Pasting, Thermal, Hydration, and Functional Properties of Annealed and Heat-Moisture Treated Starch of Sword Bean (Canavalia gladiata)

Figures & data

Figure 1 The RVA viscoamylogram of native (SBN), annealed (SAN), and heat-moisture treated (SHT 20; 25; 30) sword bean starches. (Figure provided in color online.)

Table 1 Pasting properties of sword bean physically modified starch (on dry basis)

Parameters	SBN	SHT-20	SHT-25	SHT-30	SAN
Peak Viscosity, PV (RVU)	438.33	306.58	216.58	273.58	399.17
Trough viscosity, TV (RVU)	257.47	211.83	159.00	191.83	263.83
Breakdown (PV – TV) (RVU)	180.92	94.75	57.58	81.75	135.33
Final viscosity, FV (RVU)	426.75	385.92	273.00	330.08	478.67
Setback (FV – PV) (RVU)	169.33	174.08	114.00	138.25	214.83
Peak time (min)	4.11	4.40	4.46	4.46	4.20
Pasting temperature (°C)	64.45	64.55	64.15	64.15	64.45
Results are means of triplicate determinations. SBN: Sword bean native starch; SHT-20: Sword bean starch HMT at 20% moisture; SHT-25: Sword bean starch HMT at 25% moisture; SHT-30: Sword bean starch HMT at 30% moisture; and SAN: Sword bean annealed starch.

Table 2 Gelatinisation parameters of Sword bean native and physically modified (HMT & ANN) starches (on dry basis)

Parameter ^a	To (°C)	Tp (°C)	Tc (°C)	Tc–To (°C)	ΔH gel (J/g)
SBN	78.79	83.44	88.46	9.67	13.82
SHT-20	85.78	86.28	90.29	4.41	2.66
SHT-25	87.45	90.76	93.85	6.40	3.47
SHT-30	83.96	84.61	87.75	3.80	1.39
SAN	80.62	82.97	85.71	4.08	6.74
^aTo: Onset temperature; Tp: Peak temperature; Tc: Conclusion temperature; Tc–To: Gelatinisation temperature range; ΔHgel: Enthalpy of gelatinisation; SBN: Sword bean native starch; SHT-20: Sword bean starch HMT at 20% moisture; SHT-25: Sword bean starch HMT at 25% moisture; SHT-30: Sword bean starch HMT at 30% moisture; and SAN: Sword bean annealed starch.

Table 3 Retrogradation characteristics of Sword bean native and physically modified starch

Parameter	To (°C)	Tp (°C)	Tc (°C)	Tc–To (°C)	ΔHR (J/g)
SBN	64.88	71.71	78.72	3.83	3.71
SHT-20	60.59	69.20	61.53	0.94	3.33
SHT-25	60.21	69.01	61.03	0.82	1.41
SHT-30	60.71	69.54	61.38	0.66	3.45
SAN	61.59	68.18	70.44	8.85	2.96
^aTo: Onset temperature; Tp: Peak temperature; Tc: Conclusion temperature; Tc–To: Retrogradation temperature range; ΔHR: Enthalpy of retrogration; SBN: Sword bean native starch; SHT-20: Sword bean starch HMT at 20% moisture; SHT-25: Sword bean starch HMT at 25% moisture; SHT-30: Sword bean starch HMT at 30% moisture; and SAN: Sword bean annealed starch.

Figure 2 Swelling power of native and hydrothermally treated starches of Sword bean (on dry basis). B: Sword bean native starch (SBN); C: Sword bean starch HMT at 20°C (SHT-20); D: Sword bean starch HMT at 25°C (SHT-25); E: Sword bean starch HMT at 30°C (SHT-30); and F: Sword bean annealed starch (SAN).

Figure 3 Solubility power of native and hydrothermally treated starches of Sword bean (on dry basis). B: Sword bean native starch (SBN); C: Sword bean starch HMT at 20°C (SHT-20); D: Sword bean starch HMT at 25°C (SHT-25); E: Sword bean starch HMT at 30°C (SHT-30); and F: Sword bean annealed starch (SAN).

Table 4 Oil and water absorption capacity of Sword bean starches (on dry basis)

Sample	Water absorbed (g/g)	Oil absorbed (g/g)
SBN	3.15±0.55	2.42±0.43
SAN	3.24±0.02	2.48±0.75
SHT-20	3.33±0.18	2.52±0.31
SHT-25	3.42±0.03	2.61±0.10
SHT-30	3.44±0.24	2.65±0.31
Results are means of triplicate determinations. SBN: Sword bean native starch; SHT-20: Sword bean starch HMT at 20% moisture; SHT-25: Sword bean starch HMT at 25% moisture; SHT-30: Sword bean starch HMT at 30% moisture; and SAN: Sword bean annealed starch.

Table 5 Gelation capacities of Sword bean starches (on dry basis)

		Sample concentrations (% w/v);
Sample	Remark	2	4	6	8	10	12	14
SBN	Gelation	+	+	+	+	+	+	+
	State	Viscous	Viscous	Viscous	Viscous	LGC	FG	FG
SAN	Gelation	−	−	+	+	+	+	+
	State	Liquid	Liquid	Viscous	LGC	FG	VFG	VFG
SHT20	Gelation	+	+	+	+	+	+	+
	State	Viscous	Viscous	Viscous	LGC	FG	VFG	VFG
SHT25	Gelation	+	+	+	+	+	+	+
	State	Viscous	Viscous	LGC	Gel	FG	FG	VFG
SHT30	Gelation	−	+	+	+	+	+	+
	State	Liquid	LGC	Gel	Gel	Gel	Gel	FG
^aLGC: Lowest Gel Concentration; FG: Firm Gel; VFG: Very Firm Gel; SBN: Sword bean native starch; SHT-20: Sword bean starch HMT at 20% moisture; SHT-25: Sword bean starch HMT at 25% moisture; SHT-30: Sword bean starch HMT at 30% moisture; and SAN: Sword bean annealed starch.

Figure 4 Wide-angle X-ray diffraction pattern of native Sword bean (SBN), Annealed (SAN), Heat-Moisture Treated starches at 20% (SHT-20), 25% (SHT-25), and 30 % (SHT- 30) moisture. SBN: Sword bean native starch; SHT-20: Sword bean starch HMT at 20% moisture; SHT-25: Sword bean starch HMT at 25% moisture; SHT-30: Sword bean starch HMT at 30% moisture; and SAN: Sword bean annealed starch. (Figure provided in color online.)

Figure 5 Scanning electron micrograph of Sword bean native starch (SBN) at 500 (A), 1000 (B), and 3000 × magnification.

Figure 6 Scanning electron micrograph of heat-moisture (20%) treated starch of Sword bean (SHT-20) at 500 (A), 1000 (B), and 3000 (C) × magnification.

Figure 7 Scanning electron micrograph of heat-moisture (25%) treated starch of Sword bean (SHT-25) at 500 (A), 1000 (B), and 3000 (C) × magnification.

Figure 8 Scanning electron micrograph of heat-moisture (30%) treated starch of Sword bean (SHT-30) at 500 (A), 1000 (B), and 3000 (C) × magnification.

Figure 9 Scanning electron micrograph of Sword bean annealed starch (SAN) at 500 (A), 1000 (B), and 3000 (C) × magnification.