Texture Analysis Professionals Blog

How to measure and analyse the texture of food, cosmetics, pharmaceuticals and adhesives.

Tuesday, 17 July 2018

Viscoelasticity in the Food Industry

Stretchy cheese finger
The vast majority of food materials show a combination of viscous and elastic behaviour although many show much more of one than the other.

There are some exceptions – hard crackers are generally completely elastic, whereas oil and runny honey usually show no elastic behaviour. Viscoelastic testing is best used as a comparative measure as many food products have an unusual geometry, so conventional viscoelastic equations cannot be used to find fundamental parameters.

If a cracker is not completely elastic when bitten, it may have become stale. The degree of viscous behaviour can be measured to study this effect. A sample so brittle is not easily clamped without fracturing, so tensile testing is not an option, but equally it is not a suitable shape for compression. 


Tuesday, 10 July 2018

Measuring Viscoelasticity using a Texture Analyser

Playing with 'slime'
What is viscoelasticity?
 
When a force is applied to a material, it causes the material to deform. This deformation can take one of two extremes – pure elastic deformation (e.g. a spring) or pure viscous flow (e.g. oil). 


The force causes the elastic material to instantly deform by a set amount, and the viscous material to flow for the whole time the force is applied. When the force is removed, the elastic material instantly returns to its original state, whereas the viscous material does not recover at all.

Elastic behaviour is usually caused by the bonds stretching between atoms (which is instant). Viscosity is caused by atoms or molecules moving past each other, which takes time but is also not easily reversed, unlike elasticity.

Tuesday, 3 July 2018

Texture Analysis in Action 2: Powder Vertical Shear Rig

Anyone who has handled powders has almost certainly come across a clogged hopper, and will know that this is caused by caking, arching or rat-holing. 

To measure the tendency of a powder to show these properties, the main property to consider is the powder’s bulk resistance to the initiation of flow. 

This helps to imitate the consolidation that occurs under the powder’s own weight when the outlet is shut and the feeder is switched off. It is when the outlet is opened and the feeder started again that the blockages can build up.

Tuesday, 26 June 2018

Texture Analysis in Action 2: Indexable Powder Compaction Rigs

Indexable Powder Compaction Rig (50kg)
Indexable Powder Compaction Rig (A/IPC0.5)
Many years ago we introduced two variants of Powder Compaction Rig (high tolerance and low tolerance) suited to high force applications. 

However, there is a need for powder compaction testing of similar sample volumes at lower compaction forces than the existing methods that require a TA.HDplus Texture Analyser. 

As such, we have developed two low force powder compaction fixtures – offering a choice of volumes for 10 samples – to provide indexable testing up to 50kg.f and to increase  useability and efficiency.

Tuesday, 19 June 2018

Texture Analysis in Action 2: Indexable Film Support Rig

Film Support Rig
Film Support Rig
The Film Support Rig is used in conjunction with the TA.XTplus texture analyser to measure the burst strength and resilience of a variety of personal care and pharmaceutical products.

These include oral hygiene strips, plasters, bandages, polymer film, micropore tape, synthetic skin and latex, amongst other ‘Edible Film’ applications finding their way into the food industry.

Many pharmaceutical products, particularly plasters and bandages, are designed to be extremely thin, increasing comfort and ease of storage or use. Other films are designed to dissolve on the tongue.

Texture Analysis in Action 2: Unconfined Yield Stress Rig

Stable Micro Systems have launched the Unconfined Yield Stress Rig for the measurement of powder flowability.

In industries that handle powders on a regular basis it is very important to understand how a powder or granular material responds to pressure. In storage, the weight of powder in a container exerts pressure on the particles at the bottom.

If the powder has good flow behaviour it will not consolidate and will flow out of the silo or hopper without sticking – this is very desirable. The longer a powder is stored for, the more likely it is to form a cake in its hopper and refuse to flow without further assistance.

Tuesday, 5 June 2018

Texture Analysis in Action 2: Nail Polish Adhesion Rig

Nail Polish Adhesion Rig
The Nail Polish Adhesion Rig and method have been developed by Stable Micro Systems to provide the solution to this assessment requirement. 

During the polish drying time test, a channel 20cm long is filled with polish to a depth of 0.5 mm and wiped level using a glass rod. 


At this point a timer within the Exponent software test sequence is started. This depth is representative of a typical coat of polish on a fingernail; a depth of 0.5mm dries to approximately 0.2mm. This channel is seated on top of the Adhesive Indexing System that has ten detents and so ten test sites are available by simply sliding the platform along. 


Tuesday, 29 May 2018

Texture Analysis in Action 2: Ring Pull Rig

Ring Pull Rig
The Ring Pull Rig was developed to allow manufacturers of food tins and beverage cans to measure the force needed to lift the ring pull and open the container. 

This relatively new development could signal the end of consumer frustration with trying to open metal packaging that is too stiff, or where the ring pull detaches from the lid. 

Understanding and quantifying the force needed to use a ring pull is vital for both packaging manufacturers and their customers to ensure safety, functionality and consumer experience.