Rheology and How it Affects Food Perceptions

Rheology and How it Affects Food Perceptions

Rheology studies the flow of matter, mainly in a liquid state but also as ‘soft’ solids. This is becoming extremely useful when it comes to studying the various states of food, and rheological variables can help fine tune food perceptions. For example, suspension viscosity can impact shelf life of foods, and even the sensory appeal of liquid based foods such as soups and drinks. Yield stress can also help analyse the consistency of foods such as sauces.

Common uses of rheology

With most food products, sensory testing is paramount and the most common method of analysis relies on taste and texture. However, rheology can go as far as to help with mouth feel and the release of flavours. This means that that the analysis process can be re-engineered, reducing the overall level of subjectivity and increasing the efficiency of the end to end process.

Typically, sensory analysis of food is a costly and time consuming endeavour. While the complex human system of food perception does have its place, the highly subjective nature of such testing can lead to results which are not analytically ideal. Scientists have long experimented with instrumental analysis of food in an attempt to bring some structure and consistency to the food development industry.

Where rheology is being used commonly at present lies primarily within the parameters of the appearance and feel of foods. This involves using rotational rheometers to understand the internal structures of food and their liquid based form characteristics. However, society’s increasing obsession with low fat yet better tasting foods has prompted the use of rheology to try and replicate the eating or mastication process – that is, how food reacts and breaks down as it is being eaten, and the effects of this on the overall human sensory experience. The simulation of human chewing and the subsequent internal behaviour of the foods can be implemented through the use of a rheometer such as the Malvern Kinexus rotational rheometer.

Malvern Kinexus rotational rheometer

This particular model has both rotational shear-based movement and vertical axial-based movement. These two movements can be combined to simulate the motion of chewing, and the variables can be further fine tuned due to its sensitivity air bearing and torque range settings (in the Ultra+ model). The number of chewing cycles (often considered to be an average of 10) and the force of chewing motions can all be tailored for accurate results.

In a laboratory environment test settings are easy to set up, saving valuable laboratory time, and sample loading guides ensure a consistently loaded sample every time. This is particularly important as it allows consistent conclusions to be formed. The use of rheology in food development does require significant testing and adjustment of parameters, and this is made simpler due to the Kinexus’ live data feed during all testing processes. The live data feed allows the user to monitor the data in real time, making adjustments as necessary. Further to this, all reporting is handled automatically, saving valuable time and providing a complete history of the end to end process.

If rheology is to be used more comprehensively in the food development process, consistency, sensitivity and speed is vital. Rotational rheometers such as the Kinexus make this a significantly more controllable process, while yielding consistent results with obvious resulting time efficiencies. The overall impact is a lower cost development process with a faster turnaround time. This type of innovation has the potential to have an extremely large impact on the food development industry as a whole. The Kinexus comes in three models: the Ultra+ for advanced research, the Pro+ for high end research and the Lab+ for quality control. All models benefit from intelligent software that is capable of updates and a platform that also allows for upgradeability.

To the future

Studies conducted by the University of Massachusetts have compared human sensory evaluation with analyses done by rotational rheometers and the results have been promising. When testing for the sensory attributes of sauces, they have managed to align the results of subjective human testing with quantitative results from simulated mastication. This is an exciting prospect for the food development industry, and one which is sure to result in greater cost savings and efficiencies. It will also provide more quantifiable results and data, greater assisting the quality of food being developed for the end consumer.

ATA Scientific carries a range of Malvern Kinexus products that can be used for rheology. Contact us today to find out which one suits your needs.

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