5.5.2 Interactions of sensory product attributes

Clear definition of the desired sensory properties by the consumer may be difficult because of their interaction in consumer acceptance. The consumer may not be able to separate the sensory attributes that influence their liking or disliking of the food. It is this interaction of even simple tastes such as acidity and sweetness, colour and fruit flavours that can make sensory testing and product design complex. An example of interaction was shown in a study by a trained Canadian sensory panel which showed that the perceived intensity of sourness in lemonade decreased with increasing levels of sucrose added as in Table 5.7.


Table 5.7 Sourness of lemonade with increasing sucrose

Sucrose (%) 0 2 4 6 8 Mean sourness score 13.5 11.0 4.5 3 2.5

Source: After Poste et al., 1991.


Another problem is the interaction of the sensory testing with other consumer characteristics; for example consumers may have a stereotype of the product that disagrees with the sensory properties of the new product, or they may be slimming and therefore will downgrade creaminess and their acceptance of a new ice cream. Also there are differences in national preferences for sensory properties, even between what one would think are similar groups - such as Australians and New Zealanders (Cooper and Brown, 1990). Australian products (potato chips and canned soups) were found to be saltier than New Zealand products; New Zealand products (chocolate biscuits, fruit juices) sweeter. There appeared to be genuine differences in the types of products desired by consumers on opposite sides of the Tasman. Cooper and Brown suggested that one should always regard the consumers' 'norm', what they are familiar with, as a very powerful factor in product acceptability. For example 'tropical' flavour - a mixture of pineapple, passionfruit and orange and having a strong yellow- orange colour - is very popular in New Zealand in many products because it was one of the earliest juices introduced onto the New Zealand market in 1981 and became very popular. But it is much too sweet a flavour for Australians; they like their juices more sour and often lighter in colour.

Sensory acceptance and its relation to overall product acceptance is not predictable from a straightforward simple sensory panel, but needs a more complex research of consumer needs, wants and behaviour (Cardello, 1996). The total product has a strong effect on acceptance. The advertising, the information given, the appearance, the aroma or smell all lead the consumer to expect certain sensory qualities in the food and they will rate their acceptance against this. If it reinforces their good expectation, then the sensory properties will be acceptable; if it is better than their bad expectation, they may even score the sensory properties more highly. In Table 5.8 are shown the consumer scoring in Germany of one sample of Dutch tomatoes with different labels, to show the effect of labels and information on quality determination by consumers (Vesseur, 1990).


Table 5.8 Taste of one sample of Dutch tomatoes with different labels

Label Average judgement* German organic 2.5 German open air 2.5 Dutch open air 2.6 Mediterranean 2.8 German greenhouse 3.0 Dutch greenhouse 3.0 * Based on a scale 1 = very good, 6 = inadequate.

Source: Adapted from Vesseur, Acta Horticulturae 259, 1990 by permission of ISHS (International Society for Horticultural Science) Leuven, Belgium.


Another important factor is the amount of a food product eaten and how often it is eaten. Consumers may become tired of a product and stop buying it - they may find it boring or may find some sensory aspect overwhelming when eating a large quantity. Köster (1990) tested two kinds of tomatoes with 200 families over four weeks, one group using product A and one using product B. Product B had a higher liking score than Product A at first sight, but from their diaries:

     More of Product A was used than Product B.

     More of Product B was thrown away than Product A.

     More outside tomatoes were bought when they had Product B than
        when they had Product A.

In developing a new product, it is important to test for several times with the consumer and with the amount that they normally eat. In home-testing it is useful for them to keep diaries to show how much they use.

Think Break Contrast the sensory product attributes when consumers buy, serve and eat     · fruit juices;     · fresh porterhouse steak. 1. List the sensory product attributes that you identify from buying to after     eating. 2. What sensory attributes interact in buying, eating and serving? 3. Identify all the sensory attributes that affect your sensory liking/disliking. 4. What other product attributes would you include in determining your     acceptance of the two products? 5. Are there any interactions between these and the sensory attributes?

The consumers' liking and disliking of the sensory properties are complex because they are bringing their product stereotypes, expectations, past experiences, and some of the other product attributes that influence their acceptance of the product.

The problem in product development is how to relate future consumer and market needs, wants and behaviour to product, production, processing and marketing technologies; and also how to relate new technologies to future consumer and market needs. This interrelationship is important in every stage of the PD Process. Therefore the consumer needs to be involved at every stage either directly or through their recorded needs and wants. The product development is focused on the consumers or in the case of the industrial and food service product development on both the customers and the consumers.