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

Tuesday, 1 April 2014

Developing food for an ageing population with the help of Texture Analysis

Mature shopper in supermarket with basketThe boom of 2 billion people over the last century has resulted in an ageing world population. By 2025, the world will have almost 800 million people over the age of 65. 

About 556 million of them will be in developing countries, another 254 million in developed ones. In fact, the United Nations estimates that the global population age 60+ will soar from 11% in 2000 to 22% by 2050. While age is just a number, the numbers are certainly on the rise.

Yet another challenge is that sensory perceptions necessary for the palatability of food – sight, touch, smell, and taste – diminish as humans age. While taste is the most important factor for all consumers, texture of food products may be a greater concern for older consumers than younger ones because, according to Peter Halley at the Australian Institute for Bioengineering and Nanotechnology, 40% of the elderly have trouble chewing and swallowing. The importance of food texture for the older adult is therefore paramount.

A question of maintaining texture
When developing food and beverage products for the ageing consumer, manufacturers have a number of factors to take into consideration in addition to functional and nutritional qualities. The ageing process is accompanied by decreased efficiency in sensory perception, which is defined as the combination of olfaction (smell), gustation (taste), chemical and non chemical skin senses, vision, audition, and kinesthesis (body movements).

This is how an individual receives information about a food’s flavour, temperature, colour, appearance, and texture so this functional decline can lead to decreased palatability of food and a failure to develop sensory-specific satiety. This could account for the fact that in Western countries the elderly population is the single largest demographic group at risk of inadequate diet and malnutrition. Product developers have to keep in mind the sensory losses older consumers experience when formulating their food and beverages, while at the same time realising that all senses and consumers are not affected in the same way.

Texture is often taken for granted. The acts of chewing (mastication) and swallowing play a huge role not only in nutrient intake, but also in an enjoyable eating experience. This becomes difficult when dental health starts to degrade and salivary flow diminishes. Missing teeth and wearing dentures both impact the act of chewing and decrease biting forces. Chewing efficiency can also be affected by a decrease in biting and chewing forces attributed to age-related changes in muscle strength.

The process of mastication is also very dependent upon accurate sensory feedback from the oral cavity. Receptors in the oral cavity respond to pressure, vibration, position, pain, and temperature, as well as to taste. Tactile feedback allows determination of the food position in the mouth, of the proper force needed for chewing, and the formation of the correct size and consistency of the food for swallowing.

Unfortunately, in responding to consumer demand for healthier products, manufacturers usually have to remove or add ingredients, which can have an adverse effect on the texture and palatability of the finished product. As a consequence, the consumer’s quest for healthier alternatives often leads to the sacrifice of optimum texture.

Elderly man taking meal from care assistant
Good-Tasting and Easy to Swallow
Caregivers of older adults face unique challenges when providing nutrient-rich foods to those with chewing/swallowing problems. Optimally, foods designed for the elderly should not only taste good and be healthy; they should also be easy to chew and swallow, since these two basic eating processes so often give older people problems. Spaces between the teeth, loose teeth, and badly fitting dentures often make it impossible to chew efficiently. But foods that are too soft, or too fluid can also lead to problems and can also have dangerous consequences – such as acute difficulty in breathing, or infection caused by food remains that could not be completely expelled from the respiratory tract.

The challenge for the food industry is to develop delectable food that can be easily ingested despite the consumers’ disabilities. Elderly people may need to eat only soft foods, or they may require that foods be cut up, or ground/minced/pureed with a food processor. Offering foods that are normally the desired texture, such as mashed potatoes, cooked cereal, pudding and yogurt is recommended. Gravies and sauces may also need to be added to foods to ensure that foods are moist enough to swallow but can also change the flavour of the food. 

Enhancing Texture-modified Foods
As food texture is lost with grinding and puréeing, the taste of the food also changes and foods may become less acceptable. Enhancing the flavor and appearance of texture-modified foods will help to improve the acceptability and enjoyment of these foods. The use of food thickeners and gelatin can help the texture of certain foods.  

Undesirable affects of texture-modified foods can be avoided through targeted food design and foods can be formulated to meet the special needs of this particular target group. Exactly how to go about this was the objective of Karin Wendin and her colleagues from the Swedish Institute for Food and Biotechnology (SIK).

Once texture has been modified, taste becomes a very important sense used to identify the food. Enhancing the natural flavour of the food may help with food recognition. Sweeter foods are preferred by older adults. Adding a little sugar or other sweetener goes a long way to improving the acceptability of some texture-modified foods such as sweet vegetables, while adding salt, gravy or a flavour enhancer to meats is recommended. Serving "hot foods hot" and "cold foods cold" improves flavour and acceptability too. Enhancing the flavor of foods has also been shown to increase the flow of saliva and improve immunity. Highly-flavoured food stimulates swallowing and mastication.

Plate with salmon and vegetables
Food Presentation
The appearance of the food is dramatically changed with grinding and puréeing. The appearance of the food often changes so much that the individual receiving the meal may not know what foods are being served. Colour becomes a key to food recognition. Mixing vegetables, such as a purée of peas and carrots, may make it impossible to identify the food as both the colour and taste of the original vegetables are lost.

With the loss of food texture, the ability to see, taste, and smell is essential to the enjoyment of the food. However, illness, medications and disease conditions can alter these senses in the older adult and further decrease the enjoyment of foods. Ensuring natural, vibrant colors and delicious flavors and aromas in texture-modified foods may result in food enjoyment and improved food intake.

Texture Analysis: Measuring the effects of re-formulation and processing
Numerous surveys have demonstrated that a product’s texture is closely linked to its popularity.
Texture analysis provides manufacturers with an effective way of scientifically testing the textural properties of their products to evaluate consumer appeal. The toughness of a sausage, for example, could impact on the success of a brand. Consumer loyalty, on the other hand, could be influenced by the softness of a loaf. With a wide range of application possibilities, texture analysis can be used across many sectors of the food industry – from meat to bakery and dairy – in order to achieve greater consumer satisfaction when it comes to textural issues in foods for the elderly.

TA.XTplus texture analyser with bloom jar Texture Analysis: aiding development of food for the elderly
About 40% of elderly people have difficult chewing and swallowing food, and this difficulty has an obvious flow on effect for their health in terms of nutrition, wellbeing, and general quality of life. 

How to make food more palatable while still easy to swallow is an area of ongoing research. By applying rheology, developing new texture models, and looking at the nutrition and swallowing behaviour of foods, a more scientific approach can be brought to the formulation and design of novel texture-modified food.

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.

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

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