Gel properties of rice varieties in relation to bread baking potential

Figures & data

Figure 1. Rice gels. Gel A: soft gel that could not maintain its shape without a glass tube. Gel B: firm gel with a jelly-like consistency maintained its shape without a glass tube.

Table 1. Protein and amylose content of rice.

Rice	Protein(%)	Amylose(%)
Manmibyeo	6.24 ± 0.10^e	10.93 ± 1.46 ^f
Hanareumbyeo	6.79 ± 0.10 ^cd	15.03 ± 1.72^e
Jinsumi	6.43 ± 0.00^de	15.12 ± 1.45^e
Milyang241	6.07 ± 0.60^e	15.34 ± 3.85^e
Seolgaeng	6.21 ± 0.04^e	15.38 ± 3.05^e
Chuchung	6.84 ± 0.15^c	16.81 ± 1.66^de
Milyang240	5.46 ± 0.15 ^f	18.07 ± 0.50^cde
Dasanbyeo	7.95 ± 0.16^a	18.70 ± 0.09 ^cd
Milyang260	7.31 ± 0.14^b	20.82 ± 1.03^bc
Goamibyeo	8.28 ± 0.19^a	22.94 ± 1.56^b
Suweon517	6.64 ± 0.13 ^cd	22.99 ± 3.11^b
Milyang261	7.31 ± 0.15^b	31.79 ± 1.48^a

Data are expressed as mean ± standard deviation. ^a,bDifferent letters within a column indicate significantly different values (p < 0.05; Duncan’s multiple range test).

Table 2. Comparison of amylose and protein content to gel-forming properties.

Variable	Gel A	Gel B	p-value
Protein content	6.50 ± 0.73	7.39 ± 0.62	0.0008
Amylose content	14.17 ± 2.59	25.06 ± 4.89	0.0000

Gel A: soft gel that could not maintain its shape without a glass tube. Gel B: firm gel with a jelly-like consistency maintained its shape without a glass tube.

Table 3. Texture profile of rice gels.

Rice	Hardness (kg)	Fracturability (kg)	Adhesiveness (g.s)	Springiness	Cohesiveness
Manmibyeo	-	-	-	-	-
Hanareumbyeo	-	-	-	-	-
Jinsumi	-	-	-	-	-
Milyang241	-	-	-	-	-
Seolgaeng	-	-	-	-	-
Chuchung	-	-	-	-	-
Milyang240	-	-	-	-	-
Dasanbyeo	-	-	-	-	-
Milyang260	0.35 ± 0.32^a	0.0 ± 0.0^b	−21.1 ± 12.9	0.63 ± 0.16^a	0.18 ± 0.09^a
Goamibyeo	0.25 ± 0.40^b	0.0 ± 0.0^b	−21.7 ± 11.6	0.61 ± 0.07^a	0.24 ± 0.03^a
Suweon517	0.12 ± 0.18^c	0.84 ± 0.01^b	−96.4 ± 97.2	0.27 ± 0.06^b	0.17 ± 0.02^a
Milyang261	0.28 ± 0.87^ab	0.24 ± 0.11^a	−23.7 ± 12.4	0.30 ± 0.08^b	0.16 ± 0.02^a

Data are expressed as mean ± standard deviation. ^a,bDifferent letters within a column indicate significantly different values (p < 0.05; Duncan’s multiple range test). -Not determined because gel could not maintain its shape without a glass tube.

Figure 2. Rice breads.

Table 4. Specific loaf volume and crumb firmness of yeast-leavened rice breads.

Rice	Bread Shape	Specific loaf volume (mL/g)	Crumb firmness (kg)
			Fresh	Stored for 24 h	Ratio
Wheat flour	Maintain	4.85 ± 0.13^a	0.09 ± 0.01 ^cd	0.25 ± 0.06^b	2.78
Manmibyeo	Collapse	3.66 ± 0.46^dc	0.08 ± 0.00 ^cd	-
Hanareumbyeo	Collapse	3.86 ± 0.52^bc	-	-
Jinsumi	Collapse	2.95 ± 0.41^e	-	-
Milyang241	Maintain	1.17 ± 0.01 ^g	0.08 ± 0.01 ^cd	1.29 ± 2.14^b	16.13
Seolgaeng	Collapse	4.66 ± 0.16^a	-	-
Chuchung	Maintain	1.03 ± 0.06 ^g	0.38 ± 0.01^ab	4.51 ± 0.83^a	11.87
Milyang240	Maintain	1.01 ± 0.07 ^g	0.38 ± 0.03^ab	4.93 ± 1.49^a	12.97
Dasanbyeo	Maintain	1.15 ± 0.11 ^g	0.42 ± 0.01^a	5.55 ± 0.24^a	13.21
Milyang260	Maintain	4.39 ± 0.25^ab	0.04 ± 0.03^d	0.25 ± 0.02^b	6.25
Goamibyeo	Maintain	2.96 ± 0.20^e	0.06 ± 0.06 ^cd	0.37 ± 0.06^b	6.17
Suweon517	Maintain	2.18 ± 0.29 ^f	0.33 ± 0.02^b	1.82 ± 0.15^b	5.52
Milyang261	Maintain	3.19 ± 0.18^de	0.13 ± 0.01^c	0.50 ± 0.03^b	3.85

Data are expressed as mean ± standard deviation. ^a,bDifferent letters within a column indicate significantly different values (p < 0.05; Duncan’s multiple range test). Ratio of the hardness of bread crumbs stored for 24 h to the hardness of fresh bread crumbs. -Not determined because bread could not maintain its shape after cooling.

Table 5. Correlation coefficients between mechanical gel properties (TPA) and specific loaf volume/crumb firmness.

Gel texture (TPA)	Specific loaf volume	Crumb firmness
		Fresh	Stored for 24 h
Hardness	0.80**	−0.80**	−0.85**
Fracturability	−0.39	0.37	0.35
Adhesiveness	0.46	−0.62*	−0.61*
Springiness	0.77**	−0.64**	−0.69**
Cohesiveness	0.65**	−0.26	−0.27

*p < 0.05. **p < 0.01

Table 6. Comparison of mechanical gel properties (TPA) with crumb hardness of fresh bread.

Gel texture	Soft crumb	Hard crumb	p-value
Hardness (g)	302.37 ± 65.40	198.42 ± 100.57	0.060
Fracturability (g)	0.00 ± 0.00	163.20 ± 109.84	0.015
Adhesiveness (g.s)	−21.38 ± 10.97	−60.05 ± 73.69	0.232
Springiness	0.62 ± 0.11	0.28 ± 0.07	0.000
Cohesiveness	0.21 ± 0.07	0.17 ± 0.02	0.178

Hard crumb: hardness was 0.1 kg or more; soft crumb: hardness was 0.1 kg or less. p-value of independent sample t-test.