Sensory science

Sensory and consumer scientists ensure that our food tastes as it should and is good to eat, says David Kilcast.

In the increasingly affluent societies of the developed countries, consumers expect a wide choice of food that is safe, enjoyable to eat, nutritious and of consistent quality. If food falls short of these criteria, there is sufficient choice in a commercially competitive environment for consumers to change their allegiances and find alternative products. Provided that the food is safe, how enjoyable it is to eat is the most important factor that will determine consumer choice. Food and drink manufacturers, ingredient suppliers and retailers now employ sensory scientists to minimise the risk of product failure (90 per cent of new product launches fail), and to ensure that sensory quality is maintained in long-term production. 

The primary role of the sensory scientist is to employ the senses of selected and trained human subjects to identify the individual perceptible characteristics of food, and to quantify their intensities. These characteristics are defined by the chemical composition of the food, and the structural organisation that gives foods their expected form and texture. All the important senses in determining consumer liking need to be addressed: appearance, odour, taste, trigeminal response (the last three constituting flavour), touch and hearing. The more general discipline of consumer science then examines how consumers integrate these responses, usually at a subconscious level, to come to a judgement on how much they like the product.

Given the nature and range of sensory responses, and the need to understand how consumers respond to them, it is inevitable that sensory and consumer scientists employ a wide range of disciplines in their jobs. Flavour responses are related directly to chemical composition, and indirectly to structure and texture, and the underlying physical properties. Measuring these responses using trained panels requires a knowledge of human physiology and psychology, and analysing these complex and variable responses makes extensive use of statistics. Understanding why consumers choose what they do encompasses aspects of the behavioural sciences. 

The scientific techniques that are usually used in conjunction with sensory measurements are becoming increasingly sophisticated. For example, advanced mass spectrometry techniques are used to analyse trace chemical components (often at levels less than 1 part per trillion) that are important in delivering many characteristic flavours, and which can give rise to unpleasant flavours or taints when present in the wrong context. Magnetic resonance imaging techniques are used to monitor changes in the location of components such as water, and those that can have important influences on texture and shelf life. Sophisticated multivariate statistical techniques are needed to analyse and interpret large sensory and consumer data sets, and to recognise segmentation in responses, which can have important commercial implications.

A broad range of skills in sensory and consumer science is inevitably required, and in the UK there are insufficient academic courses to deliver enough graduates with the skills needed by industry. Consequently, many sensory and consumer scientists have backgrounds in a wide range of other scientific subjects, particularly chemistry, statistics and psychology. My own background involved a chemistry degree, a PhD in physical organic chemistry, postdoctoral research in spectroscopy, and a spell in the photographic industry researching novel photographic imaging systems. Perhaps surprisingly, during my career as a sensory and consumer scientist at Leatherhead Food International in Surrey, I have been able to employ knowledge accrued in all these earlier career stages.

One consequence of the limited training in the necessary skills is that organisations such as Leatherhead are relied on by industry to provide short courses in different aspects of sensory science. The Sensory and Consumer Science staff at Leatherhead regularly provide targeted training for industry. Support is also given by professional organisations in the UK, in particular the Consumer and Sensory Research Group of the Society for Chemical Industry and the Professional Food Sensory Group at the Institute of Food Science and Technology.

Whilst all food and drink companies must have in place employees with basic skills in sensory science, the complexity of the area has resulted in much research and testing being outsourced to organisations such as Leatherhead. My team carries out commissioned projects for industrial clients and government bodies. These range from routine product testing to scientific research into sensory perception and consumer attitudes and perception.

Projects can be set up from a detailed brief produced by the client, but commonly the client’s requirements are probed and the sensory scientist employs his/her skills to formulate a suitable experimental programme. The projects can be carried out by the sensory and consumer science team alone, or can use the wider range of expertise available in a membership-based organisation such as Leatherhead. For example, we have recently investigated the nature of creaminess in conjunction with colleagues with expertise in food ingredients and product development, and the relationship between perceived and measured release of flavours together with colleagues with expertise in chemical analysis

The food and drink industry has long recognised the importance of addressing consumer needs and the importance of perceived quality. The primary measurement tool will continue to be the human subject, used in the skilful hands of sensory and consumer scientists.

Source: Chemistry in Britain

Acknowledgements

David Kilcast