Unpolished Rice Grains Research Articles

Palatability and Bio-Functionality of Chalky Grains Generated by High-Temperature Ripening and Development of Formulae for Estimating the Degree of Damage Using a Rapid Visco Analyzer of Japonica Unpolished Rice.

Global warming inhibits grain filling in rice and leads to chalky grains, which are damaged in physical and cooking qualities. In the present paper, we evaluated 54 Japonica unpolished rice grains harvested in Japan in 2020, and these samples (original grains) were divided to two groups (whole grains and chalky grains). Using rice grains of 100% whole grains or those blended with 30% of chalky grains, we measured contents of sugars and amino acids, and textural properties of boiled rice grains. It was shown that the α-amylase activity and proteinase activity of raw chalky rice were significantly higher than those of whole rice grains, which led to the significant increase of low-molecular-weight sugars and free amino acids after boiling. Furthermore, hardness and toughness of the boiled rice grains were decreased markedly by blending chalky grains. The ratio of α-amylase activity of chalky grains to that of whole grains was shown to be a useful indicator for damage degree by high-temperature ripening. It became possible to estimate the degree of high-temperature damage of rice grains based on only the pasting properties of unpolished rice.

Nutritional Composition, Mineral Content and Antioxidant Properties of Unpolished Red Rice Cultivars of Assam, India

Background: Assam is a rich source of different types of colored rice cultivars. Very few colored rice cultivars are studied regarding nutritional and phytochemical properties. The objective of present study was to assess the nutritional composition and antioxidant properties of traditional red rice cultivars of Assam. Methods: Ten different red rice cultivars were collected for the study. The unpolished rice grains were analysed for proximate composition, mineral content, total phenolic, flavonoid content and DPPH free radical scavenging activity. Result: Amylose content was found to be low in the red rice cultivars. The carbohydrate and crude protein content varied significantly among the red rice cultivars. The studied cultivars were found to be good source of Fe, Mn and Zn. Highest total phenolic (1357.22 mg /100 g) and flavonoid content (896.37 mg/100 g) were found in the Hal aus, whereas the lowest value for total phenolic (336.49 mg/100 g) and flavonoid content (127.51 mg/100 g) were observed in Basanta bahar. Antioxidant capacity of colored rice varieties ranged from 33.33 to 84.24% for DPPH radical scavenging activity. The red rice cultivars contain a significant amount of nutrients and antioxidants including phenolic and flavonoids.

Deep learning based high-throughput phenotyping of chalkiness in rice exposed to high night temperature

BackgroundRice is a major staple food crop for more than half the world’s population. As the global population is expected to reach 9.7 billion by 2050, increasing the production of high-quality rice is needed to meet the anticipated increased demand. However, global environmental changes, especially increasing temperatures, can affect grain yield and quality. Heat stress is one of the major causes of an increased proportion of chalkiness in rice, which compromises quality and reduces the market value. Researchers have identified 140 quantitative trait loci linked to chalkiness mapped across 12 chromosomes of the rice genome. However, the available genetic information acquired by employing advances in genetics has not been adequately exploited due to a lack of a reliable, rapid and high-throughput phenotyping tool to capture chalkiness. To derive extensive benefit from the genetic progress achieved, tools that facilitate high-throughput phenotyping of rice chalkiness are needed.ResultsWe use a fully automated approach based on convolutional neural networks (CNNs) and Gradient-weighted Class Activation Mapping (Grad-CAM) to detect chalkiness in rice grain images. Specifically, we train a CNN model to distinguish between chalky and non-chalky grains and subsequently use Grad-CAM to identify the area of a grain that is indicative of the chalky class. The area identified by the Grad-CAM approach takes the form of a smooth heatmap that can be used to quantify the degree of chalkiness. Experimental results on both polished and unpolished rice grains using standard instance classification and segmentation metrics have shown that Grad-CAM can accurately identify chalky grains and detect the chalkiness area.ConclusionsWe have successfully demonstrated the application of a Grad-CAM based tool to accurately capture high night temperature induced chalkiness in rice. The models trained will be made publicly available. They are easy-to-use, scalable and can be readily incorporated into ongoing rice breeding programs, without rice researchers requiring computer science or machine learning expertise.

Rice (Oryza sativa L.) seedlings enriched with zinc or manganese: Their impacts on cadmium accumulation and expression of related genes

Cadmium (Cd) contamination in paddy soils means that the rice produced there may be unsafe for human consumption. A hydroponic study was conducted to enrich rice seedlings with zinc (Zn) or manganese (Mn), and the uptake and transport characteristics of Cd in these Zn- and Mn-rich seedlings were subsequently investigated using a greenhouse pot trial. The results showed that hydroponic cultivation in 10–50 µmol L–1 Zn (ZnSO4·7H2O) or 50–250 µmol L–1 Mn (MnSO4·H2O) for 30 d had no significant impact on rice growth, while the accumulation of Zn and Mn was 7.31–18.5 and 25.4–47.7 times higher, respectively, than in the control (no Zn or Mn addition). The accumulation of Cd in the Zn- and Mn-rich rice plants was 26.3%–38.6% and 34.4%–44.5% lower than that in the control, respectively, and the translocation factors of Cd from roots to shoots also decreased by 23.3%–41.3% and 25.3%–37.0%, respectively, after transplanting to Cd-contaminated soils. Furthermore, the relative expression levels of OsIRT1 (Oryza sativa iron-regulated transporter 1) were downregulated by 40.1%–59.3% and 16.0%–25.9%, respectively, in the Zn- and Mn-rich seedling roots. This downregulation may indicate a possible mechanism contributing to the reductions in Cd absorption. Field experiments confirmed that the Zn- and Mn-rich seedlings produced brown rice (unpolished rice grains) with significantly decreased concentrations of Cd (34.2%–44.4%). This study provides an innovative method for reducing the food safety risks from rice grown on slightly to moderately Cd-contaminated paddy soils.

Iron modification to silicon-rich biochar and alternative water management to decrease arsenic accumulation in rice (Oryza sativa L.)

Production of rice grains at non-toxic levels of arsenic (As) to meet the demands of an ever-increasing population is a global challenge. There is currently a lack of investigation into integrated approaches for decreasing As levels in rice agro-ecosystems. By examining the integrated iron-modified rice hull biochar (Fe-RBC) and water management approaches on As dynamics in the paddy agro-ecosystem, this study aims to reduce As accumulation in rice grains. The rice cultivar, Ishikari, was grown and irrigated with As-containing water (1 mg L−1 of As(V)), under the following treatments: (1) Fe-RBC-flooded water management, (2) Fe-RBC-intermittent water management, (3) conventional flooded water management, and (4) intermittent water management. Compared to the conventional flooded water management, grain weight per pot and Fe and Si concentrations in the paddy pore water under Fe-RBC-intermittent and Fe-RBC-flooded treatments increased by 24%–39%, 100%–142%, and 93%–184%, respectively. The supplementation of Fe-RBC decreased the As/Fe ratio and the abundance of Fe(III) reducing bacteria (i.e. Bacillus, Clostridium, Geobacter, and Anaeromyxobacter) by 57%–88% and 24%–64%, respectively, in Fe-RBC-flooded and Fe-RBC-intermittent treatments compared to the conventional flooded treatment. Most importantly, Fe-RBC-intermittent treatment significantly (p ≤ 0.05) decreased As accumulation in rice roots, shoots, husks, and unpolished rice grains by 62%, 37%, 79%, and 59%, respectively, compared to the conventional flooded treatment. Overall, integrated Fe-RBC-intermittent treatment could be proposed for As endemic areas to produce rice grains with safer As levels, while sustaining rice yields to meet the demands of growing populations.

Effect of Milling and Parboiling Processes on Arsenic Species Distribution in Rice Grains

This study identified the role of milling and parboiling on arsenic (As) content and its species in large numbers of rice samples. Total As contents were 108±33μg/kg in polished rice grains (PR), 159±46μg/kg in unpolished rice grains (UR), 145±42μg/kg in parboiled polished rice grains (PPR) and 145±44μg/kg in parboiled unpolished rice grains (PUR). The percentages of inorganic As (iAs) were 66%±8% in PR and from 72% to 77% in other grain categories. The polishing process reduced the As content in the rice grains, removing outer part of the UR with high amount of As, whereas the parboiling technique transferred the semimetal content within the grain. Total As and iAs contents were not significantly different in UR, PPR and PUR, homogenizing its distribution inside the grains. The results allowed to understand how different operations affect As fate and its chemical forms in grains.

Genetic Analysis Reveals a Major Effect QTL Associated with High Grain Zinc Content in Rice (Oryza sativaL.)

Molecular mapping and application of quantitative trait loci (QTL) associated with a higher level of grain Zinc is a viable option to enhance zinc content in rice through breeding. An F2 population derived from a cross between a high yielding variety, BRRI dhan28, and a locally adapted Zn enriched cultivar, Kalobokri was used to map QTLs associated with higher levels of Zn in rice grain. The F2:3 progenies varied significantly (P ＜ 0.0001) in Zinc contents with a mean value remarkably higher than those in the superior parent. Through marker by trait analysis using IciMapping, we detected a large-effect QTL, qGZn3 on chromosome 3 between RM5419 and RM1164 spanning 1.83 Mb interval at the 0.05 level of significance with a threshold LOD of 10.61. This QTL showed a21.1% (R2 value) contribution to the total phenotypic variation for zinc content in the unpolished rice grains with 4.68 μg/g additive effect of Kalobokri alleles. We also detected 11 metal homeostasis related genes within the interval of qGZn3. In-silico analysis showed that four expressed sequence tags of one candidate gene (LOC_Os03g22810) encoding Cu/Zn superoxide dismutase, a metal-binding protein, are highly active in the endosperm as well as in the embryonic tissue of rice grain. Taken together, our results suggest that qGZn3 is a major QTL associated with high grain Zn content in the F2 progenies of rice. Our findings offer valuable genetic resources to facilitate breeding for high yielding and Zinc-enriched rice variety.

Environmental Health Risk Assessment of Fe, Zn, As, Cd and Pb Concentration in Selected Asian Rice Grain (Oryza sativa)

This study was carried out to determine the concentration of chemical elements in food grains (Oryza Sativa). A total of eight brands of rice grains was selected which are commonly sold in major hypermarkets in Malaysia. The selection was based on the countries of origin (COO) namely Cambodia, Indonesia, Malaysia, Thailand, Vietnam, China, Japan and Taiwan. A total of 16 rice grain samples included both polished and unpolished rice grains in order to determine the concentration of Fe, Zn, As, Cd and Pb. From the laboratory result, it was found that the concentration of Fe, Zn, As, Cd and Pb was ranged from 0.067-14.446 mgkg‑1, 0.308-12.335 mgkg‑1, 0.000-0.048 mgkg‑1, 0.000-0.604 mgkg‑1 and 0.000-0.418 mgkg‑1 respectively. The rice grains samples from Vietnam, China and Cambodia showed that carcinogenic cancer risk for both adults and infants’ group (Cumulative lifetime cancer risk, CLCR >1x10-4).

An integrated approach of rice hull biochar-alternative water management as a promising tool to decrease inorganic arsenic levels and to sustain essential element contents in rice

Arsenic (As) in rice agroecosystems causes a loss of both rice yield and quality of rice grains. In this study, an integrated approach of biochar (BC) and alternative water management is proposed to reduce As content while sustaining essential elemental concentrations in rice. The rice cultivar, Jayanthi, was grown, irrigated with 1 mg L−1 of As-containing water, under rice hull BC (RBC)-flooded, RBC-intermittent, conventional flooded, and intermittent treatments. The RBC has increased rice yield by 11%−19% in RBC-intermittent and -flooded treatments compared to the flooded treatment. Inorganic As content in rice tissues and abundance of Fe(III) reducing bacteria in the rhizosphere were lowered by 10%−83% and 40–70%, respectively, in RBC-flooded, -intermittent, and intermittent treatments over flooded treatment. Essential elemental concentrations (Fe, Mn, Zn, Mg, and Ca) in unpolished rice grains increased by 45%−329% in RBC-flooded and -intermittent treatments compared to flooded treatment. Overall, the integrated approach of RBC-intermittent practices has lowered inorganic As concentration in unpolished rice grains, while sustaining the levels of essential elements in rice grains, compared to other treatments. An integrated approach of RBC-intermittent practices is suggested for rice grown with As-contaminated water to improve the quality of rice, as well as tackling food-related malnutrition in people.

Effect of heat-moisture treatment of unpolished red rice on its starch properties and in vitro and in vivo digestibility

Changes in physicochemical and digestible characteristics of starches isolated from untreated and heat-moisture treated unpolished rice grains were investigated in this study. Heat-moisture treatment (HMT) at moisture content of 20%, 25% or 30% and heating temperature of 100 °C or 120 °C were applied for treating unpolished rice grains. The results indicated that granular morphology and crystalline structure of starches remained almost unchanged. However, a significant difference in the format and degree of agglomeration of starches of the rice grains treated at moisture content of 30% was observed. The HMT also suppressed the swelling and breakdown of the starch granules when treating at high moisture content and heating temperature. After HMT, amounts of resistant starch (RS) in the treated rice grains significantly increased as compared to that in the untreated rice grains. Moreover, the rice grains were heat-moisture treated with higher moisture contents or heating temperatures had higher RS contents. As a result, the rice grains treated at moisture content of 30% and heating temperature of 120 °C contained the highest amount of RS (49.1%), released the lowest blood glucose level and had GI value of 55, which is considered as low GI food.

Harmful and nutrient elements in paddy soils and their transfer into rice grains (Oryza sativa) along two river systems in northern and central Vietnam.

Thirty soil samples and 24 corresponding unpolished rice samples along the Red and Huong Rivers in northern and central Vietnam respectively, were analyzed in order to evaluate (a) soil geochemistry, (b) factors that determine the transfer of harmful and nutrient elements from soils into rice grains, (c) health risk to the local population through rice consumption. The concentrations of As, Bi, and U in the soils of this area are higher relative to those of average shale probably due to natural redox-related processes. Also, Zn, Ce, Th, La, Sn, Pb, and Cd are accumulated in some soils because of mining activities or industrial wastewater application. Arsenic concentrations exceed the Vietnamese allowable limit of 15mgkg-1 in 80% of the tested soils. Twelve percent of the unpolished rice grains surpass the permissible maximum concentration of 0.2mgCdkg-1 grain dry matter by FAO/WHO and European Union, and all samples are below the Pb limit. The daily intake of As is within the range of the tolerable intake levels proposed by the European Food Safety Authority. Influences of soil parameters such as pH value, contents of soil organic matter, oxides/hydroxides of Al, Fe, and Mn cause a broad spread of transfer factors from soil to grains. Positive trends exist between the transfer factors within the groups (a) As, Sb, and U, (b) Co, Cu, Ni, and Zn, (c) Cd and Mn which indicate similar influences of soil parameters on their uptake. We propose that the allowable Cd maximum concentration for rice should be set to less than 0.2mgkg-1. The analysis of As and Cd concentrations in soils and corresponding rice grains as well as the soil pH value should be made obligatory in order to prevent intoxication. In addition, critical elements from nonferrous metal mining and industrial areas should also be evaluated.

Facilitated citrate-dependent iron translocation increases rice endosperm iron and zinc concentrations

Iron deficiency affects one third of the world population. Most iron biofortification strategies have focused on genes involved in iron uptake and storage but facilitating internal long-distance iron translocation has been understudied for increasing grain iron concentrations. Citrate is a primary iron chelator, and the transporter FERRIC REDUCTASE DEFECTIVE 3 (FRD3) loads citrate into the xylem. We have expressed AtFRD3 in combination with AtNAS1 (NICOTIANAMINE SYNTHASE 1) and PvFER (FERRITIN) or with PvFER alone to facilitate long-distance iron transport together with efficient iron uptake and storage in the rice endosperm. The citrate and iron concentrations in the xylem sap of transgenic plants increased two-fold compared to control plants. Iron and zinc levels increased significantly in polished and unpolished rice grains to more than 70% of the recommended estimated average requirement (EAR) for iron and 140% of the recommended EAR for zinc in polished rice grains. Furthermore, the transformed lines showed normal phenotypic growth, were tolerant to iron deficiency and aluminum toxicity, and had grain cadmium levels similar to control plants. Together, our results demonstrate that deploying FRD for iron biofortification has no obvious anti-nutritive effects and should be considered as an effective strategy for reducing human iron deficiency anemia.

Effect of cadmium on growth parameters and plant accumulation in different rice (Oryza sativa L.) varieties in Sri Lanka

Rice (Oryza sativa L.) has the ability to uptake and accumulate cadmium (Cd) in different amounts within the plant parts. A pot experiment was conducted to investigate the variations of plant growth and levels of accumulation of Cd among eight rice genotypes (new improved varieties-NIVs and traditional varieties- TVs) grown under different soil Cd levels. Two soil Cd concentrations (50 and 100 mg/kg) were provided in the form of cadmium chloride and the effect of Cd on rice plant growth was measured with respect to the plant height, number of tillers, flag leaf chlorophyll content, leaf area of the flag leaf, and root dry weight. The soil without added Cd was considered as the control. The initial Cd concentration in the soil used was 1.958 mg/kg. The total amount of Cd in unpolished rice grains, shoots and roots were analyzed with Graphite Furnace Atomic Absorption Spectrophotometer and Flame Atomic Absorption Spectrophotometer. The results revealed that the rice variety, soil Cd level and interactions between rice variety and Cd level significantly affected (p Tropical Agricultural Research Vol. 25 (4): 532 – 542 (2014)

NOD promoter-controlled AtIRT1 expression functions synergistically with NAS and FERRITIN genes to increase iron in rice grains.

Rice is a staple food for over half of the world’s population, but it contains only low amounts of bioavailable micronutrients for human nutrition. Consequently, micronutrient deficiency is a widespread health problem among people who depend primarily on rice as their staple food. Iron deficiency anemia is one of the most serious forms of malnutrition. Biofortification of rice grains for increased iron content is an effective strategy to reduce iron deficiency. Unlike other grass species, rice takes up iron as Fe(II) via the IRON REGULATED TRANSPORTER (IRT) in addition to Fe(III)-phytosiderophore chelates. We expressed Arabidopsis IRT1 (AtIRT1) under control of the Medicago sativaEARLY NODULIN 12B promoter in our previously developed high-iron NFP rice lines expressing NICOTIANAMINE SYNTHASE (AtNAS1) and FERRITIN. Transgenic rice lines expressing AtIRT1 alone had significant increases in iron and combined with NAS and FERRITIN increased iron to 9.6 µg/g DW in the polished grains that is 2.2-fold higher as compared to NFP lines. The grains of AtIRT1 lines also accumulated more copper and zinc but not manganese. Our results demonstrate that the concerted expression of AtIRT1, AtNAS1 and PvFERRITIN synergistically increases iron in both polished and unpolished rice grains. AtIRT1 is therefore a valuable transporter for iron biofortification programs when used in combination with other genes encoding iron transporters and/or storage proteins.Electronic supplementary materialThe online version of this article (doi:10.1007/s11103-015-0404-0) contains supplementary material, which is available to authorized users.

Changes in carbohydrates and amylolytic activity during malting of a local variety of rice

A local variety of paddy, “Mottaikaruppan” variety was selected for this study. Both paddy and its dehusked unpolished rice grains were steeped and allowed to germinate. Steep liquor analysis revealed that there was an increase in the release of the soluble materials with steeping time. Germination of dehusked unpolished rice (77.7%) was better than paddy (59.6%) on the fifth day. A change in moisture content during germination was almost the same for both paddy and dehusked unpolished rice after 2½ days. Appreciable drop in starch content (from 89.1 to 84.5g/100g dry matter) was observed from the third day. Increase in reducing sugar and total sugar contents were observed during germination. Increase in malt amylase (40.0 to 367.8Ug -1 dry matter) activity was observed from the second to fifth day of germination. Addition of 0.1gL -1 gibberellic acid improved the germination of dehusked unpolished rice by 11.7% at 4th day, while addition of Tween-80 (1.0mL/L) with gibberellic acid decreased the germination. Ving. Journal of Science 2012, Vol. 11, No. 1, 1-11

Expression patterns of QTL based and other candidate genes in Madhukar × Swarna RILs with contrasting levels of iron and zinc in unpolished rice grains.

Identifying QTLs/genes for iron and zinc in rice grains can help in biofortification programs. Genome wide mapping showed 14 QTLs for iron and zinc concentration in unpolished rice grains of F7 RILs derived from Madhukar × Swarna. One line (HL) with high Fe and Zn and one line (LL) with low Fe and Zn in unpolished rice were compared with each other for gene expression using qPCR. 7 day old seedlings were grown in Fe+ and Fe- medium for 10 days and RNA extracted from roots and shoots to determine the response of 15 genes in Fe- conditions. HL showed higher upregulation than LL in shoots but LL showed higher upregulation than HL in roots. YSL2 was upregulated only in HL roots and YSL15 only in HL shoots and both up to 60 fold under Fe- condition. IRT2 and DMAS1 were upregulated 100 fold and NAS2 1000 fold in HL shoot. NAS2, IRT1, IRT2 and DMAS1 were upregulated 40 to 100 fold in LL roots. OsZIP8, OsNAS3, OsYSL1 and OsNRAMP1 which underlie major Fe QTL showed clear allelic differences between HL and LL for markers flanking QTL. The presence of iron increasing QTL allele in HL was clearly correlated with high expression of the underlying gene. OsZIP8 and OsNAS3 which were within major QTL with increasing effect from Madhukar were 8 fold and 4 fold more expressed in HL shoot than in LL shoot. OsNAS1, OsNAS2, OsNAS3, OsYSL2 and OsYSL15 showed 1.5 to 2.5 fold upregulation in flag leaf of HL when compared with flag leaf of Swarna. HL and LL differed in root length, Fe concentration and expression of several genes under Fe deficiency. The major distinguishing genes were NAS2, IRT2, DMAS1, and YSL15 in shoot and NAS2, IRT1, IRT2, YSL2, and ZIP8 in roots. The presence of iron increasing QTL allele in HL at marker locus close to genes also increased upregulation in HL.

Mapping QTLs and candidate genes for iron and zinc concentrations in unpolished rice of Madhukar × Swarna RILs

Identifying QTLs/genes for iron and zinc in rice grains can help in biofortification programs. 168 F7 RILs derived from Madhukar×Swarna were used to map QTLs for iron and zinc concentrations in unpolished rice grains. Iron ranged from 0.2 to 224ppm and zinc ranged from 0.4 to 104ppm. Genome wide mapping using 101 SSRs and 9 gene specific markers showed 5 QTLs on chromosomes 1, 3, 5, 7 and 12 significantly linked to iron, zinc or both. In all, 14 QTLs were identified for these two traits. QTLs for iron were co-located with QTLs for zinc on chromosomes 7 and 12. In all, ten candidate genes known for iron and zinc homeostasis underlie 12 of the 14 QTLs. Another 6 candidate genes were close to QTLs on chromosomes 3, 5 and 7. Thus the high priority candidate genes for high Fe and Zn in seeds are OsYSL1 and OsMTP1 for iron, OsARD2, OsIRT1, OsNAS1, OsNAS2 for zinc and OsNAS3, OsNRAMP1, Heavy metal ion transport and APRT for both iron and zinc together based on our genetic mapping studies as these genes strictly underlie QTLs. Several elite lines with high Fe, high Zn and both were identified.

Speciation and Localization of Arsenic in White and Brown Rice Grains

Synchrotron-based X-ray fluorescence (S-XRF) was utilized to locate arsenic (As) in polished (white) and unpolished (brown) rice grains from the United States, China, and Bangladesh. In white rice As was generally dispersed throughout the grain, the bulk of which constitutes the endosperm. In brown rice As was found to be preferentially localized at the surface, in the region corresponding to the pericarp and aleurone layer. Copper, iron, manganese, and zinc localization followed that of arsenic in brown rice, while the location for cadmium and nickel was distinctly different, showing relatively even distribution throughout the endosperm. The localization of As in the outer grain of brown rice was confirmed by laser ablation ICP-MS. Arsenic speciation of all grains using spatially resolved X-ray absorption near edge structure (micro-XANES) and bulk extraction followed by anion exchange HPLC-ICP-MS revealed the presence of mainly inorganic As and dimethylarsinic acid (DMA). However, the two techniques indicated different proportions of inorganic:organic As species. A wider survey of whole grain speciation of white (n=39) and brown (n=45) rice samples from numerous sources (field collected, supermarket survey, and pot trials) showed that brown rice had a higher proportion of inorganic arsenic present than white rice. Furthermore, the percentage of DMA present in the grain increased along with total grain arsenic.

Method of Testing Palatability of Glutinous Rice-cake.

Palatability of rice-cake was evaluated by the following method using the samples used for yield test at Niigata Crop Research Center. Unpolished rice grains thicker than 1.85mm were collected passing the thinner grains through a sieve, and the collected grains were polished to 89% polishing rate. The polished rice samples were stored at 10°C for one week to make the water content uniform. The designated amount of the sample was immersed in water for 15 hours, dehydrated, and set into a rice-cake making machine (SD-3603, National, Osaka) supplied with a prescribed volume of water. Rice-cake was made automatically, and placed on a vinyl sheet in the frame. It was covered with another vinyl sheet, and flattened to a plate, 1.5cm thick, in the frame using a rolling bar. It was then cooled down overnight, and cut into blocks of 4×6×1.5cm on the next day. Four kinds of samples including WATABOUSHI as standard, were tested by panel of more than 15 skilled persons. The rice-cakes were boiled at 75°C for 10 min, served in a dish, and ranked in 11 grades for appearance, whiteness, koshi (hardness and elasticity), stickiness, smoothness, flavor, taste and overall palatability in comparison with standard. Judging from the evaluation of palatability of breeding materials harvested in different years and KOGANEMOCHI used for comparison, this method was considered to be useful.

酒造好適米新品種「千本錦」の醸造特性

he sake brewing properties of a new rice cultivar, Senbonnishiki, were examined and compared with Yamadanishiki. Senbonnishiki had a lodging resistance and could be harvested earlier. The unpolished and polished rice grains of Senbonnishiki were not significantly different from those of Yamadanishiki. The two rice cultivars had the same value in the koji-making test. In the Ginjo sake brewing test, there was no significant difference in sake meter, alcohol, acidity, amino acidity and the concentration of flavor components for these cultivars, but there was a difference in the concentration of phosphoric acid. In the sensory evaluation of fresh sake, the two rice cultivars had the same value. These results suggest that Senbonnishiki has the same excellent characteristics as Yamadanishiki for sake brewing.