Infrared heating can have little influence on dried rice physicochemical properties.
Heating products using infrared radiation has shown great promise for achieving high drying rates and good milling quality for rough rice, and for effectively stabilizing rice bran.
Scientists at the University of California at Davis characterized the changes in the pasting, thermal and cooking properties of infrared-dried rice during storage. They found that drying the product using infrared heating at a temperature of 60 C, followed by 4 hours of tempering and natural cooling, has no adverse effects on the physicochemical properties of rice during storage.
Freshly harvested medium grain rice with a moisture content of 0.2% was used in this research. The researchers divided the samples into three portions. They were dried using infrared heating, hot air and ambient air. For infrared heating, the samples were heated to temperature of 60 C using a catalytic emitter under a radiation intensity of 5348 W per [m.sup.2]. This treatment was followed by tempering and naturally cooling the samples for 4 hours.
All of the dried rice was stored at 35 C for 10 months. The scientists determined the pasting and thermal properties, texture attributes, water uptake, volume expansion ratio and solid loss during cooking during the storage period.
The investigators observed similar trends among the samples when analyzing the properties of rice dried using infrared heating, hot air and ambient air. The peak viscosity and breakdown of the samples increased within the first four months of storage and then decreased.
The peak viscosity of the infrared-dried rice samples was less than that of those rice samples dried with hot and ambient air. There was no significant change in the thermal properties among the rice samples tested.
Cooking properties, including volume expansion, water uptake, solids loss and texture, changed in a similar fashion for rice samples dried using infrared heating, hot air and ambient air. Further information. Zhongli Pan, Department of Biological and Agricultural Engineering, 3018 Bainer Hall, University of California, Davis, CA 95616; phone: 530-752-4367; email: email@example.com.
Additional research covering the effects of infrared radiation on the physicochemical properties of rice during storage is needed.
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|Publication:||Emerging Food R&D Report|
|Date:||May 1, 2016|
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