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The physicochemical characteristics of five types of rice-based home meal replacement (HMR) products (instant rice, doshirak, kimbab, frozen fried rice, and freeze-dried rice) were measured before and after microwave cooking, and principal component analysis (PCA) was performed. HMR products contained grains from 8.42 to 8.72 mm before and after the microwave cooking. The amylose content and water absorption index (WAI) ranged from 20.10-23.15% and 0.50-2.87%, respectively. Frozen fried rice showed high amylose content but low WAI, and dry rice showed low amylose content but high WAI. There was a change in the moisture content of freeze-dried rice: moisture increased from 1.3 to 60.3% after cooking. The rehydration rate of freeze-dried rice was about twice higher than that of other HMR products, while instant rice showed a low rehydration rate. The texture profile's hardness and cohesiveness respectively were 306.1 g/cm2 and 47.9% before cooking, but 209.6 g/cm2 and 66.0% after cooking. The lightness value decreased from 72.5 to 68.9 after the microwave cooking, while there was little change in the lightness value of instant rice, and that of the frozen fried rice decreased. PCA revealed that, microwave cooking apparently affected WAI and rehydration rate in the freeze-dried rice yellowness in the frozen fried rice, and stickiness and lightness in the instant rice, respectively.

In recent years, many rice varieties with improved processing quality have been developed to promote domestic rice consumption along with the increasing preference for plant-based food and by-products. This study aimed to assess the quality characteristics of rice milk using a set of rice varieties, including saeilmi (normal brown rice, NBR; and normal white rice, NWR), milyang355 (aromatic brown rice, ABR; and aromatic white rice, AWR) and milyang365 (pigment brown rice, PBR). Among these, the amylose content ranged from 5.13-23.50%, and the highest crude protein content was recorded in ABR (7.95%). In addition, brown rice showed a higher initial pasting temperature than did white rice; however, its viscosity properties were relatively low. Our data showed that the soluble solid content of rice milk was 6.5-7.7 °Brix, and viscosity ranged from 2.8-4.8 cP. Reducing sugar and free sugar content was high in AWR (p

We investigated the germination rate, color values, physicochemical properties, antioxidant capacity, and amino acid content of germinated brown rice varieties (milyang356, nampyeong, and dasan), and their statistical correlation were analyzed. Milyang356 rice was characterized by the highest germination percentage and total color difference value (3.89) at 24 h. In all varieties, the amylose and crude protein content increased on the 1st day of germination but decreased over time (p

The physicochemical and structural characteristics of high­yield, tongil­type mirchal glutinous rice, Milyang 328 (hereafter referred to as mirchal), were compared to those of a set of well-characterized glutinous rice varieties i.e., baegokchal, dongjinchal, and sinseonchal. The results revealed that mirchal exhibited the highest crude protein content (8.47%), water binding capacity (209.00%), and swelling power (55.82 g/g) under long term soaking. Analysis under identical conditions revealed that mirchal rice flour presented the minimum mean and median particle diameters of 50.54 μm and 22.72 μm, respectively, among the tested varieties. Furthermore, the particle diameter and onset temperature (To, 57.15°C) under these conditions were significantly lower than those under other conditions. The crystalline fraction of glutinous rice flour exhibited an A-type structure, irrespective of the soaking time. Mirchal exhibited the highest breakdown viscosity of 1,416.0 cP under short term soaking. The branch chain length distribution of the amylopectin A chain in the glutinous rice flours was arranged in the following sequence: baegokchal (30.82%) > mirchal (29.59%) > dongjinchal (28.74%) > sinseonchal (27.10%). The length distribution of the B1 chain in the glutious rice flours was arranged in the following sequence: dongjinchal (47.85%) > mirchal (47.17%) > baegokchal (45.83%) > sinseonchal (44.47%). Thus, this study revealed that mirchal possessed optimal processing characteristics owing to its high swelling power and excellent physicochemical properties, therby facilitating its application in the synthesis of yukwa and food processing materials.

In this study, we fermented ‘Makgeolli’ prepared using brown or white rice from ‘Mirchal’ for seven days to investigate the differences in their quality characteristics. Moreover, the physicochemical characteristics and antioxidant activities of ‘Makgeolli’ were assessed using principal component analysis (PCA). From the second day of fermentation, brown rice ‘Makgeolli’ exhibited a higher alcohol content (7.00%) than that of white rice ‘Makgeolli’ (3.60%). Additionally, the total polyphenol contents and antioxidant activities increased with the duration of fermentation (p

In the tropics (Southeast Asian countries), indica rice is more common than japonica. Japonica rice is mainly cultivated in temperate regions, including Korea, Japan, and China (northeast regions) due to its poor adaptation to tropical areas. To develop tropically-adapted high-yielding japonica rice, breeders should overcome the challenges, including extremely early flowering, low biomass accumulation, and inferior panicle traits. This study investigated 180 F9 recombinant inbred lines (RILs) developed from a cross between Ilpum (temperate japonica) and Zenith (indica) as a case population to identify quantitative trait loci (QTLs) that influence the said traits. Here we identified two major QTLs, qHD6-SD and qHD6- LD, conferring days to heading under short day (SD) and long day (LD) conditions, respectively. Finer mapping revealed that both qHD6-SD and qHD6-LD located in the similar 98 kb region harbored the Hd1 gene. Days to heading in the RILs harboring the Zenith allele type of qHD6-SD under SD conditions were significantly longer than those in the RILs harboring the Ilpum allele type. On the contrary, days to heading in the RILs harboring the Zenith allele type of qHD6-SD under LD conditions were significantly shorter than those in the RILs harboring the Ilpum allele type. This bi-functionality of qHD6-SD upon heading strongly support the claim that both qHD6-SD and qHD6-LD might be the Hd1 gene. Our findings further support the claim that the functional allele type of Hd1 gene delays long-day heading and promotes extremely early short-day heading. Therefore, a non-functional Hd1 type is critical to tropical adaptation of japonica rice since it delays the heading date, which is essential to attain prolonged vegetative state in order to achieve optimum biomass, increased spikelet number, and grain filling capacity.

Four near-isogenic lines (NILs) with different allele combinations of the

Glutinous rice is a key grain quality trait occupying an important part during rice processing in most rice growing areas. In this study, a gene pyramiding approach was used to introduce two dull genes, responsible for low amylose content, for glutinous rice breeding using marker assisted selection (MAS). The genotyping results revealed that rice cultivar Milyang319 carries both dull genes on chromosome 6, derived from cv. Milky-queen (Wx-mq) and cv. LGS-soft (du12(t)), respectively. Milyang319 had a significantly low amylose content (9.0%) compared to those observed in donor parents Milky-queen (15.7%) and LGS-soft (14.5%). In addition, the amylogram analysis of Milyang319 showed a similar pattern of glutinous rice. Originally, Milyang319 had a low hardness and more stickiness compared to those recorded in cooked rice of both dull parental lines. Therefore, Milyang319 is proposed as a promising candidate rice cultivar that could be used as a new source of waxy germplasms with same physicochemical features of glutinous rice in further breeding programs.

The purpose of this study was to improve the processability of rice powder using fluidised-bed granulation technology. Bukkyungmi-rice granules were prepared by fluidised-bed granulation for 1 and 2 h using water, 5% lactose (w/v) and 5% dextrin (w/v) solutions as dispersants. The particle size of Bukkyungmi-rice granules increased from 574.83 to 728.07 μm. Granules were produced due to pore formation, and the produced particles could be dispersed easily without any entanglement. The water solubility of the produced rice granules is 1.91–6.74%, which reflects the improvement in their quality with increased treatment time. In particular, Bukkyungmi-rice granules processed in 5% dextrin showed excellent settleability. The enthalpy (ΔH) was found to be the highest for Bukkyungmi-rice granules processed in 5% dextrin for 2 h by differential scanning calorimetry. The results indicated that rice granules obtained by fluidised-bed granulation could be used in various types of rice-based foods.

In order to increase the usability of rice, this study was investigated the quality characteristics of extruded rice snacks based on the rice cultivar (‘Aromi’, ‘Hanahreum’, ‘Jasmin 85’ and ‘Bukkyeong 2012’) and ratio of corn flour (0, 30, 50, 70 and 100% w/w) to rice flour. The moisture content and bulk density decreased as the amylose content decreased, whereas the porosity and expansion ratio tended to decrease with increasing amylose content. The strength and hardness increased significantly with the amylose content. The water solubility index and water absorption index decreased and increased, respectively, as the amylose content increased. The moisture content and the L value increased significantly as the proportion of rice flour was increased, whereas the b value decreased significantly. The bulk density increased with increasing rice flour content. The porosity, expansion ratio and specific length tended to increase as the amount of rice flour was increased. The strength and hardness were the lowest in extruded snacks made with 70% of rice flour. The water solubility index and water absorption index increased significantly with increasing rice flour content. Therefore, the best quality characteristics were observed in extruded snacks made with the Aromi, and the optimal proportion of rice flour was 70%.

In rice, high radial oxygen loss (ROL) has been associated with the reduction in the activity of methanogens, therefore reducing the formation of methane (CH

Temperate japonica rice is mainly cultivated in temperate regions. Many temperate japonica varieties have a superior grain quality that is preferred in Northeast Asian countries such as Japan, Korea, and China. The changes in consumers’ preferences in Southeast Asia and Western countries has contributed to increasing the demand for temperate japonica. Most temperate japonica varieties developed in temperate regions typically exhibit extra-early flowering under the short-day conditions in the tropics, which usually results in severely reduced yields. Since 1992, we have been developing temperate japonica varieties that can adapt to tropical environments to meet the increasing demand for temperate japonica rice, having released six varieties in the Philippines. Especially, the yield of one of the temperate japonica varieties, Japonica 7, was comparable to the yields of leading indica varieties in the Philippines. Here, we discuss the current breeding initiatives and future plans for the development of tropical-region-bred temperate japonica rice.

The National Institute of Crop Science, Rural Development Administration (RDA) of Korea is presently developing new rice varieties suitable for producing Western rice-based foods, such as risotto, a well-known Italian-style product. The study considered different milled rice from five Tongil-type and six Japonica-type varieties. Besides the biometric properties, cooking behaviour, starch properties, and in vitro digestibility of Korean rice samples were compared with those of the ‘Carnaroli’ Italian variety. The physicochemical traits of the Korean varieties extended over a vast range; the amylose content stood out (from 13.0 to 41.7%), influencing the hardness and stickiness of cooked samples, and their starch digestibility. Although none of the Korean varieties seemed to guarantee cooking performances for risotto similar to the ‘Carnaroli’ one, ‘Saemimyeon’ and ‘Shingil’ cvs were judged the best for this purpose up-to-now.

The green rice leafhopper (GRH, Nephotettix cincticeps Uhler) is one of the most important insect pests causing serious damage to rice production and yield loss in East Asia. Prior to performing RNA-Seq analysis, we conducted an electrical penetration graph (EPG) test to investigate the feeding behavior of GRH on Ilpum (recurrent parent, GRH-susceptible cultivar), a near-isogenic line (NIL carrying Grh1) compared to the Grh1 donor parent (Shingwang). Then, we conducted a transcriptome-wide analysis of GRH-responsive genes in Ilpum and NIL, which was followed by the validation of RNA-Seq data by qPCR. On the one hand, EPG results showed differential feeding behaviors of GRH between Ilpum and NIL. The phloem-like feeding pattern was detected in Ilpum, whereas the EPG test indicated a xylem-like feeding habit of GRH on NIL. In addition, we observed a high death rate of GRH on NIL (92%) compared to Ilpum (28%) 72 h post infestation, attributed to GRH failure to suck the phloem sap of NIL. On the other hand, RNA-Seq data revealed that Ilpum and NIL GRH-treated plants generated 1,766,347 and 3,676,765 counts per million mapped (CPM) reads, respectively. The alignment of reads indicated that more than 75% of reads were mapped to the reference genome, and 8859 genes and 15,815,400 transcripts were obtained. Of this number, 3424 differentially expressed genes (DEGs, 1605 upregulated in Ilpum and downregulated in NIL, 1819 genes upregulated in NIL and downregulated in Ilpum) were identified. According to the quantile normalization of the fragments per kilobase of transcript per million mapped reads (FPKM) values, followed by the Student’s t-test (p &lt, 0.05), we identified 3283 DEGs in Ilpum (1935 upregulated and 1348 downregulated) and 2599 DEGs in NIL (1621 upregulated and 978 downregulated) with at least a log2 (logarithm base 2) twofold change (Log2FC ≥2) in the expression level upon GRH infestation. Upregulated genes in NIL exceeded by 13.3% those recorded in Ilpum. The majority of genes associated with the metabolism of carbohydrates, amino acids, lipids, nucleotides, the activity of coenzymes, the action of phytohormones, protein modification, homeostasis, the transport of solutes, and the uptake of nutrients, among others, were abundantly upregulated in NIL (carrying Grh1). However, a high number of upregulated genes involved in photosynthesis, cellular respiration, secondary metabolism, redox homeostasis, protein biosynthesis, protein translocation, and external stimuli response related genes were found in Ilpum. Therefore, all data suggest that Grh1-mediated resistance against GRH in rice would involve a transcriptome-wide reprogramming, resulting in the activation of bZIP, MYB, NAC, bHLH, WRKY, and GRAS transcription factors, coupled with the induction of the pathogen-pattern triggered immunity (PTI), systemic acquired resistance (SAR), symbiotic signaling pathway, and the activation of genes associated with the response mechanisms against viruses. This comprehensive transcriptome profile of GRH-responsive genes gives new insights into the molecular response mechanisms underlying GRH (insect pest)–rice (plant) interaction.

The green rice leafhopper (GRH, Nephotettix cincticeps Uhler) is one of the most important insect pests causing serious damage to rice production and yield loss in East Asia. Prior to performing RNA-Seq analysis, we conducted an electrical penetration graph (EPG) test to investigate the feeding behavior of GRH on Ilpum (recurrent parent, GRH-susceptible cultivar), a near-isogenic line (NIL carrying Grh1) compared to the Grh1 donor parent (Shingwang). Then, we conducted a transcriptome-wide analysis of GRH-responsive genes in Ilpum and NIL, which was followed by the validation of RNA-Seq data by qPCR. On the one hand, EPG results showed differential feeding behaviors of GRH between Ilpum and NIL. The phloem-like feeding pattern was detected in Ilpum, whereas the EPG test indicated a xylem-like feeding habit of GRH on NIL. In addition, we observed a high death rate of GRH on NIL (92%) compared to Ilpum (28%) 72 h post infestation, attributed to GRH failure to suck the phloem sap of NIL. On the other hand, RNA-Seq data revealed that Ilpum and NIL GRH-treated plants generated 1,766,347 and 3,676,765 counts per million mapped (CPM) reads, respectively. The alignment of reads indicated that more than 75% of reads were mapped to the reference genome, and 8859 genes and 15,815,400 transcripts were obtained. Of this number, 3424 differentially expressed genes (DEGs, 1605 upregulated in Ilpum and downregulated in NIL; 1819 genes upregulated in NIL and downregulated in Ilpum) were identified. According to the quantile normalization of the fragments per kilobase of transcript per million mapped reads (FPKM) values, followed by the Student’s t-test (p < 0.05), we identified 3283 DEGs in Ilpum (1935 upregulated and 1348 downregulated) and 2599 DEGs in NIL (1621 upregulated and 978 downregulated) with at least a log2 (logarithm base 2) twofold change (Log2FC ≥2) in the expression level upon GRH infestation. Upregulated genes in NIL exceeded by 13.3% those recorded in Ilpum. The majority of genes associated with the metabolism of carbohydrates, amino acids, lipids, nucleotides, the activity of coenzymes, the action of phytohormones, protein modification, homeostasis, the transport of solutes, and the uptake of nutrients, among others, were abundantly upregulated in NIL (carrying Grh1). However, a high number of upregulated genes involved in photosynthesis, cellular respiration, secondary metabolism, redox homeostasis, protein biosynthesis, protein translocation, and external stimuli response related genes were found in Ilpum. Therefore, all data suggest that Grh1-mediated resistance against GRH in rice would involve a transcriptome-wide reprogramming, resulting in the activation of bZIP, MYB, NAC, bHLH, WRKY, and GRAS transcription factors, coupled with the induction of the pathogen-pattern triggered immunity (PTI), systemic acquired resistance (SAR), symbiotic signaling pathway, and the activation of genes associated with the response mechanisms against viruses. This comprehensive transcriptome profile of GRH-responsive genes gives new insights into the molecular response mechanisms underlying GRH (insect pest)–rice (plant) interaction.

Seeds of 15 diverse rice accessions, representing aus, indica, temperate japonica and tropical japonica subpopulations, were produced under temperate climate conditions in Korea and used for vitamin E analysis and seed storage experiments at 45°C and 10.9% seed moisture content. High γ-tocotrienol was significantly positively correlated with seed longevity. In addition, a high β-tocopherol proportion relative to δ-tocopherol was significantly negatively correlated with seed longevity. Using high-density single-nucleotide polymorphism marker data, DNA haplotype analysis showed clear allelic variations in the region of two S-adenosylmethionine synthetase genes: LOC_Os04g42095 and LOC_Os11g15410, which regulate the conversion of δ-tocopherol into β-tocopherol. Four indica accessions with rare and subpopulation-specific alleles showed a 2.3-fold lower β-/δ-tocopherol ratio compared with accessions from other subpopulations.

Shoot branching is considered as an important trait for the architecture of plants and contributes to their growth and productivity. In cereal crops, such as rice, shoot branching is controlled by many factors, including phytohormones signaling networks, operating either in synergy or antagonizing each other. In rice, shoot branching indicates the ability to produce more tillers that are essential for achieving high productivity and yield potential. In the present study, we evaluated the growth and development, and yield components of a doubled haploid population derived from a cross between 93-11 (P1, indica) and Milyang352 (P2, japonica), grown under normal nitrogen and low nitrogen cultivation open field conditions. The results of the phenotypic evaluation indicated that parental lines 93-11 (P1, a high tillering indica cultivar) and Milyang352 (P2, a low tillering japonica cultivar) showed distinctive phenotypic responses, also reflected in their derived population. In addition, the linkage mapping and quantitative trait locus (QTL) analysis detected three QTLs associated with tiller number on chromosome 2 (qTNN2-1, 130 cM, logarithm of the odds (LOD) 4.14, PVE 14.5%, and qTNL2-1, 134 cM, LOD: 6.05, PVE: 20.5%) and chromosome 4 (qTN4-1, 134 cM, LOD 3.92, PVE 14.5%), with qTNL2-1 having the highest phenotypic variation explained, and the only QTL associated with tiller number under low nitrogen cultivation conditions, using Kompetitive Allele-Specific PCR (KASP) and Fluidigm markers. The additive effect (1.81) of qTNL2-1 indicates that the allele from 93-11 (P1) contributed to the observed phenotypic variation for tiller number under low nitrogen cultivation. The breakthrough is that the majority of the candidate genes harbored by the QTLs qTNL2-1 and qTNN4-1 (here associated with the control of shoot branching under low and normal nitrogen cultivation, respectively), were also proposed to be involved in plant stress signaling or response mechanisms, with regard to their annotations and previous reports. Therefore, put together, these results would suggest that a possible crosstalk exists between the control of plant growth and development and the stress response in rice.

Shoot branching is considered as an important trait for the architecture of plants and contributes to their growth and productivity. In cereal crops, such as rice, shoot branching is controlled by many factors, including phytohormones signaling networks, operating either in synergy or antagonizing each other. In rice, shoot branching indicates the ability to produce more tillers that are essential for achieving high productivity and yield potential. In the present study, we evaluated the growth and development, and yield components of a doubled haploid population derived from a cross between 93-11 (P1, indica) and Milyang352 (P2, japonica), grown under normal nitrogen and low nitrogen cultivation open field conditions. The results of the phenotypic evaluation indicated that parental lines 93-11 (P1, a high tillering indica cultivar) and Milyang352 (P2, a low tillering japonica cultivar) showed distinctive phenotypic responses, also reflected in their derived population. In addition, the linkage mapping and quantitative trait locus (QTL) analysis detected three QTLs associated with tiller number on chromosome 2 (qTNN2-1, 130 cM, logarithm of the odds (LOD) 4.14, PVE 14.5%; and qTNL2-1, 134 cM, LOD: 6.05, PVE: 20.5%) and chromosome 4 (qTN4-1, 134 cM, LOD 3.92, PVE 14.5%), with qTNL2-1 having the highest phenotypic variation explained, and the only QTL associated with tiller number under low nitrogen cultivation conditions, using Kompetitive Allele-Specific PCR (KASP) and Fluidigm markers. The additive effect (1.81) of qTNL2-1 indicates that the allele from 93-11 (P1) contributed to the observed phenotypic variation for tiller number under low nitrogen cultivation. The breakthrough is that the majority of the candidate genes harbored by the QTLs qTNL2-1 and qTNN4-1 (here associated with the control of shoot branching under low and normal nitrogen cultivation, respectively), were also proposed to be involved in plant stress signaling or response mechanisms, with regard to their annotations and previous reports. Therefore, put together, these results would suggest that a possible crosstalk exists between the control of plant growth and development and the stress response in rice.

Potassium chlorate (KClO3) has been widely used to evaluate the divergence in nitrogen use efficiency (NUE) between indica and japonica rice subspecies. This study investigated the transcriptional regulation of major genes involved in the NUE in rice treated with KClO3, which acts as an inhibitor of the reducing activity of nitrate reductase (NR) in higher plants. A set of two KClO3 sensitive nitrate reductase (NR) and two nitrate transporter (NRT) introgression rice lines (BC2F7), carrying the indica alleles of NR or NRT, derived from a cross between Saeilmi (japonica, P1) and Milyang23 (indica, P2), were exposed to KClO3 at the seedling stage. The phenotypic responses were recorded 7 days after treatment, and samples for gene expression, physiological, and biochemical analyses were collected at 0 h (control) and 3 h after KClO3 application. The results revealed that Saeilmi (P1, japonica) and Milyang23 (P2, indica) showed distinctive phenotypic responses. In addition, the expression of OsNR2 was differentially regulated between the roots, stem, and leaf tissues, and between introgression lines. When expressed in the roots, OsNR2 was downregulated in all introgression lines. However, in the stem and leaves, OsNR2 was upregulated in the NR introgression lines, but downregulation in the NRT introgression lines. In the same way, the expression patterns of OsNIA1 and OsNIA2 in the roots, stem, and leaves indicated a differential transcriptional regulation by KClO3, with OsNIA2 prevailing over OsNIA1 in the roots. Under the same conditions, the activity of NR was inhibited in the roots and differentially regulated in the stem and leaf tissues. Furthermore, the transcriptional divergence of OsAMT1.3 and OsAMT2.3, OsGLU1 and OsGLU2, between NR and NRT, coupled with the NR activity pattern in the roots, would indicate the prevalence of nitrate (NO3¯) transport over ammonium (NH4+) transport. Moreover, the induction of catalase (CAT) and polyphenol oxidase (PPO) enzyme activities in Saeilmi (P1, KClO3 resistant), and the decrease in Milyang23 (P2, KClO3 sensitive), coupled with the malondialdehyde (MDA) content, indicated the extent of the oxidative stress, and the induction of the adaptive response mechanism, tending to maintain a balanced reduction–oxidation state in response to KClO3. The changes in the chloroplast pigments and proline content propose these compounds as emerging biomarkers for assessing the overall plant health status. These results suggest that the inhibitory potential of KClO3 on the reduction activity of the nitrate reductase (NR), as well as that of the genes encoding the nitrate and ammonium transporters, and glutamate synthase are tissue-specific, which may differentially affect the transport and assimilation of nitrate or ammonium in rice.