Flavor enhancement as a tool for increasing pleasantness and intakeof a snack product among the elderly

Flavor enhancement as a tool for increasing pleasantness and intakeof a snack product among the elderly

Research Report

Flavor enhancement as a tool for increasing pleasantness and intake

of a snack product among the elderly

S Koskinen*, N Ka¨lvia¨inen1, H Tuorila

Department of Food Technology, University of Helsinki, P.O Box 27, Helsinki 00014, Finland

Accepted 29 April 2003

Abstract

A yogurt-like fermented oat bran product, flavored with regular and heightened concentrations of red currant aroma, was tested in two tasting sessions (side-by-side) and, between these, in a six-day home-use (monadic testing daily, 3 þ 3 packages of the snack) by the elderly (n ¼ 50; mean age 73.7, range 63–85 years) and the young (n ¼ 58; mean age 23.1, range 18–34 years) The subjects rated the odor and flavor intensity and pleasantness and also conducted an odor detection and identification test In home-use, the subjects reported the quantity consumed, willingness to eat, buy or recommend the snack The young outperformed the elderly in the olfactory test The heightened aroma samples were initially rated as less pleasant by both age groups, but among the elderly, the ratings given to the two samples merged during exposure For the young, the large difference in perceived odor and flavor intensities reflected marked differences in pleasantness, while the elderly were less responsive to intensity differences in their pleasantness ratings Overall, both age groups ate less of the heightened aroma sample Despite the impaired olfactory capabilities of the elderly, no clear indication of benefit of the enhanced flavor was found for either pleasantness or intake

q2003 Elsevier Ltd All rights reserved

Keywords: Elderly; Flavor enhancement; Olfactory test

Introduction

People’s food choices change during the course of aging

The daily volume of consumed foods and beverages

(grams/day) declines as a function of age Adjustments in

intake are due to many physiological changes associated

with age, including altered function of smell and taste

(Drewnowski & Shultz, 2001) According toRolls (1992),

the elderly rate flavor perception as a strong determinant of

their food choices However, the elderly are often unaware

of their impaired ability to smell and report no decrease in

their appreciation of foods (Wysocki & Pelchat, 1993)

Rolls (1993) suggests that when sensory losses occur

gradually over a period of years, their impact on appetite

also gradually declines

In the geriatric literature, the term successful aging has

been brought up, and it can refer to any type of function

(Rowe & Kahn, 1987) The term healthy aging is used in

a similar context Simons, McCallum, Friedlander, and Simons (2000)suggest that healthy aging is associated with reduced and delayed disability.Hoffman, Ishii, and Macturk (1998)reported that individuals’ overall health status, other sensory impairments, and functional limitations were associated with an increase in the rate of chemosensory disorders

According toSchiffman and Warwick (1993), addition of flavor can compensate for age-related perceptual losses, improve food palatability and acceptance, and increase intake in the elderly Tuorila, Niskanen, and Maunuksela (2001) found a slight indication that by adding an appropriate aroma the hedonic quality of food could be improved among the elderly Mattes and Cowart (1994)

proposed that while increasing the appeal of foods by adding flavor may enhance the quality of life for people who have suffered chemosensory loss, it would probably have little nutritional relevance Griep, Mets, and Massart (2000)

found a clear increase in preference for flavor-enhanced food in the elderly, but a preference for a particular food

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doi:10.1016/S0195-6663(03)00054-0

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1 Present address: Seina¨joki Polytechnic, Finland.

* Corresponding author.

E-mail address: sari.ml.koskinen@helsinki.fi (S Koskinen).

did not necessarily imply increased intake De Jong,

De Graaf, and van Staveren (1996)studied different sucrose

concentrations in breakfast items and showed that flavor

concentration rated as being most pleasant by the elderly in

a laboratory setting failed to predict pleasantness and food

intake in realistic settings

Wysocki and Pelchat (1993)suggest that olfactory loss is

not uniform across odorants Additionally,De Graaf, Polet,

and van Staveren (1994) and De Graaf, van Staveren, and

Burema (1996) reported that differences were present

between age groups in pleasantness ratings of different

types of flavors According to Murphy (1993), the age

effects on preference do not appear to be related to generally

lower perceived intensity The overall odor or flavor

complex may be differentially perceived by the elderly

and the young Thus, when some of the components fall

below an older person’s threshold, the altered flavor may

then drive the preference

Most preference tests are based on first impressions of

an evaluated product, and thus do not reflect preferences

that result after a longer exposure to the product The

natural eating environment at home also contributes to

realistic hedonic ratings (Porcherot & Issanchou, 1998)

Moreover, Cardello and Maller (1982) have questioned

the respondent’s ability to form an opinion on the basis

of a very short exposure to a product that is normally

used in larger quantities

Sensory impairments over the course of aging have

been widely studied, and relatively abundant literature

also exists on the hedonic responses of the elderly

towards foods with enhanced flavor However, little is

known about the effects of exposure on the hedonic

responses of the elderly towards such foods In addition,

very few reported studies are available that examine the

relation between olfactory capability and hedonic

responses over time One such study has been conducted

by Pelchat and Schaefer (2000), who hypothesized that

the age difference in liking a vanilla beverage might be

mediated by different olfactory sensitivity However, they

found no correlation between odor sensitivity (measured

with phenyl ethyl alcohol, PEA) and liking of the vanilla

beverage at any phase of the study

The aim of the present study was to examine the effects

of heightened aroma concentration on the pleasantness and

intake of a snack product in elderly and young consumers

over a longer exposure To obtain additional information on

the effects of olfactory sensitivity and health-related issues

on sensory and hedonic responses, the elderly were

sub-grouped based on their olfactory function and health status

We hypothesized that the enhancement of flavor by adding

aroma would increase the pleasantness and intake of the

elderly with diminished olfactory capability (De Graaf et al.,

1994, 1996) Furthermore, we anticipated that poor health

status of the elderly would impair their olfactory

perform-ance (Schiffman, 1997) and predict decreased intake (Rolls,

1993; Schiffman, 1994)

Methods Subjects

A total of 57 elderly and 62 young subjects were initially recruited, but seven of the former and four of the latter group missed one of the three test sessions and were therefore excluded from the data analysis The indepen-dently living elderly subjects (n ¼ 50; 38 females and 12 males, mean age 73.7, range 63 – 85 years) were recruited from the visitors of four service centers for the elderly in Helsinki by personal contacts The young subjects (n ¼ 58;

55 females and 3 males, mean age 23.1, range 18 – 34 years) were recruited from the staff and students of the University

of Helsinki by announcements The study was conducted according to the general principles of sensory testing in our laboratory, which have been approved by the ethical committee of the faculty The subjects signed an informed consent before the study began The subjects participated in two evaluation sessions lasting approximately 30 min each

In addition to the tasting sessions, the subjects participated

in a six-day home-use test Subjects received a small food reward after the last evaluation session

Samples The sample material was a fermented oat bran product (Yosaw, Bioferme, Finland), which is a cereal-based snack food similar to flavored yogurt Samples were flavored with

a 20% (w/w) red berry jam (Valio Ltd, Finland), containing strawberry, red currant, lingonberry, and chokeberry Two concentrations of red currant aroma (Valio Ltd, Finland) were also added to the samples The aroma concentrations (regular 0.02% and heightened 0.78%) were selected after pre-testing by an experienced laboratory panel (n ¼ 10; 7 females, 3 males, aged 25 – 41 years), which evaluated the odor (by sniffing) and flavor intensity (by tasting) of five concentrations of red currant aroma in the oat bran product The two selected concentrations differed from each other significantly in odor and flavor intensities (means: 3.8 vs 7.1 for odor and 3.5 vs 7.4 for flavor on a 9-point scale)

A sensory profile of the two snack product samples was created by a laboratory panel (n ¼ 9; 7 females, 2 males, aged 25 – 41 years) trained to evaluate attributes selected in advance The attributes were evaluated on a 9-point scale that was anchored from 1 ¼ weak to 9 ¼ strong The heightened aroma sample was perceived as more intense in currant odor and total odor, but less intense in strawberry odor It was also perceived to be less sweet, more bitter and more intense in currant flavor and in overall flavor, and stronger in after-taste than the sample with a regular aroma concentration The heightened aroma concentration caused

a slight off-flavor described as ‘artificial’

The manufacturer packaged the samples in 150 ml white plastic cups, which were coated with yellow cardboard and sealed with white aluminum lids The packaging was similar

to the commercial version, except for being blank The

samples were stored refrigerated at 4 8C

Tasting sessions

The tasting sessions for the young subjects were

conducted in the sensory laboratory at the University of

Helsinki, and for the elderly in the dining rooms or

clubrooms of the service centers Tests were conducted

before and after a six-day home-use period The subjects

received two samples of the snack product successively in

both sessions and were asked to rate the odor intensity (by

sniffing) and flavor intensity (by tasting) of the samples

using a 9-point intensity scale that was anchored from

1 ¼ weak to 9 ¼ strong Overall pleasantness of the

samples was rated on a 9-point hedonic scale, anchored

from 1 ¼ do not like at all to 9 ¼ like very much The odor

intensity was rated right after opening the lid, and the

pleasantness and flavor intensity after tasting 3 – 4 spoonfuls

of the sample The serving temperature of the samples was

4 – 6 8C Subjects rinsed their mouths with tap water before

tasting the samples and between samples The samples were

coded with three-digit random numbers, and their

presen-tation order was individually randomized for each subject

Before evaluating the samples in the first tasting session,

the subjects filled in a background questionnaire covering

their demographic background and nutritionally related

diseases (Table 1) Furthermore, the subjects reported their

familiarity and liking of the target product, as well as those

of yogurt and porridge Since no main or interaction effects

of those variables were found on any of the ratings, the data

on familiarity and liking are not reported here The lack of

effect of familiarity and liking of the target product on the

ratings was probably due to its resemblance to yogurt

Home-use test

For the home-use test, subjects received three cups

(150 g each) of the snack product at regular aroma

concentration and three cups at heightened aroma

concen-tration and were instructed to refrigerate them The samples

were coded with numbers 1 – 6, indicating the eating order

of the samples Half of the subjects ate the regular aroma

samples first and half ate the heightened aroma samples first

The subjects were asked to rate one sample a day at any time

of the day they wanted Similarly to the tasting sessions,

the odor intensity was rated right after opening the lid, and the pleasantness and flavor intensity after tasting 3 – 4 spoonfuls of the sample The scales used were the same as in the tasting sessions Subjects were also asked to evaluate the amount of eaten snack product using a 5-point visual scale with simple boxes black and white in color, the black part indicating the amount of left-over in the cup after eating In data treatment, the visual scale points were converted into rough percentages: 0 (sample tasted only), 25, 50, 75 and 100% consumed of the total amount The subjects were also asked to mark the time and meal context in which they ate it The data on the eating context and time are not reported here After the third and sixth days, subjects rated separately their boredom with and willingness to eat and buy the product and recommend it to their friends on a 9-point scale, anchored from 1 ¼ not willing/bored at all to 9 ¼ very willing/bored

Originally the subjects (young and elderly separated) were divided into three groups, which were given different information on the samples for the home-use One group in both age cohorts was informed about the organic quality of the sample and another group received information about the sample’s healthiness and low fat content A third group served as control, receiving no additional information, except for the list of ingredients The written information was provided on the front page of the home-use booklet Preliminary data analysis revealed no significant main effects and only one significant interaction of day and aroma

on the pleasantness ratings of the young, implicating an increase in pleasantness of the heightened aroma sample in the presence of health-related information Since the effects

of information were negligible, and not relevant enough for this study, the data were pooled together over the information conditions

Olfactory test

As the final task in the second tasting session, most of the subjects (53 young, 39 elderly) participated in a test that measured their olfactory performance, the European Test of Olfactory Capabilities (ETOC) The test consists of 16 common food and non-food odors that were presented to the subjects in 16 series of four vials: three of the vials were blanks and one contained the odor stimulus Subjects were asked first to detect which of the four vials contained the odor (detection) After detection, the subjects were

Table 1

Total number, gender distribution, age distribution, mean age, and nutritionally related diseases of the subjects

Age group Characteristics

Total number Gender

(male/female)

Age range (years)

Mean age (years)

High blood pressure ðnÞ

High cholesterol ðnÞ

Diabetes ðnÞ

No diseases ðnÞ

presented a list of four possible odors and asked to select the

one they thought was correct (identification) (for more

information on the test, see (Thomas-Danguin et al.,

2003a))

Data analysis

Repeated measures analysis of variance was used to test

the within-subject effect of aroma concentration of the

sample (two levels) and the day of eating (three levels) on

sensory and hedonic ratings and intake ratings in home-use

Age group (two levels) was used as a between-subject factor

The boredom ratings and the willingness ratings to eat, buy,

and recommend were tested using aroma (two levels) and day

(two levels, third and sixth day) as within-subject factors and

age group (two levels) as a between-subject factor In the

tasting sessions, the within-subject effects tested were aroma

concentration of the sample (two levels) and the session (two

levels, before and after the home-use) Age group (two

levels) was used as a between-subject factor These statistical

analyses were also conducted with gender as a

between-factor to examine its effect No trend towards the main effect

or interaction of gender was found, and therefore, the effect

of gender was not treated in results

The data of the olfactory test (ETOC) were analyzed with

one-way analysis of variance, comparing the detection and

identification scores of the young and the elderly The effect

of gender was examined in the group of the elderly with

one-way analysis of variance The olfactory scores were

compared with the mean scores of age-matched sub-groups

in data on 1100 subjects using paired t-test Furthermore, the

elderly were divided into two subgroups based on their

identification scores in ETOC using a score of 10 as a cut-off

point: (subgroups: identification score 0 – 10 and 11 – 16)

With this cut-off point we could expect differences in

perceived odor and flavor intensities (Tuorila & Koskinen,

2003) These two subgroups were referred to as ‘low score’

and ‘high score’, respectively Next, the effect of

perform-ance in the odor identification test on hedonic ratings and

intake was tested using repeated measures analysis of

variance (within aroma, between identification score) The

odor identification scores of the young were not subdivided

because of their low variation

The elderly were also divided into two subgroups based

on the number of nutritionally related diseases they had

These subgroups were designated ‘good health’ (one or no

diseases) and ‘poor health’ (two or more diseases) The

difference between these groups in odor detection and

identification scores and intake was tested with one-way

analysis of variance

The variation in the within-groups degrees of freedom

associated with F-values is due to some missing values in

the data of the elderly In the case of intake, there was also

missing data from the young The number of subjects used

in analyses of the intakes was 53 (out of 58) for the young

and 42 (out of 50) for the elderly

Results Tasting sessions Sensory ratings Both age groups rated odor intensity as stronger in the heightened aroma sample (Fð1; 106Þ ¼ 139:48; p # 0:001) However, the young perceived a larger difference in odor intensity between the samples than the elderly (interaction

of age group and aroma, Fð1; 106Þ ¼ 13:84; p ¼ 0:007) The young tended to rate the odor as more intense than the elderly (Fð1; 106Þ ¼ 3:67; p ¼ 0:058) No significant differ-ence was present in odor intensity ratings between the two tasting sessions The ratings of flavor intensity were very similar to those of odor intensity Both age groups rated flavor intensity as stronger in the heightened aroma sample (Fð1; 105Þ ¼ 77:90; p # 0:001) The young perceived a larger difference in flavor intensity between samples than the elderly (interaction of age group and aroma, Fð1; 105Þ ¼ 8:50, p ¼ 0:004) The flavor intensity ratings did not differ significantly between the first and second tasting sessions or between age groups

Hedonic ratings

In the pleasantness ratings, the aroma concentration had a similar effect on both age groups in the first tasting session: the heightened aroma sample was rated as less pleasant than the regular aroma sample (Fð1; 106Þ ¼ 54:90; p # 0:001) However, the difference between the pleasantness ratings of the two samples was smaller for the elderly than for the young (interaction of age group and aroma, Fð1; 106Þ ¼

19:55; p # 0:001) A change in the pleasantness ratings of the two age groups between the samples occurred from the first tasting session compared with the second one (Fig 1) According to the young, the pleasantness ratings of the regular aroma sample were almost the same in both tasting sessions, while the pleasantness ratings of the heightened

Fig 1 Mean pleasantness ratings (þ SEM) of the young ðn ¼ 58Þ and the elderly ðn ¼ 50Þ given to regular and heightened aroma samples in the tasting sessions , regular aroma; B, heightened aroma.

aroma sample decreased in the second tasting session

compared with the first session Among the elderly, the

regular aroma sample was perceived to be slightly less

pleasant in the second tasting session than in the first one,

whereas the pleasantness of the heightened aroma sample

increased in the second tasting session compared with the

first one (interaction of age group and aroma and tasting,

Fð1; 106Þ ¼ 10:41; p ¼ 0:002)

Home-use test

Sensory ratings

In home-use, the odor and flavor intensity ratings were

affected by aroma concentration but not by age group The

odor intensity (Fð1; 106Þ ¼ 13:95; p # 0:001) and flavor

intensity (Fð1; 103Þ ¼ 14:79; p # 0:001) of the heightened

aroma sample were perceived as stronger in both age

groups Compared to the side-by-side tasting, both age groups rated less difference in odor and flavor intensity between the samples in the home-use (monadic testing) (Fig 2a – d)

Hedonic ratings The heightened aroma concentration decreased plea-santness ratings of both age groups also in home-use (Fð1; 105Þ ¼ 21:48; p # 0:001) Again, the difference between the pleasantness ratings of the two samples was smaller for the elderly than for the young (interaction of age group and aroma, Fð1; 105Þ ¼ 5:23;

p ¼ 0:024) The pleasantness of the heightened aroma sample increased during the home-use, while the pleasantness of the regular aroma sample remained virtually unchanged (interaction of aroma and day, Fð2; 210Þ ¼ 6:12; p ¼ 0:003) (Fig 2e – f)

Fig 2 (a – f) Mean odor intensity ratings (þ SEM); (a – b), flavor intensity ratings (þ SEM) (c – d), and pleasantness ratings (þ SEM) (e – f) of the young

ðn ¼ 58Þ on the left (fig a,c,e) and the elderly ðn ¼ 50Þ on the right (fig b,d,f) given to the regular and heightened aroma samples in the tasting sessions and during home-use , regular aroma; , heightened aroma.

Willingness and boredom ratings

After the third and sixth days of home-use, subjects rated

their willingness to eat the product again, to buy it and to

recommend it to their friends They also rated how bored

they were with the product Overall, the heightened aroma

concentration decreased willingness to eat the product again

(Fð1; 106Þ ¼ 6:34; p ¼ 0:013), to buy it (Fð1; 106Þ ¼ 8:12;

(Fð1; 105Þ ¼ 6:89; p ¼ 0:010) The heightened aroma

concentration did not, however, affect willingness of the

elderly consumers to eat the product again (interaction of

aroma and age group, Fð1; 106Þ ¼ 4:15; p ¼ 0:044), to buy

the product (interaction of aroma and age group,

Fð1; 106Þ ¼ 3:89; p ¼ 0:051), or to recommend it

(inter-action of aroma and age group, Fð1; 105Þ ¼ 6:89;

p ¼ 0:010) In general, the elderly were more willing to

buy the product than the young (Fð1; 106Þ ¼ 6:86;

p ¼ 0:010) The boredom ratings were unaffected by either

aroma concentration or age group

Intake

Eighty-two percents of the young and 68 percents of the

elderly ate at least 75% of the total amount served There

was no significant difference in the intake between the age

groups, although the mean intake of the elderly was slightly

lower Both age groups ate significantly less of the

heightened aroma than the regular aroma sample

(Fð1; 93Þ ¼ 13:04; p # 0:001) The intake of neither age

group changed during the period of home-use

Olfactory test

The young subjects detected (Fð1; 90Þ ¼ 18:05;

p # 0:001) and identified (Fð1; 90Þ ¼ 53:12; p # 0:001) a

larger number of odors than the elderly The mean scores

(SEM, range) for the young subjects were 15.8 (0.18, 14 –

16) for detection and 13.5 (0.30, 9 – 16) for identification of

a possible 16 The corresponding scores for the elderly were

14.7 (0.20, 8 – 16) and 10.1 (0.35, 3 – 15) Variation in the

scores of the elderly was greater than in the scores of the

young In the elderly group, females scored higher in odor

identification than males (Fð1; 37Þ ¼ 6:10; p ¼ 0:018), their

respective scores (SEM, range) being 10.7 (0.48, 3 – 15) and

8.2 (0.88, 5 – 12) Gender had no significant effect on odor

detection scores Normative data are not yet available for

ETOC, but the mean scores of the tested sample of elderly

did not differ from the means of age-matched sub-groups in

data on 1100 subjects (Thomas-Danguin et al., 2003b)

Effect of olfactory performance and health status on hedonic

ratings and intake of the elderly

The detection and identification scores of the elderly

were explored further, revealing an association between the

scores and the number of diseases the elderly had The mean

detection score (SEM, range) for the elderly in the good

health group (n ¼ 31; 23 females, 8 males, mean age 74.2 years) was 15.1 (0.31, 10 – 16) and for the poor health group (n ¼ 7; 6 females, 1 male, mean age 73.1 years) it was 13.0 (0.66, 8 – 16) The difference in the detection scores between the two groups was significant (Fð1; 36Þ ¼ 8:31; p ¼ 0:007) The mean identification scores (SEM, range) were 10.5 (0.50, 5 – 15) and 8.9 (1.04, 3 – 13), respectively, but the difference in these scores was not significant

Hedonic ratings The pleasantness ratings of the ‘low score’ and ‘high score’ groups tended to differ from each other, but the difference was not significant (Fig 3a) The elderly scoring low in odor identification rated pleasantness of the heightened aroma sample approximately at the same level during exposure, while their pleasantness ratings of the regular aroma sample decreased towards the end of home-use Among the elderly scoring high in odor identification, the pleasantness ratings of the samples merged over exposure at home (Fig 3b) Contrary to our expectations,

‘low score’ and ‘high score’ groups did not differ significantly in the rated odor intensity or flavor intensity

of the samples

Fig 3 (a – b) Mean pleasantness ratings (þ SEM) (tasting sessions and home-use) of the elderly sub-grouped according to their scores in the odor identification (ETOC): low score group, n ¼ 19 (a); the high score group,

n ¼ 20 (b) , regular aroma; , heightened aroma.

A significant difference was present in mean intake of

both samples between the elderly scoring low (0 – 10) and

those scoring high (11 – 16) in odor identification

(Fð1; 31Þ ¼ 4:55; p ¼ 0:041); the ‘low score’ group ate

less than the ‘high score’ group (Fig 4) There also seemed

to be a connection between intake and number of

nutritionally related diseases that the elderly subjects had

The subjects who had more diseases ate less of the snack

product than their healthier counterparts The mean intake

of both samples in the elderly with good health tended to

stay approximately at the same level, while the intake of the

elderly with poor health tended to decrease during home-use

(interaction of health status and day Fð2; 38Þ ¼ 3:06;

p ¼ 0:066) (Fig 5)

Discussion

Four major findings emerged from this study:

1 During the exposures, the pleasantness ratings of the two

samples merged because of the increasing popularity of

the heightened aroma sample, especially in the elderly

2 However, flavor enhancement did not increase intake among the elderly

3 In general, the elderly were less responsive to differences

in odor and flavor intensity of the samples

4 The olfactory performance of the elderly was not associated with their hedonic responses

Sensory and hedonic responses to two flavor levels Although both age groups rated the odor and flavor intensity of the samples similarly during the testing period, their hedonic responses towards the samples differed Both age groups initially preferred the regular aroma sample to the heightened aroma sample In the young, the hedonic responses were relatively consistent, with the regular aroma sample being rated as more pleasant throughout the testing period In the elderly, by contrast, the pleasantness ratings of the two samples merged and towards the end both samples were rated as equally pleasant In a study by Philipsen, Clydesdale, Griffin, and Stern (1995), the hedonic responses

of the elderly did not change with increasing aroma concentration, whereas the young responded strongly to a change in flavor intensity.Zandstra and de Graaf (1998)also found that variability in hedonic responses towards samples with different flavor intensity decreased with increasing age Thus, the elderly may be more adaptive to slight changes in the flavor of food

Our hypothesis was that the elderly with poor olfaction would appreciate the sample with heightened aroma concentration more than the sample with regular aroma concentration The hypothesis was based on studies byDe Graaf et al (1994, 1996) and Griep, Mets, and Massart (1997) and Schiffman and Warwick (1993), all of whom found that the elderly prefer food with added flavor, likely because it compensates for their diminished olfactory function However, none of these studies actually measured the olfactory function of their subjects Therefore, whether the preference for the stronger flavor was due to compen-sation for loss of smell remains unknown In the present study, no connection between poor olfactory performance and appreciation of the heightened aroma concentration was found

The merging of pleasantness ratings given to the samples

by the elderly suggests that during the test period, the elderly might have adapted to the intense flavor Sensory losses occur gradually over a period of years, and the elderly may adjust their diets to the sensory loss (Rolls, 1993) Thus, with the snack products differing in flavor intensity, they first rated the regular aroma sample as more pleasant since the flavor intensity was more familiar to them, but with exposure they got used to the more intense flavor and thus slightly increased their liking for the initially less pleasant heightened aroma sample

The heightened aroma concentration of the sample decreased the willingness of the young subjects to eat

Fig 4 Mean intake (þ SEM) (during home-use) of the elderly according to

their scores in the odor identification (ETOC): low score group, n ¼ 16;

high score group, n ¼ 17 , regular aroma; B, heightened aroma.

Fig 5 Mean intake (þ SEM) (during home-use) of the elderly according to

their health status: ¼ poor health group, n ¼ 7; ¼ good health

group, n ¼ 31:

the product again, to buy it, and to recommend it to their

friends, whereas the willingness ratings of the elderly were

unaffected by the aroma concentration This finding also

indicates that the elderly are less sensitive to variations in

flavor intensity than the young in their hedonic responses

(Philipsen et al., 1995; Zandstra & de Graaf, 1998)

Intake of the samples with two flavor levels

In both age groups, the intake of the heightened aroma

sample was lower than that of the regular aroma sample

The finding that the elderly also ate less of the heightened

aroma sample is not congruent with earlier studies byGriep

et al (1997) and Schiffman and Warwick (1993), who found

that flavor enhancement of food increased intake of the

elderly However, the evidence for the increase in intake of

foods with enhanced flavor in these studies is not

particularly compelling since the increase was not

signifi-cant in most cases This brings us back to the notion of

Mattes and Cowart (1994) that increasing the appeal of

foods by adding flavor is of little nutritional relevance In

the present study, the heightened aroma concentration may

have been too high for both age groups, resulting in the

intake being lower for the heightened aroma sample even

among the elderly According to Rolls (1992), an

exces-sively strong flavor may decrease food intake.Vickers and

Holton (1998)found that upon repeated consumption of ice

tea subjects liked weaker tea better than strong tea, although

initially they preferred the strong tea During the exposure,

they also consumed more of the weaker tea than the stronger

one In our study, the intake of neither of the two samples

changed during home-use According toHetherington, Bell,

and Rolls (2000), the way subjects regard the foods, i.e

whether they are considered to be staple or special foods,

affects the development of monotony In their study, the

consumption of staple food (French fries) remained constant

whereas the consumption of special food (chocolate)

declined Our subjects might have considered the snack

product to be a staple food since it is yogurt-type product

and thus the consumption was unaffected by repeated use

Olfactory performance as a predictor of intake and health

status of the elderly

The young were superior to the elderly in terms of odor

detection and identification This finding is in line with

former studies (e.g Hummel, Sekinger, Wolf, Pauli, &

Kobal, 1997; Koskinen, Ka¨lvia¨inen, & Tuorila, 2003;

Nordin, Nyroos, Maunuksela, Niskanen, & Tuorila, 2002)

Furthermore, in the group of elderly, females outperformed

males in the odor identification task Similar results have

been reported byDoty et al (1984) and Nordin et al (2002)

We expected the elderly with low identification scores to

appreciate the heightened aroma sample more than the

regular aroma sample After exposure, a slight trend

occurred in that direction, however, the effect was not

significant The finding that indicates a failure of the increased flavor to increase pleasantness among the elderly with low odor identification ability may be due to the nature

of the olfactory task that was conducted The odor identification task requires memory and semantic proces-sing (Cain, de Wijk, Lulejian, Schiet, & See, 1998), and is not necessarily related to a person’s ability to perceive odor and flavor intensity, which affect the hedonic responses as well However, current notions (Doty, Smith, McKeown, & Raj, 1994; Nordin et al., 2002) suggest that olfactory tests largely measure general olfactory performance, regardless

of the type of the test Furthermore,Tuorila and Koskinen (2003) found an indication, although a slight one, of predictive value of odor detection and identification tests in odor and flavor intensity ratings The validity of different olfactory tests in the prediction of performance needs further attention

There was a tendency that the elderly in poor health (i.e more reported diseases) performed more poorly in the olfactory test and ate less of the sample than the elderly in good health Although the groups were not equal in size, the health status of the elderly did appear to have a role in sensory and nutritional issues The poorer odor detection and identification ability may be due to the cognitive limitations of the subjects The nutritionally related diseases may in part result from insufficient and unhealthy eating, which is more likely for subjects with poorer cognitive ability According to Darnton-Hill (1992), physical, social, and psychological factors potentially contribute to nutri-tional problems of elderly people However, these factors were not measured in this study The trend of smaller intake

of the subjects in poor health compared with those in good healths, although not significant, is of concern Again, the total intake of the elderly with poorer performance in odor identification test was smaller than of those who performed better in the test Thus, an association existed between intake and olfactory performance and health of the elderly The subjects of this study were independently living and active elderly people According to the literature, alongside aging, different diseases manifest that affect appetite, and the risk of developing anorexia of aging increases However, anorexia among the aged is more common in institutionalized persons Unexplained losses in food intake and body weight occurring near the end of life are characteristic of this syndrome (Horwitz, Blanton, & McDonald, 2002)

Method Both the young and the elderly perceived greater differences in odor and flavor intensities in the tasting sessions than during home-use, probably because it is easier

to find a difference in samples presented side-by-side, compared with monadic presentation, as in the home environment According to La¨hteenma¨ki and Tuorila (1994), side-by-side presentation enables direct comparisons

to be made of samples, thus emphasizing any differences

between them When a direct comparison is not allowed,

respondents use their own expectations as a reference

point (Cardello & Sawyer, 1992) Another reason for the

larger difference between the samples may be that the

evaluation conditions were more controlled in the tasting

sessions than at home, enabling better concentration on

the evaluations

The gender distribution of the subjects was unequal,

since, due to availability, more females than males were

included However, gender had no significant effect on

ratings of the samples Hence, we may conclude that the

uneven gender distribution did not affect results

appreciably

The home-use period was conducted using a

within-subject design, meaning that the within-subjects had to taste the

same samples three times and rate the same attributes six

times A drawback was the possibility that the subjects

would get bored over the course of the study, which would

in turn affect their responses According to Stubenitsky,

Aaron, Catt, and Mela (1999), subjects may express their

feeling of discontinued interest in the study itself instead of

that of the products, when they are asked how bored they are

with the studied products In the present study, neither the

boredom ratings increased nor the hedonic ratings decreased

during exposure at home It appears that the study period

was not too long or monotonous to bore the subjects

Since this was a cross-sectional study, a generation effect

might be present in the results Behavioral and/or cultural

factors may have influenced the responses of subjects

According to earlier studies (Pelchat & Schaefer, 2000;

Tuorila, Andersson, Martikainen, & Salovaara, 1998), the

elderly tend to rate samples more positively than the young

On the other hand, the elderly do express their dislike, when

a sample does not appeal to them, as was the case in

Koskinen et al (2003)

The usefulness of flavor enhancement of foods in

changing food choices and nutrition behavior of the elderly

needs further investigation, since there are ambiguous

results and evidence for and against on that matter

Acknowledgements

The authors thank practical trainees Linda van Mierlo

and Pascalle Weijzen from Wageningen University, The

Netherlands, for assistance with data collection Bioferme

Oy, especially the managing director Merja Scharlin, is

thanked for providing samples and for co-operation This

study was financially supported by the European

Commis-sion’s Quality of Life Fifth Framework Program QLK1-CT

1999-00010, project HealthSense: ‘Healthy eating: how

changes in sensory physiology, sensory psychology, and

socio-cognitive factors influence food choice’

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