Characterization of the dough rheological and steamed bread fortified with extruded purple sweet potato flour

Figures & data

Table 1. Effect of purple sweet potato flour on freezable water content and thermal properties of composite doughs

Sample	Tm (°C)	FWC (%)	To (°C)	Tp (°C)	Te (°C)	∆H (J·g^−1)
Control	3.27 ± 0.55c	11.61 ± 1.69a	58.20 ± 0.56a	68.78 ± 0.34a	79.47 ± 0.36a	0.31 ± 0.03a
UP5	3.12 ± 0.37c	13.99 ± 0.68b	58.69 ± 1.07ab	68.90 ± 0.74a	80.18 ± 1.50a	0.38 ± 0.09a
UP10	3.81 ± 0.14d	15.63 ± 0.04cd	59.81 ± 0.72abc	69.41 ± 0.62a	80.56 ± 0.44a	0.37 ± 0.02a
UP15	3.63 ± 0.16d	17.26 ± 1.13d	59.92 ± 0.89abc	70.34 ± 0.17ab	81.04 ± 0.29a	0.33 ± 0.05a
EP5	3.28 ± 0.30c	15.28 ± 0.47bc	62.38 ± 4.18cd	71.98 ± 2.56bc	83.13 ± 1.24c	0.32 ± 0.10a
EP10	2.72 ± 0.40b	15.87 ± 0.59cd	61.82 ± 0.26bcd	72.20 ± 0.48bc	83.20 ± 1.42b	0.25 ± 0.03a
EP15	2.25 ± 0.10a	16.66 ± 1.27cd	63.61 ± 0.45d	73.44 ± 0.50c	83.19 ± 1.35b	0.33 ± 0.02a

T_m, melting temperature; FWC, freezable water content; T_o, onset temperature; T_p, peak temperature; T_e, end temperature; ΔH, enthalpy value.

Results are presented as means ± standard deviations. Means followed by different letters in the same line are significantly different at P < 0.05.

Table 2. Alveograph rheological properties of the wheat-purple sweet potato composite doughs

Sample	P (mm)	L (mm)	W (J. 10^−4)	P/L
Control	91.0 ± 2.3ab	71.1 ± 0.3e	236.5 ± 2.4 f	1.28 ± 0.09a
UP5	97.2 ± 0.5c	41.5 ± 0.4a	117.2 ± 1.6b	2.37 ± 0.06d
UP10	89.1 ± 0.7a	42.4 ± 0.2a	111.6 ± 1.1a	2.12 ± 0.02c
UP15	92.6 ± 1.1b	49.1 ± 0.7c	146.7 ± 2.4c	1.88 ± 0.14b
EP5	91.5 ± 0.9b	71.8 ± 1.1e	236.3 ± 2.0f	1.28 ± 0.11a
EP10	102.3 ± 0.7d	47.5 ± 0.4b	174.1 ± 0.9d	2.17 ± 0.07c
EP15	105.4 ± 1.3e	54.8 ± 0.6d	197.0 ± 0.7e	1.89 ± 0.04b

Note: P, tenacity; L, extensibility; P/L, configuration ratio; W, the deformation energy.

Results are presented as means ± standard deviations. Means followed by different letters in the same line are significantly different at P < 0.05.

Figure 1. Fermentation properties of the wheat-purple sweet potato composite doughs

Table 3. Technological properties of the wheat-purple sweet potato composite steamed bread

Sample	SV(ml/g)	Hardness (g)	Springiness	Cohesiveness	Stickiness	Chewiness(g)
Control	2.70 ± 0.18a	633.72 ± 6.09g	0.99 ± 0.01a	0.86 ± 0.00b	542.24 ± 6.02 g	537.99 ± 2.95e
UP5	2.42 ± 0.03ab	736.40 ± 23.33f	1.01 ± 0.01a	0.83 ± 0.01c	611.90 ± 21.1 f	617.15 ± 24.98de
UP10	2.39 ± 0.05ab	1359.33 ± 48.86b	0.99 ± 0.02a	0.83 ± 0.01c	1134.35 ± 52.54b	1124.79 ± 60.68b
UP15	2.17 ± 0.22b	1636.50 ± 8.05a	0.99 ± 0.01a	0.82 ± 0.01c	1350.76 ± 23.21a	1339.83 ± 31.54a
EP5	2.44 ± 0.05ab	813.26 ± 9.96e	0.98 ± 0.01a	0.84 ± 0.01bc	687.34 ± 2.90e	672.86 ± 3.55d
EP10	2.40 ± 0.09ab	938.24 ± 23.47d	1.05 ± 0.09a	0.87 ± 0.01a	821.34 ± 17.34d	860.50 ± 99.17c
EP15	2.27 ± 0.2b	985.19 ± 7.47c	1.00 ± 0.02a	0.85 ± 0.01b	842.69 ± 1.38c	838.14 ± 19.06c

SV, specific volume. Results are presented as means ± standard deviations. Means followed by different letters in the same line are significantly different at P < 0.05.

Figure 2. Effect of addition of purple sweet potato flour on total phenolic content and antioxidant properties of composite steamed breads

Table 4. Correlation coefficients between dough and steamed bread properties

	Thermal properties					Water	Alveography
	To	Tp	Te	∆H	Tm	FW	P	L	W	P/L
To	1
Tp	0.982**	1
Te	0.960**	0.963**	1
∆H	-0.377	-0.502	-0.523	1
Tm	-0.638	0.710*	-0.605	0.409	1
FW	0.639	0.714*	0.679*	0.018	-0.036	1
P	0.607	0.688*	0.602	-0.366	-0.935**	0.341	1
L	0.141	0.155	0.117	-0.355	-0.079	-0.439	-0.247	1
W	0.331	0.378	0.321	-0.542	-0.349	-0.340	0.041	0.951**	1
P/L	-0.071	0.073	-0.028	0.259	-0.102	0.376	0.406	-0.974**	-0.881**	1
Hm	-0.385	-0.335	-0.400	-0.116	-0.106	-0.897**	-0.185	0.720**	0.666	-0.642
Tx	0.228	0.285	0.182	-0.521	-0.583	-0.526	0.302	-0.674*	0.803*	-0.552
Vt	0.134	0.220	0.294	-0.545	0.060	0.566	0.206	-0.480	-0.346	0.436
SV	-0.461	-0.455	-0.428	-0.138	0.078	-0.950**	-0.331	0.736*	0.469	-0.47
Hardness	0.048	0.028	0.007	0.170	0.455	0.743*	-0.207	-0.482	-0.533	0.296
Springiness	0.158	0.260	0.326	-0.579	-0.497	0.117	0.657	-0.456	-0.211	0.587
Cohesiveness	0.271	0.363	0.338	-0.790*	-0.619	-0.345	0.470	0.360	0.574	-0.217
Stickiness	0.079	0.063	0.041	0.129	0.426	0.759*	-0.175	0.484	-0.522	0.303
Chewiness	0.087	0.077	0.060	0.090	0.402	0.768*	-0.140	-0.512	-0.536	0.337
	Fermentation			Technological properties
	Hm	Tx	Vt	SV	Hardness	Springiness	Cohesiveness	Stickiness	Chewiness
To
Tp
Te
∆H
Tm
FW
P
L
W
P/L
Hm	1
Tx	0.716*	1
Vt	-0.627	-0.367	1
SV	0.853**	0.649	-0.484	1
Hardness	-0.771*	-0.716*	0.574	-0.764*	1
Springiness	-0.225	0.115	0.630	-0.051	-0.167	1
Cohesiveness	0.430	0.852**	0.103	0.520	-0.601	0.582	1
Stickiness	-0.784*	-0.693*	0.602	-0.768*	0.999**	-0.132	-0.562	1
Chewiness	-0.800*	-0.688*	0.647	-0.772*	0.994**	-0.070	-0.526	0.998**	1

T_m, melting temperature; FWC, freezable water content; T_o, onset temperature; T_p, peak temperature; T_e, end temperature; ΔH, enthalpy value; P, tenacity; L, extensibility; P/L, configuration ratio; W, the deformation energy; Hm, dough height; T_x, the time of porosity; V_T, total volume of gas produced. *Significant at p < .05.**Significant at p < .01.