Testing texture in reformulated food

Measuring strength and stickiness in low-salt 

According to the World Health Organization (WHO), adult salt intake of less than five grams per day can help to reduce blood pressure and the risk of cardiovascular disease.

In response, WHO member states have pledged to reduce the global population’s intake by a relative 30% by 2025. As such, low-salt launches, including the revolutionary change to Heinz soup recipes to provide reduced sodium options, are rife in the market. Yet, while health authorities worldwide agree too much salt can be bad for health, it does have an important role in texture – particularly in cooked meats, where it ensures firmness and “bite,” and baked goods, in which it plays a multitude of textural roles.

To ascertain whether the removal of fat in cooked meat products presents a compromise to texture a cutting test is commonly used to slice through the meat product and measure the force required (Figure 1). The higher the maximum force and/or total energy required to perform this test, the more firm or higher ‘bite’ a sample will have. 

A common problem on reducing the fat in meat products such as burgers is that the product becomes dry and bland with a hard, rubbery texture. Other problems that occur with low-fat (5-10%) fresh or cooked/smoked sausages are reduced cook yields, soft mushy interiors, rubbery skin formation, shorter shelf-life and changes in sensory qualities after cooking or reheating. 

The graph (Figure 2) shows that a higher force was measured for a low fat burger product than its full-fat counterpart.  Manufacturers can use the results of their sensory panel work on new formulations to determine the value of force at which the ‘bite’ of the product has a negative impact on the acceptability of the product and hence discover the band of acceptance into which a product show fall in order to be most texturally successful.

Consensus Action on Salt and Health (CASH) conducted a UK survey in 2011 that revealed bread is responsible for up to a fifth of daily salt intake, making baked foods a clear opportunity for salt reduction reformulation in many western markets. However, salt is pivotal to dough strength and stickiness, which is required for the desired crumb structure of the final product and also to hold the folded layers of dough together, ensuring consistency of aeration in the baked bread.

Bakers have to tread a fine line: excessive stickiness causes processing difficulties, but if cutting salt content also leads to a weakening of the dough, problems of a different nature, but equal importance, become evident. To gauge the impact of a salt reduction programme on dough quality, samples should be prepared and tested prior to bulk preparation to identify the ideal formulation. 

The Warburtons Dough Stickiness System (Figure 3) places a retaining plate on top of the dough, applying a slight pressure. A narrow blade is driven through a slot in the plate, to a defined distance - obtaining the compression peak and area of the dough. As the blade is withdrawn, Exponent software calculates the adhesion peak and area, with a higher peak/area associated with a stickier dough. Comparing the results of a low-salt dough with a dough containing regular levels of salt can give a good indication of the effects of salt reduction (Figure 4).

Additionally, salt tightens the gluten structure and helps loaves retain the carbon dioxide gas formed during fermentation. This has a great impact on volume after baking. As a result, lowering salt content can lead to smaller, less attractive breads. Using instruments such as Stable Micro Systems’ VolScan Profiler (Figure 5) can help to provide quantifiable volume and density measurement and, again, can be used as a comparative tool during reformulation.

As well as impacting the texture of fresh bread asit hits the shelf, salt also has an effect further along the line. Traditionally used as a preservative, salt is paramount in extending shelf life as the water it attracts can help keep bread from staling too quickly in a dry environment. Measuring the firmness of reduced-salt bread over an extended period of time, in different conditions and then comparing with other formulations is key to discovering how quality of the bread may be affected over time (Figure 6). 

There is a Texture Analysis test for virtually any physical property. Contact Stable Micro Systems today to learn more about our full range of solutions.

---

For more information on how to measure texture, please visit the Texture Analysis Properties section on our website.

The TA.XTplus texture analyser is part of a family of texture analysis instruments and equipment from Stable Micro Systems. An extensive portfolio of specialist attachments is available to measure and analyse the textural properties of a huge range of food products. Our technical experts can also custom design instrument fixtures according to individual specifications.

No-one understands texture analysis like we do!

To discuss your specific test requirements, click here...