Among dairy products, cheese constitutes the largest proportion of overall volumes of production. Texture is an important indicator for evaluating cheese quality and functional characteristics, which is also commonly used to differentiate many varieties of cheese. It tells the manufacturers about the cheese freshness, ripeness, hardness, firmness, spreadability, flakiness and many other properties that represent the quality of cheese.
With the growing market of low-fat foods, there are different types of cheeses available in the market suiting every consumer need. They are available in many variants ranging from hard, soft, semi-soft, molten to low-fat, high-fat or medium-fat cheese. During cheese production, the proportion of moisture, fat, protein, and salt is manipulated by blending other dairy products such as cream, butter, skim milk powder. Unbalanced proportions of these additions can affect the textural properties of a cheese, which makes them too hard, too soft or inconsistent in texture. Additionally, cheese texture can also get influenced by different processing conditions heating temperature, stretching, and ripening, which cause variations in its chemical composition. Storage temperature is another factor that can affect cheese quality.
To ensure that the above-mentioned factors have no impact on cheese texture or to rectify the conditions causing the texture to vary, manufacturers employ texture analysers in the production line. It plays an essential role in the development of low-fat cheese where the manufacturers wish to mimic the texture profile of its full-fat counterparts.
How Cheese texture is Measured?
A texture analyser enables the measurement of attributes of cheese which reflect consumers’ experience. It is done by simulating various possible interactions with cheese such as compression, extrusion, shear, tension, penetration, bend and break. These interactions represent the different ways with which a consumer can interact with a cheese, such as chewing, biting, squeezing, slicing, or grating.
A cheese sample is placed on the analyser test bench and arm of the texture analyzer contains the loadcell, to which a probe or fixture is attached. The arm then in either an up or down direction at a defined rate of speed in order to compress or extend the cheese sample. Depending on the type of cheese to test, an appropriate probe/fixture is selected.
Let’s see how texture analysis can be performed in various kinds of cheeses.
Processed Cheddar
To measure the cutting force of hard cheese such as cheddar, the texture analyser is fitted with a wire cutter. When the wire blade cuts through the sample, the cutting strength (or force) and work done to cut the cheese sample is measured. These measurements are an indication of sample quality and texture. The maximum load value calculated by the software is the degree of hardness of the cheese. It also provides negative load values that are the result of the wire cutter reversing its way through the sheared cheese sample.
To measure the firmness of hard cheese, a spherical probe can also be used to apply a gentle form of deformation on the sample over a specified distance. This test can measure the surface hardness, as well as the ripeness, of hard cheese. In addition, by measuring the force required to puncture the surface of a cheese sample by penetrating to a greater distance, its inner and outer firmness can be compared.
Cream Cheese
In order to measure the flow and consistency of creme cheese, ball probes can be used. They can be screwed directly into the Load Cell of a texture analyser. This is mainly to test the texture of creme cheese while it’s being squeezed out of a bottle and its spreadability on food items such as bread. If the substance is too dense, consumers will find it difficult to extract it. If it is too runny in consistency, the product could leak. The ball probe is that uniformly distributes compression force at a normal angle to the surface area of the ball. To measure the texture of creme cheese, the sample is placed in a small purpose-built container and the ball probe penetrates it to check its flow.
Cheese Sauce
The viscosity of a cheese sauce is an important parameter for it to have mouth coating potential and spinnability. A Back-Extrusion Food Cell is used to measure the texture of cheese sauce. It consists of a circular plunger that is driven into a larger cylinder to compress the food sample placed in the cylinder. It forces the sample through the gap between the plunger and the container until the peak force is achieved. This results in a peak compression force and then a fluctuating compression force.
Molten Cheese
The extensibility of cheese is an important textural characteristic in a wide range of food products, especially pizza. The traditional approach to test the stretchability of cheese involved lifting it manually with a fork and estimating the force required to stretch it and the length up to which it stretches. However, this method is inherently subjective and unreliable. Therefore, manufacturers employ Cheese Extensibility Fixture in the texture analyser to measure the extensibility of molten cheese sample to breaking point. The test rig comprises a microwavable vessel, sample retainer and a fork probe. Microwaved cheese is placed in the vessel, which is securely attached to the base of the texture analyser. After the fork probe is attached, the arm of the texture analyser pulls the fork in the upward direction through the molten cheese. The software, then, measures the force required to stretch the cheese and the total distance to its breakpoint. The longer the distance, the stretchier the cheese.
The TA1 texture analyser allows the use of the above-mentioned probes to conduct texture analysis for different textural requirements of cheese. With the help of NEXYGENPlus texture analysis software, users can monitor the force, distance and time during the entire simulation process and calculate texture critical parameters such as adhesion force, chewiness, hardness, springiness, resilience and other factors. Reach out to us for enquiry about the texture analyser.
