Introduction
To identify the influence of sensory properties on food choice is
difficult as it is affected by a wide range of consumer motives
which, among others, include the desire to satisfy hunger, social
and cultural believes, and attitudes towards prices, brands, and
convenience. However, there is convincing evidence that taste
is a main driver of food choice (Garcia-Bailo, Toguri, Eny, &
El-Sohemy, 2009; Hasselbalch, Heitmann, Kyvik, & Sorensen,
2008).
Because of a general trend towards well-being and health, con-
sumers increasingly demand health-supportive food (Block et al.,
2011). Facilitating healthy food consumption is also important
from the policy maker perspective since the prevalence of diet-
related diseases (e.g., type 2 diabetes) is dramatically growing
(Liebl, 2007; Von Ferber, Koster, & Hauner, 2007). This has been
linked to several risk factors (obesity, central adiposity, physical
inactivity) and can be prevented by life style change and diet mod-
ification (Lindstrom et al., 2006; Schwarz et al., 2007). However,
health and taste motives may be conflicting (Roininen & Tuorila,
1999; Tuorila & Cardello, 2002). Raghunathan, Naylor, and Hoyer
(2006), for instance, demonstrated that many consumers associate
unhealthy with tasty food. This unhealthy = tasty intuition implies
that consumers who strive for health and taste often struggle with
food choice: they demand healthy products on a conscious cogni-
tive level, but prefer a less healthy option on a sensory level. If this
was the case, self-reporting scales would indicate that, e.g., fat-
reduced yoghurt is more, and yoghurt rich in fat is less successful
in the market, whereas sensory tests in controlled environment
might indicate the opposite. We attempt to overcome this bias
by using a new methodical approach that combines both perspec-
tives and gives new insight into the conflicting influence of intrin-
sic and extrinsic expressions of the same attribute.
The knowledge on food choice drivers is still limited, mainly
because research is isolated and fragmented (Köster, 2009). Food
technologists primarily focus on analysing the impact of composi-
tion or processing on intrinsic sensory properties which determine
perceived quality (e.g., flavour, texture). In marketing, it is particu-
larly important to obtain knowledge on how the decision of an
individual is affected by informational stimuli that are provided
by packaging or advertising and which can be changed without
physically modifying the product (e.g., price or brand). Unlike in
complex buying decisions (e.g., car purchase), food choice is
conducted repeatedly so that, when a particular item is selected,
its sensory properties are usually known from previous consump-
tion. In addition, packaging layout and supplementary information
0195-6663/$ - see front matter ? 2012 Elsevier Ltd. All rights reserved.
http://dx.doi.org/10.1016/j.appet.2012.09.005
qAcknowledgement: The study was performed within the project Innovative
Strategies to Overcome Implicit Product-based and Personality-based Obstacles to
Consume Healthy Food, funded by the Federal Ministry of Education and Research,
Berlin (Grant 0315670).
⇑Corresponding author.
E-mail address: harald.rohm@tu-dresden.de (H. Rohm).
Appetite 59 (2012) 949–955
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Appetite
journal homepage: www.elsevier.com/locate/appet
such as nutritive or health-related claims may shape the final deci-
sion (Johansen, Næs, Øyaas, & Hersleth, 2010; Visschers & Siegrist,
2009; Wansink & Park, 2002).
Contradictory results in literature may be explained by taking
into account that intrinsic and extrinsic attributes evoke different
responses which jointly determine the decision for a particular
food. For example, studies carried out with cheese revealed posi-
tive (Childs & Drake, 2009; Drake, Lopetcharat, & Drake, 2009;
Yates & Drake, 2007) or negligible (Levis, Chambers, & Johnson,
2000; Ritvanen et al., 2005) effects of an increasing fat content
on product acceptance. Because intrinsic and extrinsic attributes
are processed by different senses (only vision is responsible for
extrinsic attribute perception), different mechanisms come into
play. In this context, we expect that fat content is evaluated differ-
ently: with increasing fat content, there might be a steady increase
in sensory liking. Considering its extrinsic expression, consumer
judgments may be strongly affected by health-orientation and/or
social norms so that a higher fat content might be viewed rather
negatively. The final choice is then a holistic expression of both
processes. To date, only few studies (e.g., Ares, Giménez, & Deliza,
2010; Enneking, Neumann, & Henneberg, 2007; Johansen et al.,
2010) examined the perception of intrinsic and extrinsic attributes
simultaneously. However, only a limited set of attributes was ex-
plored, and the same attributes were not manipulated both intrin-
sically and extrinsically at the same time so that it remains unclear
how both processes interact in food choice.
We aim at filling this void by presenting an approach that con-
siders intrinsic and extrinsic expression of three attributes of yo-
ghurt. Two of them (fat and sugar content) can be considered as
health-related, whereas the third one (flavour) is health-unrelated.
We intend to answer the following questions: (1) Are intrinsic
properties of real yoghurt or extrinsic information supplied with
the product primarily responsible for food choice? (2) How do
effects of intrinsic and extrinsic processes differ for the same attri-
bute? (3) Do isolated approaches, which neglect the divergent pro-
cessing of intrinsic and extrinsic attributes, bias the assessment of
consumer preferences? For that purpose, we establish a procedure
which combines sensory experiments with conjoint analysis (CA)
that is frequently used for assessing the impact of extrinsic attri-
butes on product evaluation (e.g., Enneking et al., 2007; Jaeger,
2000; Jervis, Lopetcharat, & Drake, 2012; Valeeva, Meuwissen,
Oude Lansink, & Huirne, 2005). For the first time, we include both
aspects of the same attributes: subjects evaluated yoghurt with
different intrinsic intensities which were systematically modified
through yoghurt formulation, and simultaneously considered
extrinsic information given by labelling. Owing to the fact that
traditional full profile CA is restricted to only a small number of
attributes and levels, we apply a computer-based, adaptive type.
The evaluation tasks of adaptive conjoint analysis (ACA; Johnson,
1987) are optimised on the basis of previous decisions so that reli-
able results can be achieved with a small number of assessments.
To the best of our knowledge, ACA in this setup has not been used
until now in combination with sensory assessment of foods.
Materials and participants
Materials
Plain stirred yoghurt with a fat content of 0.1% or 10% (residual
lactose: 6.0% or 4.8%; protein content: 4.7% or 3.5%, respectively)
was obtained from Molkerei Hainichen-Freiberg GmbH & Co
(Freiberg, Germany). A natural vanilla flavouring preparation was
provided by Zentis GmbH & Co KG (Aachen, Germany). Sucrose
was purchased in a supermarket, and ß-carotene was from Rudolf
Wild GmbH (Berlin, Germany).
Variation of intrinsic properties: Preparation of yoghurt samples
Plain yoghurt and yoghurt mixtures (0.1%, 1.5%, 3.5% or 10% fat)
served as basis for vanilla yoghurt preparation. By considering
residual lactose, total sugar content was adjusted to 16 (regular)
or 11.2% (relative reduction: 30%). A total of 16 combinations
was prepared by incorporating 4% or 7% vanilla flavouring prepara-
tion. The procedure was the following: sugar was weighed into a
beaker, dissolved in vanilla flavouring and mixed with yoghurt.
Depending on fat content and the amount of flavouring, 10–40 ll
of 1% b-carotene in demineralised water was added per 100 g to
ensure that colour differences DE?were, based on reflectance mea-
surements, <3. Sensory experiments were carried out after storage
for 24 h at 6 ?C. Approx. 40 g portions were filled into glasses
which were closed with twist-off lids. Sample serving temperature
was 10 ± 2 ?C.
Variation of extrinsic properties: Labels
Yoghurt glasses were served with labels, attached by the exper-
imenter immediately before serving. We systematically manipu-
lated nutrition declaration and other elements of the labels to
have extrinsic attributes on the same levels as intrinsic attributes.
All other extrinsic information was identical. Labels showed a
mountain motive and a fake brand name and contained the follow-
ing design elements: (1) A table with nutrition information (fat
content, sugar content, energy per 100 g) in a design typical for
the German market. (2) Claims for variation of fat content (‘‘fat
reduced’’, ‘‘cream yoghurt’’), for lower carbohydrate content
(‘‘reduced sugar’’), and for higher flavouring (‘‘more vanilla
flavour’’). In line with the study design, 16 variants (4 ? fat content,
2 ? sugar content, 2 ? flavour level) were designed and printed on
self-adhesive paper.
Participants
We recruited 101 students (65 female, average age: 24.1 ±
3.7 years; 36 male, average age: 23.7 ± 3.1 years) from lectures.
In a questionnaire, they were asked for body height and body
weight; body-mass index range was 18.1–41.3 (median: 23.1).
Fifty-seven percent of the participants claimed that they do their
shopping themselves, and 74% indicated to consume yoghurt
several times a week. For each single session, which lasted approx.
1 h, the participants received an allowance of 10 €.
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