JFS:
Sensory and Nutritive Qualities of Food
Inheritance of Nutritional and Sensory
Quality Traits in Fresh Market Tomato
and Relation to Consumer Preferences
M. CAUSSE , M. BURET, K. ROBINI, P. VERSCHAVE
ABSTRACT: In order to analyze the genetic control of fresh-market tomato quality, the genetic variation of quality
attributes was analyzed in 45 hybrids and their 13 parental lines, grown in 2 contrasted environments. Fruit quality
was assessed by physical measurements, fruit composition, and sensory analyses (descriptive analysis by a trained
panel and hedonic tests by randomly chosen consumers). Most of the physicochemical traits, flavor attributes, and
firm texture showed a simple additive inheritance on the contrary to the aroma and other texture traits. Specific
networks of relationships among traits were shown in hybrids. Consumers perceived significant differences among
hybrids and seemed to particularly appreciate the hybrids among old and modern lines.
Keywords: L. esculentum, quantitative genetics, fruit quality, sensory analysis
Introduction
T
omatoes are 1 of the 3 most important vegetables in the
world. Adapted to winter greenhouse conditions, fresh tomatoes are now available all year long and their consumption has increased regularly during the last 10 years. The overall tomato consumption is not only important because of the amount consumed
(46.8 kg per capita per year in the U.S.A. in 1999, 26.7 on average in
Europe, with large variation: for example, 139.7 in Greece, 12.8 in
Germany), but also because the original composition in secondary
metabolites of tomatoes make them an important source of antioxidant and vitamin compounds. Tomato consumption has been
shown to reduce the risks of certain types of cancer and cardiovascular diseases (Giovannucci 1999). Much of the health benefit derived from tomatoes can be attributed to lycopene content (Bramley 2000), but tomatoes are also an important source of vitamin C
(Offord 1998). Consumers have been complaining about tomato
taste for years (Hobson 1988; Bruhn and others 1991), often blaming modern cultivars for lack of flavor.
Tomato fruit quality for fresh consumption is determined by a
set of attributes that describe external (size, color, firmness) and
internal (flavor, aroma, texture) properties. Sensory analysis is an
efficient way of describing these properties and has to be compared
to consumer preferences. Relationships between tomato taste and
fruit characteristics have been widely studied. For the most part,
flavor comes from the ratio of reducing sugars to organic acids
(Stevens and others 1977; Stevens and others 1979; Bucheli and
others 1999) and volatile aromas. More than 400 volatiles have
been identified (Petro-Turza 1987), some of them contributing to
the particular aroma of tomato fruit. Sweetness and acidity are re-
Sensory and Nutritive Qualities of Food
MS 20020492 Submitted 5/27/02, Accepted 12/5/02, Revised 5/29/03. Author
Causse is with INRA, Centre d’Avignon, Unité de Génétique et d’Amélioration
des Fruits et Légumes, Domaine Saint-Maurice, BP 94-84143 Montfavet
Cedex, France. Author Buret is with INRA, Centre d’Avignon, UMR Sécurité
et Qualité des Produits d’Origine Végétale, Domaine Saint-Paul, 84 914
Avignon, Cedex 9, France. Author Robini is with Maison de l’Alimentation
(CCIAV) BP1201, 84911 Avignon, France. Author Verschave, Vilmorin S.A.,
Recherche Sud, La Costière, Lédenon 30210 Remoulins, France. Direct inquiries to author Causse (E-mail: [email protected]).
2342
JOURNAL OF FOOD SCIENCE—Vol. 68, Nr. 7, 2003
lated to sugar and acid content (Stevens and others 1977; Janse and
Schols 1995; Malundo and others 1995). Depending on the studies,
acidity is more related to the fruit pH or to the titratable acidity
(Baldwin and others 1998; Auerswald and others 1999). Both sugars and acids contribute to sweetness and to overall aroma intensity (Baldwin and others 1998). Texture traits are more difficult to
relate to physical measures, although firmness of a tomato in
mouth is partly related to instrumental measure of fruit firmness
(Causse and others 2002), and mealiness was found to be related
to the texture parameters of the pericarp ( Verkeke and others
1998). Several studies have set out to identify the most important
characteristics for consumer preferences. Acceptable fruit must be
high in tomato-like aroma intensity and in sweetness, but intermediate in acidity ( Jones 1986; Baldwin and others 1998). Malundo
and others (1995) showed that given levels of sweetness correspond to optimal acid concentrations, beyond which acceptability
decreases. Baldwin and others (1998) related the overall acceptability to the ratio of sugars to titratable acidity and to the concentration
of several aroma compounds. Verkeke and others (1998) underlined the role of texture traits in the preference of consumers.
Fresh market tomato breeders have improved yield, resistance
to diseases, adaptation to greenhouse conditions, and fruit aspect but have lacked clear targets for improving sensory fruit
quality. To respond to consumers’ complaints, breeders need efficient selection criteria and must know the potential of improvement, that is, the range of genetic variability available, mode of
inheritance, and influence of growing conditions and environment on quality traits. Genetic variability for quality traits has
been reviewed by Davies and Hobson (1981), Stevens (1986), and
Dorais and others (2001). Scattered analyses have revealed genetic variation for sugars (Stevens 1972), acids, volatile compounds
(Langlois and others 1996), and secondary metabolites (Davies
and Hobson 1981; Grolier and Rock 1998). Most of the studies on
genetic variation in fruit quality describe a few cultivars or compare groups of cultivars, and preferences of consumers faced with
genetic variability have rarely been studied. Cherry tomatoes
have been identified as having the best flavor (Hobson and Bedford 1989), with fruits rich in acids and sugars. On the contrary,
© 2003 Institute of Food Technologists
Further reproduction prohibited without permission
Inheritance of quality traits in tomato . . .
Table 1—Characteristics and codes of the lines used in the 2 factorial cross designs
Line
Fruit
FirmCode weight a nessa
Sugars Titratable Parent in Parent in
contenta acidity a
factorial1b factorial 2b
Large fruits
VilB
VilG
VilF
B
G
F
125
135
115
84
77
80
3.2
3.2
2.8
5.7
4.4
5.6
M
M
M
M
M
M
VilL
Ferum
L
M
142
130
71
78
3.1
3.4
4.6
5.0
F
M
—
M
Ferum rin
Apeline
I
A
128
130
53
3.0
4.5
M
F
M
—
Saint Pierre
Rodade
S
R
156
142
54
71
3.0
3.1
4.9
7.7
F
F
—
M
Sekaichi
K
198
49
3.4
5.0
F
M
Cherry fruits
Gardeners Delight
Cervil
D
C
27
8
59
47
3.8
6.6
7.7
10.0
—
—
F
F
WVA700
W
5
37
4.1
6.7
—
F
Origin and characteristics
modern line (Vilmorin)—very firm
modern line (Vilmorin)
modern line (Vilmorin)—low sugars,
rich in pigments—determinate
growth
modern line (Vilmorin)
old line (INRA selection)—rich in
sugars
rin mutant, near-isogenic of Ferum
old line (INRA selection) - soft, rich in
sugars
old line, traditional cultivar
South African line (Bosch and others
1985) rich in acids
old line, pink fruit (Takii) very soft and
juicy
old cultivar (genetic resources)
genetic resources (Vilmorin) rich in
sugars, acids, ascorbic acid
genetic resources (L. pimpinellifollium),
rich in lycopene
a Fruit weight (g), instrumental firmness, sugars content (g/100g fresh weight), and titratable acidity (meq) correspond to the average of the plants grown in
the greenhouse trials.
b The use of lines as male (M) or female (F) genitor are indicated for each factorial design.
URLs and E-mail addresses are active links at www.ift.org
ence of the long shelf life mutation on sensory quality? (7) What
prospects can we propose for tomato quality breeding based on
these results?
Materials and Methods
Plant materials
Table 1 describes the parental lines used in the two factorial designs. The 10 large-fruited lines were divided into (1) four lines
(VilB, VilF, VilG, VilL) resulting from recent selection for covered crops
(glasshouse, plastic tunnels) by the Vilmorin seed company. They
contained several disease resistance genes, and their fruits were
firm and have a mid-to-long shelf life, although they did not contain
any ripening inhibitor mutation (rin, nor, or alc). They were chosen
for their shelf life as well as their good agronomic behavior; (2) Ferum, Apeline, Saint-Pierre, Rodade, and Sekaichi were older lines
maintained in the collection of genetic resources in INRA (Montfavet, France), adapted to field conditions, chosen for their diversity, their nice fruit color, or the good internal structure of their
fruits. On the other hand, their fruits were not firm enough to be
commercially attractive; (3) Ferum rin was a near-isogenic line of
Ferum in which the rin mutation (providing long shelf life) was introduced by five backcross generations.
The three cherry fruit lines (Cervil, Gardeners Delight, and
WVa700) had much smaller fruits, but their flavor was supposed to
be more appreciated by consumers. Cervil was provided by Vilmorin and used as parent traits in a previous study on the genetic bases
of quality traits (Saliba-Colombani and others 2001). Gardeners
Delight is an old line, long appreciated in the United Kingdom
(Hobson and Bedford 1989), and WVa700 is a wild accession of Lycopersicon pimpinellifolium. Forty-five hybrids were produced and
studied. The first factorial design included 18 large-fruit hybrids;
the second included 17 hybrids between cherry and large-fruit
lines. Hybrids were coded by 2 letters, each one corresponding to
parental line codes.
Vol. 68, Nr. 7, 2003—JOURNAL OF FOOD SCIENCE
2343
Sensory and Nutritive Qualities of Food
long–shelf life cultivars have been described as generally less tasty
than traditional ones ( Jones 1986), with lower volatile content
(Baldwin and others 1991). The studies of trait inheritance,
through classical analysis of cross designs, only dealt with a few
traits, particularly the solid and acid content (Stevens 1986). More
recently, molecular markers have made it possible to identify the
major chromosomal regions controlling trait variation (Quantitative Trait Loci) in a progeny. Such an approach has been used to
study several quality attributes of fresh market tomatoes in the
progeny of a cross between a cherry tomato and a large-fruit line
(Saliba-Colombani and others 2001; Causse and others 2001b).
Most of the traits appeared polygenically inherited.
This article presents the analysis of the inheritance of various
components of tomato fruit quality, including physical and chemical traits, and also sensory evaluation by a trained panel and hedonic tests by randomly chosen consumers. The study relies on 13
parental lines from various origins (traditional inbred cultivars or
experimental lines, and lines used as parents of modern hybrid
varieties) and 35 of their hybrids, produced following 2 factorial
cross designs. As fruit size is known to influence the sensory evaluation by taste panels, 2 experiments were set up, one involving
large fruits, the other including cherry tomatoes as one of the parents. Each experiment was studied during the spring in soil-less,
glasshouse condition and during the summer in an open field or
under an unheated plastic tunnel, in order to estimate the overall
influence of environmental conditions on quality traits.
The cross designs were planned to answer several questions: (1)
What is the influence of environment on quality traits? (2) What is
the amount of genetic variability in instrumental and sensory quality traits? (3) How are these traits inherited: what is the influence of
parental line on hybrid performance, and can we predict the quality
of hybrids based on the knowledge of their parental lines? (4) What
are the relationships among the quality traits? (5) Are consumers
able to identify differences among genotypes? What are the most
relevant traits influencing their preference? (6) What is the influ-
Inheritance of quality traits in tomato . . .
Growing conditions
Two trials were set up for each cross design: in 1999 for the largefruit trial, one in a spring, soil-less glasshouse in Montfavet, France
(sowing in January, harvest in May to June), the other in a field in
Ledenon, France (harvest in September); in 2000 for the small-fruit
trial, one in a spring, soil-less glasshouse and the second in an unheated plastic tunnel (harvest in September). Each genotype was
represented by a 12-plant plot in completely randomized trials.
Fruit quality analyses
Fruits were harvested when fully ripe, twice a week during a 4- to
6-wk period. A total of 42 fruits were sampled per genotype (7/wk)
for physical analyses, which included fruit weight, firmness (measured by a Durofel®), and color—L* (brightness), a* (green to red),
b* (blue to yellow) (measured with a chromameter Minolta CR-200).
Groups of 7 fruits were then frozen and ground in liquid nitrogen for
chemical analysis. Dry matter weight, soluble solids, reducing sugars, pH, titratable acidity, carotene, and lycopene contents were
measured following the procedure described by Saliba-Colombani
and others (2001). Ascorbic acid content was determined following
the microfluorimetric method described by Zerbini and others
(1991).
Sensory analyses were performed with 2 panels: a trained panel
for descriptive analyses and a consumer panel for preference tests.
The sensory panel was composed of 22 judges, previously trained
for quantitative description of tomato attributes, as described in
Causse and others (2001b). Fruits were kept at room temperature
and tasted the day after harvest in a sensory analysis laboratory
(AFNOR norm V09-105). Each panelist tasted 6 fruits per assay.
Fruits were grouped depending on their size and at least 20 replications per genotype were obtained. The attributes, chosen to describe the intensity of taste (sweetness and acidity), aroma (overall tomato aroma and strange or foreign aroma), and texture
(firmness, juiciness, mealiness, and difficulty in swallowing skin)
were noted on a 9-point scale. In the trial of hybrids between cherry
and large-fruit lines, separated analyses were performed on largefruit lines and small-fruit hybrids. The consumer panel consisted
of 4 groups of more than 250 people recruited in the vegetable department of the Auchan store in Le Pontet, France. Hedonic tests
were performed in the store, only on hybrids, for 2 d for each trial.
Each consumer had to score 3 fruits for pleasantness on a 9-point
scale: “dislike very much” (left) to “like very much” (right). Each
genotype was assayed by at least 42 consumers per trial. The order
of presentation was based on an incomplete design built from
mutually orthogonal latin squares, balanced so that each sample
appeared in a given position an equal number of times.
Statistical analyses
Sensory and Nutritive Qualities of Food
Means were compared by several analyses of variance, separately performed on lines and hybrids. Differences among genotypes, environments, and their interaction were first tested, followed, on the hybrids, by a dissection of the male and female
effects. Sensory profiles were analyzed to assess the effects of genotype, panelist, replicate, and their interactions. Newman-Keuls
multiple comparison tests were performed when the genotype effects were significant in the analysis of variance, in order to know
which genotype was significantly different. Multiple factorial analysis also was performed to evaluate the heterogeneity among panelists: a few panelists with inconsistent behavior were withdrawn
from the analyses. The consumer tests were analyzed by calculating the weighted mean of each genotype taking into account the
overall mean (y, any product, any consumer), the “i” genotype
mean (yi), and the mean of all the scores attributed to all the gen2344
JOURNAL OF FOOD SCIENCE—Vol. 68, Nr. 7, 2003
otypes evaluated by all the consumers who have evaluated genotype i [y(i)]. All the statistical analyses were performed using Splus
software (AT&T, Greensboro, N.C., U.S.A.).
Results and Discussion
Influence of environmental conditions on quality
traits
Growing conditions are known to influence quality traits at the
composition level (reviewed by Dorais and others [2001] for glasshouse conditions), and at the sensory level (Hobson and Bedford
1989). Differences between the 2 environments were significant for
most of the traits in the 2 cross designs (Table 2 and 3). Firmness
was higher in the 2 spring greenhouse conditions, whereas brightness (L*) was lower. Soluble solid content was lower in greenhouse
conditions in the large-fruit trial than in the late summer open-air
trial. The genotype by environment interactions were usually
much less significant than the main genotype or environment effects, as also observed by Auerswald and others (1999) and Johansson and others (1999), who found that variety differences affected
more fruit quality than growing conditions. In the large-fruit trial,
significant interactions were detected for fruit weight, pH, sweetness, acidity, firmness, and mealiness. This may result from the
differences in adaptation to the field conditions between the old
and modern lines. In the small-fruit trial, sweetness was the only
trait showing significant genotype by environment interactions,
confirming that fruit weight, firmness, color, soluble solid, and titratable acidity had high heritability,. This is in contrast to the pigment content, as shown by Saliba-Colombani and others (2001),
and confirms that panelists often constitute the first source of variation in sensory evaluation (Causse and others 2001b).
Genetic variation among lines and hybrids
Apart from fruit weight, parental lines significantly differed in
many traits. Large-fruit lines differed mainly in firmness and titratable acidity (Table 1). Lines were divided into 2 groups, modern
and old, to study the influence of recent selection (although fruit
composition has never been a breeding objective). The classification as either an old or a modern genotype was difficult for Rodade
and Ferum lines, which were selected in the 80s and showed intermediate firmness between soft lines (Sekaichi, Apeline, and Saint
Pierre) and very firm ones (VilB, VilF, VilG, VilL). Nevertheless, the
influence of recent selection could be detected: modern lines were
on average rated less sweet and more acidic, with lower solid and
ascorbic acid content, but firmer than old ones. However, modern
lines, which all originated from Vilmorin breeding programs,
showed different patterns: VilG had the lowest titratable acidity,
the lowest sugar, and ascorbic acid contents. VilB was the mealiest
in contrast to VilF. Rodade had extreme acidity (at both pH and titratable acidity levels), which conferred the line with high acidity,
but it was poor in reducing sugars and ascorbic acid. Sekaichi, with
the largest fruits, was very sweet and juicy. The 3 cherry tomato lines
were on average richer in acids, soluble solids, and ascorbic acid,
than were large-fruit lines; although they differed from each other
in their fruit composition as well as in their sensory profiles. Significant differences were detected among hybrids for all traits (Table
2 and 3).
Influence of the parental line origin on hybrid
performance
When the hybrids were grouped according to their parental origins in old × old, modern × modern, or old × modern hybrids, significant differences in firmness, color, and ascorbic acid content were
URLs and E-mail addresses are active links at www.ift.org
Inheritance of quality traits in tomato . . .
Table 2—Large-fruit trialsa
Line means
ANOVAb
Hybrid means
Old ×
GlassParent/
Old c Modernc Old c Modernc modern c house
Field
Envi G × E j Male Female Male ×
hybrid
(n = 5d) (n = 4 e) (n = 4f) (n = 4g) (n = 10h) (n = 18) (n = 18) 1 df 17 df 3 df
5 df
female correlation ck
Instrumental traits
Weight (g) 151.37 129.14 142.70 132.83
Firmness 60.98
77.95
67.54
77.99
L* (brightness) 41.60
41.18
40.57
40.41
a* (green-red) 18.14
18.00
20.30
17.72
b* (blue-yellow) 30.76
33.54
34.20
31.44
SSC (°Brix)
4.74
4.62
5.21
4.78
pH
4.20
4.22
4.23
4.22
Titratable
5.42
5.10
5.43
5.24
acidity (meq)
Ascorbic acid 13.74
11.48
14.13
12.49
(mg/100 g FW)
Lycopene
4.04
4.19
4.74
4.44
(mg/100 g FW)
Carotene
0.83
0.84
0.98
0.92
(mg/100 g FW)
Sensory attributes (note: on 1 to 9 scale)
Sweetness
3.38
2.71
3.94
2.92
Acidity
2.60
3.14
3.18
3.40
Tomato aroma
2.53
3.10
3.46
3.35
Strange aroma
3.24
3.21
2.83
2.56
Firmness
2.53
5.18
2.97
5.75
Juiciness
5.25
4.64
5.06
4.64
Mealiness
2.65
2.75
3.81
2.15
Skin
4.23
4.06
4.95
4.01
133.37
70.35
39.96
18.12
31.51
5.02
4.22
5.48
136.95
71.48
40.56
18.68
32.84
4.99
4.21
5.53
136.57
67.57
42.02
19.82
32.36
6.08
4.19
5.41
ns
***
***
***
ns
***
ns
ns
**
ns
ns
ns
*
ns
**
**
ns
***
**
***
***
*
***
***
**
***
***
***
***
**
ns
**
*
ns
ns
ns
ns
ns
ns
ns
ns
0.91
0.69
ns
0.65
0.65
0.78
0.73
13.80
13.24
—
—
—
ns c
ns c
***c
0.54
4.49
4.28
—
—
—
**c
***c
***c
0.65
0.93
0.85
—
—
—
***c
*c
ns c
0.45
3.91
3.38
3.69
2.54
3.54
5.54
2.49
4.46
3.60
3.33
3.48
2.87
3.72
5.15
3.07
4.53
4.13
3.41
4.15
3.62
4.81
5.50
3.60
4.92
***
ns
***
***
***
**
***
***
***
ns
*
*
***
*
***
ns
***
***
***
***
***
***
***
*
*
**
ns
**
***
***
***
***
*
**
ns
*
*
*
*
**
0.79
0.49
ns
ns
0.93
ns
ns
0.71
a Average values of the instrumental and sensory traits in the lines and hybrids grouped according to their origin. ( n = number of genotypes in brackets).
b Significance levels of the ANOVA for the sources of variations (Env: environment, male and female parent) and interactions (G × E : genotype × environment,
male × female). ns, non significant; *, P < 0.05; **, P < 0.01; ***, P < 0.001.
shown. The hybrids between old lines also rated sweeter, on average, even though their sugar or soluble solid content did not significantly differ. This relation could be attributed to the different perception in the fruit texture of modern and other hybrids (Figure 1).
Hybrids involving old lines appeared less firm, juicier, and mealier than hybrids between modern lines. Such interaction between
flavor and texture traits has also been mentioned by Wolters and
van Gemerts (1990) and Causse and others (2001b). Hybrids between modern and old lines thus benefit from the qualities of the
2 groups, being sweeter, juicier, less mealy, and having stronger aroma intensity. Nevertheless a large variability was detected among
hybrids. Hybrids with cherry tomato lines had high sugar and acid
contents, in agreement with Hobson and Bedford (1989), but a
wide range of variability was shown among the offspring of these 3
cherry tomato lines (Figure 2).
Prediction of hybrid quality based on parental line
value
Significant differences were detected for most of the traits, according to the male or female effect. Interactions between male
and female parents, which result from specific combining ability,
URLs and E-mail addresses are active links at www.ift.org
were only strongly significant for ascorbic acid and lycopene contents in large fruits, and for pH and titratable acidity in the smallfruit trial. The correlations between the hybrid value and the average of the corresponding parents were high for most of the
instrumental traits, with the exception of fruit weight and color (Table 2 and 3). A strong correlation means that the trait was inherited
in an additive manner. Fruit weight was inherited differently in the
large- and small-fruit crosses. In the large-fruit crosses, the large
fruit size was dominant. On the contrary, in the small- × large-fruit
crosses, the small fruit size tended to be partially dominant. For the
sensory traits, sweetness, acidity, and firm texture seemed to be
the most additive traits; the other texture traits showing a more
variable inheritance, with the aroma traits being quite unpredictable.
Specific trends were identified: Sekaichi, the sweetest line with
soft fruits, had hybrids with much sweeter, less firm fruits, whatever
the other parent: its large fruit size was not dominant, even in the
large-fruit trials. All the hybrids with Rodade were more acidic, as
opposed to those involving VilG. In the trial involving small fruits,
the influence of the small-fruit line seemed to discriminate more
with the hybrids than the large-fruit ones (for fruit weight, firmVol. 68, Nr. 7, 2003—JOURNAL OF FOOD SCIENCE
2345
Sensory and Nutritive Qualities of Food
cEstimated in greenhouse trial only.
d Old lines are M, A, S, R, and K.
e Modern lines are B, G, F, and L.
fOld hybrids are AM, SM, RM, and KM.
g Modern hybrids are LB, LG, FB, and FG.
h Old × modern hybrids are LM, AB, AG, SB, SG, RB, RG, KB, KG, and SF (according to the codes in Table 1).
i Env: environment
j G × E, genotype × environment
k Correlation coefficients between the average values of hybrids and of their average parent.
Inheritance of quality traits in tomato . . .
Table 3—Small-fruit trialsa
Lines
ANOVA b
Hybrids
Cherry
( n = 3 c)
Cherry
× old
( n = 9 d)
Cherry ×
modern
( n = 8 e)
Glass
house
(n = 17)
13.09
47.56
36.90
10.45
26.20
7.21
4.26
40.67
56.62
36.33
11.57
28.52
6.99
4.23
33.30
59.77
36.54
11.51
28.11
6.90
4.28
36.15
58.83
36.53
11.71
28.80
7.01
4.27
34.24
56.71
40.61
11.19
29.14
7.05
4.07
***
***
***
**
ns
ns
***
ns
ns
ns
ns
ns
ns
ns
***
***
**
***
*
***
***
***
***
***
***
*
***
***
***
ns
**
**
ns
**
***
0.48
0.83
ns
0.85
ns
0.89
0.85
8.12
7.84
7.14
7.38
8.71
***
ns
***
***
***
0.71
27.84
22.88
21.22
22.11
23.01
*
ns
***
***
ns
0.95
3.14
3.25
3.77
3.44
3.44
ns
ns
***
***
ns
0.73
1.57
1.18
1.23
1.21
0.92
***
ns
***
***
ns
0.87
Sensory attributes (note: on 1 to 9 scale)
Sweetness
3.41
4.01
Acidity
3.45
3.61
Tomato aroma
3.52
4.29
Strange aroma
1.93
1.55
Firmness
3.87
4.38
Juiciness
5.70
5.85
Mealiness
2.39
2.40
Skin
3.80
3.84
3.48
3.35
4.34
1.24
4.74
5.44
2.13
4.65
3.76
3.42
4.30
1.39
4.62
5.60
2.30
4.34
3.38
3.46
3.49
1.41
4.75
5.26
3.04
4.49
***
ns
***
ns
ns
***
***
ns
**
ns
ns
ns
ns
ns
ns
ns
ns
***
ns
ns
***
**
ns
***
***
ns
ns
***
***
***
***
***
ns
ns
ns
ns
ns
*
ns
ns
ns
0.62
ns
ns
0.51
0.74
0.61
0.49
Instrumental traits
Weight (g)
Firmness
L* (brightness)
a* (green-red)
b* (blue-yellow)
SSC (°Brix)
pH
Titratable
acidity (meq)
Ascorbic acid
(mg/100 g FW)
Lycopene
(mg/100 g FW)
Carotene
(mg/100 g FW)
Field
Env
(n = 17) 1 df
G×E
16 df
Parent/
Male Female Male ×
hybrid
6 df
2 df
female correlationfg
a Average values of the instrumental and sensory traits in the lines and hybrids grouped according to their origin. ( n = number of genotypes in brackets).
b Significance levels of the ANOVA for the sources of variations (Env: environment, male and female parent) and interactions (G × E : genotype × environment,
male × female). ns, non significant; *, P < 0.05; **, P < 0.01; ***, P < 0.001.
cCherry lines are D, C, and W.
dCherry × old hybrids are CM, CR, CK, DM, DR, DK, WM, WR, and WK.
e Cherry × modern hybrids are CB, CF, CG, DB, DF, DG, WB, and WG (according to the codes in Table 1).
fEstimated in greenhouse trial only.
g Correlation coefficients between the average values of hybrids and of their average parent.
Sensory and Nutritive Qualities of Food
Figure 1—Relationship between the average scores of
hybrids for firm texture and sweetness evaluated in the 2
trials by trained panels (1 to 9 scale). 䉬, hybrids between
modern lines; 䊐, hybrids between old lines; 䊏, old × modern
hybrids; 䉭, Ferum rin × large-fruit hybrids; 䊉, hybrids between modern lines and cherry tomato lines; 䊊, hybrids
between old lines and cherry tomato lines; +, hybrids between Ferum rin and cherry tomato lines.
2346
JOURNAL OF FOOD SCIENCE—Vol. 68, Nr. 7, 2003
Figure 2—Relationship between the average soluble solid
content and titratable acidity. 䉬, hybrids between modern
lines; 䊐, hybrids between old lines; 䊏, old × modern hybrids; 䉭, Ferum rin × large-fruit hybrids; 䊉, hybrids between
modern lines and cherry tomato lines; 䊊, hybrids between
old lines and cherry tomato lines; +, hybrids between Ferum
rin and cherry tomato lines.
URLs and E-mail addresses are active links at www.ift.org
Inheritance of quality traits in tomato . . .
Table 4—Correlation matrix of the mean instrumental measures and sensory attributes among hybridsa
FW
FW
FIR
L*
a*
b*
SSC
pH
TA
SUG
ASC
LYC
SWE
ACI
TOM
STR
FIT
JUI
MEA
SKI
PLEAS
—
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
FIR
L*
a*
b*
SSC pH
TA
0.72 0.68
ns
ns –0.69 ns
ns
—
0.67
ns
ns
ns
ns –0.54
0.55
—
0.48
ns
ns
ns
ns
0.51 0.55
—
0.82 –0.59 ns
ns
0.53 0.80 0.73
—
ns
ns
ns
ns
ns
ns
ns
— 0.68 ns
ns
0.49
ns
ns
ns
—
ns
ns
ns
ns
ns
ns –0.77 —
–0.67 ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
–0.59 ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns –0.66 0.76
ns
ns
ns
ns
ns —0.49 ns
ns
ns
ns
ns
ns 0.53 ns
0.80
ns
ns
ns
ns
ns
ns
–0.65 –0.53 –0.70 –0.47 ns
ns
ns
ns
0.47 0.75 0.56 ns
ns
ns
ns
ns
0.44
ns
ns
ns
ns
ns –0.48 ns
ns
ns –0.50 0.57
SUG
ASC LYC
SWE
–0.74
–0.53
–0.59
–0.55
–0.35
0.97
0.64
ns
—
0.47
ns
0.64
ns
ns
ns
–0.64
ns
ns
ns
0.58
–0.79
–0.71
–0.52
–0.53
ns
0.91
ns
ns
0.94
—
—
ns
ns
ns
ns
ns
ns
ns
ns
ns
–0.74 ns
ns 0.71
–0.75 ns
ns
ns
–0.59 ns
ns 0.57
ns
ns
ns
ns
ns
ns
ns
ns
0.74
ns
ns –0.70
ns
ns
ns –0.54
ns
0.52 ns
ns
0.80
ns
ns –0.70
0.83
ns
ns –0.58
ns
ns
ns
ns
—
ns
ns
ns
–0.45 —
ns
ns
0.51
ns
—
ns
ns –0.53–0.41 —
–0.69 ns
ns
ns
0.53
ns 0.62 ns
ns
ns
ns 0.49
ns
ns
ns
ns
0.49
ns 0.48 ns
–0.67
–0.49
–0.63
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
–0.48
ns
ns
–0.54
ns
ns
ACI TOM STR
FIT
JUI
ns 0.88
0.47 0.49
ns 0.62
ns
ns
ns
ns
ns –0.80
0.70 –0.60
ns
ns
ns –0.84
ns –0.80
–0.58 ns
ns –0.65
ns
ns
ns
ns
–0.48 0.80
—
ns
ns
—
ns –0.58
ns
ns
ns
ns
MEA
SKI PLEAS
–0.65 ns –0.81
–0.49 ns –0.62
ns
ns –0.63
ns
ns –0.59
ns 0.52 ns
0.51 ns 0.86
ns
ns 0.48
ns
ns
ns
0.57 ns 0.84
0.59 ns 0.82
ns
ns
0.57 ns 0.74
ns
ns
ns
ns
ns
ns
–0.55 ns –0.68
ns
ns
ns
–0.66 ns –0.81
—
ns 0.49
0.54
—
ns
ns
ns
–
a Average values of the 2 trials.
Top: small-fruit trial, bottom: large-fruit trial. Significant ( P < 0.05) correlation coefficients are indicated; ns, not significant.
FW, fruit weight; FIR, instrumental firmness; L *, brightness; a *, green-red color; b *, blue-yellow color; SSC, soluble solid content; TA, titratable acidity; SUG,
sugar content ; ASC, ascorbic acid content; LYC, lycopene content; SWE, sweetness; ACI, acidity; TOM, tomato aroma; STR, strange aroma; FIT, firmness in
mouth; JUI, juiciness; MEA, mealiness, SKI: embarrassing skin; PLEAS, pleasantness attributed by consumers.
Relationships between sensory attributes and
physicochemical traits
Sensory assessment is time-consuming and expensive, thus
Figure 3—Relationships between the average soluble solid
content and the ascorbic acid content. 䉬, hybrids between
modern lines; 䊐, hybrids between old lines; 䊏, old × modern
hybrids; 䉭, Ferum rin × large-fruit hybrids; 䊉, hybrids between modern lines and cherry tomato lines; 䊊, hybrids
between old lines and cherry tomato lines; +, hybrids between Ferum rin and cherry tomato lines.
URLs and E-mail addresses are active links at www.ift.org
breeders are looking for instrumental measures that could replace
trained panels. Different trends of correlations among traits were
detected in small- and large-fruit hybrids (Table 4).
Stable correlations over the 2 cross designs were observed (1)
among the instrumental traits: the L*, a*, b* color parameters correlated with the lycopene content, and the ascorbic acid content correlated with the soluble solids (Figure 3); there were negative correlations between pH and titratable acidity on one hand, and
among firmness, and ascorbic acid, and lycopene contents on the
other hand; (2) among sensory attributes: acidity and tomato aroma
were positively correlated, and juiciness and mealiness were negatively related; (3) between sensory attributes and instrumental
assays: sweetness was correlated with reducing sugar content and
acidity with titratable acidity (as already shown by Baldwin and
others 1998); firm texture was correlated to instrumental firmness
Figure 4—Relationship between pleasantness rated by
consumers on the large-fruit hybrids grown in glasshouse
and in field conditions. 䉬, hybrids between modern lines;
䊐, hybrids between old lines; 䊏, old × modern hybrids; 䉭,
Ferum rin × large-fruit hybrids.
Vol. 68, Nr. 7, 2003—JOURNAL OF FOOD SCIENCE
2347
Sensory and Nutritive Qualities of Food
ness, carotene, sugars, ascorbic acids). The hybrids of the cherry tomato line Cervil were richer in sugars, acids, and ascorbic acid,
whereas the hybrids of Gardeners Delight were juicier. These results indicate that efficient selection for flavor traits could be performed, based on the choice of complementary parental lines, but
specific combinations have to be found to improve aroma and texture attributes.
Inheritance of quality traits in tomato . . .
(as mentioned by Lee and others 1999), and mealiness was positively correlated to soluble solids. Some correlations were significant only in 1 group of hybrids, for example, in large-fruit hybrids,
fruit weight with soluble solids, and sweetness with tomato aroma
and juiciness. In the small-fruit hybrids, mealiness was negatively correlated with tomato aroma. Correlations involving firmness
were even positive in one group and negative in another: instrumental firmness was positively related to fruit weight in the smallfruit sample, unlike the large-fruit one. The opposite was observed
between instrumental firmness and juiciness. The sense of the correlation between fruit weight and sugar content varied among samples, as already mentioned by Grandillo and others (1996). The
same trend was observed for pH and titratable acidity (as also observed by Davies and Hobson [1981]).
Preferences of consumers
Consumer preferences were assessed on hybrids only. Among
the large-fruit hybrids, those involving the Ferum rin or Saint-Pierre
lines as parents were systematically ranked lower. For the other
parents, specific effects were observed (Figure 4). When the hybrids were grown in field conditions, hybrids corresponding to
old × old combinations ranked higher than when they were grown
in greenhouses. This may result from the fact that these lines have
been selected for field conditions. Combinations between old lines
and modern ones, corresponding to intermediate firmness, seemed
preferred, at least for the greenhouse trial. The Sekaichi × VilB
hybrid was preferred, as it was sweet, juicy, not very firm, and
mealy. The pleasantness note was positively correlated with sugars,
titratable acidity, overall aroma intensity, and sweetness and negatively correlated with mealiness and brightness (Table 4). Among
the small-fruit hybrids, the hybrids involving Gardeners Delight
were systematically less appreciated by consumers, although they
were less mealy than hybrids of Cervil (Figure 5). Such a result confirmed that the role of sweetness and acidity was more important
than texture traits in determining preference, as already mentioned by Stevens and others (1977). The differences between the
2 environments were less important in the small-fruit design than
in the large-fruit one, except for the hybrids of WVa700, which were
less appreciated in the tunnel trial. A clear separation of hybrids
Sensory and Nutritive Qualities of Food
Figure 5—Relationship between pleasantness rated by
consumers on the small-fruit hybrids grown in glasshouse
and in plastic tunnel conditions. 䊉, hybrids between modern lines and cherry tomato lines; 䊊, hybrids between old
lines and cherry tomato lines; +, hybrids between Ferum
rin and cherry tomato lines.
2348
JOURNAL OF FOOD SCIENCE—Vol. 68, Nr. 7, 2003
based on the small-fruit parent was observed, giving rise sometimes to unexpected correlations, like the negative correlation between pleasantness and firmness or the positive one with mealiness. Nevertheless the range of mealiness was not too large and
thus remained acceptable to consumers.
Soluble solid content is the easiest measure linked to the sugar
content (Davis and Hobson 1981), and it has been suggested that
it could be the first criteria for ranking the fruit quality of commercial varieties. Although this measure can be related to sugar content, its value is strongly correlated with consumer preference only
in the small-fruit hybrids, not in large-fruit hybrids (Figure 6).
The interviewed consumers reflected a specifically French panel, and our objective was not to describe the diversity of consumer
preference, through preference mapping, but to study how the
genetic variability could be perceived by an untrained panel of
consumers. The important contribution of sugars and acids to the
overall tomato flavor and consumer preference already mentioned
by Jones and Scott (1984) was confirmed. The results also showed
the importance of texture and flavor in consumer preference, as also
mentioned by Wolter and van Gemert (1990). Mealiness has been
found as the 2nd most important attribute for Dutch consumers
(Janse and Schols 1995); firmness also has been shown to be important by Winsor (1979). Although texture comes second, if a good flavor is obtained, a good texture will be necessary (Harker and others
1997), at least in large-fruit hybrids. The aromas, particularly fruitiness, which were mentioned by Bucheli and others (1999), did not
appear as the most important attributes in our experiment.
Effect of the rin mutation on sensory quality
The major differences detected between the hybrids containing the rin mutation at the heterozygous levels and their nearisogenic hybrids, concerned the lycopene content: 18% less in
large-fruit hybrids. Smaller differences found for instrumental
firmness or sugar content were not significant. Differences were
detected by sensory profiles, rin hybrids showing fruits 17% less
sweet on average (P < 0.001), with a 12% lower tomato aroma, a
Figure 6—Relationship between soluble solid content and
the note of consumer pleasantness. 䉬, hybrids between
modern lines; 䊐, hybrids between old lines; 䊏, old × modern
hybrids; 䉭, Ferum rin × large-fruit hybrids; 䊉, hybrids between modern lines and cherry tomato lines; 䊊, hybrids
between old lines and cherry tomato lines; +, hybrids between Ferum rin and cherry tomato lines. Averages of 2
trials.
URLs and E-mail addresses are active links at www.ift.org
Inheritance of quality traits in tomato . . .
Prospects for improving sensory quality of freshmarket tomatoes
Responding to the demand of producers and retailers of fresh
market tomatoes, breeders have considerably improved yield, external aspect, and shelf life of tomato fruit. The improvement in
shelf life was obtained either by the use of the rin mutation or by the
cumulative effect of several genes improving fruit firmness. These
cultivars have invaded the market, but today the quality of modern
cultivars is criticized. Recent studies on consumer habits in the
United States, as well as in Europe (Grasselly and others 2000),
showed that consumers would accept an increase in price for better flavor and higher nutritional value of fresh vegetables and fruits.
The present work identified the important characteristics of sensory quality and how they could be improved. It has been shown
that the physical measurements made it possible to evaluate the
external aspect (color) and firmness (commercial value), important
when buying fruit. The biochemical analysis of fruit composition
only partly helped to predict flavor (titratable acidity was related to
acidity and sugar content to sweetness), but the sensory evaluation
could not be replaced for the perception of aroma and for texture
traits. A strong interaction between texture and flavor has also been
shown, and consumers seemed to prefer cultivars with intermediate firmness. The rin mutation modified the perception of aroma
and texture, but the genetic background in which the rin gene was
transferred greatly influenced the quality of the resulting hybrid.
Cherry tomato lines have been shown as a potential source for enhancement in sugars, acids, and ascorbic acid, and could be an interesting source of quality enhancement, if the negative link between these traits and fruit weight could be broken. The potential
of genetic resources for quality traits has been under exploited in
the past, because of the lack of efficient, easy, and low cost measuring tools. As instrumental measures do not constitute good predictors, molecular markers should be used as indirect tools for selection (Causse and others 2001a).
Conclusions
A
LTHOUGH PRODUCTION OF HIGH QUALITY FRUITS IS DEPENDENT
on environmental factors (light and climate) and cultural practices, a large genetic variation was shown, which could be used in
breeding strategy. The potential of cherry tomato was underlined.
The knowledge of the value of the parental lines could help in predicting the hybrid value for firmness and fruit composition, whereas aroma and texture traits seemed more difficult to predict. Consumer preferences indicated that there is an interesting potential
in some hybrids between old and modern lines.
URLs and E-mail addresses are active links at www.ift.org
Acknowledgments
Many thanks to R. Matthieu, M. Troccaz, N. Marquer, and M.
Milesi for their precious technical support, to SCOFEL and AUCHAN
who allowed the consumer tests to be performed, and to Takii who
provided the Sekaichi line. Many thanks to B. Navez, M. Faurobert,
and L. Lecomte for their helpful comments on the manuscript, and
to C. Young for editing the English. This research was funded by the
French Ministry of Research and Technology (project 98P0500).
References
Auerswald H, Peters P, Bruckner B, Krumbein A, Kuchenbuch R. 1999. Sensory
analysis and instrumental measurements of short-term stored tomatoes (Lycopersicon esculentum Mill.) Postharvest Biol Technol 15:323–34
Baldwin EA, Nisperos-Carriedo MO, Baker R, Scott JW. 1991. Quantitative analysis of flavor parameters in six Florida tomato cultivars. J Agric Food Chem
39:1135–40
Baldwin EA, Scott JW, Einstein MA, Malundo TMM, Carr BT, Shewfelt RL, Tandon
KS. 1998. Relationship between sensory and instrumental analysis for tomato
flavor. J Am Soc Hortic Sci 123:906–15
Bosch SE, Louw AJ, Aucamp E. 1985. Rodade Bacterial wilt resistant tomato. Hortscience 20:458–9
Bramley PM. 2000. Is lycopene beneficial to human health? Phytochem 54:233–6
Bruhn CM, Feldman N, Garlitz C, Harwood J, Ivans E, Marshall M, Riley A, Thurber D, Williamson E. 1991. Consumer perceptions of quality: apricots, cantaloupes, peaches, pears, strawberries, and tomatoes. J Food Qual 14:187–95
Bucheli P, Voirol E, Delatorre R, Lopez J, Rytz A, Tanksley SD, Petiard V. 1999.
Definition of nonvolatile markers for flavor of tomato (Lycopersicon esculentum Mill.) as tools in selection and breeding. J Agric Food Chem 47:659–64
Causse M, Lecomte L, Baffert N, Duffe P, Hospital F. 2001a. Marker-Assisted Selection for the transfer of QTLs controlling fruit quality traits into tomato elite
lines. Acta Hortic 546:557–64
Causse M, Saliba-Colombani V, Buret M, Lesschaeve I, Issanchou S. 2001b. Genetic analysis of organoleptic quality in fresh market tomato 2. Mapping QTLs
for sensory attributes. Theor Appl Genet 102:273–83.
Causse M, Saliba-Colombani V, Lecomte L, Duffé P, Rousselle P, Buret M. 2002.
Genetic analysis of fruit quality attributes in fresh market tomato. J Exp Bot
53:2089–98
Davies JN, Hobson GE. 1981. The constituents of tomato fruit—The influence of
environment, nutrition and genotype. Crit Rev Food Sci Nutr 15:205–80
Dorais M, Papadopoulos AP, Gosselin A. 2001. Greenhouse tomato fruit quality.
Hortic Rev 26:239–319
Giovannucci E. 1999. Tomatoes, tomato-based products, lycopene, and cancer:
review of epidemiologic literature. J Nat Canc Inst 91:317–31
Grandillo S, Tanksley SD. 1996. QTL analysis of horticultural traits differentiating the cultivated tomato from the closely related species Lycopersicon pimpinellifolium. Theor Appl Genet 95:935–51
Grasselly D, Navez B, Letard M. 2000. Tomate: Pour un produit de qualité. Paris,
France: Centre Technique Interprofessionel des fruits et Légumes. 222 p.
Grolier P, Rock E. 1998. Composition of tomato in antioxidants: variations and
methodology. In: Proceedings of the Tomato and Health Seminar, 1998 May
25–28, Pamplona, Spain. Avignon, France: Amitom. p 23–25
Harker FR, Redgwell RJ, Hallett IC, Murray SH. 1997. Texture of fresh fruit. Hortic
Rev 20:121–224
Hobson GE. 1988. How the tomato lost its taste. New Sci 19:46–50
Hobson GE, Bedford L. 1989. The composition of cherry tomatoes and its relation
to consumer acceptability. J Hortic Sci 64:321–9
Janse J, Schols M. 1995. Une préférence pour un goût sucré et non farineux.
Groenten Fruit 26:16–7
Johansson L, Haglund A, Berglund L, Lea P, Risvik E. 1999. Preference for tomatoes, affected by sensory attributes and information about growth conditions.
Food Qual Pref 10:289–98
Jones RA. 1986. Breeding for improved post-harvest tomato quality: genetical
aspects. Acta Hortic 190:77–87
Jones RA, Scott SJ. 1984. Genetic potential to improve tomato flavor in commercial F1 hybrids. J Am Soc Hortic Sci 109:318–21
Langlois D, Etievant PX, Pierron P, Jorrot A. 1996. Sensory and instrumental
characterization of commercial tomato varieties. Zeitsch Lebens Unters Forsch 203:534–40
Lee SY, Luna-Guzman I, Chang S, Barrett DM, Guinard JX. 1999. Relating descriptive analysis and instrumental texture data of processed diced tomatoes.
Food Qual Pref 10:447–55
Malundo TMM, Shewfelt RL, Scott JW. 1995. Flavor quality of fresh market tomato
(Lycopersicon esculentum Mill.) as affected by sugar and acid levels. Postharvest Biol Technol 6:103–10
McGlasson WB, Last JH, Shaw KJ, Meldrum SK. 1987. Influence of the non-ripening mutants rin and nor on the aroma of tomato fruit. Hortscience 22:632–4.
Offord EA. 1998. Nutritional and health benefits of tomato products. In: Proceedings of the Tomato and Health Seminar, 1998 May 25–28, Pamplona, Spain.
Avignon, France: Amitom. p 5–11.
Petro-Turza M. 1987. Flavor of tomato and tomato products. Food Rev Int 2:309–
51
Saliba-Colombani V, Causse M, Langlois D, Philouze J, Buret M. 2001. Genetic
analysis of organoleptic quality in fresh market tomato: mapping QTLs for
physical and chemical traits. Theor Appl Genet 102:259–72.
Stevens MA. 1972. Citrate and malate concentrations in tomato fruits: genetic
control and maturational effects. J Am Soc Hortic Sci 97:655–8
Stevens MA. 1986. Inheritance of tomato fruit quality components. Plant Breed
Vol. 68, Nr. 7, 2003—JOURNAL OF FOOD SCIENCE
2349
Sensory and Nutritive Qualities of Food
17% higher strange aroma, and 10% more mealy fruits. The differences were largely dependent on the genetic background, and
they were not so strong in the small-fruit trials, where no differences were detected between the 2 sets of hybrids. At the preference level, the rank of the rin hybrids was systematically lower
than that of their isogenic genotype, and they often obtained the
lowest ranks (Figure 4 and 5). The rin mutation thus seemed to
reduce the consumer preference. McGlasson and others (1987)
attributed the bland flavor of rin hybrids to the lack of specific
aroma compounds. Nevertheless differences among hybrid combinations were always greater than differences between the
isogenic hybrids. These results confirmed the negative influence
of the rin mutation on consumer preference but also indicated
that when transferred into a hybrid with high flavor, the negative
influence of the gene is smaller. Selection could thus be carried
out for getting much sweeter and more perfumed lines in order to
be combined in rin hybrids.
Inheritance of quality traits in tomato . . .
Rev 4:273–311
Stevens MA, Kader AA, Albright-Holton M, Algazi M. 1977. Genotypic variation
for flavor and composition in fresh market tomatoes. J Am Soc Hortic Sci
102:680-9
Stevens MA, Kader AA, Albright M. 1979. Potential for increasing tomato flavor
via increased sugar and acid content. J Am Soc Hortic Sci 104:40–52
Verkeke W, Janse J, Kersten M. 1998. Instrumental measurement and modeling
of tomato fruit taste. Acta Hortic 456:199–205
Winsor GW. 1979. Some factors affecting the quality and composition of toma-
Sensory and Nutritive Qualities of Food
2350
JOURNAL OF FOOD SCIENCE—Vol. 68, Nr. 7, 2003
toes. Acta Hortic 93:335–46
Wolters CJ, van Gemert LJ. 1990. Toward an integrated model of sensory attributes, instrumental data and consumer perception of tomatoes. Part I. Relation between consumer perception and sensory attributes. Acta Hortic
259:91–106
Zerbini PE, Gorini F, Polesello A. 1991. Measurement of the quality of tomatoes:
recommendations of an EEC working group. Milano, Italy: Instituto Sperimentale per la Valorizazzione Tecnologica dei prodotti agricoli. 36 p.
URLs and E-mail addresses are active links at www.ift.org