I don't know if you have such feelings when heating in the microwave oven: if you heat a piece of Braised pork belly or a piece of preserved fruit for dozens of seconds, the temperature will rise significantly faster, while the temperature of vegetables with simple water content will rise more slowly. In food processing and production, it can also be seen that high sugar snacks and braised meat products have a significantly higher heating rate when microwave treated than ordinary materials, which is closely related to the composition of the materials themselves.
The essence of microwave heating is to generate heat by high-speed vibration and friction of polar molecules inside the material in an electromagnetic field. Water is a polar molecule that easily absorbs microwave energy. Sugar, protein, and oil in meat are also polar substances that can absorb microwaves.
Foods with high sugar content have polar sugar molecules that absorb microwave energy together with water molecules. Sugar solution has high viscosity, and the heat generated by molecular friction is not easily dissipated outward. The heat is more likely to accumulate inside the material, and the temperature rise will be faster. Products such as candied fruits and sugar coated puffed snacks should be handled with extra care to prevent local overheating, caramelization, bitterness, and discoloration.
Looking at meat products again, braised and marinated meat not only contains water, but also protein, oil, and pickling seasonings. The protein molecules and oil molecules of meat can absorb microwaves, and multiple polar substances can absorb energy simultaneously, resulting in higher heat production efficiency. The meat structure is relatively dense, with slow heat loss, and the heating rate is naturally faster than that of simple water containing ingredients.
Compared to ordinary fruits and vegetables, only water molecules absorb microwaves, making it easier for heat to evaporate and dissipate, resulting in a much milder heating rate.
In practical production and processing, this characteristic needs to be carefully controlled. When processing high sugar foods and meat products, it is often necessary to lower the microwave power or increase the conveyor belt speed to avoid burning and flavor damage caused by rapid heating. Reasonably adjusting the process can not only achieve drying and sterilization, but also preserve the original taste and color of the ingredients, reducing the production of defective products.
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