The ketogenic diet is a low-carb, high fat diet that has been used historically to control seizures in some epilepsy patients, while causing the body to burn fat (rather than glucose) for energy. It has had a recent revival and become an extremely popular way to lose weight. While a person on the keto diet will not go hungry with the large choice of filling foods still available (meat, fish, eggs, cheese, butter, nuts, berries and cream to name a few), one thing they do lack is the comforting feeling of sitting down to a plate of pasta or a steaming jam sponge pudding and custard.
However, due to the diet’s popularity, there is a large bank of recipes available online to create alternatives to popular high-carb foods at home. More recently, ready-made alternatives have made their way to major supermarkets. The challenge of achieving more traditional textures has not been met in most cases. This blog post outlines some examples of keto alternatives and the best method of Texture Analysis to allow R&D departments to imitate the real thing.
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| Bread V Squeeze Rig A/BSR |
The first major source of carbohydrates in many diets is bread. Keto recipes may include protein flour, cheese, eggs and seeds for some added texture. Keto breads are often dense rather than fluffy, and are not springy or crusty. A common way to test the softness of a loaf is by squeezing it between the thumb and fingers, creating a ‘V’ shape with the hand. The Bread V Squeeze Rig imitates this process and allows the bakery’s R&D department to perform repeatable, scientific analysis of the freshness and appeal of bread. It consists of ‘V’ shaped rounded ‘fingers’, which are lowered onto a packaged or unpackaged loaf, and the force required to compress the bread is measured. Post-test calculations are then used as an indication of freshness – the lower the force and higher the value of springiness, the fresher the loaf. This non-destructive test offers simplicity and speed as the loaf requires no sample preparation and can be analysed within the packaging.
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| VSP600C / VSP300C |
The bread’s density can be measured using a simple volume measurement in the Volscan Profiler C within 30 seconds. This is a benchtop laser-based scanner that measures the volume, density and dimensional profiles of solid products. As the sample’s weight is measured automatically, density is output along with dimensional measurements of the loaf.
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| Tortilla/Pastry Burst Rig HDP/TPB |
Many consumers use tortilla wraps as an alternative to sandwich bread. Commercially-available keto wraps are made using protein and fibre. The textural component often lacking in this case is toughness during a bite. This can be measured in a repeatable way using the Tortilla Burst Rig. This was developed to perform extension and elasticity measurements on thin sheeted samples, which are secured between two holed plates and burst using a 1-inch spherical probe.
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| Pizza Tensile Rig A/PT |
In a similar way, keto pizza bases (frequently made using cauliflower and eggs, or else carb alternatives in the same way as bread) lack the resistance that traditional pizza offers when a consumer bites into a slice and pulls away. A pizza sample is best measured using the Pizza Tensile Rig. This is comprised of two four-pronged components. The upper component fits directly into the loadcell and the lower component into the instrument base. The sample is pushed onto the prongs. The two parts move away from each other during the test, tearing the sample and giving an indication of the pizza’s toughness.
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| Noodle/Pasta Loop Tensile Rig A/NPLT |
Keto pasta, whether homemade or shop-bought, also frequently lacks the toughness a consumer is looking for, often being described as ‘slimy’. This is commonly made from konjac flour or kelp, or even spiralised vegetables. Sample toughness may be measured using The Noodle/Pasta Loop Tensile Rig. This comprises of an annular sample cutter, hand press and sample mounting washers that fit to the rig, so sheet dough samples may be cut to fit. This rig allows pasta extensibility and tensile strength to be determined. These are important properties for assessing the quality of ingredients and the effect of formulation and, additionally, how dough may withstand further processing during manufacture.
On the sweeter side, without flour to rise and sugar to caramelise, the texture of both keto biscuits and cakes presents a challenge to bakeries. Many keto cakes have a soft, plastic pudding-like texture (similar to a chocolate fondant pudding). Others make more of an attempt to imitate traditional sponge, using ingredients such as almond flour and xantham gum. Either way, the desired springy texture is missing. The springiness of a cake sample may be measured using a relaxation test. Springiness is the rate at which a deformed sample returns to its undeformed condition after a load is removed; it is a measurement of elastic recovery. In a relaxation test, the Texture Analyser compresses a sample by a specific amount over a specific time period. The analysis capabilities of Exponent software allow the springiness to be calculated from the force-time graph.
Keto biscuits are often described as ‘flaky’ or ‘fluffy’, but do not often have the snap of a traditional biscuit. During a new product’s development, the biscuit’s snap can be measured using a Three-Point Bend test, and if coupled with an Acoustic Envelope Detector, the sound pressure level produced during the snap can be measured quantitatively. This, along with the force drop upon snapping, can be very useful in indicating whether or not a product will satisfy a consumer.
The Texture Analyser can be used to measure almost every textural property of a food product and is a crucial step in the process of delivering the best range of keto alternatives in this quickly-expanding market.
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.
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.
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