Rheological, pasting, and structural properties of potato starch by cross-linking

Figures & data

Table 1. Phosphorus content, degree of substitution (DS) and swelling factor of native (NPS), and cross-linked potato starch (CLPS) samples prepared with different concentrations of STMP/STPP.

Sample	P content (%)	DS (×10^−3)	Swelling factor
NPS	0.0564 ± 0.0001^e	–	18.24 ± 0.71^a
CLPS-0.0125	0.0531 ± 0.0002^f	5.561^e	15.85 ± 0.08^b
CLPS-0.025	0.0576 ± 0.0003^d	6.029^d	16.69 ± 0.19^b
CLPS-0.05	0.0576 ± 0.0002^d	6.031^d	13.25 ± 0.34^c
CLPS-0.5	0.0598 ± 0.0002^c	6.264^c	7.34 ± 0.62^d
CLPS-5	0.1854 ± 0.0007^b	19.489^b	5.51 ± 0.91^d
CLPS-10	0.3421 ± 0.0016^a	36.136^a	5.43 ± 0.72^e

Values with different letters within the same column differ significantly (p < 0.05).

Figure 1. Scanning electron micrographs (left: 1000×) and light micrographs (right: 20×) of native (NPS) and cross-linked potato starches (CLPS) prepared with different STMP/STPP concentrations. (a) NPS, (b) CLPS-0.0125, (c) CLPS-0.025, (d) CLPS-0.05, (e) CLPS-0.5, (f) CLPS-5, and (g) CLPS-10.

Figure 2. ³¹P-NMR spectra of native (a) and cross-linked potato starch (CLPS) prepared with 5% STMP/STPP concentration (b).

Table 2. Pasting properties of native (NPS) and cross-linked potato starches (CLPS) prepared with different STMP/STPP concentrations.

Sample	Pasting properties
	Pasting temperature (°C)	Peak viscosity (cP^1)	Trough viscosity (cP)	Breakdown (cP)	Final viscosity (cP)	Set back (cP)
NPS	68.05 ± 0.07^d	3459 ± 84^d	1398 ± 27^d	2061 ± 83^a	1767 ± 27^d	369 ± 19^d
CLPS-0.0125	68.38 ± 0.04^c	3637 ± 33^c	2980 ± 46^c	657 ± 78^b	3587 ± 29^c	607 ± 20^c
CLPS-0.025	68.78 ± 0.04^b	4297 ± 120^b	4105 ± 91^b	192 ± 43^c	5660 ± 57^b	1555 ± 35^b
CLPS-0.05	69.18 ± 0.04^a	4780 ± 75^a	4716 ± 89^a	64 ± 19^d	7476 ± 14^a	2760 ± 79^a
CLPS-0.5	N.D.^2	N.D.	N.D.	N.D.	N.D.	N.D.
CLPS-5	N.D.	N.D.	N.D.	N.D.	N.D.	N.D.
CLPS-10	N.D.	N.D.	N.D.	N.D.	N.D.	N.D.

Values with different letters within the same column differ significantly (p < 0.05).

¹cP: Centipoises;

²N.D.: not detected.

Figure 3. Shear stress versus shear rate plots of native (NPS) and cross-linked potato starch (CLPS) pastes prepared with different STMP/STPP concentrations at 25°C: (○) NPS, (×) CLPS-0.0125, (◇) CLPS-0.025, and (△) CLPS-0.05.

Table 3. Apparent viscosity (η_a,100), consistency index (K), flow behavior index (n), and Casson yield stress (σ_oc) of native (NPS), and cross-linked potato starch (CLPS) pastes prepared with different STMP/STPP concentrations at 25°C.

Sample	Apparent viscosity, ηa,100 (Pa s)	Consistency index, K (Pa s^n)	Flow behavior index, n (–)	R^2	Casson yield stress, σoc (Pa)	R^2
NPS	1.95 ± 0.03^d	10.76 ± 0.11^d	0.63 ± 0.00^a	0.99	17.81 ± 0.99^d	0.99
CLPS-0.0125	3.19 ± 0.03^c	27.12 ± 0.40^c	0.54 ± 0.00^b	0.99	84.90 ± 1.56^c	0.98
CLPS-0.025	5.42 ± 0.04^b	55.55 ± 0.64^b	0.49 ± 0.00^c	0.99	222.44 ± 7.67^b	0.94
CLPS-0.05	8.48 ± 0.12^a	93.40 ± 2.38^a	0.48 ± 0.00^d	0.99	430.62 ± 12.36^a	0.92

Values with different letters within the same column differ significantly (p < 0.05).

Figure 4. Plots of log G′, G″, η*, and tan δ versus log ω of native (NPS) and cross-linked potato starch (CLPS) pastes prepared with different STMP/STPP concentrations at 25°C: (○) NPS, (×) CLPS-0.0125, (◇) CLPS-0.025, and (△) CLPS-0.05.

Table 4. Storage modulus (G′), loss modulus (G″), complex viscosity (η*), and tan δ at 6.28 rad/s of native (NPS) and cross-linked potato starch (CLPS) pastes prepared with different STMP/STPP concentrations at 25°C.

Sample	G′ (Pa)	G″ (Pa)	η* (Pa s)	tan δ
NPS	11.57 ± 0.36^d	7.96 ± 0.16^d	2.23 ± 0.06^d	0.69 ± 0.14^a
CLPS-0.0125	42.37 ± 0.08^c	12.16 ± 0.19^c	7.00 ± 0.01^c	0.29 ± 0.08^b
CLPS-0.025	90.03 ± 0.74^b	19.81 ± 0.23^b	14.65 ± 0.10^b	0.22 ± 0.36^c
CLPS-0.05	335.69 ± 2.83^a	74.74 ± 2.03^a	54.59 ± 0.51^a	0.22 ± 0.56^c

Values with different letters within the same column differ significantly (p < 0.05).