Jos Mojet

Compensation for age-associated chemosensory losses and its effect on the pleasantness of a custard dessert and a tomato drink

Differences between elderly subjects (n=52, 60-85 years) and young subjects (n=55, 18-35) in their food liking and their olfactory capability were investigated. Two food systems were used: custard desserts and tomato drinks. Flavor enhancement/enrichment, textural change, and/or irritant addition were incorporated as compensatory strategies into these foods. The addition of low concentrations of both cherry flavor and cream flavor to the custard desserts influenced their pleasantness for the majority of the elderly. The addition of cream topping increased the pleasantness of the custard desserts for both the elderly and the young. The elderly equally liked the tomato drinks with no or with low irritant addition, whereas the young generally disliked an irritant addition. However, the food liking of the elderly was not generally increased by these different compensatory strategies. Instead, subgroups were observed for each compensatory strategy, in which applied compensatory strategies led to an increase in product pleasantness. Age-associated losses in olfactory capabilities did not sufficiently explain differences in food liking, as only elderly with similar olfactory capabilities to the young demonstrated a liking of enhanced flavor. The present study does not support the assumption that age-associated impairment in olfactory capability will inevitably lead to changes in food liking.

The role of novelty detection in food memory

Memory plays a central role in food choice. Recent studies focusing on food memory in everyday eating and drinking behaviour used a paradigm based on incidental learning of target foods and unexpected memory testing, demanding recognition of the target among distractors, which deviate slightly from the target. Results question the traditional view of memory as reactivation of previous experiences. Comparison of data from several experiments shows that in incidentally learned memory, distractors are rejected, while original targets are not recognised better than by chance guessing. Food memory is tuned at detecting novelty and change, rather than at recognising a previously encountered food.

Simple improvement of consumer fit in external preference mapping

In the common implementation of external preference mapping consumer preferences are fitted as polynomial functions of the first two principal components (PCs) of the sensory data. A major weakness of the method is the relatively small number of consumers that can be significantly fitted. Several researchers have proposed to improve the consumer fit by including higher-numbered PCs in the analysis. We have explored the possibility of including higher-numbered PCs while restricting the model choice to the simplest polynomial function, i.e. the (linear) vector model. In addition, we have developed a heuristic decision rule for determining the number of PCs to keep in the fit. A practical example is discussed where the consumer fit improved from 51% (two PCs, polynomial) to 80% (five PCs, vector).

Electro-olfactograms are present when odorous stimuli have not been perceived

After chemical stimulation of the human olfactory epithelium it is possible to record a negative response (electro-olfactogram, EOG) which is interpreted as the summated generator potential of olfactory neurons. The aim of the present investigation was to test whether the EOG is present when olfactory stimuli have not been perceived. Stimulation was performed with vanillin and eugenol at supraliminal and subliminal levels. Twelve healthy volunteers participated in the experiments. Stimuli were applied at an interstimulus interval of approximately 60s. Although recordings were successful in 4 of the 12 subjects, for both stimulants EOG could be obtained even when the stimuli had not been perceived by the subjects. EOG recordings in response to supra- and subliminal stimuli exhibited no major differences, except for the onset of the EOG in response to subliminal eugenol-stimuli which were prolonged compared to supraliminal stimulation. All in all, the present data provide a physiological basis for the subliminal influence of odorous stimuli on human behavior.

Complexity of Consumer Perception

Abstract The complexity of consumer perception of food products is still underestimated. Simply determining a products averaged pleasantness in a single test may not be the best way to predict the products future in the market. Not only is there a multitude of aspects and their mutual interactions that come into play, but the relationship between the consumer and the product also changes over repeated exposure, and these changes often determine the duration of the products life cycle in the market. Predicting these changes over repeated exposure is probably more important than the momentary appreciation of the product on which most market research is based nowadays. The role of “collative properties,” like perceived complexity, in the development of liking over exposure is discussed, and methods for predicting these changes and for the introduction of the product into the market are described. The effects of these methods on the possibility of producing more durable products are indicated.

9 – Flavor Memory

Odor, taste, texture, temperature, and pain all contribute to the perception and memory of food flavor. Flavor memory is also strongly linked to the situational aspects of previous encounters with the flavor, but does not depend on the precise recollection of its sensory features as in vision and audition. Rather, flavor memory is directed at novelty and change detection and thus effectively warns us of the possible dangers of new foods. It also plays a special role in evoking autobiographical memories and crossmodal visual images. In normal everyday life, flavor memory is mainly implicit and merely provides feelings of familiarity. Explicit flavor memory is used by experts and in gastronomic circles. Methods for studying normal implicit flavor memory are still insufficiently used.