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

Tuesday, 13 February 2018

Low and Light Foods – the potential textural compromises

ermarket shopperFor decades, food companies lured consumers to their processed and packaged products with an
irresistible combination of fat, salt and sugar.

However, every day a news headline appears warning us of the dangers of high quantities of these ingredients in our diets. It comes as no surprise then that ‘low and light’ products with reduced proportions are more popular than ever.

The Consumer Goods Forum carried out a survey of 102 large food companies earlier this year, finding that the number of products aimed to “support healthier diets and lifestyles and address public health priorities” increased from 84,000 in 2015 to over 180,000 in 2016. An enormous budget of $1.8 trillion was set aside to reduce sugar in 2015. Trans fats and saturated fats were also under high reduction pressure.

Reducing fat and sugar contents delivers food manufacturers with a major textural challenge. Fat and sugar provide bulk and mouthfeel that is not easily replaced by other ingredients. Instead, the processing method is often adjusted to make up for this. With a negative perception of commonly used sweeteners, manufacturers are looking into alternative sources of sweetness such as coconut sugar, date paste and sweet potato puree. These can adjust texture in unpredictable ways, and so the finished product texture must be monitored.

In the US, nearly 70% of yoghurt launches featured low fat claims in 2014, which suggests that low and light characteristics can now more or less be taken for granted, with most products even putting more emphasis on other aspects of the item. With yoghurts, this is often a hint at the naturalness of the product (such as high fruit content or live cultures) or the addition of protein or vitamins. Fat gives yoghurt a thick, creamy texture, and low fat yoghurts often feel more ‘set’ in the mouth if thickened, otherwise they can taste watery. 

Comparison of consistencies of
full-fat and low-fat yoghurt when
subjected to backward extrusion
To test for either of these properties, the Back Extrusion Rig by Stable Micro Systems is particularly useful, as the yoghurt can be tested inside its own container, straight off the supply line. A compression disc is automatically pushed into the product and then fully retracted. The product is broken apart on entry (and a thickened low fat yoghurt will now show a rough force-time curve as the structure is broken) and stretched as the probe is withdrawn. A thick, luxurious yoghurt will break from the probe after a longer travel, which will show as a longer time for the force to drop on the graph).

While sugar has very rarely been described as a health food throughout history, it has certainly been a food villain in recent years. Many consumers would like to reduce their sugar intake but still desire fully flavoured products. The reduction of sugar does not just present flavour difficulties. It also plays many functional roles – controlling water activity, acting as a bulking agent, giving baked goods structure, altering mouthfeel along with hyrdocolloids, acting as a binder in bars and providing softer textures. Many sugar substitutes available on the market do not fulfil these functional properties, and so the reduction of sugar can require the addition of other ingredients or processing changes. 

To test for the springiness of cake made with sugar replacements, a compression test to a set distance held for 60 seconds can provide useful information on the elasticity perceived by a consumer in the hand or mouth. Crust strength is easily tested using a penetration test; the force peak on entering the surface of the sample is related to the fracture strength of the crispy topping. Sugar alcohols can be used when the physical structure of sugar is really important, but these can cause adverse digestive reactions. If used in boiled sweets, the brittleness of the final product must be maintained. A shatter test (using a large, flat probe on the heavy duty platform) will help with this analysis.

Thinking of starting your own Low and Light product line to keep up with your competitors? Talk to Stable Micro Systems today for Texture Analysis solutions.

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

TA.XTplus texture analyser with bloom jar 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!

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Watch our video about texture analysis Replicating Consumer Preferences Texture Analysis applications

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