Temperature Control Systems in the Food Industry

Temperature is an essential part of many processes within the food industry. This is evident in the uninterrupted cold chain, a sufficiently high temperature during processing, and a constant temperature fermentation, however there are many other processes where temperature is essential also.

They range from testing and calibrating flow sensors, to pre-temperature conditioning individual ingredients when developing new recipes, to maintaining a constant temperature in water baths. Without precise temperature management in the manufacturing and processing procedures, food products such as chocolate, for example, would lose everything we love it for.

Temperature Control Systems for the Calibration of Flow Sensors

Liquid ingredients and products are transported through pipelines within the food industry. The viscosity and flow rate changes on certain food items depending on the temperature. Flow sensors measure the flow rate of the food to ensure consistent flow. This helps optimise production output and is necessary to coordinate the systems in filling or portioning.

External influences, such as deposits on the measuring sensors, can lead to their measuring accuracy decreasing over time or the defined measuring tolerances changing. To ensure precise measuring results and optimum process control, the flow sensors must be calibrated regularly. High-precision temperature control systems are used for this purpose. They allow precise calibration and control of the flow sensors. Calibration conditions must be as close as possible to the application, as the measuring accuracy relies on the ambient conditions.

Stress Tests of Flow Sensors

Before measuring sensors can even be used in the manufacturing process, they must undergo numerous suitability tests. Temperature stress tests where the flow sensors are subjected to substantial alternating temperatures are also included. Highly dynamic and quick temperature control systems from 20 to +40°C can simulate alternating low and high shock temperature. The extreme temperature differences stress the material and the precision of the measurement electronics. A flow sensor that is not influenced significantly by the substantial temperature fluctuations needs to be used in the food industry.

Temperature Control when Developing New Recipes

The temperature control systems perform valuable tasks in food industry laboratories. Work is continuously carried out on new recipes and products, for optimising the taste of food items, and the pressure. All parameters need to be regulated according to laboratory standards to ensure 100% reproducibility.

The temperature of the ingredients at the time of addition determines both the binding behaviour and consistency of the product, as well as influences the release of aromas and taste. To optimise a recipe and for a consistent result, precise pre-conditioning of the ingredients and precisely constant water temperature is therefore essential. Due to the wide range of requirements, highly variable temperature control systems as refrigerated circulators are mainly used here. They are characterized by a wide working temperature as well as flexible and sophisticated connection and control systems.

Temperature Control Application in the Food Industry using Chocolate as an Example

The base of chocolate consists of cocoa mass, cocoa butter, sugar, and milk. Each variety of chocolate has its own mixing ratio, which is regulated by law. Spices and aromas can also be added into these mixtures. The specific recipes, along with the duration and temperature control of individual process steps, are among the best-kept company secrets. 

The ingredients are first mixed in a kneading mixer then the mass then passes through a rolling mill where its consistency is refined to particle sizes of 0.02 mm. The mass is then stirred and kneaded (conched) in special stirring equipment, known as a conche, for several days at temperatures between 55 and 90 °C. This process causes the bitter substances of the cocoa to evaporate, and the chocolate acquires its perfect consistency and full aroma.

After conching, the chocolate mass is cooled down, whereby a specific temperature curve must be maintained for each variety of chocolate. This is necessary because the chocolate forms crystalline structures during cooling and hardening. Depending on the temperature, up to six different crystal shapes are created. One of the crystal shapes produces the perfect chocolate with a pleasant colour, shiny surface, good hardness, and breaking properties along with a delicate melting consistency. This crystal shape is stable in dark chocolate up to 34.5 °C, while the five unwanted crystal shapes melt starting at a temperature of 27 °C. The chocolate mass is therefore reheated according to a precisely defined temperature profile. The ideal processing temperatures for dark chocolate are between 31 and 32 °C (milk chocolate: 29-30 °C; white chocolate: 27-28 °C). The crystal shape that is stable and desired at this temperature ensures that the re-liquefied mass takes on the same crystal structure when it cools down again. For this reason, the temperature control application in chocolate production is also referred to as pre-crystallization. 

In addition to the final temperature to be reached, the temperature sequence also has a significant influence on the crystallization, fast-reacting, and precisely adjustable temperature control systems as heating circulators are used in chocolate production. They allow complete process automation and ensure a consistently high quality of the chocolate.

Conclusion

Temperature control systems are used at many points in the production process in the food industry. They optimise and calibrate the production systems as well as guarantee a consistently high quality of the end products. Chocolate production has been simplified since the development of state-of-the-art temperature control systems with precisely adjustable temperature windows and temperature curves.

Here at Lab Unlimited, we offer temperature control systems and circulators that are used in numerous food processing plants. Our refrigerated circulator baths can be perfectly tailored to your requirements, so that expensive custom-made products are not necessary. Please get in contact with a member of our sales team today!

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