Home About us Contact
|
Home About us Contact | ||
|
|
||
Rice Grains (rice + grain)
Selected AbstractsPhysicochemical, mechanical and thermal properties of brown rice grain with various moisture contentsINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 9 2004Wei Cao Summary The effects of moisture content on the mechanical and thermal properties of either a short-grain variety (Akitakomachi) or two long-grain varieties (Delta and L201) of brown rice were studied. Total starch contents of the three varieties were comparable, but the amylose content of L201 was significantly higher than that of the other two varieties. The maximum compressive strength of brown rice grain was much higher than the maximum tensile strength. L201 showed the highest maximum compressive and tensile strengths. The phase transition temperatures (glass transition temperature Tg and melting temperature Tm) were examined by differential scanning calorimetry. The Tg and Tm for L201 were higher than those for Delta and Akitakomachi. The maximum compressive strength, maximum tensile strength, Tg and Tm for the three varieties of brown rice grains decreased with increasing moisture content. The Tg of individual brown rice kernels decreased from 53 to 22 °C as moisture content increased from 12 to 25% wet basis. A statistical model was calculated by using linear regression to describe the change in Tg in terms of moisture content. [source] Arsenic accumulation by rice grown in soil treated with roxarsoneJOURNAL OF PLANT NUTRITION AND SOIL SCIENCE, Issue 4 2009Chen-Wuing Liu Abstract Poultry litter is widely used as a fertilizer for lowland rice in Taiwan and China. However, the organic-arsenic compound roxarsone (additive of poultry feed) in poultry litter can be absorbed by the plants and the resulting arsenic (As) contamination may pose a serious threat to human health. This study used various amounts of poultry litter contaminated with roxarsone in pot experiments to evaluate the effect of roxarsone on rice agronomic parameters and the bioaccumulation of total and inorganic As in rice-plant tissues. Rice-grain yield decreased significantly with increasing As content of the soil, and the critical threshold that killed rice was 200 mg roxarsone (kg soil),1. The As concentrations in root, straw, leaf, husk, and grain increased with increasing soil As (p < 1%). At 100 mg roxarsone per,kg of soil, the As concentration in the rice grain exceeded the statutory permissible limit of 1.0 mg As (kg dry weight),1 and at 25 mg roxarsone (kg soil),1, the inorganic As concentrations in grains exceeded the statutory limit of 0.15 mg of inorganic As,kg,1 in China. For all treatments, the As concentrations in various plant tissues at maturity follow the order: root > stem > leaf > husk > grain. Arsenite was the predominant species in root, straw, and grain, while arsenate was the predominant species in leaf and husk. No significant difference existed between the amounts of arsenite and arsenate when various amounts of poultry litter were applied. This result illustrates that large amounts of added roxarsone are not only toxic to rice but also accumulate in grains in the inorganic As forms, potentially posing a threat to human health via the food chain. [source] Variations in cadmium accumulation among rice cultivars and types and the selection of cultivars for reducing cadmium in the dietJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 1 2005Jianguo Liu Abstract A pot trial was conducted with 52 rice cultivars of different types collected from different origins. The results showed that there were great differences in Cd concentrations in straw, brown rice and grain chaff among the rice cultivars grown in a soil containing a Cd concentration of 100 mg kg,1; the Cd concentrations in brown rice ranged from 0.22 to 2.86 mg kg,1. The great genotypic differences in Cd concentrations indicated that it is possible to lower the Cd content of rice through cultivar selection and breeding. Significant differences were found in the Cd concentrations of the rice types of Indica consanguinity and those of Japonica consanguinity, but not between their origins. There were significant correlations between straw and brown rice in Cd concentration and in the total amount of Cd accumulated. The distribution ratios of the Cd accumulated in brown rice to the total Cd accumulation in the above-ground rice plant varied greatly from 12.9 to 137.8 g kg,1, and there was significant correlation between the distribution ratios and Cd concentrations in brown rice. These indicated that Cd concentration in rice grain is governed by the transport of Cd from root to shoot and also from shoot to grain. Cd concentrations in brown rice also correlated significantly with some important agronomic traits, as well as with nitrogen concentrations, one of the most important criteria for rice quality. Copyright © 2004 Society of Chemical Industry [source] Bioengineered ,golden' indica rice cultivars with ,-carotene metabolism in the endosperm with hygromycin and mannose selection systemsPLANT BIOTECHNOLOGY JOURNAL, Issue 2 2003Karabi Datta Summary Vitamin-A deficiency (VAD) is a major malnutrition problem in South Asia, where indica rice is the staple food. Indica-type rice varieties feed more than 2 billion people. Hence, we introduced a combination of transgenes using the biolistic system of transformation enabling biosynthesis of provitamin A in the endosperm of several indica rice cultivars adapted to diverse ecosystems of different countries. The rice seed-specific glutelin promoter (Gt-1 P) was used to drive the expression of phytoene synthase (psy), while lycopene ,-cyclase (lcy) and phytoene desaturase (crtI), fused to the transit peptide sequence of the pea-Rubisco small subunit, were driven by the constitutive cauliflower mosaic virus promoter (CaMV35S P). Transgenic plants were recovered through selection with either CaMV35S P driven hph (hygromycin phosphotransferase) gene or cestrum yellow leaf curling virus promoter (CMP) driven pmi (phophomannose isomerase) gene. Molecular and biochemical analyses demonstrated stable integration and expression of the transgenes. The yellow colour of the polished rice grain evidenced the carotenoid accumulation in the endosperm. The colour intensity correlated with the estimated carotenoid content by spectrophotometric and HPLC analysis. Carotenoid level in cooked polished seeds was comparable (with minor loss of xanthophylls) to that in non-cooked seeds of the same transgenic line. The variable segregation pattern in T1 selfing generation indicated single to multiple loci insertion of the transgenes in the genome. This is the first report of using nonantibiotic pmi driven by a novel promoter in generating transgenic indica rice for possible future use in human nutrition. [source] The redistribution of protein sulfur in transgenic rice expressing a gene for a foreign, sulfur-rich proteinTHE PLANT JOURNAL, Issue 1 2003N. D. Hagan Summary Sulfur amino acid composition is an important determinant of seed protein quality. A chimeric gene encoding sunflower seed albumin (SSA), one of the most sulfur-rich seed storage proteins identified so far, was introduced into rice (Oryza sativa) in order to modify cysteine and methionine content of the seed. Analysis of a transgenic line expressing SSA at approximately 7% of total seed protein revealed that the mature grain showed little change in the total sulfur amino acid content compared to the parental genotype. This result indicated that the transgenic rice grain was unable to respond to the added demand for cysteine and methionine imposed by the production of SSA. Analysis of the protein composition of the transgenic grain showed changes in the relative levels of the major seed storage proteins, as well as some non-storage proteins, compared to non-transgenic controls. Changes observed at the protein level were concomitant with differences in mRNA accumulation but not always with the level of transcription. The limited sulfur reserves appeared to be re-allocated from endogenous proteins to the new sulfur sink in the transgenic grain. We hypothesize that this response is mediated by a signal transduction pathway that normally modulates seed storage protein composition in response to environmental fluctuations in sulfur availability, via both transcriptional and post-transcriptional control of gene expression. [source] Mathematical modeling of water uptake through diffusion in 3D inhomogeneous swelling substratesAICHE JOURNAL, Issue 7 2009L. R. van den Doel Abstract Diffusion-driven water uptake in a substrate (imbibition) is a subject of great interest in the field of food technology. This is a particular challenge for rice grains that are preprocessed to accelerate the water uptake, i.e., to reduce the cooking time. Rice preprocessing disrupts the mesostructural order of starch and induces a microporous structure in the grains. The meso- and microstructural length scales have not been considered in joint approach until now. The (re)hydration of rice grains can be modeled by free (concentration-driven) diffusion or by water demand-driven diffusion. The latter is driven by the ceiling moisture content related to the extent of gelatinization of the rice substrate network. This network can be regarded as a fractal structure. As the spatial resolution of our models is limited, we choose to model the apparent water transport by a set of coupled partial differential equations (PDEs). Current models of water uptake are often limited to a single dimension, and the swelling of the substrate is not taken into account. In this article, we derive a set of PDEs to model water uptake in a three-dimensional (3D) inhomogeneous substrate for different types of water diffusion as well as the swelling of the substrate during water uptake. We will present simulation results for different 3D (macroscopic) structures and diffusion models and compare these results, qualitatively, with the experimental results acquired from magnetic resonance imaging. © 2009 American Institute of Chemical Engineers AIChE J, 2009 [source] Alternate wetting and moderate soil drying increases grain yield and reduces cadmium accumulation in rice grainsJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 10 2009Jianchang Yang Abstract BACKGROUND: Rice is the most important staple food in Asia but has also been identified as one of the major sources of cadmium (Cd) intakes for some Asian population. This study investigated whether grain yield could be maintained but Cd in grains be reduced through proper irrigation management when rice was grown in Cd-contaminated soil. RESULTS: Compared to the well watered treatment, the alternate wetting and moderate soil drying (MD, re-watered when soil water potential decreased to ,20 kPa) increased grain yield by 10,12% and improved milling and appearance quality of rice when grown in a soil containing a water-soluble Cd content of 18 g kg,1. An alternate wetting and severe soil drying (SD, re-watered when soil water potential decreased to ,40 kPa) showed an opposite effect. Both MD and SD significantly increased Cd content in roots while they reduced it in the straw. MD reduced Cd content by 19,21% in the grain and by 40% in milled rice. The SD significantly increased Cd content in the grain but reduced it in milled rice. CONCLUSION: An alternate wetting and moderate soil drying could increase rice yield and quality and also reduce Cd in the diet of rice. Copyright © 2009 Society of Chemical Industry [source] Effect of fermentation metabolites on rheological and sensory properties of fermented rice noodlesJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 12 2008Zhan-Hui Lu Abstract BACKGROUND: Considering the effect of natural fermentation on the textural improvement of fermented rice noodles in China and South Asia, and given the lack of reports concerning the roles of fermentation metabolites (enzymes, organic acids, glucose and maltose), this study aims to determine fermentation metabolites produced during fermentation of raw milled rice grains, and investigate their effects on rheological and sensory properties of rice noodles. RESULTS: ,-Amylase activity was correlated with reducing sugar content significantly in the supernatant during fermentation process (r = 0.76, P < 0.05). Lactic acid was the dominant organic acid produced by fermentation. Protein and lipid content decreased significantly by fermentation. Treating the rice grains with trypsin, lipase or lactic acid could modify the rheological characteristics and improve the sensory properties of rice noodles. Removal of protein and lipid by physical extraction confirmed the results. The residue of glucose and maltose in rice flour weakened the noodle texture. CONCLUSIONS: Fermentation of raw milled rice decreased protein and lipid content, increased the purity of rice starch, and thus improved the texture of fermented rice noodles. The low molecule weight sugars produced during fermentation should be removed for their negative effect on texture. Copyright © 2008 Society of Chemical Industry [source] Speciation and distribution of arsenic and localization of nutrients in rice grainsNEW PHYTOLOGIST, Issue 1 2009E. Lombi Summary ,,Arsenic (As) contamination of rice grains and the generally low concentration of micronutrients in rice have been recognized as a major concern for human health. Here, we investigated the speciation and localization of As and the distribution of (micro)nutrients in rice grains because these are key factors controlling bioavailability of nutrients and contaminants. ,,Bulk total and speciation analyses using high-pressure liquid chromatography (HPLC),inductively coupled plasma mass spectrometry (ICP-MS) and X-ray absorption near-edge spectroscopy (XANES) was complemented by spatially resolved microspectroscopic techniques (µ-XANES, µ-X-ray fluorescence (µ-XRF) and particle induced X-ray emission (PIXE)) to investigate both speciation and distribution of As and localization of nutrients in situ. ,,The distribution of As and micronutrients varied between the various parts of the grains (husk, bran and endosperm) and was characterized by element-specific distribution patterns. The speciation of As in bran and endosperm was dominated by As(III),thiol complexes. ,,The results indicate that the translocation from the maternal to filial tissues may be a bottleneck for As accumulation in the grain. Strong similarities between the distribution of iron (Fe), manganese (Mn) and phosphorus (P) and between zinc (Zn) and sulphur (S) may be indicative of complexation mechanisms in rice grains. [source] Carbohydrate,ethanol transition in cereal grains under anoxiaNEW PHYTOLOGIST, Issue 3 2001Lorenzo Guglielminetti Summary ,,Cereal grains differ greatly in their reponses to anaerobiosis. Here, the in vivo conversion of carbohydrates to ethanol and CO2 under anoxia is reported for three cereal grains. ,,The conversion of glucose, fructose or sucrose to ethanol under anaerobic conditions was investigated in rice (Oryza sativa), barley (Hordeum vulgare) and wheat (Triticum aestivum) grains; alcohol dehydrogenase (EC 1.1.1.1) and pyruvate decarboxylase (EC 4.1.1.1) activities were also analysed under aerobic and anaerobic incubation. ,,Our data suggest that rice grains are able to produce ethanol under anoxia for the whole period of anoxic treatment, whereas barley and wheat grains can produce this terminal product of fermentation only during the first days of anaerobiosis. The level of enzymes involved in the fermentation pathway increases strongly under anoxic conditions in all three cereals. ,,Conversion of hexose to CO2 is nearly unaffected by anoxia in wheat, barley and rice, whereas only rice grains are able to degrade and utilize sucrose efficiently under anoxia. By contrast, wheat and barley do not utilize sucrose efficiently under anaerobic conditions. [source] QTL analysis of cooked rice grain elongation, volume expansion, and water absorption using a recombinant inbred populationPLANT BREEDING, Issue 2 2005X. J. Ge Abstract The traits of elongation, volume expansion, and water absorption are very important in determining the quality of cooked rice grains. In this study, quantitative trait loci (QTL) analysis of these traits was performed using a recombinant inbred population derived from a cross between two indica cultivars, ,Zhenshan 97' and ,Minghui 63,' which are the parents of the most widely grown hybrid rice in China. Using a linkage map based on 221 molecular marker loci covering a total of 1796 cM, a total of 33 QTLs were identified for the nine traits tested. QTLs were detected on chromosomes 1,3, 5,9, and 11, respectively. The QTLs identified included three for cooked rice grain length elongation (chromosomes 2, 6, and 11), six for width expansion (chromosomes 1- 3, 6, 9, and 11) and two for water absorption (chromosomes 2 and 6). Interestingly, a single QTL located near the wx gene on chromosome 6 seemed to influence all the traits tested for the cooked rice quality. [source] | |||||||||||||