Adhesion Testing for Texture Analysis & Materials Testing

What is an adhesion test?

Adhesion is the force that resists the separation of two bodies in contact. An adhesion test measures the adhesive characteristics of a product by measuring the forces to separate the product from the test surface which it comes into contact with. Adhesiveness ('Stickiness') is most commonly measured with a cylinder probe, which is pressed (application of compression), onto the surface of the sample after which the force to pull the probe off it is measured. The higher the force to separate these surfaces, the more adhesive is the product. The distance the probe needs to be pulled away from the product before the two surfaces are separated will also indicate its viscoelastic behaviour, and depending upon the product, its ‘tailing’ or ‘stringiness’ characteristic.

Cutting/Shearing Testing for Texture Analysis and Materials Testing

What is a cutting/shearing test?

In general, any texture analysis test that involves the use of a type of blade to perform the test, is performing a cutting or shearing action on the sample. A number of empirical fixtures feature a single blade or a number of blades which cut/shear through the sample, under specified conditions. The maximum force required and/or the work necessary to achieve this (i.e. the area under the curve) is taken as an index of firmness, toughness or fibrousness of the sample. Whilst empirical or imitative, shearing tests are very popular, particularly for the assessment of food texture and in particular the measurement of ‘bite force’.

The Volscan Profiler in Bakery Research

Loaf volume is of paramount importance to bread quality evaluation. It is a vital aspect of the consumer’s perception of value as in bread and other leavened goods, higher volume for a given weight is invariably associated with a more aerated crumb and superior texture.

For a baker or bread manufacturer, each batch of flour has to be evaluated by test baking to ensure that bread is made to a uniformly high quality. One component of this quality control is measurement of the volume of the bread, which can give information relating to the density of the bread crumb and the strength of the gluten in the flour. This volume information can then be used to modify the dough mix used in bread production to produce bread of the appropriate quality. This procedure is important, not only for the inherent qualities of the bread, but to ensure that the selected dough-piece weight produces a loaf of the correct size for the standard tins used in the baking process.

Fracture/Bending Testing for Texture Analysis and Materials Testing

What is a fracture/bending test?

This type of test can measure the fracture and break strength of hard and brittle products (or their flexibility) by bending the sample, usually until a break occurs. If a break does not occur whilst the sample is flexed then a measure of its flexibility can be performed instead – a degree of flexibility can be desirable or a characteristic to be avoided, depending upon the sample. Stable Micro Systems enables a wide range of tests in this field, using fixtures such as the Three Point Bend Rig which are adaptable to many types of sample, and also specialist attachments like the Crisp Fracture Support Rig or the Spaghetti Flexure Rig.

Use of by-products for agricultural benefit

Crop protection, including weed management, is a critical issue in agriculture. Mulching, which consists of covering the soil surface with organic or inorganic materials, is used to control soil moisture, soil temperature, nutrient loss, salinity, erosion, soil structure, etc. Its benefits for the growth and yield of annual and perennial crops have long been recognised. Although it is an age-old practice for managing weeds, mulching has largely dwindled since the widespread use of herbicides; however, now it is gaining importance in the context of sustainable agriculture. Different mulching materials have been used in different crops in different climatic environments for weed management, and results vary according to the chosen approach, growing practices, conditions and species. These materials include crop residues, non-degradable plastic films, and also biodegradable films. The lifetime of an agricultural mulch varies considerably (i.e., months to years) depending on the nature of the material, its application, its thickness, and the environmental conditions.

Extrusion Testing for Texture Analysis and Materials Testing

What is an extrusion test?

There are generally two types of extrusion test in texture analysis: backward (or back) and forward. Of the various extrusion techniques the one favoured in recent years is back extrusion. The sample is contained in a strong cell with a solid base and an open top. A rod with a disc is then forced down into the container until the food flows up (backwards) through the space between the disc and the container walls which is called the annulus.

How Texture Analysis is progressing the development of even better gluten-free products

The global demand for gluten-free products is expanding and continues to be a significant technological challenge for the bakery industries. One of the principle challenges is producing gluten-free baked goods and pasta with similar textural quality to the gluten-loaded counterparts.

The market demand of gluten-free (GF) baked goods and pasta is expanding. Despite the health halo associated with GF food category, commercially available GF cereal-based foods are often characterised by lower nutritional quality than their gluten-containing counterparts, having lower dietary fibre, protein and resistant starch (RS) contents, along with enhanced starch digestion rates and extents.

Tensile Testing for Texture Analysis and Materials Testing

What is a tensile test?

A tensile test pulls or stretches a sample and as a result the extensibility/elongation and tensile strength properties are measured in terms of force required to stretch and distance something can be stretched to.

The ultimate tensile strength of a material is defined as the maximum attainable load, acting on a specimen in a tensile test, divided by the original cross-sectional area of the specimen.

A conventional tensile test assumes that the sample fractures almost instantaneously in a plane that is approximately perpendicular to the plane of the applied tension. The maximum force is the tensile strength of the material.