Rice Qualities in Cambodian Markets: Market Survey on Qualities of Phka Rumduol and Somali in Takeo, Phnom Penh and Battambang, Cambodia

Abstract

General qualities (moisture, grain size and quality level), cooking qualities (grain elongation), sensory evaluation and judgment of fungi, using Phka Rumduol and Somali collected from three markets in Takeo Province, Phnom Penh City and Battambang Province were determined. Rice qualities and grade of the two varieties among three markets in each of the three locations were rather stable. On the other hand, those among the three locations were not always stable. Grain size and grain grade were generally higher in the rice from Battambang Province. Grain size before and after cooking had almost similar tendencies. Rice qualities between the two varieties showed a tendency for Phka Rumduol to be longer than Somali in grain length, while Somali was wider and heavier than Phka Rumduol in grain width and weight. Sensory evaluation by local panelists showed that all cooked rice was highly evaluated in grain dimension, whiteness, hardness, aroma and favorability. No fungi were detected in any of the rice samples. The overall results of this experiment showed two rice varieties collected in three markets in three locations in Cambodia were generally and permissively high in quality both for domestic uses and exportation.

Introduction

Rice production in Cambodia during 2012–2017 increased from 9 290 940 tons to 10 350 000 tons (as paddy rice) and the surplus of paddy rice was around 5 110 000 tons (3 270 000 ton as white rice)ⁱ⁾. The amounts of rice exported from Cambodia grew in these years, and were estimated at 635 679 tons in 2017 and 626 225 tons in 2018 according to the Cambodian Rice Federationⁱⁱ⁾. The main share of the exports was aromatic rice (more than 60%) followed by long grain white rice and parboiled rice, showing a recent increase in the share of extra-long aromatic rice. The European Union was the largest destination for Cambodian rice followed by China and Association of Southeast Asian Nation countries. However, exports to the European Union have decreased in the last 2 years (2017–18) due to an increase in the tariff rate by the Phnom Penh Post. In order to increase the export of rice from Cambodia, it is necessary to ensure and enforce quality and safety levels through processing and transportation improvements and also to shift informal export of paddy rice to formal export (Ministry of Commerce, Cambodia, 2014).

In 2018, Cambodian white rice was sold at $470 per ton, aromatic (fragrant) rice ranged between $785 and $790 per ton, while jasmine rice (extra-long aromatic rice including Phka Rumduol and Somali used in this experiment) was sold for $890 per tonⁱⁱⁱ⁾. However, according to the Cambodia Rice Federation, white rice was sold between $475 and $478 per ton, fragrant rice was between $790 and $805, and premium jasmine rice (extra-long aromatic rice harvested in the wet season; Phka Rumduol and Somali were included) was $1 035 and $1 045 per ton. There were fluctuations in price, depending upon the year and season.

Cambodia is geographically divided into four agro-climatic zones, plains, Tonle Sap, coastal zones and plateau/mountains, and the main types of rice ecosystems are rain-fed upland and lowland rice, deep/floating rice, and dry-season rice (Seila et al., 2012). Phka Rumduol and Somali are rain-fed lowland rice and are harvested once a year around from early November to mid-January mainly in plain areas, including in the Tonle Sap water system.

The marketing system in Cambodia was investigated by the Japan International Cooperation Agency et al. (2001). Paddies harvested by farmers are milled by commercial mills and white rice is transferred to local markets via retailers or to urban markets (consumption area) via wholesalers and retailers.

The markets in Takeo and Battambang Provinces can easily sell Phka Rumduol and Somali and those in Phnom Penh City sell not only these two varieties, but also many other varieties. Most Cambodian households purchase white rice from markets. Major factors in choosing rice are price, taste, texture, swelling capacity and aroma. The main and most important reasons for choosing a rice variety for household consumption were reported to be taste and price, in addition to texture, swelling capacity and aroma (Seila et al., 2012). Moreover, in recent years, more Cambodian households in urban areas cook rice in a rice cooker.

Rice qualities and safety, using four varieties collected from six markets in Phnom Penh, Cambodia, were examined and reported in a previous paper (Ek et al., 2018). The largest rice markets in Cambodia are located in Phnom Penh City, Battambang Province and Takeo Province (Bunhak and Gummert, 2003).

In this paper, Phka Rumduol and Somali, which are the leading long aromatic rice varieties and are essential not only for domestic use but also for export, were collected from three markets in Takeo Province, Phnon Penh City and Battambang Province. The purpose of this paper was to survey the quality level and stability of two varieties from three markets in each of the three locations. General qualities (moisture, grain length, width, weight, and grain quality level related to grain standard), cooking qualities (elongation of grain length and width), sensory evaluation and the existence of fungi were investigated.

Materials and Methods

Materials    Phka Rumduol and Somali samples were collected from three local markets in three geographical areas including Takeo Province, Phnom Penh City and Battambang Province. From three markets in each of Takeo Province, Phnom Penh City and Battambang Province, nine samples of Phka Rumduol and Somali were randomly collected from retailers. In Table 1, the names of the markets in each of the three locations are shown. In the following tables and figures, Takeo Province, Phnom Penh City and Battambang Province are abbreviated as Takeo, PP and BTB, respectively. Furthermore, the three markets in Takeo shown in the tables are abbreviated as TA, TB and TC, the three markets in PP are abbreviated as PA, PB and PC and the three markets in BTB are abbreviated as BA, BB and BC respectively.

Table 1. Names of the markets, locations and rice varieties used in the experiments

City/Province name	Rice varieties	Market name	Sample number
Takeo Province (Takeo)	Phka Rumduol	Tram Khna Market (TA)	9
		Som Rong Young Market (TB)	9
		Ang Tasom Market (TC)	9
	Somali	Tram Khna Market (TA)	9
		Som Rong Young Market (TB)	9
		Ang Tasom Market (TC)	9
Phnom Penh City (PP)	Phka Rumduol	Ra Rotest Ploueng Market (PA)	9
		Orussey Market (PB)	9
		Demkor Market (PC)	9
	Somali	Ra Rotest Ploueng Market (PA)	9
		Orussey Market (PB)	9
		Demkor Market (PC)	9
Battambang Province (BTB)	Phka Rumduol	New Market (BA)	9
		Beung Chouk Market (BB)	9
		Moung Russey Market (BC)	9
	Somali	New Market (BA)	9
		Beung Chouk Market (BB)	9
		Moung Russey Market (BC)	9

Samples were collected starting on January 17, 2018 and were properly packaged, transported and stored (about at 14 °C), and then sent to the laboratory. The samples were separately stored and packed in polyethylene bags and kept at about 5 °C until analyzed in the laboratory.

Examination of quality grade of rice samples

Measurement of moisture content    Moisture content was measured using a moisture meter (Kett PM 650, Tokyo, Japan). The equipment is an electrical capacitance-type moisture meter, which utilizes electromagnetic waves applied to a sample between a pair of electrodes. The absorption ratio of the waves has a close relationship with the electrical capacitance of the sample, which is almost in proportion to the moisture content. For the measurement of the moisture content, a lump of rice (240 mL; about 300 g) was used.

Measurement of weight of 1,000 grains    A sample of 100 grains was counted out, weighed and multiplied by 10.

Measurement of grain length and width    The length and width of grains were mechanically measured for 100 whole grains using a grain scanner (Satake RSQI10A, Higashi Hiroshima, Japan).

Measurement of the percentages of matured, glutinous, chalky grains and accepted/defected grains by a grain scanner (Satake RSQI10A)    The measurements by a grain scanner were the same as those in a previous paper (Ek et al., 2018). Two grams (about 100 grains) of rice were placed on the tray of the grain scanner, and the shape and color of each individual grain were recorded. Statistical data for all samples were also displayed with histograms and average values. Following the manual of the grain scanner, white rice L was selected and clicked. Then, the Cambodian standard was selected (Ek et al., 2018). The length and width of grains were mechanically measured using 100 grains of whole rice while eliminating broken grains on the screen of the scanner. The rate of glutinous, chalky grains and maturity level were also measured. In the measurement of accepts and defects, the acceptable grains and defective grains were differentiated after the Cambodian standard was applied to determine the conditions of each quality grade.

Cooking quality

Grain elongation after cooking    For cooking, 8 g of milled rice were taken separately in an empty tea bag and the set was presoaked for 30 min in 160 mL water in a tall beaker. The length and width of 10 raw rice grains (whole grain) were measured beforehand (L1 and W1). The length and width of the 10 rice grains after cooking were also measured (L2 and W2). The ratios of the length and width of cooked rice to those of raw kernel (L2 / L1 and W2 / W1) were calculated as the grain elongation ratio. In the following tables, the length before and after cooking are shown as (L)1 and (L)2 and the width before and after cooking are shown as (W)1 and (W)2, since a sampling of grains was measured again for cooking tests. These measurements after cooking were done by hand with a caliper.

Sensory evaluation    Table 2 shows the attributes of the panelists and the questions asked before the sensory evaluation. The panelists were local people from each location who were involved in rice study/business and had also received intensive training. Cambodian authors of this paper went to each location and talked to the panelists about the purpose of the sensory evaluation. They consented to participate and provided their full cooperation.

Table 2. Attributes of the panelists and the questions asked before sensory evaluation

	n	Female, Male	age	Do you like cooked rice?	How many times you eat cooked rice in a day?	Do you eat long rice or short rice in dairy meals?	Do you think Cambodian rice is superior to rice of other countries?
Takeo	40	F/19,M/21	25.25	1=Yes, 2= So-So, 3= Don't	1= 3 times, 2= 2 times, 3= 1 time	1=Long, 2= Short	1=Yes, 2=No, 3=Other idea
PP	40	F/19,M/21	25.25
BTB	40	F/21,M/19	25.30
	total 120	total F/59,M/61	AD 27.27

In the sensory evaluation, the same amounts of the nine samples from each of the three markets were well-mixed and cooked rice was prepared from the mixture. Well washed (25 g) milled rice was put in a metal vessel (d; 73 mm, h; 54 mm). In the set, 30 mL of water was added and cooked in an electric rice cooker (Panasonic model: SR-ZG185). Cooked rice was separated into three parts, put on three plates and eaten by three panelists. The evaluation was noted by scoring on a preference scale from 1 to 5 (1 = best; 5 = worst) for grain dimension (length), aroma, hardness, color (whiteness) and favorability (taste or overall acceptability).

Judgment of fungi    The judgment method for fungi was also the same as in a previous paper (Ek et al., 2018). Sample rice (350 g) was placed in a 200-mL flask and mixed with 50 mL of saline and kept. The supernatant was thrown out and the rice grains were washed with sanitized water repeatedly (20 times) and put on filter paper in a Petri dish. After coagulating the agar (agar medium with Potato Dextrose Agar added to 100 mg of chloral phenicol/I), four to five washed grains were placed on the agar medium. The plate was kept at 20–25 °C for 10 days and examined for the growth of colonies around the grains. The ratio of the grains on which fungi grew and did not grow was determined.

Statistical analysis of the data    The data for the measurements of general and cooking qualities and for sensory evaluation are reported as averages and standard deviations. One-way analysis of Excel-Tokei (Social Survey Research Information Co. Ltd., Tokyo Japan) was used to examine general and cooking quality data for statistical analysis of differences among markets, locations and varieties and followed by Tukey's test.

Results and Discussion

The names of Takeo Province, Phnom Penh City and Battambang Province are abbreviated to Takeo, PP and BTB, respectively and the three markets in Takeo, PP and BTB are also abbreviated to TA, TB, TC; PA, PB, PC and BA, BB, BC, respectively in the following tables and figures.

The percentages of defected grains were 100 — accepted grains so that only the percentages of accepted grains are reported in Tables 3, 4 and 5.

Variation among markets    Variation among the three markets in Takeo, PP and BTB is shown in Table 3, divided into Phka Rumduol (Table 3-1) and Somali (Table 3-2).

Table 3-1. Variation of grain size and quality grade of Phka Rumduol among the three markets in the three locations

Location 3	n 27		Moisture %	Weight g	Length mm	Width mm	Maturity %	Chalkiness %	Glutinous %	Accepted %
Takeo	TA	AV	11.433	16.518	7.090	1.594	89.444	6.911 C	0.022	79.500
		SD	0.755	0.850	0.346	0.030	2.073	0.672	0.044	6.216
	TB	AV	11.167	16.617 B	7.088	1.621	89.011	6.411	0.022	76.544
		SD	0.758	1.017	0.367	0.039	3.527	2.088	0.044	6.640
	TC	AV	10.789	17.188 B	7.054	1.605	91.078	4.444 C	0.244	78.900
		SD	0.627	0.601	0.311	0.028	1.641	2.085	0.368	3.511
PP	PA	AV	12.600	17.950	7.177	1.628	88.378	6.011	0.222	77.444
		SD	0.695	0.826	0.338	0.066	3.825	2.336	0.667	5.570
	PB	AV	12.300 A	17.439	7.148	1.646	90.833	4.322	0.444	78.111
		SD	0.873	0.457	0.174	0.043	2.920	1.077	1.014	2.667
	PC	AV	11.633 A	18.122	7.186	1.671	89.756	4.367	0.444	74.444
		SD	0.581	0.221	0.117	0.029	2.636	1.766	0.726	3.575
BTB	BA	AV	11.944	17.941	7.198	1.624	93.067	8.278	0.011	87.000
		SD	0.700	0.417	0.108	0.031	2.860	2.975	0.033	5.449
	BB	AV	12.356	18.097	7.232	1.633	91.856	6.411	0.011	89.778
		SD	0.621	0.511	0.071	0.014	2.702	2.394	0.033	2.976
	BC	AV	11.767	17.694	7.196	1.637	91.056	8.000	0.011	88.856
		SD	0.581	0.631	0.192	0.039	3.127	3.379	0.033	4.099

Table 3-2. Variation of grain size and quality grade of Somali among the three markets in the three locations

Location 3	n 27		Moisture %	Weight g	Length mm	Width mm	Maturity %	Chalkiness %	Glutinous %	Accepted %
Takeo	TA	AV	11.333	17.230	6.884	1.733	87.956	3.244	0.011	79.167
		SD	0.814	1.110	0.197	0.049	3.022	2.648	0.033	4.708
	TB	AV	11.000	16.772 A	6.838	1.701	86.944	5.156	0.000	74.233
		SD	0.480	0.798	0.206	0.018	3.663	2.515	0.000	5.195
	TC	AV	11.433	17.412 A	6.924	1.710	88.400	4.900	0.244	75.789
		SD	0.602	0.481	0.204	0.027	2.962	2.247	0.324	6.987
PP	PA	AV	11.878	17.696	7.161	1.683	88.511	5.167	1.000	78.889
		SD	0.728	1.431	0.356	0.110	2.580	1.225	1.118	6.566
	PB	AV	11.678	18.280	7.032	1.722	86.711	5.056	0.778	77.111
		SD	0.435	0.911	0.228	0.078	3.439	2.007	1.202	5.840
	PC	AV	12.056	18.721	7.063	1.688	88.144	5.200	0.667	81.111
		SD	0.332	1.077	0.301	0.076	3.699	2.076	1.118	4.622
BTB	BA	AV	12.367	18.382	7.234	1.707	86.800	9.967 B	0.044	83.278
		SD	0.644	0.419	0.146	0.056	2.419	1.557	0.053	2.508
	BB	AV	11.956	18.440	7.186	1.670	90.856	5.911 B	0.156	85.067
		SD	0.403	0.641	0.132	0.061	1.541	0.812	0.194	1.172
	BC	AV	12.267	18.199	7.279	1.667	87.989	8.422	0.089	85.911
		SD	0.606	0.836	0.090	0.056	5.267	5.623	0.162	3.447

In Tables 3-1 and 3-2, only significant deviation based on Tukey's test among markets, locations and varieties are reported. A 5 % significant deviation based on Tukey's test is shown by capital letters. Takeo Province, Phnom Penh City and Battambang Province are abbreviated as Takeo, PP and BTB, respectively. Furthermore, the three markets in Takeo shown in the tables are abbreviated as TA, TB and TC, the three markets in PP are abbreviated as PA, PB and PC and the three markets in BTB are abbreviated as BA, BB and BC respectively.

As shown in Table 3-1 and 3-2, general qualities (moisture, grain size and quality grade) among the three markets were not variable. Variations among markets were found for only four cases with a 5% significant deviation based on Tukey's test: in moisture between PB and PC of Phka Rumduol, in weight between TB and TC of Somali, and in chalky, between BA and BB of Somali and TA and TC of Phka Rumduol.

In the Cambodia standards for extra white rice long grains, it was defined as a rule that all white rice has a length ≥ 7 (mm). Only rice grains in Takeo of Somali were under the standard.

Generally speaking, the quality grade of the two varieties in all markets at all locations were high, showing high values in matured and accepted grains and low values in chalky and glutinous grains.

Variation in general qualities among locations    Variation in grain size and quality grade of the two varieties among the three locations are shown in Table 4-1 and 4-2, respectively.

Table 4-1. Variation of grain size of the two varieties among the three locations

Variety	Location 3		Moisture %	Weight g	Length mm	Width mm
Phka Rumduol	Takeo	AV	11.130 ab	16.774 ef	7.077	1.607 k
		SD	0.739	0.862	0.329	0.033
	PP	AV	12.178 a	17.837 e	7.170	1.648 k
		SD	0.810	0.614	0.221	0.050
	BTB	AV	12.022 b	17.911 f	7.209	1.631
		SD	0.661	0.534	0.130	0.029
Somali	Takeo	AV	11.256 cd	17.138 gh	6.882 ij	1.715
		SD	0.649	0.850	0.198	0.035
	PP	AV	11.870 c	18.232 g	7.085 i	1.698
		SD	0.529	1.194	0.293	0.088
	BTB	AV	12.196 d	18.340 h	7.233 j	1.681
		SD	0.568	0.638	0.126	0.059

Table 4-2. Variation of quality grade of the two varieties among the three locations

Variety	Location 3		Maturity %	Chalkiness %	Glutinous %	Accepted %
Phka Rumduol	Takeo	AV	89.844 a	5.922 A	0.096	78.315 j
		SD	2.608	1.999	0.233	5.562
	PP	AV	89.656 b	4.900 e	0.370 h	76.667 k
		SD	3.211	1.907	0.792	4.279
	BTB	AV	91.993 ab	7.563 eA	0.011 h	88.544 jk
		SD	2.912	2.95	0.032	4.292
Somali	Takeo	AV	87.767 c	4.433 f	0.085	76.396 n
		SD	3.166	2.53	0.214	5.878
	PP	AV	87.789 d	5.141 g	0.815 i	79.037 p
		SD	3.244	1.741	1.111	5.754
	BTB	AV	88.548 cd	8.100 fg	0.096 i	84.752 np
		SD	3.752	3.685	0.151	2.695

Total sample numbers in Table 4-1 and 4-2 were 27. Only significant deviation based on by Tukey's test are reported. A 1 % significant deviation based on Tukey's test is shown by small letters and a 5 % of that is shown by capital letters. Takeo Province, Phnom Penh City and Battambang Province are abbreviated Takeo, PP, and BTB respectively.

The variation among the three locations as shown in Table 4 was much bigger than those among the markets shown in Table 3. Regarding grain size, rice grains in Takeo were smaller than PP and BTB in moisture, weight and length with a 1% significant difference. Regarding quality grade, rice grains in BTB were higher than those in Takeo and PP in maturity, chalky grains (smaller in BTB), and accepted grains with a 1% significant difference. For glutinous grains, a 1% significant difference was found in Phka Rumduol between PP and BTB; however, the percentages of glutinous grains in this experiment were very low. Generally speaking, the values in moisture and grain size of Takeo were lower than the other two locations and those in quality grade of BTB were higher than the other two locations.

However, quality grade of these rice samples in the three locations was permissively high, even if there was slight variation among locations. Rice production in BTB is known to be good because of its fertile soil and irrigation system. In addition, many millers/exporters there transfer their technique to farmers.

In order to compare the quality level among Takeo, PP and BTB, grain weights and the percentages of accepted grains were determined in Figure 1 and 2. In Figure 1, sample moisture (as is) was used but weights in Takeo were still significantly lower after revising moisture. Grain weights were higher in Somali than Phka Rumduol. The percentages of accepted grains were clearly higher in BTB than those in the other two locations.

Fig. 1.

Comparison in grain weight of the two varieties among the three locations Asterisks ** show a 0.01% significant deviation based on Tukey's test.

Fig. 2.

Comparison in accepted grains of the two varieties among the three locations Asterisks ** show a 0.01% significant deviation based on Tukey's test.

Variation in general qualities between the two varieties    The variation between Phka Rumduol and Somali is shown in Table 5-1 and 5-2. Regarding grain size, grain length of Phka Rumduol was longer than that of Somali with a 1% significant difference. On the other hand, grain width and weight of Somali were longer and heavier than Phka Rumduol with a 1% significant difference. As for grain grade, Phka Rumduol was higher than Somali in maturity and Somali was lower than Phka Rumduol in chalky grains both with a 1% significant difference. Glutinous grains in both samples were almost zero.

Table 5-1. Variation of moisture and grain size between the two varieties

Variety	Markets (3x9), Location (3)		Moisture %	Weight g	Length mm	Width mm
Phka Rumduol	81	AV SD	11.777 0.865	17.507 a 0.854	7.152 b 0.244	1.629 c 0.042
Somali	81	AV SD	11.774 0.698	17.904 a 1.062	7.017 b 0.279	1.698 c 0.065

Table 5-2. Variation of quality grade between the two varieties

Variety	Markets (3x9), Location (3)		Matured %	Chalky %	Glutinous %	Accepted %
Phka Rumduol	81	AV SD	90.498 a 3.075	6.128 b 2.555	0.073 0.231	81.175 7.067
Somali	81	AV SD	88.035 a 3.374	4.905 b 2.040	0.172 0.368	80.062 6.055

Only significant deviation based on Tukey's test are reported. A 1% significant deviation based on Tukey's test is shown by small letters.

Cooking qualities

Variation in cooking qualities among markets    The variations in cooking qualities of Phka Rumduol and Somali among the three markets in the three locations are shown in Table 6-1 and 6-2, respectively.

Table 6-1. Variation of cooking qualities of Phka Rumduol among the three markets in the three locations

Location (3)	Sample (9)		Before cooking (L)1 mm	After cooking (L)2 mm	Elongation (L2/L1)	Before cooking (W)1 mm	After cooking (W)2 mm	Elongation (W2/W1)
Takeo	TA	AV	7.022	11.414 B	1.627 D	1.630	2.406	1.477
		SD	0.204	0.291	0.078	0.029	0.073	0.051
	TB	AV	6.963	10.746 B	1.543 D	1.650	2.405	1.460
		SD	0.157	0.548	0.066	0.032	0.096	0.060
	TC	AV	6.926	10.951	1.581	1.664	2.358	1.417
		SD	0.156	0.520	0.049	0.037	0.074	0.048
PP	PA	AV	7.204 A	11.221	1.703	1.527	2.430	1.593 F
		SD	0.158	0.852	0.079	0.046	0.125	0.080
	PB	AV	7.130 aA	10.833	1.559	1.589	2.297	1.451 F
		SD	0.133	0.609	0.072	0.116	0.122	0.129
	PC	AV	7.392 a	11.559	1.540	1.604	2.428	1.518
		SD	0.119	0.580	0.095	0.066	0.199	0.155
BTB	BA	AV	7.390	11.156 bC	1.510 cE	1.621	2.373	1.463
		SD	0.069	0.376	0.049	0.019	0.123	0.068
	BB	AV	7.320	11.764 bC	1.607 E	1.640	2.283	1.393
		SD	0.111	0.088	0.026	0.037	0.106	0.070
	BC	AV	7.303	11.599	1.588 c	1.641	2.312	1.411
		SD	0.093	0.496	0.071	0.037	0.130	0.081

Table 6-2. Variation of cooking qualities of Somali among the three markets in the three locations

Location (3)	Sample (9)	AV SD	Before cooking (L)1 mm	After cooking (L)2 mm	Elongation L2/L1	Before cooking (W)1 mm	After cooking (W)2 mm	Elongation (W2/W1)
Takeo	TA	AV	7.246	10.542	1.480 b	1.692	2.430	1.436
		SD	0.107	0.973	0.187	0.055	0.143	0.112
	TB	AV	7.129	11.189	1.614 b	1.654	2.453	1.483 e
		SD	0.112	0.421	0.100	0.031	0.118	0.080
	TC	AV	7.228	11.183	1.600	1.695	2.333	1.376 e
		SD	0.178	0.452	0.051	0.042	0.090	0.096
PP	PA	AV	7.246	11.156	1.545	1.571	2.433	1.548
		SD	0.107	0.376	0.099	0.101	0.174	0.079
	PB	AV	7.129	11.764	1.577	1.596	2.351	1.473
		SD	0.112	0.088	0.063	0.041	0.209	0.070
	PC	AV	7.228	11.599	1.563	1.630	2.327	1.423
		SD	0.178	0.496	0.055	0.078	0.112	0.081
BTB	BA	AV	7.226	12.301 aA	1.564 cd	1.630	2.343	1.438
		SD	0.105	0.499	0.136	0.025	0.133	0.087
	BB	AV	7.367	11.478 A	1.561 c	1.632	2.296	1.407
		SD	0.173	0.452	0.073	0.023	0.164	0.093
	BC	AV	7.333	11.289 a	1.600 d	1.628	2.297	1.413
		SD	0.194	0.746	0.108	0.031	0.063	0.053

Only significant deviation based on Tukey's test is reported. A 1 % significant deviation based on Tukey's test is shown by small letters and a 5 % of that is shown by capital letters. Takeo Province, Phnom Penh City and Battambang Province are abbreviated as Takeo, PP and BTB, respectively. Furthermore, the three markets in Takeo shown in the tables are abbreviated as TA, TB and TC, the three markets in PP are abbreviated as PA, PB and PC and the three markets in BTB are abbreviated as BA, BB and BC respectively.

In Phka Rumduol, a 1% significant difference was observed in (L)1 between PB and PC, in (L)2 between BA and BB and in (L)1/(L)2 between BA and BC. In Somali, a 1% significant difference was observed in (L)2 between BA and BC, in (L)2/(L)1 between TA and TB, BA and BB and BA and BC, and in (W)2/(W)1 between TB and TC. There were more irregular variations among the three markets in terms of cooking qualities than in general qualities due to irregularities in the cooking procedure.

Variation in cooking qualities among locations    The variations in cooking qualities among the three locations are shown in Table 7. In Table 7, (L)1 values before cooking samples from Takeo were smaller than PP and BTB with a 1% significant difference. (L)2 after cooking samples from Takeo had a tendency to be smaller than other locations naturally. (W)1 after cooking samples from PP were smaller than the other two locations with a 1% significant difference.

Table 7. 7 Variation of cooking qualities among the three locations

Variety	Location 3	n		Before cooking (L)1 mm	After cooking (L)2 mm	Elongation L2/L1	Before cooking (W)1 mm	After cooking (W)2 mm	Elongation (W2/W1)
Phka Rumduol	Takeo	27	AV	6.970 ab	11.037 A	1.584	1.647 f	2.389	1.427
			SD	0.172	0.532	0.072	0.035	0.082	0.091
	PP		AV	7.242 a	11.204	1.548	1.573 fg	2.385	1.483
			SD	0.174	0.729	0.102	0.085	0.160	0.121
	BTB		AV	7.338 b	11.507 A	1.569	1.634 g	2.323	1.421
			SD	0.097	0.436	0.066	0.032	0.121	0.079
Somali	Takeo	27	AV	7.028 cd	10.971 e	1.564	1.680 hi	2.405 C	1.432
			SD	0.252	0.710	0.136	0.046	0.126	0.093
	PP		AV	7.201 c	11.242 B	1.561	1.500 h	2.370	1.487 D
			SD	0.141	0.525	0.073	0.078	0.170	0.121
	BTB		AV	7.309 d	11.689 eB	1.600	1.630 i	2.312 C	1.419 D
			SD	0.167	0.715	0.108	0.025	0.124	0.078

Only significant deviation based on Tukey's test is reported. A 1% significant deviation based on Tukey's test is shown by small letters and a 5% of that is shown by capital letters. Takeo Province, Phnom Phen City and Battambang Province were abbreviated Takeo, PP, and BTB.

Variation in cooking qualities between the two varieties    Table 8 shows the variations in cooking qualities between the two varieties. Somali was longer than Phka Rumduol in (W)1 but Somali was shorter than Phka Rumduol in (W)2 with a 1% significant difference. No significant difference between (L)1 of the two varieties was observed. The results above were somewhat incompatible with the data in Table 5-1.

Table 8. Variation of cooking qualities between the two varieties

Variety	n	AV SD	Before cooking (L)1 mm	After cooking (L)2 mm	Elongation (L2/L1)	Before cooking (W)1 mm	After cooking (W)2 mm	Elongation (W2/W1)
Phka Rumduol	81	AV SD	7.154 0.205	11.249 0.604	1.567 0.082	1.618 a 0.064	2.366 b 0.127	1.465 0.103
Somali	81	AV SD	7.181 0.223	11.301 0.713	1.579 0.111	1.898 a 0.360	2.079 b 0.419	1.446 0.102

Only significant deviation base on Tukey's test is reported. A 1% significant deviation base on Tukey's-test is shown by small letters.

Grain elongation is especially important for Cambodian consumers; however, there was no difference in grain elongation between Phka Rumduol and Somali in this experiment.

Sensory evaluation

Cambodian panelists' impressions of cooked rice    Table 9 shows the results of questionnaires completed by the Cambodian panelists (n=120). Only between Takeo and PP, a 5% significant difference was observed for the question “Do you think Cambodian rice is superior to rice of other countries?”. Many panelists from the three locations wrote that they liked cooked rice (“yes” was 58%) and ate it more than two times per day. They preferred longer grains (“yes” was 61%; here, short means rice with shorter length in Cambodian rice varieties). Moreover they were proud of Cambodian rice (“yes” was 76%). The results supported high consumption of rice in Cambodia, where rice contributes 65% of energy intake and is consumed at a rate of 465 g / person / day.

Table 9. Results of questionnaires completed by the Cambodian panelists

	n		Do you like cooked rice?	How many times you eat cooked rice in a day?	Do you eat long rice or short rice in dairy meals?	Do you think Cambodian rice is superior to rice of other countries?
Takeo	40	AD	1.43	2.08	1.45	1.43 A
		SD	0.594	0.694	0.504	0.636
PP	40	AD	1.45	2.08	1.33	1.13 A
		SD	0.552	0.694	0.474	0.335
BTB	40	AD	1.50	2.15	1.13	1.30
		SD	0.555	0.662	0.496	0.564

Do you like cooked rice? (1=Yes, 2= So-So, 3= Don't), How many times you eat cooked rice in a day? (1= 3 times, 2=2 times, 3= 1 times), Do you eat long rice or short rice in dairy meals? (1=Long, 2= Short), Do you think Cambodian rice is superior to rice of other countries? (1=Yes, 2=No, 3=Other idea) A 5% significant deviation based on Tukey's test was shown only between Takeo and PP in the last question.

Seila et al. (2012) investigated consumption behavior of rice consumers with varying qualities (n=250, being variable in location, sex, farmer or not, age, education level, living zone), with responses to the question “How often do you consume rice per day” showing that rice was consumed two times per day by 48.80%, three times per day by 48.0% and more than three times per day by 3.20%. The question asked about rice but not cooked rice. Cambodians often consume rice noodles, rice soup, steamed rice, stir-fried rice, rice croquets and rice cakes.

Figure 3 shows sensory evaluation data for Phka Rumduol and Somali. In the case of sensory evaluation, no significant difference was observed between varieties. Favorability, grain dimension (grain length of cooked rice), aroma and whiteness were almost less than 2 (1 showed the highest evaluation). Since Cambodian people like cooked rice with a firm texture, the high values for hardness were also good.

Fig. 3.

Patterns of sensory evaluation data of Phka Rumduol and Somali

Table 10 shows sensory evaluation data for the three locations. Only between PP and BTB, a 5% significant difference was shown in grain dimension. It showed the panelists of PP felt that the two varieties of rice were a little bit shorter. In aroma, whiteness, hardness and favorability, no significant difference was observed. The average grain dimension, aroma, hardness and favorability showed a range of 1.65 to 2.33, showing high appreciation for these rice samples. However, the value for whiteness was around 3.8, showing Cambodian's preference for white rice.

Table 10. Sensory evaluation data among the three locations

		Grain dimension	Aroma	Whiteness	Hardness	Favorability
Takeo	AV	2.061	1.949	3.974	2.062	1.653
	SD	0.777	0.725	0.808	0.839	0.779
PP	AV	2.330 A	2.033	3.816	2.268	1.669
	SD	0.671	0.708	0.723	0.760	0.744
BTB	AV	1.940 A	1.864	3.728	2.058	1.864
	SD	0.460	0.453	0.611	0.469	0.594

Grain dimension (1=Very long, 2=Pretty long, 3=So-So, 4=Pretty short, 5 =Short), Aroma (1=Very high, 2=Pretty high, 3=So-So, 4= Pretty low, 5=Low or no aroma), Whiteness (1=Very white, 2=Pretty white, 3=So So, 4=Pretty dark, 5= Dark), hardness Whiteness (1= Very hard, 2=Pretty hard, 3=So-So, 4=Pretty soft, 5=Soft), Favorability (1=Very much, 2=Pretty like, 3=So-So, 4=Pretty not like, 5=Dislike) A 5 % significant deviation based on Tukey's test was shown between PP and BTB in grain dimension.

The palatability of cooked Phka Rumduol and Somali was extremely high from all Takeo, PP and BTB markets evaluated by Cambodian panelists.

Judgments of fungi    The presence of fungi species was not detected in any rice samples of Phka Rumduol and Somali collected from the nine retailers at the three local markets in each of Takeo, PP and BTB. Since no fungi were found, there were no data to report. Generally, both varieties had high safety. The previous study (Ek et al., 2018) also detected no fungi species from Phka Rumduol and Somali varieties.

Conclusion

Rice qualities and grade of Phka Rumduol and Somali among markets in each of the three locations were generally stable. On the other hand, those among locations, namely, Takeo Province, Phnom Penh City and Battambang Province, were not always stable. Grain size and grain grade were generally higher in the rice from Battambang. Grain size before and after cooking had almost similar tendencies. Rice qualities between the two varieties showed a tendency for Phka Rumduol to be longer than Somali in grain length, while Somali was wider and heavier than Phka Rumduol in grain width and weight. It was difficult to suggest only based on these results whether these characteristics contributed to the characteristics of the two varieties. The sensory evaluation by local panelists showed that all cooked rice was highly evaluated in grain dimension, aroma, whiteness, hardness and favorability. No fungi were detected in these rice samples. The overall results of this study showed that the two rice varieties collected from three markets in three main rice locations in Cambodia were generally and permissively high in quality grade for exportation or domestic uses.

Since Phka Rumduol and Somali are generally high quality with a high price, much more popular varieties with a lower price should been surveyed in the future.

Acknowledgements    The authors give sincere thanks to Prof. Dr. Ngo Bunthan, Rector of Royal University of Agriculture, Cambodia, Prof. Dr. Sok Kunthy, Vice Rector of Royal University of Agriculture, Prof. Dr. Kazuko Hirao, President of Aikoku Gakuen Junior College and Mr. Kenji Emori, Kett Electric Laboratory for their warm encouragement and suggestions. We are also very thankful for the kind cooperation of the local people in Takeo Province, Phnom Penh City and Battambang Province.

References

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•  Ek,  S.,  Setka,  S.,  Mithona,  A.,  Seiha,  T.,  Thong,  K., and  Saio,  K. (2018). Quality and safety of Cambodian rice, Food Sci. Technol. Res., 24, 829-838.
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