These days, using the microwave drying technique is a surefire way to acquire the best quality foods with little to no moisture content. This is supported by the fact that, compared to more traditional drying techniques like hot air drying, spray drying, and drum drying, microwave drying is quicker, more energy-efficient, and more consistent. The manufacture of premium dehydrated foods has greatly benefited from temperature-controlled microwave drying. The most appropriate and precise method for determining the temperature of samples inside a microwave is fiber optic temperature sensor technology.
Microwaves are electromagnetic waves with a frequency range of 300 MHz to 300 GHz and a wavelength ranging from 1 millimeter to 1 meter. Many enterprises and homes use microwaves to heat things up more quickly. The food, fruits, vegetables, and livestock are all dried using a microwave heating method identical to this one.
Traditional food drying techniques had a lot of drawbacks. During the drying process, a number of food-related variables, including moisture content, temperature, mass, color, surface texture, etc., may change significantly. The most impactful aspects of food ingredients are their dielectric characteristics. The food items tend to shrink when dried using standard procedures in the final step.
In contrast to traditional drying, microwave drying is quicker and can increase the drying rate from the starting stage to the final stage. This aids in keeping the dried food's quality, color, texture, and flavor intact. Additionally, food shrinking during the drying process is prevented by microwave drying.Compared to other conventional drying methods, the goal of industrial microwave drying processes is to produce food items of higher quality quickly, effectively, affordably, and cheaply.
When drying food in a microwave, temperature monitoring is essential for maintaining the highest level of quality control. The drying temperature and the quality of the finished product are influenced by microwave power and duration. Long-term, high-power microwave cooking can result in burned food and poor color, flavor, texture, and quality. Because of this, cyclic microwave heating is used as opposed to continuous microwave heating. In cyclic microwave heating, real-time temperature monitoring and control are essential.
Because they cause sparks inside microwaves, conventional temperature sensors like thermocouples and RTDs cannot be utilized in microwave drying. Microwave heating applications use infrared thermal imaging sensors because they are contactless. The following functions of infrared sensors are imitated in temperature monitoring in microwave drying:
1. The sensors' accuracy is poor since it depends on the food's accurate emissivity constant.
2. The sensors can't be used in a microwave with a lengthy conveyor belt.
3. The sensors need routine calibration and maintenance, including cleaning and lens replacement.
The severe microwave environment of 300 MHz to 300 GHz and the radiofrequency of 100 kHz to 100 MHz can't stop the fiber optic sensors from performing well. Particularly strong, precise, and secure fiber optic temperature sensors based on gallium arsenide technology make them ideal for microwave-assisted food drying applications. In applications involving microwave drying, these sensors provide the following benefits:
1. Secure sensors; no chance of sparks or arching inside the microwave
2. Durable sensors that are more reliable
3. Biosafe, with no chance of contaminating food.
4. Perfect for microwaves with lengthy conveyor belts
5. Extremely precise from -100 °C to +300 °C over a large temperature range.
6. Sensors and monitors with no maintenance
7. There is no requirement for temperature correction or calibration.
A major innovation in the food service and packaging sectors is the use of microwaves to dry food ingredients. The primary shortcomings of conventional drying have been mitigated. The use of microwave drying includes, but is not limited to, the following areas:
Many forages and hay bales are dried in microwave ovens to remove moisture. It quickly and effectively dries the feed, but in order to prevent full or partial damage to the feed, it's crucial to keep an eye on the oven's temperature. In order to control, monitor, and report real-time temperature changes in order to improve quality and reduce losses in animal feed, the gallium arsenide-based fiber optic temperature sensor is used in this situation.
A food preservation technology called crisp drying is used to preserve food, primarily fruits, by lowering moisture content, delaying microbial growth, and extending shelf life while reducing other key costs (transportation and storage). As was already said, our fiber optic technology is essential for maintaining the quality and freshness of food goods while they are being dried.
When it comes to the dry preservation of cereal grains, vegetables, and flowers, microwave vacuum drying is quite common. For instance, dried carrots and onions are preserved for a longer period of time, and grains are pasteurized in microwave and RF ovens, among other things. GaAs-based fiber optic sensors are frequently used to monitor microwave drying process temperatures. Additionally, this technology aids in minimizing production loss while drying.
Comparing microwave drying to conventional drying, it has been found to be the faster, more energy-efficient method of drying. When compared to traditional procedures, using a microwave during freeze-drying could reduce drying time by 95% to 98%. More importantly, microwave drying results in a product with greater rehydration properties and a higher quality. For uniform microwave heating and better output, real-time temperature monitoring and control are essential. For effective temperature control in microwave drying, the best technology currently on the market is fiber optic temperature sensing. Other industrial uses for microwave heating include pasteurization, sterilization, extraction, synthesis, digestion, and many more. The use of microwaves for heating and related purposes is expanding globally. All RF and microwave heating applications have a rising need for fiber-optic temperature sensors.