Determination of Shelf Life of Milled Rice Stored at Different Temperatures

An experiment on milled rice storage was conducted to investigate storage properties and determine "best before" date. Conventional milled rice and rinse-free rice were stored in incubators controlled at temperatures from -20°C to 25°C for one year. Physicochemical properties such as free fat acidity, appearance of cooked rice, hardness and stickiness of cooked rice were examined. Sensory tests were also carried out to assess eating quality. There was very little quality deterioration of rice stored at low temperature. The higher the temperature was, the greater quality degradation was. Best before date of milled rice at each storage temperature was shown by eating quality assessed by a sensory test, which was considered the most important measurement item to determine best before date. In this study, best before dates of conventional milled rice stored at 25°C, 15°C and 5°C and less were one month, five months and seven months, respectively. Those of rinse-free rice stored at 25°C and 15°C and less were one month and seven months, respectively.Written for presentation at the 2006 ASABE Annual International Meeting Sponsored by ASABE Oregon Convention Cente

Physical Properties of NERICA Compared to Indica and Japonica Types of Rice

In Africa, rice production has been increasing due to the contribu-tion of NERICA rice. However, in-formation on physical properties of NERICA is required for designing efficient equipment for its produc-tion and expansion. Consequently, the physical properties of NERICA were compared to the Indica and Japonica types of rice. The NERICA and Indica types indicated similar-ity in dimensions of rough rice and in physical properties of milled rice. This result suggested that technol-ogy used for processing Indica rice could be transferred and inserted in countries where NERICA produc-tion has been expanding

A Glance at Aflatoxin Research in Mozambique

In Mozambique, aflatoxin research started in the 1960’s and has been carried through apparently unrelated efforts according to opportunities. However, they can be grouped in two sets: early epidemiological studies and recent agricultural research. Early investigators found a strong correlation between aflatoxin contamination and primary liver cancer. Since then, there have been efforts to examine the extent of contamination, especially in groundnuts and maize. More recent investigations and interventions aimed mostly to reduce the level of contamination, enough to allow such commodities to gain acceptance in the international market. The current status of knowledge is still marginal but the increasing involvement of local authorities, academia, and international organizations seems promising

Rice Quality Preservation during On-Farm Storage Using Fresh Chilly Air

A new technique for storing rice at a temperature below ice point using fresh chilly air was developed. Freezing temperatures and extents of freezing injury of rice with various levels of moisture content were studied, and effects of temperature below ice point during a four-year storage period on the physiological properties of rice were investigated. Rice with moisture content of less than 17.8% did not freeze even at a temperature of -80°C. Low temperature maintained the vitality of rice, minimized physiological activities and starch deterioration in rice, and preserved rice quality. One thousand tons of rough rice was stored in two silos from the end of November 1999 and was aerated from the bottom to top of each silo using fresh chilly air in January 2000. The rough rice temperature fell below ice point. At the end of July 2000, the rough rice temperature in the center of each silo was still below ice point. The rice quality stored in the silos was preserved at a level similar to that of freshly harvested rice. A combination of rice storage below ice point and utilization of fresh chilly air enables the rice quality to be preserved at a high level without the requirement of a cooling unit or electricity. The use of this storage technique has been increasing in cold regions after the on-farm experiment. In Hokkaido, the northernmost island in Japan, 26 grain-elevators have been constructed since 1996. The storage capacity of rough rice was 115,000 t at the end of 2003.Proceedings of "International Quality Grains Conference : a Global Symposium on Quality-Assured, Traceable and Biosecure Grains and Oilseeds for the 21st Century" in July 19-22, 2004.http://www.iqgc.org

Development of On-farm Storage Technique for Rice at Temperature below Ice Point Using Ambient Naturally Cold Air in Winter

The objective of this project was to develop a new on-farm storage technique for rice at a temperature below ice point using ambient naturally cold air in winter. In an on-farm storage experiment, 994 tons of rough rice was stored in two silos from the end of November 1999, and the rough rice was aerated from the bottom to the top of each silo for 91 hours in January 2000. The rough rice temperature in each silo fell down below ice point (minus 1.5 degrees Celsius on average). At the end of storage (end of July 2000), the temperature of rice grains in the center of each silo was kept still below ice point (minus 0.5 degrees Celsius). The quality of the rice stored in the silos was thereby preserved at a level similar to that of freshly harvested rice. A combination of rice storage at a temperature below ice point and utilization of ambient cold air in winter enables the quality of rice to be preserved at a high level without the requirement of a cooling unit or electricity.Written for presentation at the 2001 ASAE Annual International Meeting Sponsored by ASA

Accuracy of Near-infrared Transmission Spectroscopy for Determining Rice Constituent Contents and Improvement in the Accuracy

The accuracy in determination of rice constituent contents using a commercial near-infrared transmission (NIRT) instrument was validated. And the accuracy of measurements using this instrument was improved by modifying light filters and calibration equations used in the instrument. In the determination of moisture content, the coefficient of determination (r2) was 0.98, standard error of prediction (SEP) was 0.13%, and bias was -0.02%. In the determination of protein content, r2 was 0.90, SEP was 0.17%, and bias was 0.01%. These results show that the newly developed instrument is sufficiently accurate to be used instead of reference analysis for measuring moisture content and protein content of brown rice. An automatic rice-quality inspection system was designed. The system consisted of a rice huller, a rice cleaner, an NIRT instrument and a visible light (VIS) segregator. Based on rice-quality information, this system enables rough rice transported to a rice grain elevator to be classified into six qualitative grades.Written for presentation at the 2002 ASAE Annual International Meeting / CIGR XVth World Congress Sponsored by ASAE and CIGR Hyatt Regency Chic

Development of a New Technique for Fine Sorting of Brown Rice by Use of a Combination of a Thickness Grader and a Color Sorter

A research project was conducted to develop a new technique for fine sorting of brown rice by the use of a combination of a thickness grader and a color sorter in order to increase sorting yield and improve rice quality. It was found that a greater sorting yield and processed rice of high quality can be obtained by reducing sieve slot width of the thickness grader by 0.10 mm from the conventional standard slot width and then removing immature, damaged and discolored kernels by the combined use of a color sorter. By using the brown rice fine sorting technique developed in this study, rice farmers’ income can be increased and high -quality rice can be supplied to consumers.Written for presentation at the 2007 ASABE Annual International Meeting Sponsored by ASAB

The Use of Colors as an Alternative to Size in Fusarium graminearum Growth Studies

Size-based fungal growth studies have limitations. For example, the growth in size stops in closed systems once it reaches the borders and poorly describes metabolic status, especially in the stationary phase. This might lead mycotoxin studies to unrealistic results. Color change could be a viable alternative, as pigments result from a mold's metabolic activity. This study aimed to verify the possibility of using gray values and the RGB system to analyze the growth of Fusarium graminearum. It consisted of color and area measurements using ImageJ software for specimens grown in yeast extract agar (YEA). The results suggest the utility of color and gray values as reliable tools to analyze the growth of F. graminearum

Development of a System for Fine Cleaning of Rough Rice for High-Quality Storage

Bulk rough rice after drying consists of sound whole kernels, immature kernels, empty kernels, damaged kernels, hulled kernels and foreign materials such as straw, weed seed and dust. Fine cleaning of rough rice is an important step after drying to improve rough rice quality and to minimize quality deterioration of rough rice during storage. We developed a system for fine cleaning of rough rice. The system consists of a wind separator, gravity separator and indented cylinder separator. The wind separator removes straw, weed seed, dust and empty kernels by means of an air stream. The gravity separator discharges four streams of material: a mixture of sound whole kernels and hulled kernels; good rough rice product (mostly sound whole kernels); a mixture of sound whole kernels, damaged kernels and immature kernels, which is returned through the wind separator and gravity separator to achieve a complete separation; and a mixture of damaged kernels, immature kernels and empty kernels that is removed from the line. The indented cylinder separator removes hulled kernels from the mixture of sound whole kernels and hulled kernels discharged from the gravity separator. The sound whole kernels separated by the indented cylinder separator are mixed with the good rough rice product from the gravity separator. The fine cleaning system developed in this study enables separation and removal of immature kernels, empty kernels, damaged kernels and hulled kernels and therefore improvement in rough rice quality. The fine cleaning system has been in practical use in Japan.Written for presentation at the 2006 ASABE Annual International Meeting Sponsored by ASAB