摘要
基于一种同轴探头网络分析仪技术和混合方程的途径研究微波加热馒头的介电特性。测量馒头在不同密度下的介电特性值,运用回归分析方法得出介电特性与频率的关系,通过比较馒头介电特性混合方程计算值和测量值,得到Bottcher方程适用于计算馒头的介电常数,Landau and Lifshitz,Looyenga方程用于计算馒头的损耗因子。研究频率范围915~2 450 MHz、含水率范围40.12%~48.50%(w.b.)和温度范围25~100℃下馒头介电特性的变化规律。研究表明:馒头的介电常数随着频率的增加而减小,损耗因子随着频率的增加呈现出先减小后很缓慢增大的趋势;介电常数和损耗因子均随含水率和温度的增加而增加。馒头微波加热的穿透深度随着各影响因素的增加而减小,且在25~100℃温度范围内,915 MHz和2 450 MHz微波加热馒头最大厚度分别不超过12.82 cm和10.62 cm。
A method based on network analyzer with an open-ended coaxial cable and mixture equations was used to analyze dielectric properties of Chinese steamed bread by microwave heating. Dielectric properties of Chinese steamed bread were measured under the different densities. Regression analysis method was used to get the relationship between dielectric properties and frequency. By comparing the measured values of dielectric properties with the calculated ones,the Bottcher equation was obtained for the calculation of dielectric constants and the Landau and Lifshitz,Looyenga equation for loss factors. The effects of frequency（915-2 450 MHz）,moisture content（40.12%-48.50%（w.b.） ） and temperature（25-100 ℃） on dielectric properties were studied. Results showed that dielectric constants decreased with the increased frequency,loss factors first decreased then slowly increased with the increased frequency. Both dielectric constants and loss factors increased with increased temperature and moisture content. The penetration depth of Chinese steamed bread in microwave heating decreased with the increased factors. Within the temperature range of 25-100 ℃,the optimal thickness of steamed buns at 915 MHz and 2 450 MHz in microwave heating was 12.82 cm and 10.62 cm,respectively.
作者
宋春芳
王燕
张翰之
余华杰
崔政伟
朱海清
SONG Chunfang WANG Yan ZHANG Hanzhi YU Huajie CUI Zhengwei ZHU Haiqing(Jiangsu Key Laboratory of Advanced Food Manufacturing Equipment and Technology ,Jiangnan University, Wuxi 214122, China School of Mechanical Engineering, Jiangnan University, Wuxi 214122, China)
出处
《食品与生物技术学报》
CAS
CSCD
北大核心
2017年第5期466-472,共7页
Journal of Food Science and Biotechnology
基金
国家自然科学基金项目(21606109
51401086)
江苏省产学研-前瞻性联合研究项目(BY2016022-10)
关键词
馒头
微波加热
介电特性
混合方程
微波穿透深度
Chinese steamed bread,microwave heating,dielectric property,mixture equation, penetration depth
