Pérez-Campos Rafael, Fayos-Fernández José, Monzó-Cabrera Juan
Departamento de Tecnologías de la Información y las Comunicaciones, Universidad Politécnica de Cartagena, 30202, Cartagena, Spain.
Curr Res Food Sci. 2023 Jun 2;6:100528. doi: 10.1016/j.crfs.2023.100528. eCollection 2023.
Quinoa is a nutrient-rich pseudocereal that is gaining popularity in European countries since it is gluten-free and an interesting source of fat, proteins, minerals, and amino acids. However, up to date, the electric permittivity of quinoa seeds has not been measured and, therefore, this hampers the possibility of designing optimized recipes for its microwave processing. In this work, the permittivity of both raw and boiled quinoa seeds is measured around 2.45 GHz at several conditions for temperature, moisture content, and bulk density. The grain kernel permittivity is also estimated from the Complex Refractive Index (CRI) mixture equation and different bulk density measurements. The obtained results show different temperature behaviours for raw and boiled seeds, whereas the permittivity of quinoa seeds versus moisture content and bulk density was as expected: the permittivity (both the dielectric constant and loss factor) levels increased as the observed variables did. From the measured data, it can be concluded that both raw and boiled quinoa can be processed with microwave technology, although care must be taken with raw quinoa grain kernels since the permittivity increases significantly with temperature, and a thermal runaway may occur.
藜麦是一种营养丰富的假谷物，由于其不含麸质，并且是脂肪、蛋白质、矿物质和氨基酸的有趣来源，在欧洲国家越来越受欢迎。然而，到目前为止，尚未测量藜麦种子的介电常数，因此，这阻碍了为其微波加工设计优化配方的可能性。在这项工作中，在温度、水分含量和堆积密度的几种条件下，测量了生藜麦种子和煮过的藜麦种子在2.45 GHz附近的介电常数。还根据复折射率（CRI）混合方程和不同的堆积密度测量值估算了谷物颗粒的介电常数。所得结果表明，生种子和煮过的种子具有不同的温度行为，而藜麦种子的介电常数与水分含量和堆积密度的关系符合预期：随着观察变量的增加，介电常数（介电常数和损耗因子）水平也增加。从测量数据可以得出结论，生藜麦和煮过的藜麦都可以用微波技术进行加工，不过对于生藜麦谷粒必须小心，因为介电常数会随温度显著增加，可能会发生热失控。
