Bakery: How to measure the crunch of biscuits
Bahlsen had massive media interest in Germany after it used the Acoustic Envelope Detector by Stable Micro Systems to analyse the ‘crunch’ of its biscuits. This was used for quality control, as customers perceive a fresher biscuit when there is a louder crunch.
The AED was used in conjunction with the company’s TA.XTplus texture analyser to quickly and easily analyse acoustic emissions and quantify product texture. A highly sensitive directional microphone acquires the acoustic data while the texture analyser itself measures force, distance and time as the biscuit breaks. The procedure gave Bahlsen the confidence that the sounds emitted by its products could maximise consumer appeal.
Ralf Winopal from Winopal Forschungsbedarf GmbH, Stable Micro Systems’ distributor in Germany, said: “Texture analysis has become essential for product development and quality control. The media interest in Bahlsen and the Acoustic Envelope Detector shows that everyone, from scientists and technologists to the general public, can get excited by it.”
Bakery: How to measure the crustiness of bread rolls
By combining the Texture Analyser’s ‘V’squeeze test with simultaneous acoustic measurements, Zeelandia pioneered a new method to determine the crustiness of bakery products to obtain detailed objective analysis of crust breakage.
Henk Mulder, physical scientist at Zeelandia, commented, “Stable Micro Systems’ equipment is extremely accurate and versatile. Manual tests, and even our previous lab testing methods, didn’t give us enough detail to draw meaningful conclusions for our NPD or quality control purposes. The ‘V’ Squeeze test measures valuable parameters, but recording sound using the Acoustic Envelope Detector provides far more detailed results that can be used in new product development and for competitor analysis and QC purposes”.
Coen Sander, Zeelandia’s food scientist, added, “Perfecting texture in crusty products is particularly challenging because despite the crunchy crust, we’re often also seeking a soft centre – all with maximum shelf life. We’re now testing a wide range of finished baked products containing different Zeelandia ingredients in varying proportions. Collating and comparing these detailed test results means we can evaluate the impact of changes to recipes and processing conditions.”
Bakery: How to measure dough stickiness
When the UK’s number one bakery brand, Warburtons, teamed up with Stable Micro Systems, they found the answer to a sticky problem. Sticky dough is problematic in bakeries, causing progressive build-up of dough smears on equipment, necessitating extra cleaning and leading to waste and unplanned stoppages.
Previous test methods for quantifying dough stickiness required manipulation of the dough sample immediately prior to testing. This, along with exposure to drier atmospheres common in QC labs, introduced rheological changes which reduce stickiness, distorting test results.
Warburtons came up with a solution (the “Dough Stickiness System”) that mimicked actions performed in commercial bakeries, with a blade coming down into a sample in a sealed box under the TA.XTplus Texture Analyser to give firmness information during the compression and stickiness information under tension.
The rig continues to be a success today.
Bakery: How to perfect the science of freshness
The Puratos Cake Testing Lab helps the baking industry deliver the world’s freshest cake solutions to help increase consumer satisfaction and profitability.
As users of Stable Micro Systems Texture Analysers, these experts are able to provide the ideas and innovations that are guiding new developments in cakes everywhere. They regularly feature their Texture Analysers to articulate their product attributes while marketing their modular improver to enhance shortness of bite and chewability in soft bakery products.
According to their research: “Short bite is the opposite of chewiness. It reflects the ease to tear or break off a piece of bread as well as the ease of chewing. Consumers expect a short bite particularly in sweet bakery products and filled snacks.”
Cereals: How to accurately assess flour performance
ADM Milling, experts in flour processing, use the TA.XTplus to benefit from the flexibility to design tests which investigate specific parameters of interest, as well as improved data processing. ADM Milling require accurate measurement data on the performance of their flours in three key areas; dough extensibility, bread firmness and pasta texture. Their Texture Analysers not only fulfil these requirements but also deliver the added benefit of allowing the company to develop its own unique test procedures.
As an example, the Kieffer Dough and Gluten Extensibility Rig is used for all-important determination of the rise qualities and structure of finished dough products, measuring the dough’s resistance to extension and extensibility. They can reveal that different varieties of wheat have a markedly different effect on dough extension properties. Using the TA.XTplus therefore allows ADM Milling to determine which kinds of wheat are best suited for different types of flour and, therefore, different end-products. For example, a bread-making dough requires a great deal of extensibility, whereas this would be a negative attribute for biscuits.
As well as dough extensibility, the firmness of their bread and texture of their pasta are put to the test using recovery and compression tests with expert help from the Exponent software.
Confectionery: How to control chewing gum texture
Wrigley have been using their TA.XTplus for quality control in a range of products for decades now. In addition to new product development and troubleshooting, the effects of formulation changes on chewing gum texture have also be assessed.
Innovative attachments, including forward and back extrusion cells, craft knife blades and tensile grips, are put into action to assess characteristics such as hardness, stickiness and stringiness.
Confectionery: How to measure surface adhesion of chocolate
The University of Leeds and Nestlé Product Technology Centre used their Texture Analyser to publish a paper on the adhesive properties of chocolate in the demoulding process. For quality control purposes and hence customer satisfaction it is increasingly important to apply the right processing conditions and controlling parameters, such as the time, the temperature, the moisture content and the relative humidity of the surrounding air.
The researchers investigated the influences of these factors during the cooling stage of the chocolate manufacturing process to assess the ease of demoulding. Experimental determination of chocolate adhesion to a mould was performed using a fixture specifically developed for this work, in which the stickiness was measured of a polycarbonate probe to a solidified chocolate sample to imitate the demoulding process. The results demonstrated that processing parameters like temperature, contact time and the relative humidity of the surrounding environment had a significant impact on chocolate crystallisation and solidification processes and on the adhesion of chocolate to a mould surface.
A Peltier Controlled Cabinet made it feasible to have a controlled experimental temperature range between 0° and 50°C.The hardness of the solidified chocolate samples was also measured to determine the effect of different processing conditions on the chocolate using a stainless steel cylinder probe.
Confectionery: How to measure the crunchiness of confectionery
When faced with the difficulty of quantifying the factors that affect customers’ satisfaction of chewing gum, Bart Cortebeeck of Cargill developed a new classification of crunchiness levels based on mechanic principles that could be monitored by a new instrument-based measuring method. These parameters – coating time, crunchiness and stability – give the opportunity to benchmark ingredient performance and match them to the desired properties of an end product.
"Consumers like to hear and feel a 'crunch' when they bite into coated confectionery products", explained Bart. "The crunch is a combination of auditory and tactile sensation. In that sense, crunchiness is different from hardness. Hardness is a purely physical characteristic of the product as the product is bitten into, whereas crunchiness is related to brittleness. Typically, the harder and more brittle a coating, the crunchier.
"The machine's results make it easier and more accurate to compare the performance of coating formulations obtained with different ingredients", continued Bart. "We succeeded in getting repetitive results, proving the reliability of this method across a range of applications. For manufacturers, accurate texture testing offers genuine benefits.
"Whether customers are focusing on a shorter coating time, higher product stability, or marked bulk and texture, we can use this method to devise the ideal blends of sweeteners and polyols to achieve the desired effects, with an accuracy never dreamed before".
Dairy: How to measure the texture of dairy products
For Brian Surratt of Cargill Texturizing Solutions, there’s no such thing as a carefree day in the kitchen. If he’s whipping up a homemade take on a dairy standard, like a frozen dessert, flan or pudding, don’t expect him just to kick back and enjoy once it’s ready.
“Now you’ve got to compare it to your favourite branded version,” says Surratt, a senior scientist in dairy applications for Cargill Texturizing Solutions, Wayzata, Minn. “Is it different? How would you characterise that difference? What would you change to make homemade resemble store-bought, or vice versa? Which do you prefer, and why? Welcome to my world!”
In that world, product texture comes into unusually sharp focus, and for good reason. “I’ve become fixated on being able to detect minute changes in textures when formulating new or reformulating existing dairy products,” Surratt says. “So, personally speaking, I’ve given texture vast amounts of attention because it’s my job.”
And that is when Stable Micro Systems’ Texture Analysers are so helpful.
FRUIT AND VEGETABLES
Fruit and Vegetables: How to measure texture at the watermelon harvest
The Agricultural Research Institute in Cyprus installed a TA.XTplus Texture Analyser just in time for the harvest of watermelons for an important trial. Stable Micro Systems were very happy to be able to assist and train the new user ‘on the job’. Texture Analysis was one of several methods used to assess melons of different varieties, root stocks and post-harvest storage times.
A method was developed to accurately quantify the flesh firmness using the Multiple Puncture Probe (A/MPP). The central pins were removed so as to avoid the hard core which gave a mis-representative result. The outer ring of pins was ideally located as they punctured the heart of the melon yet avoided the seeds. Sample preparation involved cutting the melon in half and removing the blossom end with a sharp knife to provide extra stability.
The melon was presented to the texture analyser and levelled, if necessary, to ensure a flat testing surface. The penetration test was commenced. The area under the curve was taken as the flesh firmness. The melon was then passed to the next station for further destructive analysis including sugar content, colour evaluation and lycopene content.
Fruit and Vegetables: How to measure the crunchiness of table grapes
Scientists at the University of Torino have published an extremely interesting book chapter and several academic papers entitled: 'Changes in Physical and Mechanical Properties of Dehydrating Berries'. This highlights the parameters that a TA.XTplus texture analyser and Acoustic Envelope Detector can provide, as predictors of consumer acceptability of wine grapes.
Instrumental mechanical and acoustic variables were determined for the berry seeds of Cabernet Sauvignon grapes harvested at different ripening stages. The main goal of this research was to assess the influence of the developmental changes on the texture properties of the grape seed to provide useful indicators of maturity.
Fruit and Vegetables: How to use texture analysis to improve fruit quality
Sias installed a Texture Analyser with the aim of testing finished products but now also use it in new product development. For example, having identified the ideal consistency for an apple puree, it is possible to develop a blackcurrant product with a similar viscosity and mouthfeel.
Steven Smallwood, Sias NPD Manager, comments: "Each year, different fruits come into fashion and we could find ourselves handling fruits we haven't processed before. Using texture analysis enables us to quickly assess how a new fruit will process, and adjust equipment or procedures accordingly, without wasting time or money."
Because texture analysis is so flexible, it can be used throughout the food industry to test ingredients as well as finished products. Stable Micro Systems stresses that it should not be viewed as a substitute for human taste testing, but as a complement to it. As Hido Malic, Sias quality and development manager, commented: "Installing the texture analyser was a simple way of upgrading our quality control procedures. Organoleptic testing remains very important, but the Texture Analyser is now an integral part of the process. Our customers can be confident of consistently high quality, and that obviously brings great benefits to the business".
'Texture analysis has brought tangible benefits to Sias and other major European food processors by improving quality, reducing rejected product and saving time.
Fruit and Vegetables: How to apply the AACCI standard method for cooked pulse firmness measurement
A high standard of cooking is critical for pulses – peas, lentils, chickpeas and beans – because, in a variety of common uses, cooking is required to ensure that they have an acceptable sensory quality. Texture/firmness is one of the most important quality factors influencing consumer acceptance of cooked pulses, and its evaluation is critical to the assessment of cooking quality. There are several methods available for its measurement, both subjective and objective, but until recently none had been universally accepted.
Members of the AACCI Approved Methods Technical Committee announced a standard method (56-36.01) developed for the determination of the firmness of cooked pulses. A collaborative trial, based on ten laboratories’ analysis of 26 blind duplicates of thirteen different samples, was run to evaluate the repeatability and reproducibility of the method. After cooking according to the standard preparation procedure the firmness of pulse samples is determined using a TA.XTplus Texture Analyser loading approximately 7.5g of cooked sample into a Mini Kramer Shear Cell, compressing and extruding the sample.
MEAT AND FISH
Meat and Fish: How to measure the firmness and texture of fresh fish
An independent study, carried out at the University of St Andrews and published in the Journal of Food Science, has recognised the superior performance of Stable Micro Systems’ Warner-Bratzler shear blade on the TA.XTplus texture analyser in assessing firmness and texture in salmon fillets. The blade, which is used to assess the cutting force, or ‘bite’ of fresh fish, was the most sensitive method tested and yielded the most consistently accurate and repeatable data. This assists manufacturers looking to implement reliable, accurate and tested quality control procedures.
The study aimed to establish the most suitable methods of detecting firmness in salmon fillets and predicting post-cold smoking texture. Researchers compared a new tensile strength test with various established analysis methods. While the Warner-Bratzler shear blade was found to be the most effective method of measuring firmness and predicting post-smoking texture, the new tensile test provided the highest levels of accuracy when predicting post-mortem gaping (the appearance of tears or slits within the fillet on handling).
The test, which used the TA.XTplus texture analyser to pull samples apart while measuring the force required to do so, is a valuable addition to the existing pool of instrumental methods for fish flesh quality assessment. Dr Ian Johnston, Fish Muscle Research Group, commented: “The results of our study will enable manufacturers to confidently undertake precise, consistent quality control.”
Meat and Fish: How to perfect the crispness of fried fish
In his prime-time series, “In Search of Perfection”, chef and molecular gastronomist, Heston Blumenthal, turned to texture analysis to help him perfect classic dishes. With the help of food physicist, Dr. Malcolm Povey, and Stable Micro Systems’ TA.XTplus texture analyser, the popular BBC show saw top chef Blumenthal combining science and cookery in order to create the perfect crispy fish batter.
After struggling to produce the ultimate batter – one that hardens on the outside while steaming the fish gently from within – Blumenthal visits Malcolm Povey, Professor of Food Physics at Leeds University. Well-known for his extensive work in food science, Povey pioneered Stable Micro Systems’ acoustic envelope detector, which measures the bursts of sound generated when food is bitten or snapped. Utilising this revolutionary instrument along with a TA.XTplus texture analyser and ball probe, Povey and Blumenthal tested batter to identify what constitutes the ideal crispness. According to the sound pulses measured, the results showed that the more bubbles there are in batter, the crispier, and more appealing it will be.
Blumenthal’s work with Povey was testament to the wide scope of texture analysis. Providing essential data on the texture of foods, it proves to be an invaluable tool in many sectors, enabling scientists, food manufacturers and chefs alike to create perfect foods time after time.
Meat and Fish: How to measure the texture of surimi
The “punch” or penetration test, although considered an empirical test, is the single most popular gel measurement technique used in the surimi industry for evaluating “gel strength” or stiffness. The test imitates the large deformations to failure involved in mastication. Many studies have been reported that correlate puncture or penetration methods with the sensory properties of surimi gels. This attribute of the test, coupled with its convenience, has made it popular for quality control within the surimi industry.
In his book “Surimi and Surimi Seafood”, surimi expert Jae Park describes how, along with the U.S Surimi leaders, he evaluated 12 samples of surimi gels with a wide range of quality using 5 units of conventional rheometer or rheotex and 2 units of TA.XTplus Texture Analyser.
“Soft gels could not be measured using any of the five conventional units, white 2 units of TA.XTplus were able to detect the gel values. Indeed, the accuracy of the measurement, based on the standard deviations, was much higher with the TA.XTplus instrument. This accuracy is likely to be due to the ability to calibrate the instrument as needed.”
Meat and Fish: How to measure poultry tenderness
Research carried out at the University of Arkansas using their Texture Analyser helped the development of a quick, accurate and simple destructive tool for measuring poultry tenderness, the Meullenet-Owens Razor Shear Blade. Poultry tenderness is an attribute critical to customer acceptance, which was historically assessed using costly and time-consuming sensory evaluation. This method uses an extremely sharp craft knife blade of defined dimensions, attached to a TA.XTplus texture analyser, to conduct a cutting / shearing test.
Because the blade is narrow and penetrates to only 20mm, the MORS test makes only a small incision into the sample, causing far less damage to it than traditional instrumental or human cutting tests. Repeatability is also optimised because the blade can be removed and replaced regularly – or even after every test – to ensure edge sharpness. Trials of the blade show it can perform 60 measurements per hour – double the number that can be achieved with an Allo-Kramer shear test, one of the better-known instrumental poultry testing methods.
The use of the MORS blade eliminates the problem of sample dimension influence on results compared to older techniques. The new system claims to exhibit a higher correlation with human sensory test results while testing just as reliably as, but faster than, other instrumental methods.
PASTA AND RICE
Pasta and Rice: How to measure rice kernel resistance
Alongside the release of a new International Standard (ISO 11747) for rice testing, Stable Micro Systems developed a Rice Extrusion Rig that conforms with the standard testing specifications and helps to overcome the issues of lengthy, labour-intensive, difficult sensory tests. Growers, processors and food manufacturers can use it to objectively and accurately analyse the resistance to extrusion of rice samples, enabling them to select the cultivars which satisfy both their own textural requirements and the demands of customers and consumers.
Whilst the Rice Extrusion Rig provides a simple, quick, accurate and economical method for measuring the eating qualities of rice, it includes additional design features specifically focused on making the testing cell more quickly removable and replaceable between tests.
This standard is the outcome of inter-laboratory testing organised in 2010 by UNI involving nine international laboratories and was prepared by the ISO/TC34 Technical Committee for Cereals and Pulses.
Snacks: How to measure crunchiness
Researchers at the University of Leeds showed that massive bursts of ultrasound are generated during the first second of biting into crunchy food – and are simultaneously analysed by the ears and mouth. Food physicist Professor Malcolm Povey explains: “Our research shows that the sound and feel of food in the mouth is as important as taste, look and smell in deciding whether we like something or not”.
Using the Acoustic Envelope Detector from Stable Micro Systems, some simple software and an enviable supply of different biscuits, Professor Povey realised that the energy produced by the very first crack of a biscuit breaking is released as distinct pulses of ultrasound. Povey was convinced that the same measuring techniques could potentially be applied to other textures in food manufacturing as well as having major applications outside the food industry, which has since been confirmed.
“Materials testing usually requires expensive equipment, but we’ve proven that recording, measuring and comparing sound pulses is rigorous and accurate. In the same way engineers used to tap wheels on railway engines to listen for faults, we can use these microphones to record a much wider frequency range to pick up tiny defects. Its potential is enormous”.