Thick layer microwave drying of brown rice

Abstract: The microwave drying problem of thick brown rice under downstream ventilation was studied. The experimental results show that with the increase of microwave power, the temperature and drying speed of brown rice increase. If the power of the microwave drying equipment is controlled within the range of 0.05 to 0.9 kW / kg, the wind speed is controlled within the range of 0.12 to 0. 20 m / s, so that no bursting and germination rate reduction can be ensured. And other quality issues.

And the effective dry thickness of the brown rice is about 0.130 m, which is greater than the effective dry thickness of the rice under the same conditions. The efficiency of drying brown rice under microwave heating is higher than that of rice drying.

Key words: brown rice microwave drying; thick layer; ventilation; downstream

Introduction
Dry rice drying has many advantages over traditional rice drying. First, since there is no rice husk, it is not necessary to dry the moisture of the rice husk portion. Secondly, the evaporation of water is not hindered by the gap between the rice outer shell and the rice hull and the granules, which can increase the drying speed and save energy, and can also improve the volumetric efficiency of the drying and storage equipment.

At the same time, the production efficiency of the drying equipment can also be increased by about 60%, and the drying cost can be greatly reduced. To achieve the same wet water content of 14% of the final moisture content, rice drying takes 11 h, while brown rice drying takes only 5 h. Therefore, the drying efficiency can be greatly improved.

In Japan, rice is first processed into brown rice for further processing and storage. Since brown rice does not have the outer shell protection like rice, it is easy to cause problems such as bursting during the drying process. Microwave drying is a new drying technology developed in recent decades.

Although China has made great progress in the research and development of drying technology and equipment for rice in recent decades, the research and application in the drying, processing and storage of brown rice are still in the initial stage of exploration.

In addition, with the continuous improvement of the level of technology and the reduction of equipment prices, the application of microwave drying is becoming more and more extensive. Therefore, it is necessary to study the reasonable microwave drying process and equipment of brown rice. But so far there is no research report in this area. The purpose of this study was to investigate and investigate the microwave drying process of brown rice.