Brown rice

About: Brown rice is a research topic. Over the lifetime, 8180 publications have been published within this topic receiving 81079 citations.

Improvement in Shelf Life of Rough and Brown Rice Using Infrared Radiation Heating

Abstract: The objective of this study was to investigate the effect of infrared (IR) heating and tempering treatments on storage stability of rough and brown rice. Samples of freshly harvested medium grain rice variety M206 with initial moisture content of 25.03 ± 0.21 % (d.b.) were used. They were dried using IR, hot air at 43 °C, and ambient air for comparison. For IR drying, rice were heated to temperature of 60 °C under radiation intensity of 4685 W/m2, followed by 4 h tempering and natural cooling. The dried samples were divided into two portions, which were respectively used as rough and brown rice for storage at 35 ± 1 °C with relative humidity of 65 ± 3 % for 10 months. The drying characteristics and milling quality of rice were determined. Free fatty acid, peroxide value, and iodine value were determined to detect any notable degradation of lipids in rough and brown rice during storage. High heating and drying rates of rice were achieved under IR heating. It took only 58 s to heat rough rice to temperature of 60 °C with a corresponding moisture removal of 2.17 percentage points during IR heating. The total moisture removal after natural cooling reached to 3.37 percentage points without additional energy input. IR drying did not show any adverse effects on milling quality of the dried rice. Additionally, it resulted in an effective inactivation of lipase, and consequent improvement in the long-term storage stability of rough and brown rice was achieved under accelerated storage condition. It is concluded that the improvement in rough and brown rice stability during storage can be achieved through drying rough rice using IR heating to temperature of 60 °C followed by tempering for 4 h and natural cooling. IR drying provides a potential to store brown rice instead of rough rice with extended shelf life and reduced cost.

Studies on Dry Matter and Grain Production of F1 Hybrid Rice in China : I. Characteristics of grain production

Abstract: In order to make clear the high yielding capacity of the F1 hybrid rice in China, the characteristics of grain production was examined by the yield components analysis and with reference to the source of contents accumulated to the grain during the ripening period with the same varieties used in the previous paper. It became obvious from the yield components analysis that there was a highly positive correlation between total number of spikelet per unit land area and brown rice yield (Fig. 1). High yield in the F1 hybrid rice was largely depended on spikelet number (ca. 40, 000/m2) as compared with common rice varieties. The total number of spikelet in the F1 hybrid rice was due to increased spikelet number per one panicle rather than panicle number per one hill. The F1 hybrid rice showed comparatively high percentage of tilled-spikelet (ca. 80%) in spite of its huge number of spikelet. This was caused by higher ratio of LAI to total number of spikelet (Source-Sink ratio) during the ripening period. Generally, brown rice yield is decided by the total amount of photosynthetic products, a carbohydrate stored in culm and leaf sheath before flowering, and of assimilate accumulated during the ripening period. In this experiment, the ratio of the storage translocated from the culm and leaf sheath to the spikelet was larger in the F1 hybrid than in common rice varieties. In addition, there was a highly positive correlation between translocated storage and brown rice yield (Fig.4). This fact suggests that a comparatively high percentage of ripened-grain in the F1 hybrid rice was attributed to the amount of storage. It can be concluded from the results mentioned above that high yield of F1 hybrid rice was realized by both factors: 1) remarkable large number of spikelet and 2) comparatively high percentage of ripened grain, which was attained by the high ratio of the storage translocated from the culm and leaf sheath and by high LAI during the ripening period.

Determination of Trace Elements in Rice Flour by Isotope Dilution Inductively Coupled Plasma Mass Spectrometry

Abstract: Two rice flour reference materials (normal and elevated trace concentrations) were prepared from brown rice produced in Korea. As part of the certification process, trace elements such as Cr, Fe, Cd and Pb were determined by an isotope dilution ICP-MS method. About 0.4 g of rice flour samples spiked with appropriate amounts of enriched spike isotopes was decomposed in high-pressure microwave digestion bombs. For the determination of Cr and Fe, the ICP-MS instrument employed in the present work was operated under cool plasma conditions. The cool plasma was generated by inserting a copper shield between the load coil and the plasma, and by increasing the aerosol carrier gas flow rate up to 1.3 l min -1 . An approximately 2 µg ml -1 Ca matrix in the digested solution was observed to induce serious spectral interference on the determination of Fe; hence, the Ca matrix was separated from the analyte using a microcolumn loaded with silica-immobilized 8-hydroxyquinoline. Analytical results for National Institute of Standards and Technology Standard Reference Material 1568, Japan National Institute for Environmental Studies Certified Reference Material 10-a and Korea Research Institute of Standards and Science reference materials are presented together with detection limits.

Thermal characteristics of ohmically heated rice starch and rice flours.

Abstract: Thermal properties of conventionally and ohmically heated rice starch and rice flours at various frequencies and voltages were studied. There was an increase in gelatinization temperature for conventionally heated rice starches since they were pregelatinized and became more rigid due to starch-chain interactions. In addition, there was a decrease in enthalpy (energy needed) for conventionally and ohmically heated starches during gelatinization; thus, the samples required less energy for gelatinization during DSC analysis. Ohmically heated commercial starch showed the greatest decrease in enthalpy probably because of the greatest extent of pregelatinization through ohmic heating. Brown rice flour showed the greatest gelatinization temperature resulting from the delay of starch granule swelling by lipid and protein. Enthalpy of ohmically heated starches at 20 V/cm was the lowest, which was most likely due to the lower voltage resulting in a more complete pregelatinization from a longer heating time required to reach 100 degrees C. Ohmic treatment at 70 V/cm decreased onset gelatinization temperature of white flour; therefore, it produced rice flour that swelled faster, whereas the conventionally heated sample showed a better thermal resistance.