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The aim of this study was to profile the polyphenol composition and antioxidant activity of 8 Australian-grown rice varieties. UHPLC with an online ABTS system was used to identify and quantify individual polyphenols present in the rice extract whilst simultaneously measuring their respective antioxidant activity. In addition, the synergistic antioxidant activity of the rice extracts was assessed using the ferric reducing ability of plasma assay (FRAP). The study found that the pigmented rice varieties had higher total antioxidant activity than the brown non-pigmented rice varieties. The red variety Yunlu29 had the highest FRAP total antioxidant activity (303.8 ± 16.16 mg 100 g −1 Trolox equivalents). UHPLC profile of Yunlu29 revealed a wide variety of active polyphenols. In particular, the chromatogram from the red rice variety Yunlu29, contained two unidentified peaks that exhibited the highest antioxidant activity. In the purple rice extract, cyanidin-3-glucoside and peonidin-3-glucoside were profiled as having the most free-radical scavenging activity. In comparison, the brown non-pigmented rice extracts did not exhibit substantial antioxidant activity in its polyphenol UHPLC profile. The results of this study demonstrate the antioxidant potential of polyphenols present in Australian-grown pigmented and non-pigmented rice varieties which may have a future role as a potential functional food ingredient. [ABSTRACT FROM AUTHOR]

Rice is one of the most produced and consumed cereals in the world, making the control of its chemical composition, especially of minerals, important. A method of rice digestion using nitric acid and hydrogen peroxide to determine metals (Al, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, Pb and Zn) using Inductively Coupled Plasma Optical Emission Spectrometry (ICP OES) was developed. The optimized conditions were established using a factorial design 2 3 , obtaining the following digestion conditions as the most adequate: digestion time (20 min), concentration of HNO 3 (8 mol L − 1 ) and H 2 O 2 volume (2.5 mL). Recovery values ranging from 80 to 120% with RSD < 5.1% were obtained for most elements of interest and limits of detection of the method were in the range of 0.02 mg kg − 1 (Mn) to 5.6 mg kg − 1 (Ca). A table of metal composition for the different types of processed rice (white, parboiled and brown) was established through an analysis of 54 rice samples. Brown rice contributed significantly to the Recommended Dietary Allowances (RDA) of Mn (61%) and Mg (20%), parboiled rice with Cu (45%) and white rice with Mn (14%). In addition, the daily intake estimated through rice consumption, for all detected metals, was much lower than the Tolerable Upper Intake Level. The rice samples could be differentiated by their type of processing, based on their mineral composition using Principal Component Analysis (PCA). [ABSTRACT FROM AUTHOR]

Polished rice is poor source of micronutrients, however wide genotypic variability exists for zinc uptake and remobilization and zinc content in brown and polished grains in rice. Two landraces (Chittimutyalu and Kala Jeera Joha) and one popular improved variety (BPT 5204) were grown under zinc sufficient soil and their analyses showed high zinc in straw of improved variety, but high zinc in polished rice in landraces suggesting better translocation ability of zinc into the grain in landraces. Transcriptome analyses of the panicle tissue showed 41182 novel transcripts across three samples. Out of 1011 differentially expressed exclusive transcripts by two landraces, 311 were up regulated and 534 were down regulated. Phosphate transporter-exporter (PHO), proton-coupled peptide transporters (POT) and vacuolar iron transporter (VIT) showed enhanced and significant differential expression in landraces. Out of 24 genes subjected to quantitative real time analyses for confirmation, eight genes showed significant differential expression in landraces. Through mapping, six rice microsatellite markers spanning the genomic regions of six differentially expressed genes were validated for their association with zinc in brown and polished rice using recombinant inbred lines (RIL) of BPT 5204/Chittimutyalu. Thus, this study reports repertoire of genes associated with high zinc in polished rice and a proof concept for deployment of transcriptome information for validation in mapping population and its use in marker assisted selection for biofortification of rice with zinc. [ABSTRACT FROM AUTHOR]

Rice and rice products have been reported to contain high contents of toxic inorganic arsenic (iAs). The inorganic arsenic contents in microwavable ready-to-eat rice products (n = 30) and different types of Korean rice (n = 102) were determined by a gas chromatography-tandem mass spectrometry (GC–MS/MS). The method showed low limit of detection (0.015 pg), high intra- and inter-day repeatability (<7.3%, RSD), and recovery rates (90–117%). The mean iAs content in the ready-to-eat rice products was 59 μg kg −1 (dry weight basis). The mean iAs contents in polished white, brown, black, and waxy rice were 65, 109, 91, and 66 μg kg −1 , respectively. The percentages of ready-to-eat rice products, white, brown, black, and waxy rice containing iAs over the maximum level (100 μg kg −1 ) set by EU for the infant foods were 17, 4, 70, 36 and 0%, respectively. [ABSTRACT FROM AUTHOR]

Rice ( Oryza sativa L.) is the world’s third largest food crop after wheat and corn. Geographic authentication of rice has recently emerged as an important issue for enhancing human health via food safety and quality assurance. Here, we aimed to discriminate rice of six Asian countries through geographic authentication using combinations of elemental/isotopic composition analysis and chemometric techniques. Principal components analysis could distinguish samples cultivated from most countries, except for those cultivated in the Philippines and Japan. Furthermore, orthogonal projection to latent structure-discriminant analysis provided clear discrimination between rice cultivated in Korea and other countries. The major common variables responsible for differentiation in these models were δ 34 S, Mn, and Mg. Our findings contribute to understanding the variations of elemental and isotopic compositions in rice depending on geographic origins, and offer valuable insight into the control of fraudulent labeling regarding the geographic origins of rice traded among Asian countries. [ABSTRACT FROM AUTHOR]

The study presents the validation results of the method carried out for analysis of free amino acids (FAAs) in rice using l -theanine as the internal standard (IS) with o -phthalaldehyde (OPA) reagent using high-performance liquid chromatography-fluorescence detection. The detection and quantification limits of the method were in the range 2–16 μmol/kg and 3–19 μmol/kg respectively. The method had a wide working range from 25 to 600 μmol/kg for each individual amino acid, and good linearity with regression coefficients greater than 0.999. Precision measured in terms of repeatability and reproducibility, expressed as percentage relative standard deviation (% RSD) was below 9% for all the amino acids analyzed. The recoveries obtained after fortification at three concentration levels were in the range 75–105%. In comparison to l -norvaline, findings revealed that l -theanine is suitable as an IS and the validated method can be used for FAA determination in rice. [ABSTRACT FROM AUTHOR]

This study provides the first investigation of the physical traits, pasting properties and volatile compounds of Cambodian rice cultivars, including traditional, improved, and improved traditional varieties, allowing for their differentiation as high and low quality rice. Analysis of the grain quality traits illustrates interesting features of traditional varieties and correlations between traits that assist with understanding texture. Untargeted profiling of volatile compounds shows that high quality fragrant varieties not only contain 2-acetyl-1-pyrroline but also several other compounds, including aldehydes, alcohols and 2-alkylfurans that contribute to overall aroma. Moreover, low odour threshold volatile compounds, which can be derived from the oxidation of unsaturated fatty acids, were more abundant in the fragrant varieties. The percentage area of both oleic and linoleic acid were found to be significantly different among the rice varieties tested. Such findings suggest that unsaturated fatty acids in milled rice contribute to rice fragrance, and thereby to overall quality. [ABSTRACT FROM AUTHOR]

A novel method has been developed for the direct, sensitive, and rapid detection of bronopol in rice using a simple solid-phase extraction (SPE) procedure followed by liquid chromatography-tandem mass spectrometry (LC-MS/MS), with electrospray ionization (ESI). Bronopol was stable under acidic conditions, and an acidic environment was thus needed before sample loading to ensure the stability of bronopol. Rice extracts containing bronopol were pretreated using a hydrophilic-lipophilic balanced (Bond Elut Plexa) cartridge to reduce the matrix effect. An XDB-C18 column (150 mm × 2.1 mm, 3.5 μm) was used for chromatographic separations, with a mobile phase comprising methanol and aqueous ammonium formate (5 mM). The linearity of the method was satisfactory with regression coefficient ( R ) = 0.9992. The limit of quantification was 3.3 μg kg. Three spiked levels (25, 125 and 625 μg kg) were used to determine the recovery of bronopol, which was found to be 73.3-96.7%, with relative standard deviations (RSD) in the range 1.2-7.9%. The RSD for intra-day precision ( n = 7) was 7.6% and the RSD for inter-day precision ( n = 15) was 8.3%. The newly developed analytical method was successfully used to quantify bronopol in rice samples. [ABSTRACT FROM AUTHOR]

Myo-inositol hexaphosphate, also known as phytic acid (PA), is the most abundant storage form of phosphorus in seeds. PA acts as a strong chelator of metal cations to form phytate and is considered an anti-nutrient as it reduces the bioavailability of important micronutrients. Although the major nutrient source for more than one-half of the global population, rice is a poor source of essential micronutrients. Therefore, biofortification and reducing the PA content of rice have arisen as new strategies for increasing micronutrient bioavailability in rice. Furthermore, global climate change effects, particularly rising atmospheric carbon dioxide concentration, are expected to increase the PA content and reduce the concentrations of most of the essential micronutrients in rice grain. Several genes involved in PA biosynthesis have been identified and characterized in rice. Proper understanding of the genes related to PA accumulation during seed development and creating the means to suppress the expression of these genes should provide a foundation for manipulating the PA content in rice grain. Low-PA rice mutants have been developed that have a significantly lower grain PA content, but these mutants also had reduced yields and poor agronomic performance, traits that challenge their effective use in breeding programs. Nevertheless, transgenic technology has been effective in developing low-PA rice without hampering plant growth or seed development. Moreover, manipulating the micronutrient distribution in rice grain, enhancing micronutrient levels and reducing the PA content in endosperm are possible strategies for increasing mineral bioavailability. Therefore, a holistic breeding approach is essential for developing successful low-PA rice lines. In this review, we focus on the key determinants for PA concentration in rice grain and discuss the possible molecular methods and approaches for manipulating the PA content to increase micronutrient bioavailability. [ABSTRACT FROM AUTHOR]

Rice cultivar starch composition differences do not completely explain variation in rice cooking and eating quality. Rice grain storage proteins possess divergent solubility properties suggesting they may contribute to cultivar differences in rice grain quality. Application of high-performance liquid chromatography (HPLC) analysis to protein extracts derived from medium and long grain advanced rice breeding lines revealed rice grain protein composition differences which were associated with instrumental measures of grain quality. Globulin content displayed little variation in both grain types. The mean glutelin content was higher in long grain rice lines than medium grains. Although the mean content of prolamins in medium and long grain rice were similar, the prolamin content of medium grains was more variable. Individual medium grain prolamin HPLC peaks, total prolamin content and the prolamin:glutelin + prolamin ratio were positively correlated with several rapid visco analyser (RVA) parameters. The long grain HPLC data displayed a similar pattern of correlations with RVA parameters but of reduced magnitude. Protein composition was associated with instrumental measures of grain quality in this set of germplasm and although the textural properties of rice are complex, these data suggest consideration of rice grain protein composition could contribute to breeding high quality rice. [ABSTRACT FROM AUTHOR]

Rice flour can be applied into many kinds of foods, but it can have an effect on the final product quality. This study aimed to assess the properties of four different types of rice flours, namely Thai organic white (Phitsanulok; PRF), colored (Riceberry; RBF), brown Jasmine (BJF), and red Jasmine (RJF). The chemical composition (moisture, ash, crude fat, protein, fiber, and carbohydrate contents) of all samples were significantly different ( p < 0.05). PRF contained the highest amylose content (33.80%) ( p < 0.05). The highest peak (4067.33 cP) and breakdown viscosities (2077.33 cP) were observed in BJF ( p < 0.05) whereas the highest setback (1551.33 cP) was found in PRF ( p < 0.05). The onset, peak, and conclusion temperatures were significantly different ( p < 0.05) while gelatinization enthalpy were not significantly different ( p > 0.05). The highest water absorption (7.14 g/g) and water solubility indexes (7.05%) were found in colored rice flour ( p < 0.05) (RJF and BJF, respectively). Ultimately, higher amylose content resulted in lower gelatinization temperature and in percentage of crystallinity, but there was an increasing setback value for PRF. Meanwhile, low amylose content in colored rice flour promoted high values of gelatinization temperature, pasting (peak and breakdown viscosities), and functional properties (water solubility index). [ABSTRACT FROM AUTHOR]

The effects of retort treatment on rice gels made from rice of three kinds (Aichi125, Mizuhochikara, Momiroman) prepared using high speed shear treatment (HST) were investigated. The high speed shear rate was 1500 rpm. Prepared rice gel samples were stored at 25 °C for 2 months. The retort treatment was applied to the three rice gels. Viscoelastic properties and retrogradation of rice gels were measured using dynamic viscoelastic measurement, X-ray diffraction (XRD), and differential scanning calorimetry (DSC). The higher the amylose contents became, the faster the retrogradation progressed and the higher the increase of the dynamic viscoelastic moduli of the rice gel samples. Only the rice gel made from Aichi125 showed gelatinization behavior in the DSC and XRD measurements past 30 day storage. The relative crystallinity ( Cr ) in Aichi 125 and Momiroman decreased just after the retort treatment although their dynamic viscoelastic moduli increased. The results indicated that not only the starch retrogradation but also the other factors such as the change of protein induced by the retort treatment affected the physicochemical properties of HST rice gels. [ABSTRACT FROM AUTHOR]

Water is a diamagnetic molecule which can be affected by magnetic fields. Since water is the most important constitutive element of living cells, so all cellular biochemical reactions take place in water. Due to molecular characteristic of water, it is assumed that a part of these effects happened under magnetic field treatment. This study aimed to investigate the effects of magnetic water on some characteristics of growth and chemical constituent in rice (Oryza sativa L.). To this end rice seeds-paddy-were grown in rice fields as two experimental groups. A group of seeds were irrigated with normal water and in parallel the other group with magnetic water. Results revealed that in comparison to control plants, irrigating with magnetic water increases the growth parameters, photosynthetic pigments, Total carbohydrate and Total protein. Finally the magnetic water with intensity 110 mTand the time taken to work on development and operation of the plants had positive effects. [ABSTRACT FROM AUTHOR]

This study investigated changes in the phenolic composition, total antioxidant activity (TAA) and starch digestibility in white and brown rice due to three different cooking procedures, and subsequent reheating of cooked rice after storage. Among the analyzed samples, brown rice showed the highest TAA and phenolic content (622.5 mg/kg DW). All cooking methods resulted in significant decrease of phenolic content and TAA of rice ( p < 0.05). The greatest loss was observed after processing in rice cooker, which reduced phenolic content of both brown and polished rice by ∼30% and ABTS radical-scavenging activity by 20 and 28%, respectively. In general, the levels of polyphenols and TAA of cooked rice tended to further decline after storage and reheating, but to a much lesser extent when rice was prepared using microwaves. The application of in vitro digestion system disclosed that the microwave cooking resulted in the highest starch digestibility among cooking methods used. Practical applications Rice is one of the most commonly consumed staple foods worldwide. Scientific and epidemiological studies have showed that their phytochemicals exhibit antioxidant, anti-inflammatory, antihypertensive and chemopreventive effects. Therefore, their high consumption, easy availability throughout the year and use as an additive to meat and high-fat foods may make rice, especially in the form of whole grains, potentially important chemopreventive component of the diet. The appropriate cooking procedure of rice is crucial for preservation of bioactive compounds as well as digestion of starch and thus duration of the glycemic response. Preferably, this study is focused on the evaluation of the effect of cooking methods on the health-related quality of rice. The results provide practical advice that the consumption of freshly cooked rice ensures its highest nutritional quality, while rice microwaving is recommended both when cooked rice will be reheated after storage (e.g., in restaurants) and accelerated starch digestion is in favor. [ABSTRACT FROM AUTHOR]

Summary: High temperature significantly alters the amylose content of rice, resulting in mature grains with poor eating quality. However, only few genes and/or quantitative trait loci involved in this process have been isolated and the molecular mechanisms of this effect remain unclear. Here, we describe a floral organ identity gene, OsMADS7, involved in stabilizing rice amylose content at high temperature. OsMADS7 is greatly induced by high temperature at the early filling stage. Constitutive suppression of OsMADS7 stabilizes amylose content under high temperature stress but results in low spikelet fertility. However, rice plants with both stable amylose content at high temperature and normal spikelet fertility can be obtained by specifically suppressing OsMADS7 in endosperm. GBSSI is the major enzyme responsible for amylose biosynthesis. A low filling rate and high expression of GBSSI were detected in OsMADS7 RNAi plants at high temperature, which may be correlated with stabilized amylose content in these transgenic seeds under high temperature. Thus, specific suppression of OsMADS7 in endosperm could improve the stability of rice amylose content at high temperature, and such transgenic materials may be a valuable genetic resource for breeding rice with elite thermal resilience. [ABSTRACT FROM AUTHOR]

Background and aims: ‘Cd toxicity in rice’ events have resulted in vast public concern and uncertainty. Effective bioremediation could be accomplished via applying microbes that are capable of alleviating Cd content in rice grains.Methods: Here, we investigated the effect of inoculating Aspergillus aculeatus on tolerance, uptake and transportation of Cd in rice cultivated in Cd contaminated growth medium.Results: A. aculeatus facilitated rice growth in Cd polluted growth medium and alleviated Cd toxic effects according to our observations on biomass, leaf and root length and grain yield. Cd accumulation analysis indicated that the plants which were inoculated with A. aculeatus exhibited minimum Cd level in all organs. Particularly in grain we observed a 40.5% reduction compared to the Cd only treated plants. Differences in Cd accumulation in rice inoculated with A. aculeatus might be attributed to the enhancement of cell wall-bound Cd, decreasing the Cd inorganic forms in roots, and inhibiting the expression of OsNRAMP5 and OsNRAMP1. A. aculeatus inoculation also led to minimum growth medium DTPA-Cd concentration, which possibly reduced the availability of the metals for plant uptake.Conclusions: These results suggested that A. aculeatus might potentially be applicable to improve Cd tolerance and reduce Cd transportation in grains of rice. [ABSTRACT FROM AUTHOR]

Rice is considered as one of the major foods, it has a high share in the household baskets and is consumed daily by people. It can contain large amounts of heavy metals so it can be an important source of transmission of contamination of metal toxins to human. The main problem of heavy metals is that they are not metabolized in the body and thus are aggregated in body tissues. Heavy metals adversely affect nervous system, liver, kidney, skin, bones, and teeth. The method of cooking the rice, the amounts of water consumed for cooking, and its cooking time can be among the factors influencing the levels of metal toxins remained in the rice. This research studies the effect of the mentioned factors in order to achieve the best cooking conditions in terms of reducing the risk of contamination of the rice with metal toxins. The samples of rice were purchased from wholesale stores across Mashhad City with a fully random design. All samples were soaked before cooking by water, after which their water was fully removed. Next, the rice samples were cooked under conventional method of draining (boiling in profuse water). Eventually, the level of cadmium and lead in the dry, soaked, drained, and cooked rice ready for consumption was measured and evaluated by atomic absorption device. The comparison of the results indicated that the extent of the effect of the rice soaking stage has been more effective than other stages in reducing the level of cadmium and lead. Furthermore, the reduction in the level of lead and cadmium was greater in drained rice in comparison with brewed rice. Eventually, the greatest reduction in the level of lead and cadmium was obtained for "soaked, drained, brewed rice" as much as 61.3-87.8% for lead and 40-73.7% for cadmium. Also, the results revealed that across all stages, the extent of reduction in lead was greater than in cadmium. Indeed, it shows the higher resistance of cadmium in comparison with lead to reduction. Generally, the results indicated that all stages of soaking water, rice draining, rice brewing, as well as the amount of water and time required at each stage have influenced the extent of reduction in lead and cadmium present in rice. [ABSTRACT FROM AUTHOR]

This study evaluated amino acids, antioxidant capacity, and arsenic species present in Indica and Japonica rice cultivars ( Oryza sativa L.) grown in similar regions, as well as brown rice. Essential amino acids in brown rice exhibited a greater abundance when compared to white rice. Lysine was the only essential amino acid with higher concentration in white rice than in brown rice. Results showed antioxidant activity of 0.46 IC 50 (mg mL −1 ) and TPC 0.11 mg eq. GA/g of sample. Total arsenic content in rice samples was about 200 µg/kg. HPLC-ICP-MS determinations revealed iAs as the predominant species in bran samples. Through Spearman’s correlation, negative correlations between six amino acids and total arsenic content in japonica white rice were observed. Sulphur amino acid cysteine presented the highest negative correlation ( ρ = −0.758, p-value = 0.011). Based on our results, a regular benefit-risk assessment for rice products to enhance the consumption choice is recommended. [ABSTRACT FROM AUTHOR]

High light and ultraviolet-B radiation (UV-B) are generally considered to have negative impact on photosynthesis and plant growth. The present study evaluates the tolerance potential of three cultivars of Oryza sativa L. (Kanchana, Mattatriveni and Harsha) seedlings towards high light and UV-B stress on the basis of photosynthetic pigment degradation, chlorophyll a fluorescence parameters and rate of lipid peroxidation, expressed by malondialdehyde content. Surprisingly, it was revealed that Kanchana was the most sensitive cultivar towards high light and at the same time it was the most tolerant cultivar towards UV-B stress. This contrasting feature of Kanchana towards high light and UV-B tolerance was further studied by analyzing photosystem (PS) I and II activity, mitochondrial activity, chlorophyll a fluorescence transient, enzymatic and non-enzymatic antioxidant defense system. Due to the occurrence of more PS I and PSII damages, the inhibition of photochemical efficiency and emission of dissipated energy as heat or fluorescence per PSII reaction center was higher upon high light exposure than UV-B treatments in rice seedlings of Kanchana. The mitochondrial activity was also found to be drastically altered upon high light as compared to UV-B treatments. The UV-B induced accumulation of non-enzymatic antioxidants (proline, total phenolics, sugar and ascorbate) and enzymatic antioxidants (ascorbate peroxidase, guaiacol peroxidase, superoxide dismutase and glutathione reductase) in rice seedlings than those subjected to high light exposure afforded more efficient protection against UV-B radiation in rice seedlings. Our results proved that high tolerance of Kanchana towards UV-B than high light treatments, correlated linearly with the protected photosynthetic and mitochondrial machinery which was provided by upregulation of antioxidants particularly by total phenolics, ascorbate and ascorbate peroxidase in rice seedlings. Data presented in this study conclusively proved that rice cultivar Kanchana respond to different environmental signals independently and tolerance mechanisms to individual stress factors was also varied. [ABSTRACT FROM AUTHOR]

The aim of this study was to determine uptake and translocation of MeHg in the absence or presence of P in three rice cultivars, named Tianyou196 (TY196), NanJing35 (NJ35), and ZiXiangnuo (ZX). Rice seedlings from each cultivar were divided into two groups. One group was grown in normal P (+P) nutrient solution and the other in absence of P or starvation (−P) nutrient solution for 2 weeks. Both groups were subsequently exposed to 200 mg/L MeHg chloride culture solution and maintained in a greenhouse for 4 weeks. The results showed that the amount of reddish Fe plaque outside rice root was significantly increased by P starvation treatment, but in the +P treatments, rice roots remained white. It is proposed that Fe plaque formed sequestered MeHg and consequently reduced translocation of MeHg from roots to shoots. It is of interest that MeHg content in roots and shoots of TY196 and NJ35 was 11.1%-18.8% and 28.9%-32.3% lower than in ZX, respectively. Therefore, in practice, depletion of P to enhance Fe plaque formation in rice growing area is effective in preventing MeHg translocation from roots to shoots and ensures food safety in mine locations. [ABSTRACT FROM AUTHOR]

Contamination of rice ( Oryza sativa ) by Cd is of great concern. Steel slag could be used to amend Cd-contaminated soils and make them safe for cereal production. This work was conducted to study the effects of steel slag on Cd uptake and growth of rice plants in acidic and Cd-contaminated paddy soils and to determine the possible mechanisms behind these effects. Pot (rhizobag) experiments were conducted using rice plants grown on two acidic and Cd-contaminated paddy soils with or without steel slag amendment. Steel slag amendment significantly increased grain yield by 36–45% and root catalase activity, and decreased Cd concentrations in brown rice by 66–77% compared with the control, in both soils. Steel slag amendment also markedly decreased extractable soil Cd, Cd concentrations in pore-water and Cd translocation from roots to above-ground parts. It also significantly increased soil pH, extractable Si and Ca in soils and Ca concentrations in roots. Significant positive correlations were found between extractable soil Cd and Cd concentrations in rice tissues, but it was negatively correlated with soil pH and extractable Si. Calcium in root tissues significantly and negatively correlated with Cd translocation factors from roots to straw. Overall, steel slag amendment not only significantly promoted rice growth but decreased Cd accumulation in brown rice. These benefits appear to be related to improvements in soil conditions (e.g. increasing pH, extractable Si and Ca), a reduction in extractable soil Cd, and suppression of Cd translocation from roots to above-ground parts. [ABSTRACT FROM AUTHOR]

Phytic acid (PA) is considered as an anti-nutritional factor (ANF) present in cereals and legumes and bind to cationic minerals including iron (Fe) and zinc (Zn), thus reducing their bioavailability in both ruminants and nonruminants. The present study was aimed at finding the impact of PA on bioavailability of Fe and Zn. Six rice cultivars with contrasting PA were evaluated for total phosphorus (P), PA, Fe, and Zn in brown and processed rice. A significant correlation of PA of brown rice with PA of milled rice ( r = .69) was observed. PA and Zn content were negatively correlated ( r = −.55) in brown rice while no significant correlation was found between PA and Zn in milled rice. The rice cultivar Bindli, with lowest PA (0.82 g/100 g) was found to exhibit high Zn bioavailability, while PB267, with highest PA (2.62 g/100 g) showed low Zn and Fe bioavailability. Practical applications Rice is staple food for millions of people, especially the Asians. Fe and Zn are essential micronutrients required for human growth and development, but the rice grain is deficient in Fe and has only moderate amounts of Zn. The bioavailability of these minerals are impaired by PA which chelates and bind cationic minerals in both ruminants and nonruminants. Screening of rice genotypes with low PA and high minerals bioavailability may be suitable for people suffering from micronutrient malnutrition. [ABSTRACT FROM AUTHOR]

Black rice (Oryza sativa L.) is considered to be a healthy food due to its high content of anthocyanins in the pericarp. The synthetic pathway of anthocyanins in black rice grains has been identified, however, the proteomic profile of leaves during grain development is still unclear. Here, isobaric Tags Relative and Absolute Quantification (iTRAQ) MS/MS was carried out to identify statistically significant changes of leaf proteome in the black rice during grain development. Throughout three sequential developmental stages, a total of 3562 proteins were detected and 24 functional proteins were differentially expressed 3-10 days after flowering (DAF). The detected proteins are known to be involved in various biological processes and most of these proteins were related to gene expression regulatory (33.3%), signal transduction (16.7%) and developmental regulation and hormone-like proteins (12.5%). The coordinated changes were consistent with changes in regulatory proteins playing a leading role in leaves during black rice grain development. This indicated that signal transduction between leaves and grains may have an important role in anthocyanin biosynthesis and accumulation during grain development of black rice. In addition, four identified up-regulated proteins associated with starch metabolism suggested that the remobilization of nutrients for starch synthesis plays a potential role in anthocyanin biosynthesis of grain. The mRNA transcription for eight selected proteins was validated with quantitative real-time PCR. Our results explored the proteomics of the coordination between leaf and grain in anthocyanins biosynthesis of grain, which might be regulated by signal transduction and sugar metabolism in black rice leaf. [ABSTRACT FROM AUTHOR]

Total and inorganic arsenic (As) content in rice and rice-based diets (n = 59) obtained from supermarkets in South Australia were studied to investigate the contamination levels and whether consumption of these products pose potential health risks to young children and adults. Results show that of the 59 rice-based products, 31 (53%) exceeded the EU recommended value (100 μg/kg) of As for young children and 13 (22%) samples had higher than maximum level of 200 μg/kg recommended for adults. Arsenic content varies as rice crackers > baby rice > rice cakes > puffed rice > other rice-based snacks > ready-to-eat rice. Of the 6 categories of rice-based products, except ready-to-eat rice, all others exceeded the EU recommended value for young children. Even manufacture recommended servings deliver significant amounts (0.56–6.87 μg) of inorganic As. These amounts are within the range of BMDL 01 values indicated by the European Food Safety Authority (EFSA), which means the risk cannot be avoided for young children and adults considering the levels of total and inorganic As in rice-based products. [ABSTRACT FROM AUTHOR]

Cadmium uptake in rice is believed to be mediated by the Fe transport system. Phyto-available Cd can be changed by Fe fertilization of substrates. This work investigated whether and how Fe fertilization affects mitigation of Cd accumulation in paddy rice. A 90-d soil column experiment was conducted to study the change of Cd and Fe availability in soil after Fe fertilization (ionic and chelated Fe). A low-Cd accumulating cultivar (TY116) and a high-Cd accumulating cultivar (JY841) were grown in two Cd-polluted paddy soils amended with chelated Fe fertilizers. Additionally, both cultivars were grown in hydroponics to compare Fe-related gene expression in EDDHAFe-deficient and EDDHAFe-sufficient roots. The column experiment showed that EDTANa 2 Fe(II) and EDDHAFe(III) fertilization had a better mitigation effect on soil Cd availability compared to FeSO 4 ·7H 2 O. Moreover, the field experiment demonstrated that these two chelated fertilizations could reduce Cd concentrations in brown rice by up to 80%. Iron concentrations in the brown rice were elevated by Fe chelates. Compared to EDDHAFe(III), EDTANa 2 Fe(II) fertilization had a stronger mitigation effect by generating more EDTANa 2 Cd(II) in the soil solution to decrease phyto-available Cd in the soil. While EDDHAFe(III) fertilization could increase soil pH and decrease soil Eh which contributed to decreasing phyto-available Cd in a contaminated soil. In the hydroponic experiment, Fe sufficiency significantly reduced Cd concentrations in above-ground organs. In some cases, the expression of OsIRT1 , OsNRAMP1 and OsNRAMP5 was inhibited under Fe sufficiency relative to Fe deficiency conditions. These results suggest that mitigation of rice Cd by Fe chelate fertilization results from a decrease in available Cd in substrates and the inhibition of the expression of several Fe-related genes in the IRT and NRAMP families. [ABSTRACT FROM AUTHOR]

The effects of biochar (BC) and ferromanganese oxide biochar composites (FMBC 1 and FMBC 2 ) on As (Arsenic) accumulation in rice were determined using a pot experiment. Treatments with BC or FMBC improved the dry weights of rice roots, stems, leaves, and grains in soils containing different As contamination levels. Compared to BC treatment, FMBC treatments significantly reduced As accumulation in different parts of the rice plants ( P < 0.05), and FMBC 2 performed better than FMBC 1 did. Furthermore, exposure to 2% FMBC 2 decreased the total As concentration in the grain by 68.9–78.3%. The addition of FMBC increased the ratio of essential amino acids in the grain, decreased As availability in the soil, and significantly increased the Fe and Mn plaque contents. The reduced As accumulation in rice can be attributed to As(III) to As(V) oxidation by ferro - manganese binary oxide, which increased the As adsorbed by FMBC. Furthermore, Fe and Mn plaques on the rice root surface decreased the transport of As in rice. Taken together, our results demonstrated the applicability of FMBC as a potential measure for reducing As accumulation in rice, improving the amino acid content of rice grains, and effectively remediating As-polluted soil. [ABSTRACT FROM AUTHOR]

Pup1 is the major quantitative trait locus (QTL) for phosphorus deficiency (PD) tolerance in rice. The molecular markers linked to Pup1 are available for numerous rice genotypes. However, novel haplotypes of Pup1 could be detected if specific landraces are subjected to genetic analyses. A set of 30 local rice genotypes were assessed for PD tolerance and in the present study, they were characterised by sequencing K20-1, a co-dominant locus within the Pup1 locus. The DNA polymorphism was also checked for the association with PD tolerance. A total of 10 SNPs and one INDEL were discovered among the 32 genotypes including Kasalath and Nipponbare as PD tolerant and sensitive reference rice varieties, respectively. Four unique SNPs were discovered in the studied germplasm that are not present in either Kasalath or Nipponbare. The SNP located at the 209th position was very important as it is unique to highly PD tolerant landraces Murungakayan and Suduheenati, and varieties H-4, H-7 and H-10. These five genotypes lack the INDEL region present in Kasalath highlighting the presence of novel Pup1 haplotypes in country specific rice varieties/ landraces, and they can be used as parental genotypes to introduce PD tolerance into new varieties in rice breeding programmes in Sri Lanka. [ABSTRACT FROM AUTHOR]

Heavy metal in rice studies has attracted a greater concern worldwide. However, there have been limited studies on marketed rice samples although it represents a vital ingestion portion for a real estimation of human health risk. This study was aimed to determine both total and bioaccessible of trace elements and heavy metals (Cd, Cr, Cu, Co, Al, Zn, As, Pb and Fe) in 22 varieties of cooked rice using an inductively coupled plasma-optical emission spectroscopy. Both total and bioaccessible of trace elements and heavy metals were digested using closed-nitric acid digestion and Rijksinstituut voor Volksgezondheid en Milieu (RIVM) in vitro digestion model, respectively. Human health risks via Health Risk Assessment (HRA) were conducted to understand exposure risks involving adults and children representing Malaysian population. Zinc was the highest while As was the lowest contents for total and in their bioavailable forms. Four clusters were identified: (1) Pb, As, Co, Cd and Cr; (2) Cu and Al; (3) Fe and (4) Zn. For HRA, there was no any risks found from single element exposure. While potential carcinogenic health risks present for both adult and children from single As exposure (Life time Cancer Risk, LCR > 1 × 10 −4 ). Total Hazard Quotient values for adult and children were 27.0 and 18.0, respectively while total LCR values for adult and children were 0.0049 and 0.0032, respectively. [ABSTRACT FROM AUTHOR]

In this study, we developed a new method to detect dinotefuran and its metabolites (UF and DN) in Oryza sativa (Rice) by HPLC–MS/MS in multiple reaction monitoring (MRM) modes. The recovery rates for dinotefuran, UF and DN were 82.3–85.8%, 83.7–89.0%, and 81.6–90.2%, respectively. The dissipation kinetics of dinotefuran in rice followed a combined first + first kinetic model, where the half-lives of dinotefuran and its metabolites were determined to be between 0.5 and 2.3 days. The dinotefuran residue in brown rice sampled at day 7, 14, and 21 after the last application was 0.4131 mg/kg with a very low risk quotient (RQ) value. We recommend that the safety interval of application for rice is 7 days. The method developed in this study is simple and rapid, with high accuracy and precision which meet the requirements for quantitative analysis of dinotefuran in rice. [ABSTRACT FROM AUTHOR]

Strigolactones (SLs) are the latest confirmed phytohormones that regulate shoot branching by inhibiting bud outgrowth in higher plants. Perception of SLs depends on a novel mechanism employing an enzyme-receptor DWARF14 (D14) that hydrolyzes SLs and becomes covalently modified. This stimulates the interaction between D14 and D3, leading to the ubiquitination and degradation of the transcriptional repressor protein D53. However, the regulation of SL perception in rice remains elusive. In this study, we provide evidences that D14 is ubiquitinated after SL treatment and degraded through the 26S proteasome system. The Lys280 site of the D14 amino acid sequence was important for SL-induced D14 degradation, but did not change the subcellular localization of D14 nor disturbed the interaction between D14 and D3, nor D53 degradation. Biochemical and genetic analysis indicated that the key amino acids in the catalytic center of D14 were essential for D14 degradation. We further showed that D14 degradation is dependent on D3 and is tightly correlated with protein levels of D53. These findings revealed that D14 degradation takes place following D53 degradation and functions as an important feedback regulation mechanism of SL perception in rice. [ABSTRACT FROM AUTHOR]

We studied varietal difference in radiocesium accumulation by using Japanese and World rice collection for future development of low accumulation varieties. As a result, the radiocesium activity concentration varied by 12- and 22-fold in seed grains and straws, respectively. When we examined the seed grain to straw ratio of radiocesium activity concentration, paddy rice cultivars of Japonica sub-species showed a lower result than Indica and Javanica paddy rice cultivars. These observations suggest that the Japonica paddy rice cultivars may have the property of repressing radioactive cesium translocation to edible parts. [ABSTRACT FROM AUTHOR]

Amylose content (AC) is an important factor influencing the eating and cooking qualities of rice. Finding useful relationships between AC and pasting properties is a precondition to extend the use of Rapid Visco Analyzer (RVA) as an analytical tool to estimate AC in rice. In this study, a systematic literature review was conducted to identify the pasting properties that are closely related to AC in Chinese rice. We extracted the data (n = 440) of AC and pasting properties, including peak viscosity (PV), trough viscosity (TV), final viscosity (FV), breakdown (BD) and setback (SB), from 32 published studies that were conducted in China. Large variations were observed in both AC and pasting properties. AC was significantly related with all the pasting properties in the total sample. The correlation coefficient was highest between AC and SB (0.6283), followed by those between AC and FV (0.6176), between AC and TV (0.3671), between AC and BD (-0.2551), and lowest between AC and PV (0.1153). The relationships between AC and pasting properties could vary among different AC groups of rice. However, the significant correlation coefficients between AC and pasting properties within each AC group (0.2258~0.4344) were not very high. Our results suggest that SB and FV are the two pasting properties that are closely related with AC in Chinese rice, and further studies are needed to obtain optimal results on the relationships between AC and pasting properties within different AC groups of rice. [ABSTRACT FROM AUTHOR]

The popcorn-like aroma compound 2-acetyl-1-pyrroline (2-AP) is a key contributor to the desirable aroma of fragrant rice and is also important in the aroma of other foods, such as pandan leaf, popcorn and Mediterranean sausage. It can be formed enzymatically in the rice grain as it grows and is also formed, as part of the Maillard reaction, when rice is heated. This review examines the formation of 2-AP in rice and other foods, particularly its formation during cooking, focusing on the importance of the Maillard reaction between reducing sugar breakdown products and 1-pyrroline derived from the amino acids proline and ornithine. The synthesis of 2-AP is discussed alongside the attempts that have been made to stabilise this relatively unstable compound. The analysis of 2-AP by instrumental techniques, particularly gas chromatography-mass spectrometry and gas chromatography-olfactometry, alongside the use of sensory studies, is also discussed. [ABSTRACT FROM AUTHOR]

Ribosomal proteins (RPs) are indispensable in ribosome biogenesis and protein synthesis, and play a crucial role in diverse developmental processes. Our previous studies on Ribosomal Protein Large subunit (RPL) genes provided insights into their stress responsive roles in rice. In the present study, we have explored the developmental and stress regulated expression patterns of Ribosomal Protein Small (RPS) subunit genes for their differential expression in a spatiotemporal and stress dependent manner. We have also performed an in silico analysis of gene structure, cis-elements in upstream regulatory regions, protein properties and phylogeny. Expression studies of the 34 RPS genes in 13 different tissues of rice covering major growth and developmental stages revealed that their expression was substantially elevated, mostly in shoots and leaves indicating their possible involvement in the development of vegetative organs. The majority of the RPS genes have manifested significant expression under all abiotic stress treatments with ABA, PEG, NaCl, and H2O2. Infection with important rice pathogens, Xanthomonas oryzae pv. oryzae (Xoo) and Rhizoctonia solani also induced the up-regulation of several of the RPS genes. RPS4, 13a, 18a, and 4a have shown higher transcript levels under all the abiotic stresses, whereas, RPS4 is up-regulated in both the biotic stress treatments. The information obtained from the present investigation would be useful in appreciating the possible stress-regulatory attributes of the genes coding for rice ribosomal small subunit proteins apart from their functions as house-keeping proteins. A detailed functional analysis of independent genes is required to study their roles in stress tolerance and generating stress- tolerant crops. [ABSTRACT FROM AUTHOR]

Three types of modified Indica rice starch were obtained by combining mechanical activation (MA) with octenyl succinic anhydride (OSA) esterification. The samples were mechanically activated Indica rice starch (MA-IRS), mechanically activated Indica rice starch esterified by OSA (OSA-MA-IRS) and Indica rice starch that was esterified by OSA and mechanically activated (MAOSA-IRS). The physicochemical properties of the three types of modified Indica rice starch were studied. The results indicate that the particle shape of OSA-MA-IRS was the most irregular among the three types of modified Indica rice starch, and the changes in morphology of MAOSA-IRS were similar to those in mechanically activated Indica rice starch (MA-IRS), but the granules of MS-OSA-IRS were smaller than the granules of MA-IRS after an identical mechanical activation time. The results of X-ray diffraction showed that a new crystalline structure formed during preparation of OSA-MA-IRS, and the crystal structure of OSA-IRS was more easily destroyed by mechanical force than that of IRS. Therefore, for the same mechanical activation time, the transparency and reducing power for each sample were ranked in the following order: MA-OSA-IRS, MA-IRS, and OSA-MA-IRS. However, the blue value from iodine staining and apparent viscosity showed the reverse trend. The emulsifying activity index decreased in the following order: OSA-MA-IRS, MA-OSA-IRS, and MA-IRS. [ABSTRACT FROM AUTHOR]

Effects of date syrup on pasting, rheological, and retrogradation properties of low-amylose rice starch were investigated using three levels of date syrup (starch:syrup 1:1, 1:2, or 1:3). Measurements were carried out using HR-2 Discovery Rheometer equipped with a pasting cell and parallel plate geometry. The pasting measurements showed that the peak viscosity of the control is significantly higher than the samples with date syrup (p < 0.05), while the final viscosity increases with increased date syrup levels. Addition of date syrup increases the solid-like behavior of the gel in reverse order with increased date syrup levels. Low-amylose starch gel used in this study showed minor changes in elastic modulus (G′) during one week cold storage indicting that low-amylose rice starch is resistant to retrogradation. Addition of date syrup slightly resulted in increased retrogradation compared to the control. [ABSTRACT FROM AUTHOR]

The estimation of glycemic index (GI) of rice-based mixed meal either by using predicted GI (GI pred ) or adjusted GI (GI adj ) formula is unclear. This study aimed to determine the glycemic response of rice in rice alone or mixed meals and to identify the appropriate formula for estimating the GI of rice-based mixed meals. The glycemic responses produced by the rice alone (red rice, fragrant white rice or parboiled rice) and the rice-based mixed meals (fried red rice, fried fragrant white rice or fried parboiled rice) which provided 25 g available carbohydrate were assessed in 11 healthy individuals. To determine the measured GI (GI measured ) of rice alone and rice-based mixed meals, participants underwent three repeated tests of a reference food (Glucolin ® ). Tests were performed in random order on nine separate visits after an overnight fasting for at least 8 h. Capillary glucose at baseline (0 min), 15, 30, 45, 60, 90 and 120 min from starting the meals was assessed and used to determine the incremental area under the curve (iAUC 120 ). The agreement between GI measured and the estimation formulae (GI pred or GI adj ) were determined using Bland-Altman analysis. The iAUC 120 after consuming rice alone was significantly higher than the rice-based mixed meals except for fried fragrant rice, which was comparable to the rice alone ( P > 0.05). The GI measured values of rice were categorized as medium (61 for parboiled rice, 67 for fragrant white rice, and 68 for red rice). GI pred ( r = 0.40, P < 0.01) and GI adj ( r = 0.41, P < 0.01) were significantly correlated with iAUC 120 . The agreement between GI measured and GI adj is apparent suggesting the usefulness of GI adj in estimating meal GI of rice-based mixed meals. [ABSTRACT FROM AUTHOR]

The effects of polishing on proximate compositions, physico-chemical characteristics, mineral compositions and antioxidant properties of the rice flours obtained from three different pigmented rice varieties (Chak-hao Angangba, Chak-hao Amubi and Chak-hao Poireiton) were investigated. The rice varieties were significantly ( P < 0.05) different in the contents of the test characteristics. Lipids, ash, minerals, phytochemicals (phenolic acids and flavonoids) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) activity of rice flours were decreased after polishing (9% degree of milling), while amylose content and lightness were increased. X-ray diffraction pattern of rice flours exhibited A-type crystalline pattern with reflections at 15.1°, 17.1°, 18.2° and 23.0°. Pasting properties and transition temperatures were decreased after polishing treatment. Polishing resulted in changes in the crystallinity, enthalpy and morphology of rice flours. [ABSTRACT FROM AUTHOR]

Environmental exposure to cadmium can cause renal damage. Foods containing cadmium are generally regarded as the main environmental sources of human exposure to cadmium. In this study, foods that are ingested in large amounts, including rice and other types of food with a high concentration of cadmium, were investigated to determine the correlation between the foods’ cadmium content and biomarkers. The datasets required for this study, including blood cadmium concentration, biomarker concentration, and data on the amount of consumption by food item, were obtained from KNHNES. Furthermore, data on food groups with high daily exposure to hazardous amounts of cadmium were obtained by monitoring raw food sources from 2010 to 2012. The investigation was then followed by correlation analysis, which was performed to assess the relationship between the amount of rice consumption and cadmium concentration. The Pearson coefficient analysis on the relationship between the amount of food consumption and the biomarker showed that the correlation between foods’ cadmium content and blood cadmium and that of between foods’ cadmium content and other biomarkers were confirmed as statistically significant in the case of the cadmium content of white rice, while, in the case of brown rice, it was confirmed by a few biomarkers. [ABSTRACT FROM AUTHOR]

Background: Plant glutathione S-transferases (GSTs, EC 2.5.1.18) are multifunctional enzymes involved in heavy metal cellular detoxification by conjugating the tripeptide (g-Glu-Cys-Gly) glutathione to heavy metals. Previous studies demonstrated that individual rice GSTs were differentially induced by heavy metal exposure at the mRNA transcript level. However, little information is available concerning changes in protein concentration of rice GSTs under heavy metal stress. Because the correlation between changes in protein concentration and gene expression under abiotic stress is poor, direct determination of rice GSTs protein concentrations during cadmium (Cd) exposure is a more effective and reliable approach to explore possible mechanisms of rice Cd translocation and accumulation. Results: This study established an optimized and advanced liquid chromatography-tandem mass spectrometry (LC-MS/MS)-based targeted proteomics assay for quantification of OsGSTF14 and OsGSTU6 proteins in Cd-stressed rice roots. The tryptic signature peptides were chosen as surrogate analytes and winged peptides containing the isotopelabeled signature peptides were used as the internal standards. The signature peptides exhibited good linearity in the range of 0.6-60 and 0.3-30 nM, respectively. The limit of detection and limit of quantification were 4.5 and 14.5 μg/g for OsGSTF14, respectively, and 2.1 and 7.0 μg/g for OsGSTU6. The spiking recoveries rates at low, medium and high levels were in the range of 72.5-93.4%, with intra- and inter-day precisions of 5.5-9.1 and 4.2-10.2%, respectively. Conclusions: The assay successfully quantified the temporal and dose responses of OsGSTF14 and OsGSTU6 proteins in Cd-stressed rice roots, with good accuracy, precision and high-throughput. This assay will have significant application in developing quantification methods of other proteins in Cd-stressed rice, which may provide more insight into the mechanisms of Cd translocation and accumulation in rice. [ABSTRACT FROM AUTHOR]

The goal of this study was to determine the effect of phytase on true total tract digestibility of phosphorus (TTDP) and endogenous losses of phosphorus (ELP) of full-fat rice bran (FFRB) by simple linear regression. Twelve castrated pigs in the growing phase with an average live weight of 57.00 ± 2.50 kg were used. The experiment lasted 36 days, divided into three periods of 12 days each. The experimental design consisted of randomized blocks in a 2 × 3 factorial scheme, with two levels of fungal phytase (0 and 750 FTU kg-1) and three levels of phosphorus (P) coming from FFRB (5%, 10%, and 20%), totaling six treatments with six replicates. The P coming from FFRB recovered in feces was influenced by phytase (P < 0.008) and by the amount of ingested FFRB (P < 0.001). The average value of ELP was 524 mg/kg dry matter intake (DMI). The TTDP of FFRB was increased by 20 percentage points due to phytase addition. In conclusion, the ELP represented 524 mg/kg DMI on average. The addition of 750 FTU of phytase increased the TTDP of FFRB, which was 32.60% and 52.60% without and with phytase, respectively. [ABSTRACT FROM AUTHOR]

The objectives of this study were to monitor the changes in rice properties during aging and to compare kinetic parameters related to some of those changes. Paddy of three low amylose rice varieties was stored at ambient (30 ± 2ºC) and chilled (8 ± 2ºC) temperatures for 9 and 18 months, respectively. Aging led to a decrease in solid loss, peak viscosity, breakdown, and adhesiveness and an increase in head rice yield, minimum cooking time, water uptake, volume expansion, pasting temperature, final viscosity, through viscosity, setback, and hardness. Low temperature storage efficiently retarded those changes. Data of the time-dependent changes in hardness, adhesiveness, pasting temperature, peak viscosity, and breakdown of all samples stored at 30°C were fitted well with the first-order fractional conversion kinetic model (R2= 0.77 – 0.98). Higher storage temperature resulted in greater rate constant (k; up to 9 times higher) of those changes. [ABSTRACT FROM AUTHOR]

Widespread potential dietary deficiencies of calcium (Ca), iron (Fe), iodine (I), selenium (Se) and zinc (Zn) have been identified in Malawi. Several deficiencies are likely to be compounded by high phytic acid (PA) consumption. Rice ( Oryza sativa) is commonly consumed in some Malawian populations, and its mineral micronutrient content is important for food security. The considerable irrigation requirements and flooded conditions of paddy soils can also introduce or mobilise potentially toxic elements including arsenic (As), cadmium (Cd) and lead (Pb). The aim of this study was to determine the mineral composition of rice sampled from farmers' fields and markets in Malawi. Rice was sampled from 18 extension planning areas across Malawi with 21 white (i.e. polished) and 33 brown samples collected. Elemental composition was determined by inductively coupled plasma-mass spectrometry (ICP-MS). Arsenic speciation was performed using high-performance liquid chromatography (HPLC)-ICP-MS. Concentration of PA was determined using a PA-total phosphorus assay. Median total concentrations (mg kg, dry weight) of elements important for human nutrition in brown and white rice, respectively, were: Ca = 66.5 and 37.8; Cu = 3.65 and 2.49; Fe = 22.1 and 7.2; I = 0.006 and <0.005; Mg = 1130 and 265; Mn = 18.2 and 9.6; Se = 0.025 and 0.028; and Zn = 17.0 and 14.4. In brown and white rice samples, respectively, median PA concentrations were 5438 and 1906 mg kg, and median PA:Zn molar ratios were 29 and 13. Concentrations of potentially toxic elements (mg kg, dry weight) in brown and white rice samples, respectively, were: As = 0.030 and 0.006; Cd ≤ 0.002 and 0.006; Pb = 0.008 and 0.008. Approximately 95 % of As was found to be inorganic As, where this could be quantified. Malawian rice, like the more widely consumed staple grain maize, contains inadequate Ca, I, Se or Zn to meet dietary requirements. Biofortification strategies could significantly increase Se and Zn concentrations and require further investigation. Concentrations of Fe in rice grain varied greatly, and this was likely due to contamination of rice samples with soil. Risk of As, Cd or Pb toxicity due to rice consumption in Malawi appears to be minimal. [ABSTRACT FROM AUTHOR]

This study sought to investigate the possible inhibition mechanism of red rice polyphenols (RRP) on pancreatic α-amylase (PA) activity. RRP showed strong inhibition against PA activity and the half-inhibitory concentration (IC 50 ) value was 3.61 μg/mL. The fluorescence quenching of PA by RRP was a combination of static quenching and dynamic quenching. RRP could aggregate with PA and the physiochemical properties of the aggregates were closely related to the concentration of RRP. Kinetic analysis suggested that the inhibition mode of RRP on PA was reversible inhibition, which was a mixing of competitive inhibition and noncompetitive inhibition. Molecular docking speculated that RRP could form hydrogen bonds with PA by binding to the catalytic active sites (ASP197, GLU233 and ASP300) and the microenvironments of TRP58 and TRP59 were altered, thus inhibiting PA activity. [ABSTRACT FROM AUTHOR]

The purpose of the research was to identify the phenolic and flavonoid compounds of seven different traditional pigmented whole rice cultivars grown in the temperate regions of Kashmir so as to study their relationship with in vitro antioxidant capacities. The completely pigmented rice cultivars were found to have higher phenolic, flavonoid, anthocyanin contents and exhibited higher antioxidant capacities than the light colored and sparely colored rice cultivars. A total of 40 compounds had been identified in the analyzed rice cultivars that were found to be distributed in 6 major categories with 6-phenolics, 6-flavonoids, 11-hydroxycinnamic acid derivatives, 7-hydroxybenzoic acid derivatives, 3-anthocyanins and 7-flavonoid glucosides of different flavonoid compounds. Among the free and bound fractions for each cultivars the light and sparsely colored depicted higher content of phenolics and in vitro antioxidant properties in bound faction, while the completely pigmented cultivars showed higher antioxidant properties in free fractions. The anthocyanins quercetin-3- O -galactoside, cyanidin-3 -O- rutinoside and pelargonidin-3- O -diglucoside had been identified by LC-MS existing in the free fractions of the analyzed rice cultivars whereas, the free fraction of acetone + H 2 O possessed higher percentage of phenolic compounds as compared to methanolic extracts and bound fractions. The black colored cultivars possessed higher DPPH scavenging activity and lipid peroxidation inhibition. [ABSTRACT FROM AUTHOR]

Soils deficient in P are widespread in major rice (Oryza sativa L.) ecosystems. In view of declining reserves of rock phosphate and the rising costs of P fertilizers, breeding rice varieties tolerant to low P has become important for future food security. Four different methods (hydroponics without sand [H], hydroponics with sand [HS], large pots with soil [PS], and glasses with soil [GS]) were evaluated using rice aus variety Nagina 22 (N22) and its known gain-of-function (gof) and loss-of-function (lof) mutants to screen for low P tolerance in the field. In -P (no addition of NaH2PO4) shoots, dry weight was significantly higher in gof mutant NH787 than in N22 in HS, PS, and GS but not in H, with fold increases of 1.8 in HS, 5.2 in GS, and 9.4 in PS. In HS, in -P, out of six traits only shoot dry weight was significantly higher in gof and lower in lof mutants. However, in GS both root and shoot dry weight could confirm gof and lof mutants. It took 40 d in GS and 70 d in PS to differentiate between growth in -P/low P and +P (0.32 mM NaH2PO4) and between gof and lof mutants. Thus, shoot dry weight at 30 d in HS and root and shoot dry weight at 40 d in GS are best to differentiate between genotypes grown in -P/low P and +P soil and also between gof and lof mutants for low P tolerance. The HS method can be performed in ambient conditions and needs 70% less medium compared with H. If germplasm is to be screened for low P tolerance on a large scale and if there is no access to low-P soil, then screening using HS is the best approach. [ABSTRACT FROM AUTHOR]

The consumption of resistant starch (RS), which can increase satiety and reduce calorie intake, may help ameliorate lifestyle-related diseases such as diabetes, hypertension, and obesity. The identification of genes or quantitative trait loci (QTLs) may facilitate improvement in the amounts and properties of RS in cereals such as rice. A genome-wide association mapping of the RS content in milled rice grain was carried out to identify QTLs in a rice germplasm collection. The RS contents among 105 rice accessions ranged from 0.3 to 2.42%, and the apparent amylose content (AAC) was positively correlated with the RS content (R²=0.75). Four QTLs were detected, and each explained a total phenotypic variation of 10-13%. Two of these, on chromosome 6, were identified at theWaxy gene locus encoding granule-bound starch synthase I and starch synthase IIa. The other two QTLs, on chromosomes 8 and 9, were close to candidate genes encoding the starch debranching enzyme isoamylase I and ADP-glucose pyrophosphorylase small subunit 1, respectively. The results of this study should improve our understanding of the genetic basis of RS in milled rice and may assist plant breeders attempting to develop new rice varieties and food processors working to develop functional foods. [ABSTRACT FROM AUTHOR]

Photosynthesis, enzyme activities and metabolite pools associated with primary carbon metabolism in leaves were studied in O. grandiglumis and O. alta (wild relatives of rice which produce high biomass) versus O. sativa (a japonica cultivar and a indica-japonica hybrid) to assess their potential for identifying traits which might be utilized to enhance rice productivity. The wild relatives had higher rates of photosynthesis on a fresh weight basis, and higher water use efficiency than the O. sativa lines. There were no striking differences in activities of a number of key enzymes in carbon and nitrogen metabolism between the wild relatives and cultivated rice lines. Along with higher rates of photosynthesis on a fresh weight basis, the leaves of the two wild species had higher nitrate content, higher levels of starch, glucose and fructose, and higher levels of organic acids (malate, succinate and acetate), compared to the O. sativa lines. The results suggested that O. grandiglumis and O. alta have differences in physiology and primary metabolism which might be exploited to improve growth and productivity of cultivated rice. [ABSTRACT FROM AUTHOR]

Glutamate synthase (GOGAT) is a key enzyme for nitrogen metabolism and ammonium assimilation in plants. In this study, an early senescence 7 ( es7 ) mutant was identified and characterized. The leaves of the es7 mutant begin to senesce at the tillering stage about 60 day after sowing, and become increasingly senescent as the plants develop at the heading stage. When es7 plants are grown under photorespiration-suppressed conditions (high CO 2 ), the senescence phenotype and chlorophyll content are rescued. qRT-PCR analysis showed that senescence- associated genes were up-regulated significantly in es7 . A map-based cloning strategy was used to identify ES7 , which encodes a ferredoxin-dependent glutamate synthase (Fd-GOGAT). ES7 was expressed constitutively, and the ES7 protein was localized in chloroplast. qRT-PCR analysis indicated that several genes related to nitrogen metabolism were differentially expressed in es7 . Further, we also demonstrated that chlorophyll synthesis-associated genes were significantly down-regulated in es7 . In addition, when seedlings are grown under increasing nitrogen concentrations (NH 4 NO 3 ) for 15 days, the contents of chlorophyll a, chlorophyll b and total chlorophyll were significantly lower in es7 . Our results demonstrated that ES7 is involved in nitrogen metabolism, effects chlorophyll synthesis, and may also associated with photorespiration, impacting leaf senescence in rice. [ABSTRACT FROM AUTHOR]