[Nikkei BP agency reports]
Toshiba Consumer Marketing introduced IH (Electromagnetic Induction Heating) rice cooker "RC-10VS" and "RC-18VW" (FIG. 1) that reduce the pressure inside the pan to 0.6 atm through a vacuum pump. Love is called "vacuum pressure rice cooker." According to the company, the product is the first rice cooker to reduce the pressure using a vacuum pump. Through the decompression, you can receive the following effects: (1) the moisture content of rice reached the desired value of 28% to 29%, (2) to prevent oxidation of the insulation. RC-10VS with a capacity of 1.0L is priced at 97,700 yen, and the RC-18VW with a capacity of 1.8L with a listing date of September 20, 2006 is priced at ¥ 101,850 with a listing date of October 1, 2006 day.
During the cooking process, the water-immersion process in the rice largely affects the quality of the rice. Rice on the market for long-term preservation, the rice has been dried, water cut to about 15%. Therefore, some experts said that rice should be immersed in water for about 2 hours. In general, rice is soaked in water for a long time due to the air contained within the rice. The use of this new rice cooker, the pressure will be reduced to 0.6 by a vacuum pump, thereby releasing the air inside the rice, making rice more easily soaked. In this way, with the same immersion time as the original, it is guaranteed that the desired water content is 28 to 29%, and water is allowed to permeate the inside of the rice (Figure 2).
Due to the overall inhalation of rice moisture, cooked rice is not easy to lose moisture, moisture content of about 63%. After 5 hours still as high as 62 ~ 63% (Figure 3). When using the company's original product, the water content is 26-27% when soaking, about 62% after cooking and 60-61% after 5 hours. Natural water takes about 2 hours, the water content increased to 30%, but the water is only infiltrated to the surface of rice, cooking, prone to broken flowers. Although about 64% of the water is cooked after cooking, it drops to 62% in five hours and further loses moisture over time.
Another effect is to prevent the oxidation of insulation. Decompression by the vacuum pump, can reduce the concentration of oxygen in the pot, to prevent the unsaturated fatty acids contained in rice thermal reaction caused by oxidation. In addition, the hermeticity required for the vacuum state is increased, drying of rice is prevented, and yellowing of rice is prevented by drying. In terms of water content, it is still 62-63% within 32 hours after cooking.
In order to achieve the vacuum decompression function, equipped with a vacuum pump and vacuum solenoid valve (Figure 4). Because the rice cooker needs to withstand high temperature water vapor up to 110 ℃, the company has also developed a high temperature, high humidity vacuum pump in cooperation with a manufacturer. Due to the pressure cooker has been used before, has improved the closure of the inner cap and pressure regulator valve and so on. This time by further improving hermetic vacuum decompression function.
Rice cooker began to consider energy saving
Toshiba in the product uses a vacuum insulation and other adiabatic structure, improve the energy-saving insulation performance. The average hourly power consumption of RC-10LY without heat-insulating structure was 28.5Wh, while the average hourly power consumption of RC-10VS was only 14.46Wh, a decrease of 14%. This vacuum insulation material is made of aluminum vacuum sealed glass fiber, thickness 3mm, thermal conductivity of 1mW / (m · K). In order to cover the inner pot with a layer of vacuum insulation material, the softness is improved and the bending process is realized by studying the glass filament diameter, the weaving method and the density. Previously the company has successfully developed vacuum insulation for the refrigerator. This time as a rice cooker insulation materials, the heat resistance from the refrigerator for 60 ~ 70 ℃ increased to 130 ~ 140 ℃.