Dielectric properties (DPs) of two beverages, tamarind and a green drink (based on mix fruits of pineapple, guava, lemon, and nopal), were studied. The DPs were determined using the open-ended coaxial probe method in the frequency range from 0.25 to 25 GHz at 10, 30, 50, and 70 °C. The dielectric constant decreased when both frequency and temperature increased above 1000 MHz. For both beverages, the dielectric loss factor increased with increasing frequency and increasing temperature. In addition, dielectric constant values ranged from 59.7 to 82.5, and the dielectric loss factors were between 5.8 and 31.1. The penetration depth (dp ) of electromagnetic waves in the beverages increased proportionally to temperature at frequencies above 1000 MHz; dp values ranged from 0.2 to 7.5 cm. Because of its complexity and the amount of ingredients and the interactions between them, the green drink showed higher values of dielectric constants in comparison with the tamarind beverage. PRACTICAL APPLICATION The dielectric properties of the studied beverages, how they behave at different temperatures, and the penetration depth reached by microwave at the allocated frequencies, provide important parameters for further heating treatments, such as heating (microwave-assisted pasteurization) and for modeling/simulation purposes.

中文翻译：

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与微波辅助巴氏杀菌相关的饮料（罗望子和绿色）的介电特性

研究了两种饮料罗望子和绿色饮料（基于菠萝、番石榴、柠檬和胭脂树的混合水果）的介电特性 (DPs)。在 10、30、50 和 70 °C 下，使用开放式同轴探头方法在 0.25 至 25 GHz 的频率范围内确定 DP。当频率和温度都增加到 1000 MHz 以上时，介电常数下降。对于这两种饮料，介电损耗因数随着频率的增加和温度的升高而增加。此外，介电常数值介于 59.7 到 82.5 之间，介电损耗因子介于 5.8 到 31.1 之间。在高于 1000 MHz 的频率下，饮料中电磁波的穿透深度 (dp) 与温度成正比增加；dp 值范围为 0.2 至 7.5 厘米。由于其复杂性和成分的数量以及它们之间的相互作用，与罗望子饮料相比，绿色饮料显示出更高的介电常数值。实际应用 所研究饮料的介电特性、它们在不同温度下的表现以及微波在指定频率下达到的穿透深度，为进一步的加热处理提供重要参数，例如加热（微波辅助巴氏杀菌）和建模/模拟目的。