Compression Testing for Texture Analysis and Materials Testing

What is a compression test?

A compression test is perhaps the most simple and popular test of instrumental texture measurement. In its simplest method, a sample is placed on a flat base/surface and a flat probe/platen is lowered onto the sample to a given force or distance (or the sample is compressed to a percentage of its original height). The sample is deformed and the extent of the deformation and/or the resistance offered by the sample is recorded. Simple compression tests are often termed uniaxial compression which means that the sample is compressed in one direction and is unrestrained in the other two. Either a low or high degree of compression can be chosen but a high degree of compression will usually cause the product to rupture, spread, fracture, or break into pieces.

Puncture and Penetration Testing for Texture Analysis and Materials Testing

What is a puncture/penetration test?

In a penetration/puncture test a probe is made to penetrate into the test sample and the force necessary to achieve a certain penetration depth or the depth of penetration in a specified time, under defined conditions, is measured and used as an index of e.g. hardness, firmness, toughness.

Both test principles cause an irreversible change in the sample and assume that the sample being investigated is of larger area than the contact area of the probe in use; a sample smaller than the probe contact area would assume compression principles.

Texture Analysis in Research: Alternative Proteins

Across the globe, consumers are increasingly looking for non-meat options when buying protein as part of their diet.  

 

Meat has been the main source of protein in developed markets for years. However, a change in consumer behaviour has led to a growth in the alternative proteins market due to health concerns, environmental reasons and animal welfare awareness. Consequently, producers of animal protein face large risks to their sustainability if they do not join the innovative and fast growing alternative proteins market. Meat alternatives and broader protein alternatives that can act as substitutes for traditional meat products are attracting considerable financial investment.

‘Alternative proteins’ is a general term that covers any substitute to traditional animal protein. These protein sources include plant-based protein, fermented protein, algae, cultured meat, 3D printed meat and insects. The texture of traditional meat has always been the most important factor in determining consumer acceptance, and the same is true for alternative protein sources.

Texture Analysis in Plant-Based Dairy Product Development

In the nearly 40 years since soy milk was first introduced in the U.S. and Europe, the offerings for plant-based dairy alternatives have expanded significantly to include a wealth of options from nuts, seeds, legumes, fruits, grains and root vegetables. 

In fact, industry experts predict that by 2026, the market for dairy alternative products could reach $41.8 billion growing at a CAGR of 12.2%.

A variety of factors are contributing to the category’s growth, including dairy sensitivity issues, consumer perception that plant-based products are healthier for them, a desire to avoid hormones or antibiotics, and concerns about animal welfare.

Texture Analysis: A tool for developing new food packaging from byproducts (waste)

By-products and waste generation are having an impact on environmental, economic, and social sectors. 

 

To the environment, these contribute to GreenHouse Gas (GHG) emissions. Many of these biomaterials are not utilised and end up in municipal landfills where they create serious environmental problems due to microbial decomposition and leachate production. In some cases, the by-products are burned to remove fungi and parasites. From the economic point of view, the adverse impact is due to the costs related to the handling of solid waste in landfills. Moreover, the management of large amounts of different degradable materials poses a challenge.

 

However, there is an increasing need for biodegradable, environmentally friendly and functional food-packaging materials. In this regard, proteins obtained from agri-food industry by-products may become a promising and sustainable (less impact, valorisation) source of such materials.

 

Measuring the crispness of fried vegetable products

Cooking in oil is widely used in the production of snack foods of various kinds, and results in drastic changes to the structure of the food.

Penetration of oil is particularly important for structure development in products such as potato chips, tortilla chips and potato crisps. In products which become totally hard and crisp, the oil first coats the surface and begins to move into the chip. As the heat builds up inside, moisture turns to steam and exits the chip, leaving a sponge-like network of tunnels which fill with oil.

This process occurs within the first 20 seconds of frying. Starch granules gelatinise inside the chip, but not at the surface. The interior becomes smooth and plastic as protein, starch and lipids interact to form a continuous phase which hardens upon dehydration.

Tofu texture

In the Far East, tofu is the most popular soybean food whilst in the West, tofu is gaining in popularity.

Tofu is very similar to cheese in appearance, texture, and chemical composition. By controlling the amount of coagulants and pressure applied during moulding, the texture of the tofu may be varied from extra firm, firm, soft, to silken.

Measuring the consistency of vegetable purées

Purées are very thick and viscous slurries made from processed vegetables that are often concentrated and include fibrous material or fruit pieces that adds structure. 

They are commonly used in fillings for pies, ketchup or baby food. Additional ingredients are usually added to manipulate consistency and processing properties.

For the measurement of consistency, a Back Extrusion test can be carried out by fixing a suitable diameter disc to the TA.XTplus texture analyser: the disc moves down into the vessel with good clearance between the vessel and disc so as not to produce erroneous increase force readings due to ‘side effects’.