After secondary processing, such as forming, coating or heat treatment, food products are ready to be chilled and frozen. This process step not only influences food product quality, food safety, storage and logistics but it also affects your plant efficiency and energy use. So, how to measure and regulate the freezing process accurately?
In freezing, air temperature control is measured and regulated by the evaporating temperature of the refrigeration system or – for more accuracy – through temperature sensors inside the spiral freezer. The main goal of frozen food processors is however, monitoring and control of the product temperature when products exit the freezer.
In fact, product temperature at spiral freezer discharge is usually measured manually with a temperature sensor placed among products in a carton, in order to get an average, product-equilibrated temperature. This offline and manual temperature monitoring is often less accurate and not continuous, which affects the traceability of freezing process. In addition, no real-time control is possible in case of deviation from the desired product temperature. To compensate for the accuracy of product temperature measurement and make sure the end-product is frozen enough at freezer discharge, food processors are generally setting a lower product temperature value as target, which results in unnecessary higher consumption of energy.
So, how could this issue be resolved?
Freezing water into ice is one of the best-known crystallization processes. Being able to measure the phase-state of water directly, provides an absolute value in real-time of the "level-of-frozenness", and thus gives a most accurate parameter in the product freezing process. GEA CALLIFREEZE® system is based on the electromagnetic wave principle and is able to answer this issue.
Mathieu Nouhin, GEA’s Product Manager Freezing, explains: GEA CALLIFREEZE® is an innovative system for spiral and tunnel freezers and provides continuous measurement of product level-of-frozenness and temperature at the freezer exit.
’If you cannot measure it, you cannot improve it‘‘
These are the words by Sir William Thomson, 1st Baron Kelvin, a mathematical physicist, who gave his name to the absolute temperatures units of Kelvin. It applies perfectly to freezers when product frozen condition is not measured continuously and therefore eliminates any possibility for inline process optimization. Thanks to CALLIFREEZE® we can monitor and control continuously the product level of frozenness and temperature allowing a continuous optimization of freezing process.
During the process, minimum of energy consumption is achieved. CALLIFREEZE® benefits are proven on several spiral freezers and IQF tunnel freezers operating with the system. The system can be configured for freezers handling a wide range of food products, including meat, poultry and fish, ready meals, bakery and dairy products.
What is the next innovation in inline product measurement?
Looking into inline product monitoring, we see the need to be able to measure and control the moisture content of the end-product, says Mathieu Nouhin. The right balance between dry matter and moisture content does not only influence weight and yield, it is an important indicator of product quality and nutritional value. Moreover, for certain foods – such as French fries – moisture content is also part of the necessary product specifications that the food industry needs to comply to.
Using the same electromagnetic wave technology on which CALLIFREEZE® is based, GEA is able to develop an inline moisture measuring sensor system, which can be placed before the freezer. This will give food processors the opportunity to control and adjust the parameters influencing the moisture content in the Fryer and the Dryer, and therefore gain even more control of their product production process.
Would you like to learn more on how to optimize your freezing process? Get in touch with one of our experts via the 'Contact us' button below.