Physicochemical properties and structural characteristics of soluble dietary fibers from yellow and purple fleshed potatoes by-product

Figures & data

Table 1. Chemical compositions of SDFs (% dry matter).

	Moisture	Ash	Monosaccharide compositions
			Arabinose	Xylose	Mannose	Glucose	Galactose	Rhamnose
YSDF	2.95 ± 0.28 a	31.3 ± 2.1 a	15.91 ± 0.11 b	ND	1.85 ± 0.05 b	1.21 ± 0.12 a	95.77 ± 3.11 a	0.83 ± 0.09 a
PSDF	4.51 ± 0.13 b	30.9 ± 2.6 a	2.07 ± 0.09 a	ND	1.06 ± 0.09 a	2.05 ± 0.17 b	94.19 ± 4.02 a	0.63 ± 0.09 a

Different letters denote significantly different in the column (P < 0.05).

YSDF: soluble dietary fiber from yellow potato by-product; PSDF: soluble dietary fiber from purple potato by-product; ND: not detected.

Table 2. Physiochemical properties of SDFs.

	OHC (g/g)	SC (mL/g)	EA (mL/100 mL)	ES (mL/100 mL)
YSDF	15.6 ± 1.1 a	18.7 ± 0.8 a	33.8 ± 1.4 a	31.5 ± 0.3 a
PSDF	12.5 ± 0.9 b	13.5 ± 1.0 b	24.8 ± 1.1 b	19.6 ± 1.8 b

All data are means and SD of triplicate measurements; different letters denote significantly different in the column (P < 0.05).

OHC: oil-holding capacities; SC: swelling capacities; EA: emulsifying activity; ES: emulsion stability.

Table 3. Functional properties of DFs.

	TEAC (mg Trolox/g SDF)
	DPPH	ABTS	FRAP
YSDF	0.04 ± 0.01 a	1.96 ± 0.09 a	0.22 ± 0.02 a
PSDF	0.18 ± 0.01 b	2.39 ± 0.20 b	0.19 ± 0.02 a

All data are means and SD of triplicate measurements; different letters denote significantly different in the column (P < 0.05).

TEAC: trolox equivalent antioxidant capacity.

Table 4. Molecular weight of SDFs.

	Weight-average molecular weight Mw (Da)	Number-average molecular weight Mw (Da)	Polydispersity Pd (Mw/Mn)
YSDF	3967.3	1859.3	2.134
PSDF	4462.8	2677.2	1.667

Values are given as means of independent experiments.

Table 5. Thermal properties of SDFs.

	Release of water					Degradation of SDF
	TG			DSC		TG		DSC
	Ton (°C)	Changed mass	νmax (%/min)	Ton (°C)	∆H (J/g)	Ton (°C)	νmax (%/min)	Ton (°C)	∆H (J/g)	Residue (%)
YSDF	57.8	2.52	6.85	51.99	65.74	223.6	219.4	372.4	3955	67.2
PSDF	40.3	4.44	0.87	55.8	217.7	223.9	145.7	342.5	4309	67.4

TG: thermogravimetry; DSC: differential scanning calorimetry; T_on: the onset temperature; ∆H: enthalpy.

Figure 1. Thermal analysis of SDFs. (A) TG curves of SDFs; (B) DSC curves of SDFs.

Figure 2. FT-IR spectra of SDFs.

Figure 3. Scanning electronic micrographs of SDFs: (A) scanning electronic micrographs of YSDF; (B) scanning electronic micrographs of PSDF.