稻谷热风与真空干燥特性及其加工品质的对比研究

Comparision research on drying characteristics and processing quality of rice by hot-air and vacuum drying

比较稻谷热风与真空干燥特性及对其加工品质的影响,为有效改善稻谷加工品质提供依据。通过对初始水分为26.5%的稻谷进行热风和真空干燥试验,研究热风干燥和真空干燥对稻谷的干燥特性和其加工品质的影响。结果表明:干燥温度越高,稻谷的平均降水速率越大,且真空干燥平均最大降水速率大于热风干燥平均最大降水速率;热风干燥在干燥开始后的5～10min降水速率出现最大值,真空干燥在干燥开始后的5～15min降水速率出现最大值。随着干燥温度的升高,稻谷的爆腰率上升,出糙率和整精米率下降;相同的干燥温度下,真空干燥稻谷的加工品质优于热风干燥稻谷的,其中爆腰率最为明显。对于高水分稻谷采用真空干燥可以提高稻谷的加工品质。

The drying characteristics ard processing quality of rice by hot-air and vacuum drying were studied. The objective was to provide optimum process conditions for improving the processing quality of paddy rice. The effect of hot-air and vacuum drying on drying characteristics and processing quality of rice with the initial moisture content of 26. 5% were investigated. Results showed that the average drying rate is proportional to the drying temperature; the average drying rate under the vacuum condition is larger than that under the hot-air condition; the drying rate reaches the maximal value in 5-10 min after the drying beginning for the hot-air drying, and 5-15 rain for the vacuum drying. The ratio of rice kernel cracking is proportional to the drying temperature,brown rice yield and whole kernel yield is inverse proportional to the drying temperature. The processing quality of rice by vacuum drying is better than it by hot-air drying under same drying temperature condition, of which the ratio of rice kernel cracking is most obvious. Vacuum drying can improve processing quality to high-moisture paddy rice.