Comparison of eating quality and physicochemical properties between Japanese and Chinese rice cultivars

Figures & data

Table 1. Analysis of iodine absorption curve, amylose content, and main chemical components of milled rice.

No.	Sample	Moisture		Protein		Amylose		λmax		Aλmax		New λmax		λmax/Aλmax
		%	SD	%	SD	%	SD	nm	SD		SD		SD		SD
1	Koshihikari	13.2d	0.0	6.5c	0.0	12.1c	0.4	558.0b	0.0	0.28b	0.0	0.26a	0.0	1982.2b	0.0
2	Tsuyahime	13.8d	0.1	6.2c	0.0	12.9c	0.4	561.0b	2.8	0.29b	0.0	0.25a	0.0	1954.7b	0.0
3	Yumepirika	13.6d	0.0	6.4c	0.2	9.7b	0.2	550.5b	4.9	0.26a	0.0	0.23b	0.0	2142.0a	0.0
4	Sagabiyori	13.8d	0.1	6.4c	0.1	14.6d	0.3	572.5c	0.7	0.30b	0.0	0.24b	0.0	1924.4b	0.0
5	Kinumusume	10.6a	0.1	6.8c	0.1	14.4d	0.4	568.0b	0.0	0.30b	0.0	0.25a	0.0	1896.5c	0.0
6	Kenjing 5	10.8a	0.0	9.0a	0.0	14.7d	0.3	574.0c	1.4	0.30b	0.0	0.23b	0.0	1932.7b	0.0
7	Shendao 529	9.9a	0.0	7.9b	0.5	15.2e	0.2	576.5c	3.5	0.30b	0.0	0.23b	0.0	1908.9b	0.0
8	Jinyuan 45	10.0a	0.1	8.6a	0.4	14.5d	0.9	576.0c	0.0	0.29b	0.0	0.22c	0.0	1982.8b	0.0
9	Changyou 5	8.6b	0.1	8.8a	0.1	15.7e	0.2	575.5c	2.1	0.31b	0.0	0.24b	0.0	1871.5c	0.0
10	Lianjing 7	11.5c	0.0	7.4b	0.1	17.2f	0.4	578.5c	2.1	0.33b	0.0	0.26a	0.0	1771.8d	0.0
11	Longjing 31	9.9a	0.0	7.5b	0.2	14.2d	0.2	573.5c	0.7	0.29b	0.0	0.23b	0.0	1964.0b	0.0
12	Nanjing 9108	9.8a	0.0	6.8c	0.1	6.6a	0.4	537.0a	4.2	0.21a	0.0	0.11d	0.0	2553.2a	0.0
13	Jinongda 878	9.6a	0.1	7.7b	0.1	15.7e	0.2	569.5b	0.7	0.31b	0.0	0.27a	0.0	1813.7c	0.0
14	Shennong 265	7.9b	0.1	7.8b	0.4	14.1d	0.2	569.0b	1.4	0.29b	0.0	0.24b	0.0	1942.0b	0.0
15	Daohuaxiang	11.4c	0.1	7.0c	0.4	16.3f	0.3	576.5c	0.7	0.32b	0.0	0.25a	0.0	1830.2c	0.0
16	Jinchuan1	10.5a	0.0	7.5b	0.0	13.4c	0.1	564.5b	2.1	0.29b	0.0	0.24b	0.0	1963.5b	0.0

Fig. 1. Validation test of the formula for estimating AAC in Chinese rice cultivars.

Notes: (A) Estimation formula: AAC = 73.31 × A_λmax + 0.11 × λmax – 73.02. (B) Estimation formula: AAC = −0.84 × Pt + 37.76 × SB/Con – 13.09 × Max/Min + 103.92 × Max/Fin – 8.02. 1, Kenjing 5; 2, Shendao 529; 3, Jinyuan 45; 4, Changyou 5; 5,Lianjing 7; 6, Longjing 31; 7, Nanjing 9108; 8, Jinongda 878; 9, Shennong 265; 10, Daohuaxiang; 11, Jinchuan 1.

Table 2. Pasting properties of Chines and Japanese rice cultivars.

No.	Sample	Maximum.vis.		Min.vis.		Break.d		Final.vis		Setback		Pasting.t		Consistency		Setback/Cons		Max/Min		Max/Final
		RVU	SD	RVU	SD	RVU	SD	RVU	SD	RVU	SD	°C	SD		SD		SD		SD		SD
1	Koshihikari	377.3d	1.4	160.4f	2.2	216.8d	3.5	277.6d	3.6	–99.7e	2.2	68.6e	1.0	117.2c	5.8	–0.85d	0.07	2.35b	0.04	1.36c	0.01
2	Tsuyahime	378.6d	0.3	183.9g	5.9	194.8b	5.7	311.0e	2.1	–67.6c	1.8	66.1c	0.5	127.1d	3.8	–0.53b	0.00	2.06a	0.07	1.22b	0.01
3	Yumepirika	366.0d	0.7	145.5d	1.6	220.5d	0.9	244.7b	2.9	–121.3f	2.2	66.8c	0.5	99.1b	1.4	–1.22f	0.04	2.51c	0.02	1.50d	0.02
4	Sagabiyori	322.5a	2.6	153.6e	1.3	168.9a	1.3	287.2d	1.2	–35.3a	1.4	64.2a	0.0	133.6e	0.1	–0.26a	0.01	2.10a	0.00	1.12a	0.00
5	Kinumusume	355.3c	2.4	152.7e	0.4	202.6c	2.7	281.5d	0.9	–73.7c	1.5	64.6a	0.6	128.9d	1.2	–0.57b	0.01	2.33b	0.02	1.26b	0.00
6	Kenjing 5	320.3a	1.1	133.6c	0.1	186.7b	1.2	277.5d	1.4	–42.8a	0.3	64.0a	0.0	143.9f	1.5	–0.30a	0.01	2.40b	0.01	1.15a	0.00
7	Shendao 529	355.2c	1.0	129.9b	1.4	225.3d	0.4	259.0c	1.7	–96.2e	0.7	67.2d	0.0	129.1d	0.3	–0.74c	0.01	2.73d	0.02	1.37c	0.01
8	Jinyuan 45	265.4b	2.0	97.5a	1.0	168.0a	1.0	214.7a	1.2	–50.7b	0.8	65.7b	0.0	117.2c	0.2	–0.43b	0.01	2.72d	0.01	1.24b	0.00
9	Changyou 5	405.7e	0.1	159.3e	0.1	246.4e	0.2	310.5e	0.4	–95.1e	0.3	67.9d	0.0	151.3g	0.5	–0.63c	0.00	2.55c	0.00	1.31c	0.00
10	Lianjing 7	320.0a	2.2	121.7b	5.4	198.3b	3.2	236.5b	4.9	–83.4d	2.7	69.3f	0.0	114.8c	0.5	–0.73c	0.02	2.63d	0.10	1.35c	0.02
11	Longjing 31	347.6c	5.9	137.5c	0.8	210.1c	6.7	263.6c	0.6	–84.0d	6.5	66.5c	0.1	126.2d	0.1	–0.67c	0.05	2.53c	0.06	1.32c	0.03
12	Nanjing 9108	383.3d	0.5	135.4c	1.6	248.0e	1.1	224.1a	1.9	–159.3g	1.4	65.8b	0.1	88.7a	0.3	–1.80g	0.02	2.83e	0.03	1.71e	0.01
13	Jinongda 878	327.3a	1.0	132.3c	0.1	195.0b	0.9	253.0c	0.0	–74.3c	1.0	65.7b	0.1	120.7d	0.1	–0.62c	0.01	2.47c	0.01	1.29b	0.00
14	Shennong 265	372.5d	4.9	138.6c	2.4	233.9d	2.5	254.3c	0.7	–118.3f	4.2	67.5d	0.5	115.6c	1.7	–1.02e	0.05	2.69d	0.01	1.47d	0.02
15	Daohuaxiang	355.9c	6.4	162.5f	2.7	193.4b	3.7	305.5e	3.1	–50.4b	3.3	63.1a	0.5	143.0f	0.4	–0.35b	0.02	2.19a	0.00	1.17b	0.01
16	Jinchuan1	400.3e	2.9	130.2c	1.1	270.1f	1.8	249.1c	0.8	–151.2 g	2.1	67.5d	0.5	118.9c	0.3	–1.27f	0.02	3.07e	0.00	1.61e	0.01

Table 3. The physical properties of the cooked rice grains.

Sample	Surface layer	SD	Overall	SD	Surface layer	SD	Overall	SD	Surface layer	SD	Surface layer	SD	Overall	SD	Surface layer	SD	Overall	SD
	Hardness (H1) × 10^5 (N/cm^2)		Hardness (H2) × 10^5 (N/cm^2)		Stickiness (–H1) × 10^5 (N/cm^2)		Stickiness (–H2) × 10^5 (N/cm^2)		Adhered (L3) (mm)		Balance degree (–H1/H1)		Balance degree (–H2/H2)		Balance degree (A3/A1)		Balance degree (A6/A4)
Koshihikari	654.9c	15.8	16985b	131.2	–166.8f	5.2	–3603c	38.6	3.2b	0.3	0.26d	0.05	0.21c	0.03	0.47c	0.11	0.14c	0.03
Tsuyahime	600.6b	19.2	15681a	191.9	–133.2d	4.3	–2716a	63.9	3.2b	0.1	0.23c	0.06	0.17a	0.03	0.44c	0.13	0.13c	0.03
Yumepirika	632.3c	16.5	17475b	130.1	–176.8g	5.1	–4040e	38.5	3.2b	0.2	0.28d	0.06	0.23d	0.03	0.57d	0.16	0.16d	0.04
Sagabiyori	789.5e	19.9	18790d	170.7	–179.4g	5.1	–3630c	42.6	3.2b	0.2	0.23c	0.04	0.20b	0.03	0.36b	0.10	0.11b	0.03
Kinumusume	803.6e	19.4	18319c	158.7	–145.5e	3.6	–3869d	33.2	3.2b	0.1	0.19b	0.06	0.21c	0.03	0.29b	0.11	0.10b	0.03
Kenjing 5	1016.9f	23.7	21084e	205.4	–151.6e	4.9	–3897d	48.0	3.2b	0.0	0.15a	0.04	0.19b	0.04	0.20a	0.08	0.07a	0.02
Shendao 529	816.5e	17.2	18721d	125.7	–179.2g	6.0	–4059e	47.7	3.1b	0.4	0.22v	0.06	0.22d	0.02	0.31b	0.07	0.11b	0.02
Jinyuan 45	707.7d	15.9	16769b	143.6	–120.7c	3.3	–3050b	46.6	3.2b	0.0	0.18b	0.05	0.18a	0.03	0.28b	0.11	0.10b	0.02
Changyou 5	802.4e	23.7	17907c	175.0	–183.2g	4.8	–3361b	26.1	3.1b	0.4	0.23c	0.05	0.19b	0.02	0.36b	0.12	0.12b	0.03
Lianjing 7	753.0d	21.0	20770e	132.3	–88.9a	3.4	–4144f	39.5	2.9a	0.7	0.12a	0.04	0.20b	0.02	0.19a	0.09	0.06a	0.02
Longjing 31	710.3d	13.5	17672c	95.8	–114.7c	2.9	–3678c	41.4	3.2b	0.0	0.16a	0.02	0.21c	0.03	0.26b	0.06	0.09b	0.01
Nanjing 9108	592.4b	15.6	16946b	161.1	–106.6b	4.9	–4239f	47.3	3.2b	0.2	0.18b	0.05	0.25e	0.03	0.34b	0.12	0.11b	0.03
Jinongda 878	509.5a	9.3	14808a	134.4	–90.5a	2.4	–3099b	22.9	3.0a	0.6	0.18b	0.04	0.21c	0.02	0.36b	0.12	0.13c	0.03
Shennong 265	603.5b	24.2	16397b	196.7	–105.5b	2.9	–3782d	39.7	3.1b	0.3	0.19b	0.06	0.23d	0.03	0.39c	0.16	0.13 c	0.04
Daohuaxiang	785.8e	15.0	18083c	159.1	–137.6d	3.7	–4230f	39.9	3.2b	0.1	0.18b	0.04	0.24e	0.03	0.24b	0.06	0.10b	0.03
Jinchuan1	636.1c	12.1	16750b	159.8	–102.1b	3.6	–4097e	44.4	3.0a	0.5	0.16a	0.05	0.25e	0.03	0.27b	0.09	0.11b	0.04

Table 4. Correlation between physical parameters of cooked rice with analysis of iodine absorption curve, amylose contents, RS contents, pasting properties, and main chemical components of 16 Chinese and Japanese rice varieties.

	AAC	λmax	Aλmax	λmax/Aλmax	New λmax	Min.vis	Past. T	Fin. vis	Max/Min	Cons	α-amylase activity
(A)
H1
H2
–H1
–H2						0.99**
L3							–0.88*
–H1/H1			–0.90*	0.90*							0.97**
–H2/H2								–0.95**	0.96**
A3/A1	–0.96*	–0.92*	–0.96*	0.93*						–0.88*	0.96**
A6/A4	–0.96*	–0.95*	–0.94*	0.89*	0.89*						0.93*
	Moisture content	Protein content	λmax	Protein 13 kDa prolamin	Cons	Fin.vis	Max. vis	BD	SB	SB/Cons	Max/Final	Glucose contents	RS
(B)
H1					0.68*
H2
–H1					–0.70*	–0.62*
–H2				–0.69*
L3
–H1/H1	–0.68*
–H2/H2		–0.80*	–0.65*				0.60*	0.62*	–0.73**	–0.74**	0.72*	0.80**	–0.77**
A3/A1	–0.89**
A6/A4	–0.77**

Notes: A; Japanese rice cultivars, B; Chinese ricew cultivars, Correlation is significant at 5% (*) or 1% (**) by the method of t test.

Fig. 2. The starch structure was expressed as a linear function based on the relationship between λmax and “New λmax.”

Notes: The vertical axis represents λmax and the horizontal axis is “New λmax.” ▲: Chinese rice cultivars, ●: Japanese rice cultivars 1, Koshihikari; 2, Tsuyahime; 3, Yumepirika; 4, Sagabiyori; 5, Kinumusume; 6, Kenjing 5; 7, Shendao 529; 8, Jinyuan 45; 9, Changyou 5; 10, Lianjing 7; 11, Longjing 31; 12, Nanjing 9108; 13, Jinongda 878; 14, Shennong 265; 15, Daohuaxiang; 16, Jinchuan 1. Fig. 2 shows that a coefficient of determination of 0.827 was obtained due to the high correlation between λmax and “New λmax.”

Fig. 3. Formula for estimating the balance degree of the surface layer (A3/A1) based on the iodine absorption curve of milled rice.

Notes: Estimation formula: A3/A1 = –0.002 × λmax/A_λmax – 16.335 × A_λmax + 9.428. ▲: Chinese rice cultivars, ●: Japanese rice cultivars. 1, Koshihikari; 2, Tsuyahime; 3, Yumepirika; 4, Sagabiyori; 5, Kinumusume; 6, Kenjing 5; 7, Shendao 529; 8, Jinyuan 45; 9, Changyou 5; 10,Lianjing 7; 11, Longjing 31; 12, Nanjing 9108; 13, Jinongda 878; 14, Shennong 265; 15, Daohuaxiang; 16, Jinchuan 1. The equation had a multiple coefficient of determination of 0.628 based on the calibration. Thus, we could estimate the texture (A3/A1) of the cooked rice grains based on the iodine absorption curve obtained for the milled rice.

Fig. 4. SDS–PAGE analysis of proteins extracted from raw milled rice grains.

Notes: (a) polypeptide; (b) glutelin α-subunit; (c) α-globulin; (d) glutelin β-subunit, (e), (f), (g) prolamin. Shunyo is a low gluterin rice, and Koshihikari is a high-quality rice from Japan. a, Shunyo; b, Koshihikari; 1, Kenjing 5; 2, Shendao 529; 3, Jinyuan 45; 4, Changyou 5; 5, Lianjing 7; 6, Longjing 31; 7, Nanjing 9108; 8, Jinongda 878; 9, Shennong 265; 10, Daohuaxiang; 11, Jinchuan 1. Chinese rice cultivars were characterized by high-intensity 13-kDa prolamin spots, where Kenjing 5, Lianjing 7, and Nanjing 9108 had very high values.