Unpolished Rice Research Articles

Rice caryopsis structure in relation to distribution of micronutrients (iron, zinc, β-carotene) of rice cultivars including transgenic indica rice

The transgenic indica rice lines of IR68144 and BR29, developed using endosperm-specific promoters were analyzed for their iron, zinc and β-carotene content in the endosperm. Biochemical analysis clearly revealed the presence of higher accumulation of iron, zinc and β-carotene in transgenic rice grains in comparison with control. Prussian blue staining reaction evidenced the presence of iron in the endosperm cells of transgenic rice grains in comparison with control where iron is restricted only to aleurone and embryo. The rice grain structure of IR64, IR72, IR68144, Swarna, BRRI Dhan 29 (BR29), BR28, Taipai 309 (T309) and New Plant Type-3 (NPT3) indicated that the number of aleurone layers, size of the embryo and size of the caryopsis determines the quantity of important micronutrients (iron, zinc) in the grains. Biochemical analysis revealed that iron and zinc content drastically varies in polished and unpolished rice and among the varieties examined. During the polishing process almost entire aleurone and most part of the embryo is removed which are the main storehouse for major micronutrients. It is estimated that more than 70% of micronutrients are lost during polishing process.

Multiresidue analysis and monitoring of pesticides in rice by pressurized liquid extraction

The aim of this study was to assess the performance of a method of analyzing pesticides in rice by using pressurized liquid extraction (PLE) and to perform a preliminary monitoring by using that method. The instrumental quantification limit, instrumental detection limit, method quantification limit, and method detection limit were determined. PLE temperature was also optimized for 6 target pesticides. Mean recoveries of spiked rice with target pesticides (4 ng/g and 40 ng/g) were 83%–109% with the repeatability of the analysis, represented as relative standard deviations, ranged from 1.3% to 11% (n = 5) for PLE at 130°C. These results were satisfactory according to the method of positive list in Japan. In a preliminary analysis of 10 target pesticides in 54 commercial rice samples, ferimzone was detected in only one unpolished rice sample.

Development of a real‐time multiplex PCR system for the quantitative detection of Chinese GM rice

AbstractBACKGROUND: Rice is one of the most important staple food crops for more than half the global population, who rely on it for as much as 80% of their diet. By one estimate, the world population is projected to grow to approximately 11 billion people by the year 2050. So it is a formidable task to meet the future demand. For this reason, breeders make a great deal of effort to produce new rice varieties with traits such as higher yield, improved nutritional content and better resistance to disease and pests, via transgenic biotechnological protocols. Dozens of transgenic rice lines have been developed since the first transgenic rice plant production in the late 1980s. With the rapid approach of transgenic rice commercialisation, it is becoming necessary to develop techniques capable of detecting and quantifying genetically modified (GM) rice.RESULT: Here we describe a method in which transgenic DNA is quantified by amplifying part of the 35S‐CaMV promoter and standardising it against an amplified portion of an endogenous single copy, rice specific gene encoding sucrose phosphate synthase. Both reactions are performed simultaneously in a single tube. Standard calibration curves were developed by diluting DNA extracted from a blend of non‐transgenic (c.v., Nipponbare) and 5% KMD2 transgenic rice. The method was tested for the quantification of the five GM rice events, including KMD2, Wan 21A, GC‐1, H1597 and TR4, which contain the 35S‐CaMV promoter. The coefficient of variation varied from 3.15% to 12.84%, which is up to acceptance criterion over the dynamic range of the method.CONCLUSION: In this study, we successfully applied a multiplex real‐time PCR assay to GM rice, which employed SPS as the endogenous reference gene and the gene regulation element 35S‐CaMV promoter as a GMO marker. The detection limit and limit of quantification is sufficient to comply with all relevant regulations in the EU and worldwide. The detection system could be applied in routine analysis for the quantification of GM rice in food materials, such as instant rice, unpolished rice, rice flours, biscuit powders, and starch. It may prove useful with regard to a robust screening technique of broad utility as transgenic rice enters global commodity markets. Copyright © 2009 Society of Chemical Industry

Occurrence of D-serine in rice and characterization of rice serine racemase

Germinated, unpolished rice was found to contain a substantial amount of D-serine, with the ratio of the D-enantiomer to the L-enantiomer being higher for serine than for other amino acids. The relative amount of D-serine (D/(D + L)%) reached approximately 10% six days after germination. A putative serine racemase gene ( serr, clone No. 001-110-B03) was found in chromosome 4 of the genomic DNA of Oryza sativa L. ssp. Japonica cv. Nipponbare. This was expressed as serr in Escherichia coli and its gene product (SerR) was purified to apparent homogeneity. SerR is a homodimer with a subunit molecular mass of 34.5 kDa, and is highly specific for serine. In addition to a serine racemase reaction, SerR catalyzes D- and L-serine dehydratase reactions, for which the specific activities were determined to be 2.73 and 1.42 nkatal/mg, respectively. The optimum temperature and pH were respectively determined for the racemase reaction (35 °C and pH 9.0) and for the dehydratase reaction (35 °C and pH 9.5). SerR was inhibited by PLP-enzyme inhibitors. ATP decreased the serine racemase activity of SerR but increased the serine dehydratase activity. Kinetic analysis showed that Mg 2+ increases the catalytic efficiency of the serine racemase activity of SerR and decreases that of the serine dehydratase activity. Fluorescence-quenching analysis of the tryptophan residues in SerR indicated that the structure of SerR is distorted by the addition of Mg 2+, and this structural change probably regulates the two enzymatic activities.

Efficient bait for sampling the wireworm Melanotus okinawensis (Coleoptera: Elateridae) in a sugarcane field

Bait trap efficiencies were compared to construct a sampling method for wireworms, larvae of the click beetle Melanotus okinawensis (Coleoptera: Elateridae). Various combinations of bait material, bait preparation methods, and bait exposure periods were compared. Wireworms were more efficiently attracted by germinating rice seeds than other bait materials, such as sweet potato, potato, and carrot. Among the bait materials related to rice, germinating rice seeds attracted significantly more wireworms than other materials, such as unpolished rice, polished rice, rice seeds, and rice husks. Rice bran and germinating unpolished rice were lesser attractants than germinating rice seeds. Attractiveness increased only slightly with increasing periods of incubation of rice seeds. Attractiveness increased more slowly with the increase of rice seeds, indicating that 30 g was sufficient for attraction. The number of captured wireworms increased with increasing periods of field exposure, but we judged that three days of exposure might be an appropriate choice because the difficulty of handling traps increased with increasing periods of exposure. Under semiarid soil conditions, bait attractiveness was greatly enhanced by daily irrigation. It was shown that germinating rice seeds with moistened sphagnum moss are as effective as germinating rice seeds with daily irrigation.

Mechanical Properties and Radical Scavenging Activity of Unpolished Rice Noodles with Added Tamarind

Mechanical Properties and Radical Scavenging Activity of Unpolished Rice Noodles with Added Tamarind

An economical approach for d-lactic acid production utilizing unpolished rice from aging paddy as major nutrient source

In order to reduce the raw material cost of d-lactic acid fermentation, the unpolished rice from aging paddy was used as major nutrient source in this study. The unpolished rice saccharificate, wheat bran powder and yeast extract were employed as carbon source, nitrogen source and growth factors, respectively. Response surface methodology (RSM) was applied to optimize the dosages of medium compositions. As a result, when the fermentation was carried out under the optimal conditions for wheat bran powder (29.10 g/l) and yeast extract (2.50 g/l), the d-lactic acid yield reached 731.50 g/kg unpolished rice with a volumetric production rate of 1.50 g/(l h). In comparison with fresh corn and polished rice, the d-lactic acid yield increased by 5.79% and 8.71%, and the raw material cost decreased by 65% and 52%, respectively, when the unpolished rice was used as a major nutrient source. These results might provide a reference for the industrial production of d-lactic acid.

Pyrrospirones A and B, apoptosis inducers in HL-60 cells, from an endophytic fungus, Neonectria ramulariae Wollenw KS-246

Pyrrospirones A and B have been isolated from unpolished rice cultures of the endophytic fungus Neonectria ramulariae Wollenw KS-246. Their absolute stereostructures (1 and 2) were elucidated through spectroscopic methods using 1D and 2D NMR techniques and chemical transformations, including the modified Mosher’s method. The compounds exhibited cytotoxicity and induced apoptosis in human promyelocytic leukemia HL-60 cells.

Multivitamins: Use or misuse?

It has been more than a century since an Englishman, William Fletcher in 1905 while researching the cause of the disease Beriberi, discovered that it could be prevented by eating unpolished rice. He concluded that the husk of rice must have special nutrients, which we know today as vitamins. The term vitamin originated from “vitamine,” a word first used in 1911 by the Polish scientist Casimir Funk to designate a group of compounds considered vital for life; each was thought to have a nitrogen-containing component known as an amine. The final “e” of vitamine was dropped when it was discovered that not all of the vitamins contain nitrogen and, therefore not all are amines.

Evaluation of pressurized liquid extraction for the analysis of four pesticides in unpolished rice

The aim of to evaluate efficiency of this study was extraction pressurized liquid extraction (PLE) for the analysis of four pesticides, fthalide, etofenprox, fenitrothion, and isoprothiolane, in unpolished rice by comparing with homogenization as a reference technique. The concentrations of four selected pesticides obtained by PLE with acetonitrile at 130°C for 10 min × 2 cycles were comparable to those by homogenization with water-soaking. The repeatability of the analysis, represented as relative standard deviations (RSDs), were 1.4–3.6% (n = 3) for PLE at 130°C and 1.2–3.8% (n = 3) for homogenization with water-soaking. Recovery yields of surrogates were 75–88% and 87–109% for PLE at 130°C and homogenization with water-soaking, respectively, and these were satisfactory according to the method of positive list. This study suggested that PLE can be applied for the analysis of selected four pesticides in unpolished rice as well as homogenization with water-soaking.

High Percentage Inorganic Arsenic Content of Mining Impacted and Nonimpacted Chinese Rice

Two approaches were undertaken to characterize the arsenic (As) content of Chinese rice. First, a national market basket survey (n = 240) was conducted in provincial capitals, sourcing grain from China's premier rice production areas. Second, to reflect rural diets, paddy rice (n = 195) directly from farmers fields were collected from three regions in Hunan, a key rice producing province located in southern China. Two of the sites were within mining and smeltery districts, and the third was devoid of large-scale metal processing industries. Arsenic levels were determined in all the samples while a subset (n = 33) were characterized for As species, using a new simple and rapid extraction method suitable for use with Hamilton PRP-X100 anion exchange columns and HPLC-ICP-MS. The vast majority (85%) of the market rice grains possessed total As levels < 150 ng g(-1). The rice collected from mine-impacted regions, however, were found to be highly enriched in As, reaching concentrations of up to 624 ng g(-1). Inorganic As (As(i)) was the predominant species detected in all of the speciated grain, with As(i) levels in some samples exceeding 300 ng g(-1). The As(i) concentration in polished and unpolished Chinese rice was successfully predicted from total As levels. The mean baseline concentrations for As(i) in Chinese market rice based on this survey were estimated to be 96 ng g(-1) while levels in mine-impacted areas were higher with ca. 50% of the rice in one region predicted to fail the national standard.

Modulation of experimental osteoporosis in rats by the antioxidant beverage effective microorganism-X (EM-X)

Osteoporosis is a disease of aging associated with bone loss that often occurs without symptoms until microarchitectural deterioration becomes so significant that bone fracture occurs. The effective microorganism-X (EM-X) is an antioxidant beverage derived from ferment of unpolished rice, sea weeds and papaya with effective microorganisms of lactic acid bacteria, yeast and photosynthetic bacteria (containing minerals, α-tocopherol, lycopene, ubiquinone, saponin and flavonoids). The levels of serum estradiol (E 2) and the bone density of the middle and epiphysis of femurs were assessed in order to determine the effect of EM-X on osteoporosis in ovariectomized rat (an animal model of postmenopausal osteoporosis). EM-X (1 ml/rat/day) was initially administrated by gavage to rats which were then allowed to consume 10% (v/v) EM-X in water freely for 3 months. There was no statistical significance of E 2 level between sham operation group and control group, indicating that sham operation did not affect E 2 level. However, the E 2 levels in the ovariectomized rats tended to increase after treatment of EM-X for 3 months. The bone density of the middle and epiphysis of femur in both sham operation and ovariectomy group decreased with time. Rats receiving EM-X for 3 months after sham operation or ovariectomy had increased bone density of the middle of femur that was statistically significant ( P < 0.01 and P < 0.05). The bone density of the epiphysis of femur in both sham operation and ovariectomy group were significantly increased, an outcome highly suggestive of the beneficial effects of EM-X on bone density of the middle and the epiphysis of femur in the rats with or without ovariectomy.

Distribution of Protein Bodies and Phytate‐Rich Inclusions in Grain Tissues of Low and High Iron Rice Genotypes

ABSTRACTThe present study aims to understand whether genotypic differences in grain iron (Fe) concentration in four rice genotypes are related to its association with protein bodies containing phytate‐rich inclusions. Rice genotypes with high and low grain Fe concentrations in unpolished brown rice were grown in a greenhouse at Chiang Mai, Thailand, and grains were harvested at maturity. The presence of protein bodies and phytate‐rich inclusions in rice grain tissues were examined by means of light and transmission electron microscopy (TEM). The composition of mineral elements in different grain tissues was examined using energy dispersive X‐ray microanalysis (EDX) and chemical analysis. The relative distribution pattern of protein bodies in the tissues was similar among the four rice genotypes, which resembled the pattern of grain N concentrations in these tissues. The high grain Fe genotypes (based on brown rice Fe concentration) had more protein bodies containing phytate‐rich inclusions in the embryo and aleurone layer tissues than the low Fe genotypes. Phytate‐rich inclusions were not detected in the endosperm tissues in all genotypes. In conclusion, the presence of protein bodies with phytate‐rich inclusions predominantly in the embryo and aleurone regions of the grain is an important parameter contributing to the variation in brown rice Fe concentration among the genotypes, but not in the white rice (the endosperm). Iron associated with the phytate‐rich inclusions present in the embryo and aleurone layer tissues are largely lost during the polishing process to produce white rice.

Effects of secondary ingredients on the mechanical properties of unpolished rice noodles

Effects of secondary ingredients on the mechanical properties of unpolished rice noodles

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.

Copper and Zinc in a paddy field and their potential ecological impacts affected by wastewater from a lead/zinc mine, P. R. China

As well known, at normal levels, copper and zinc are essential micronutrients for plants, animals, and humans. However, excessive Cu and Zn are toxic and disturb a wide range of biochemical and physiological processes. Using Atomic Absorption Spectrophotometer (AAS; Perkin-Elmer 3030, USA), soil and rice plant (Oryza sativa L.) samples collected from a paddy field in Lechang lead-zinc mine area, Guangdong Province, China were analyzed and their potential ecological impacts to local human and livestock were evaluated. The results showed that the paddy soils were contaminated with Cu and Zn. Both metals in soils had low bio-available fractions for paddy plants, animal and human by three chemically analytical techniques. Generally, were concentrations of copper and zinc root >> straw > stalk > grain with hull > grain without hull (i.e. unpolished rice) and in the normal ranges indicating no ecological risk for local livestock and residents. All positive correlation coefficients, however, between heavy metals in rice plant and total, exchangeable (step 1 in Tessier's method established in 1979) and DTPA-extractable fractions in soils were found in this study indicating that elevated heavy metal in soils would increase long-term exposition and possible consequence of ecological hazard through food chains.

Comparison of antioxidant properties of persimmon vinegar and some other commercial vinegars in radical-scavenging assays and on lipid oxidation in tuna homogenates

Five kinds of vinegars (two kinds of persimmon vinegars, unpolished rice vinegar, polished rice vinegar, and apple vinegar) were evaluated for their scavenging activity towards 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals, superoxide radicals, and hydroxyl radicals, and for their antioxidant activity in tuna homogenate. The total phenolic content was also determined by the modified Folin-Ciocalteu method. Markedly high phenolic contents and radical-scavenging activities were found for vinegar made from persimmon Saijyo varieties, and unpolished rice vinegar. When incorporated into fatty tuna homogenates, persimmon vinegar effectively inhibited lipid oxidation in the homogenates. Persimmon vinegar may be as useful in fish processing as are other naturally occurring antioxidants, helping to prevent the formation of off-flavour in fish and their products and to increase shelf life.

Mycotoxins in rice

Mycotoxin contamination in rice is usually lower as in wheat or corn. However, there are some reports that rice has been contaminated with mycotoxins such as aflatoxin B 1, B 2, G 1, G 2 (AFS), citrinin, deoxynivalenol (DON), fumonisin B 1, B 2, B 3 (FMS), fusarenon-X (Fus.-X), nivalenol (NIV), ochratoxin A (OTA), sterigmatocystin (STE), and zearalenone. Rice in Japan is preserved in warehouses where moisture content and temperature are regulated. Therefore, mycotoxin contamination from post harvest fungal growth occurs very seldom. Trichothecenes, aflatoxins, and STE in rice were recently analyzed in our laboratory. In 1998, a typhoon struck before rice harvesting in Japan, and the unpolished rice was found to be stained brown. Samples were collected and analyzed for the presence of trichothecenes. Mycotoxins DON, Fus.-X, and NIV were detected and confirmed with GC-MS. The quantity of trichothecenes was determined using GC-ECD. STE is a carcinogenic mycotoxin produced by Aspergillus versicolor and some other fungi. STE contamination of rice was studied in our laboratory since 1973. GC-MS, LC-MS, LC-MS/MS, and LC-UV methods for STE determination were examined, giving good results for the LC-UV method using a photo diode array detector. Different techniques for the extraction of STE from rice were also studied. Finally, brown rice was ground, and the ground rice was extracted with acetonitrile-water. An Autoprep MF-A 1000 column was used to clean up AFS and STE. The cleaned-up extract was analyzed with HPLC-UV. Forty-eight brown rice samples were analyzed, and none of them were contaminated with STE. These rice samples were also analyzed for AFS and FMS, and none of the samples were contaminated. The Ministry of Agriculture, Forestry and Fisheries in Japan is making the appropriate Institutes develop analytical methods for mycotoxins and survey mycotoxin contamination on rice as well as wheat, corn, and some other cereals.

Infants and children consuming atypical diets: Vegetarianism and macrobiotics

Alternative diets have been recognized for centuries. In his 1813 pamphlet, A Vindication of Natural Diet, the poet Shelley wrote, “There is no disease, bodily or mental, which adoption of vegetable diet and pure water has not infallibly mitigated, wherever the experiment has been fairly tried” (1). In the rapidly expanding multicultural population of North America, vegetarianism is a popular dietary practice. It may be based on religious or cultural beliefs, or on economic, health or ethical concerns. A 2002 survey (2) found that approximately 4% of Canadian adults consumed a vegetarian diet that excluded meat, poultry and fish. Furthermore, 20% to 25% of adults in the United States reported eating four or more meatless meals weekly, or that they ‘usually or sometimes maintain a vegetarian diet’, suggesting an increasing interest in vegetarianism (2). Because parents are the principal providers of what their infants eat, vegetarian parents often wean their children onto the family’s vegetarian diet. It is important to note that atypical diets are more likely to cause problems of malnutrition in children than in adults due to their greater nutrient requirements relative to body weight. Thus, without the appropriate care for these children, health issues may arise that could concern health care professionals. Vegetarianism is a very broad category consisting of diets with varying degree of animal product consumption. This distinction is important because the more strictly vegetarianism is followed, the more difficult it becomes to guarantee an adequate diet for growing infants and children. For example, lacto-ovo-vegetarians include eggs, milk and dairy products along with a plant food selection; however, they refrain from animal flesh. On the other hand, a lacto-vegetarian diet consists of plant foods such as grains, legumes, nuts, fruits and vegetables, complemented with milk and milk products, with avoidance of eggs and animal flesh. Pure or total vegetarians (or ‘vegans’) reject all foods of animal origin, including milk and eggs. Finally, another atypical diet that is far more restrictive than pure vegetarianism is the macrobiotic diet. The original macrobiotic dietary regimen comprised of 10 diets, ranging from the lowest level, which includes 10% cereal, 30% vegetables, 10% soups, 30% animal products, 15% salads and fruits, and 5% desserts, to the highest level, which is composed of 100% cereals (3). The revised macrobiotic diet may contain whole-grain cereals (mainly unpolished rice), vegetables and pulses, with small additions of seaweeds, fermented foods, nuts, seeds and seasonal fruit (4).

Market Basket Survey Shows Elevated Levels of As in South Central U.S. Processed Rice Compared to California: Consequences for Human Dietary Exposure

We report the largest market basket survey of arsenic (As) in U.S. rice to date. Our findings show differences in transitional-metal levels between polished and unpolished rice and geographical variation in As and selenium (Se) between rice processed in California and the South Central U.S. The mean and median As grain levels for the South Central U.S. were 0.30 and 0.27 mimcrog As g(-1), respectively, for 107 samples. Levels for California were 41% lower than the South Central U.S., with a mean of 0.17 microg As g(-1) and a median of 0.16 microg As g(-1) for 27 samples. The mean and median Se grain levels for the South Central U.S. were 0.19 microg Se g(-1). Californian rice levels were lower, averaging only 0.08 and 0.06 microg Se g(-1) for mean and median values, respectively. The difference between the two regions was found to be significant for As and Se (General Linear Model (GLM): As p < 0.001; Se p < 0.001). No statistically significant differences were observed in As or Se levels between polished and unpolished rice (GLM: As p= 0.213; Se p= 0.113). No significant differences in grain levels of manganese (Mn), cobalt (Co), copper (Cu), or zinc (Zn) were observed between California and the South Central U.S. Modeling arsenic intake for the U.S. population based on this survey shows that for certain groups (namely Hispanics, Asians, sufferers of Celiac disease, and infants) dietary exposure to inorganic As from elevated levels in rice potentially exceeds the maximum intake of As from drinking water (based on consumption of 1 L of 0.01 mg L(-1) In. As) and Californian state exposure limits. Further studies on the transformation of As in soil, grain As bioavailability in the human gastrointestinal tract, and grain elemental speciation trends are critical.