.6 ± 1	1.440 ± 0.21
TGH-1.0+Vc-0.5	14.2 ± 0.3	9.6 ± 0.1	1.479 ± 0.22
TGH-10+Vc-5	13.1 ± 0.15	8.9 ± 0.2	1.472 ± 0.24

^aTG_H-0.4: 1.0 g of TG reacted with 0.4 mM of H₂O₂.

^bTG_H-0.4+Vc-0.2: 1.0 g of TG reacted with 0.4 mM of H₂O₂ and 0.2 mM of V_C.

Figure 1. FT-IR spectrum of native TG and its degradation products (a: TG; b: DP prepared by H₂O₂ system; c: DP prepared by H₂O₂+V_C system).

Figure 2. AFM images of oxidative degradation products of TG: (A) TG; (B) DP1, 10 mM H₂O₂; (C) DP2, 50 mM H₂O₂; (D) DP3, 0.4 mM H₂O₂+0.2 mM V_C; (E) DP4, 1.0 mM H₂O₂+0.5 mM V_C.

Figure 3. The steady flow behavior of aqueous solution of TG galactomannans with various molecular weight: (A) DP1, 941 × 10³ g/mol; DP2, 335 × 10³ g/mol, DP3, 35.1 × 10³ g/mol; DP4, 14.2 × 10³ g/mol; 0.5%, w/v; 25°C; (B) shear rate: 50 s^–1.

Figure 4. Mechanical spectra of degradation products of TG (1%, w/v) at 25°C and shear stress 1.1 Pa: (A) DP1; (B) DP2.