Maataloustieteellinen A ikakauskirja
Vol. 61: 113—122, 1989

Effects of different fertilization practices on the glucose, fructose,
sucrose, taste and texture of carrot

AINO-MAIJA EVERS
Kemira Oy, Espoo Research Centre, Luoteisrinne 2,
SF-02270 Espoo, Finland

Abstract. The effects of different fertilization practices on the glucose, fructose, sucrose,
taste and texture of carrot cv. Nantes Duke Notabene 370 Sv were studied in field experiments
carried out in southern Finland in 1985 and 1986. The effects of unirrigated and irrigated place-
ment and broadcast fertilization, NPK fertirrigations without basic fertilization, NPK fertirri-
gations with NPK basic fertilization, and PK placement with N fertirrigations were compared.
Further, the effects of single application were compared with those ofsplit applications. Sug-
ar analyses were made by high performance liquid chromatography, and sensory evaluations
were performed for taste and texture. The results were analysed by contrast analysis.

In 1985, fertilization and fertilization practices had no effects on sugar contents. In 1986,
the unfertilized treatments had a tendency to yield higher glucose and fructose, and thus also
total sugar contents than did the fertilized treatments on the average. Placement fertilization
had a tendency to increase the glucosecontent as compared to NPK fertirrigations. No signifi-
cant differences or tendencies were found in sucrose content.

The glucose and fructose contents were higher in 1985 than in 1986. The sucrose content
was mainly opposite, being higher in 1986.Weather conditions were more favourable for pho-
tosynthesis in 1986 than in 1985. The mean total sugar content in fresh weight was 7.8 % in
1985 and 6.7 % in 1986. Indicative results of taste and texture are presented. The sugar con-
tent in organically cultivated carrots did not differ from that of conventionally grown carrots,
but the taste was worse.

Index words: fertilization practices, carrot, quality, sugars, sensory evaluation, taste, texture, organic culture

Introduction

The sugar contents and flavour of carrot
(Daucus carota L.) are influenced by genotype
and environment (Simon et al. 1980 a, 1980 b,
1982). Many researchers have reported that
year and location have a considerable effect

on both overall quality and the sugar contents
of carrots (HArdh 1975, Balvoll et al. 1976,
Martens 1985).

The literature contains contradictory results
concerning the influence of fertilization on the

113

JOURNAL OF AGRICULTURAL SCIENCE IN FINLAND

https://www.c-info.fi/en/info/?token=3_tsQnEsNC_2lYaQ.5MXhZT3zwVRWFDgOkXv0Mw.Vy__e0y95MexT1XKicoJWGH4bPH2zTvYp3ugPHVklw5kGQziNXk3Gb70WL5163y4nadvE-jld9gZSEiegLnuJXfJOiPhosBXfWIGQzFalfFCpmJCUZSwunm4sTaoW6ShAfmfMCwy_DkW_rLEHDhdYrrEFV3-GTSCf6Lut9Fs


sugar contents of carrots. Barnes (1936)
reported that increasing nitrogen levels in-
creases the amount of glucose, but at the same
time he found decreasing sucrose amounts.
Habben (1972) reported that increasing nitro-
gen levels increases the amount of reducing su-
gars (glucose and fructose) but do not affect
the sucrose content. According to Dragland

(1978), an increasing amount of nitrogen does
not effect the glucose content, but decrease the
sucrose content of carrots. In Nilsson’s (1979)
study, the content of sugars (glucose, fructose,
sucrose) in carrots is unaffected by either the
type of fertilizer (organic or inorganic) or the
amount of fertilizer applied. Barnes (1936)
reported that increasing phosphorus levels in-
creases the amount of sucrose but do not af-
fect the glucose level. Potassium has been
noted to decrease the total sugar content and
the amount of reducing sugars, and to increase
the sucrose content (Habben 1972). On the
other hand, Gallagher (1966) reported that
potassium has no effect on the sugar contents
of carrots.

In a review Simon (1985) lists the following
components affecting carrot flavour; the free
sugars (glucose, fructose, sucrose), which con-
tribute to sweetness; volatile mono- and
sesquiterpenoids, which contribute harshness
and carrot flavour; 2-nonenal, which imparts
cooked flavour; “iso-cumarin” and other
phenolic compounds, which impart bitterness;
2-methoxy-3-butylpyrazine, which contributes
to carrot aroma; free amino acids, which con-
tribute to delicate flavour; and ionones, which
impart floral off-flavour. The importance of
texture to carrot sensory quality has also been
noted.

Only a few studies have been published con-
cerning the effects of fertilization practices or
split application on the sugar contents and
flavour of carrots. The aim of the present
study is to examine the effect of unirrigated
and irrigated placement and broadcast fertili-
zation, NPK fertirrigations without basic fer-
tilization, NPK fertirrigations with NPK basic
fertilization, and PK placement with N fertir-
rigations on the glucose, fructose and sucrose

content and on the taste and texture of car-
rots.

Material and methods

The field experiments were conducted in
Vihti, at the Kotkaniemi experimental farm of
Kemira Oy (southern Finland, 60°22'N,
24°22'E) during the growing seasons of 1985
and 1986. Carrot cv. Nantes Duke Notabene
370 Sv was grown consistently as reported in
Evers (1988). The fertilizer treatments and
macronutrient amounts are presented in Ta-
ble 1. The field experiment was arranged by
completely randomized block design, with
four blocks, ten treatments and 25 m 2 plots.
Samples for analysis were collected from two
blocks in 1985 and from four blocks in 1986.
The differences between treatments were
studied statistically by contrast analysis and
correlations between parameters were calcu-
lated (Steel & Torrie 1980).

Sugar analyses

Carrot samples for glucose, fructose, su-
crose analyses and for sensory evaluation of
taste and texture were collected at harvest, on
30th September 1985 and 6th October 1986.
The sugars mentioned above were determined
by high performance liquid chromatography
(HPLC) on a bonded aminopropylsilica sta-
tionary phase with refractive index (RI) detec-
tion (Schwarzenbach 1976). 60 grams carrot
tissue (hypocotyl and root tip omitted) was
grated and mixed with acetonitril water mix-
ture (1:1), crushed in a blender, stirred for 10
minutes, filtered and analyzed by HPLC. The
total sugar content given in the Results were
calculated as the sum of glucose, fructose and
sucrose. The weighed value of the sweetness
of sugars was also calculated. The relative
sweetness of glucose, fructose and sucrose de-
pends on temperature and acidity (Hyvönen et
ai. 1978). When the sweetness of sucrose is
considered to be 100 at room temperature, the
relative sweetness of glucose is 70, and that
of fructose 120 (Hyvönen et ai. 1978, Kelm
1985).

114



Table 1. The fertilization treatments and the total amounts of nutrients and irrigation water.

1 Hall' of the nutrients were given in basic placement fertilization and half in NPK fertirrigations.
: Phosphorus and potassium were given in basic placement fertilization and nitrogen in fertirrigations.
' The nutrient amounts were 30 % higher in 1985 than 1986.

Taste and texture determinations

The sensory evaluation was performed at
the Technical Research Centre of Finland,
Food Research Laboratory. Ten trained
tasters evaluated the taste and texture of car-
rot samples, in randomized order. They gave
their evaluations on numerical and verbal
nine-degree Karlsruhe quality scales. Each
taster evaluated two carrots per treatment,
four treatments at a time. At each session, car-
rots from unfertilized and unirrigated treat-
ment were present as a comparison sample;
thus three evaluation sessions were needed.
Because the comparison sample was given
somewhat different scores at each of three
evaluation sessions, the scores of the second
and third evaluation sessions were corrected.
This was done by multiplying the scores of
each taster and each treatment with the quo-
tient comparison sample mean for the first
evaluation session/comparison sample mean
for the evaluation session in question. Because
the residuals of taste and texture grades fol-

Organically cultivated carrots

Results

Sugar contents

lowed a normal distribution, it was possible
to use parametrical tests for statistical analy-
sis. The data were analyzed statistically by
contrast analysis.

In 1986, carrots were also grown on two or-
ganically cultivated fields in central Finland
(in Varkaus and Rantasalmi). The same seed
material was used, but the geographical situ-
ation and soil conditions were different. These
samples were not statistically compared to fer-
tilizer treatments.

The glucose and fructose contents were
higher in 1985 than in 1986 (Table 2). The su-
crose content was mainly opposite, being
higher in 1986. Placement fertilized treatment,

Treatment Number and time Macronutrient Irrigation water
of fertilizer amounts in 1986' amounts in
applications kg/ha 1985 and 1986

N P K

Unfertilized
Unirrigated 0 0 0 0 0
Irrigation 0 0 0 0 3xlo

NPK placement
Unirrigated 1 before sowing 80 35 133 0
Irrigation 1 before sowing 80 35 133 3xlo

NPK broadcast
Unirrigated 1 before sowing 80 35 133 0
Irrigation 1 before sowing 80 35 133 3xlo

NPK fertirrigations
No basic 3 during season 80 29 160 3xlo
Half the basic 1 1 before sowing and 80 32 142 3xlo

3 during season
PK placement 2

3N-fertirrigations 1 before sowing and 81 56 133 3xlo
3 during season

4N-fertirrigations 1 before sowing and 155 56 133 4xlo
4 during season

115



116

1 Table
2.
The
effects
of

different
fertilization

practices
on

the
glucose,

fructose,
sucroseand

calculated
total

sugarcontents
and

on
the
calculated
value
for
the

sweetness
of

sugars.

Treatment

The
sugar

content,
°/o
in
fresh

weight

Calculated
value

~""for
the

sweetness

Glucose

Fructose

Sucrose

Calculated

roi
sugars

total
sugars

1985
1986
x

1985
1986
x

1985
1986
x

1985
1986
x

1985
1986
x

Unfertilized

1.9
1.6

1.75

1.7
1.4
1.55

4.1
4.2
4.15

7.7
7.1

7.40

7.5
6.9
7.20

Unfertilized
and
irrigated

2.0
1.5

1.75

1.8
1.3
1.55

3.6
4.2
3.90

7.4
7.1

7.25

7.1

6.9
7.00

Placement
fertilized

2.0
1.5

1.75

1.8
1.3
1.55

4.4
4.1
4.25

8.2
7.0
7.60

7.9
6.8
7.35

Placement
fertilized
and
irrigated

2.2
1.4

1.80

2.1
1.2
1.65

3.6
4.1

3.85

7.9
6.7
7.30

7.6
6.5
7.05

Broadcast
fertilized

2.1

1.3

1.70

1.9
1.1

1.50

3.7
4.2
3.95

7.7
6.6
7.15

7.4
6.5
6.95

Broadcast
fertilized
and
irrigated

2.3
1.2

1.85

2.0
1.3
1.60

3.6
3.9
3.75

7.9
6.6
7.25

7.7
6.5
7.10

NPK
fertilizations,
without

basic

2.0
1.5

1.65

1.9
1.2
1.55

3.5
4.1

3.80

7.4
6.5
6.95

7.1

6.4
6.75

NPK
fertilizations,
half
the
basic

1.9
1.2

1.55

1.8
1.1

1.45

3.9
4.4
4.15

7.6
6.8
7.20

7.3
6.6
6.95

PK
placement

with
3N

fertirrigations
2.1

1.5

1.80

1.9
1.3
1.60

3.7
3.7
3.70

7.7
6.5
7.10

7.4
6.3
6.85

PK
placement
with
4N

fertirrigations
2.2
1.2

1.70

2.0
1.1

1.55

4.2
4.2
4.20

8.4
6.5
7.45

8.0
6.4
7.20

x

2.1

1.4

1.75

1.9
1.2
1.60

3.8
4.1

4.00

7.8
6.7
7.30

7.5
6.6
7.05

Organically
cultivated

carrots
Location
1

1.5

1.2

4.3

7.0

6.8

Location
2

1.5

1.2

3.9

6.6

6.4

x

1.5

1.2

4.1

6.8

6.6



however, yielded a higher sucrose content in
1985 than in 1986, and PK placement with 3
or 4 N fertirrigations yielded a similar sucrose
content in the two years (Table 2). Both the
calculated total sugars and the calculated value
for the sweetness of sugars were higher in 1985
than in 1986 (Table 2).

In 1985, no statistically significant differ-
ences were found between fertilized and un-
fertilized treatments or between fertilization
practices. Irrigation, nitrogen amount, place-
ment of NPK or PK fertilizer, fertirrigations
or split applications did not affect the sugar
contents.

In 1986, the unfertilized treatments had a
tendency to yield higher glucose and fructose
contents than did the fertilized treatments on
the average (p<0.08). Placement fertilization
had a tendency to increase the glucose con-

tent as compared to NPK fertirrigations with-
out or with basic fertilization (p<o.l). No sig-
nificant differences or tendencies were found
in sucrose content. Unfertilized treatments
yielded a higher total sugar content and a
higher calculated value for the sweetness of
sugars than did fertilized treatments (p =

0.03*), but there were no differences between
fertilization practices.

Taste

Fertilization, irrigation or N amount did not
affect taste in 1985 or 1986 as compared to
unfertilized, unirrigated or treatments with
high amounts of N, respectively. But in both
years, NPK fertirrigations without basic fer-
tilizationproduced better taste than didplace-
ment fertilization (p<o.o4*) (Fig. 1).

Fig. I. The effect of different fertilization practices on the taste and textureot carrot in 1985 and 1986.

117



In 1985, broadcast fertilizations and NPK
fertirrigations without basic fertilization
produced better taste than did PK placement
with N fertirrigations (p<o.o2*). When P and
K were not given by placement technique, a
significantly better taste was obtained than
when P and K were given by placement tech-
nique (p<o.oo3**) (Fig. 1).

In 1986, broadcast fertilization (p = 0.02*),
split application (p< 0.007**), NPK fertirri-
gations without or with basic fertilization
(p = 0.01 *) and PK placement with N fertirri-
gations (p<o.o3*) produced better taste than
did placement fertilization (Fig. 1).

Texture

No significant differences between fertilized
and unfertilized treatments or between fertili-
zation practices were found in 1985.

In 1986, NPK fertirrigations without basic
fertilization produced better texture than did
placement fertilization (p<o.oo2**), single
application (p<o.o4*) or unirrigated single

application (p<o.o3*) (Fig. 1). Irrigation did
not affect texture as compared to unirrigated
treatments. Broadcast fertilization (p =

0.002**), split application (p =0.001 **), NPK
fertirrigations without or with basic fertiliza-
tion (p<o.oo2**) and PK placement with b
fertirrigations (p<o.o2*) produced better tex-
ture than did placement fertilization. When P
and K were not given by placement technique,
a better texture was obtained than when P and
K were given by placement technique (p<
0,005**) (Fig. 1).

The taste and texture scores given by ten
tasters were plotted individually for all fertili-
zation treatments (Fig. 2). The range of vari-
ation was great for each fertilization treat-
ment, i.e. ten tasters gave very different scores
for the same fertilization treatment.

Correlations between parameters

The glucose and fructose contents, and the
sucrose and total sugar contents, correlated
positively in both years (Table 3). Further, in

Fig. 2. The effect of different fertilization practices on the taste and texture of carrot. The scores given by ten tasters
are plotted individually.

118



Table 3. The correlation coefficients between glucose, fructose, sucrose, total sugars, taste and texture in 1985
and 1986.

• significant at the 5 % level
** significant at the I % level
*** significant at the 0.1 % level
n.s. not significant

1986 the glucose and fructose contents cor-
related negatively with the sucrose content, the
glucose and fructose contents correlated posi-
tively with total sugars, and taste correlated
positively with texture (Table 3).

Carrots from organic cultivation

The glucose, fructose, sucrose, total sugar
contents and the calculated value for the
sweetness of sugars were on the same level in
organically cultivated carrots as in the carrots
grown during the fertilization experiment (Ta-
ble 2). The organically cultivated carrots did
not taste good (Fig. 1).

Discussion

Sugar contents

Simon et al. (1980 a, 1980 b, 1982) demon-
strated that there is significant genetic and en-
vironmental variation for carrot sugar quan-
tities. Sucrose was influenced most by geno-
type (Simon et al. 1982). In the present study,
neither fertilization (as compared to unferti-
lized treatments) nor fertilization practices af-

fected the sucrose content at all in either year.
In 1986, unfertilized treatments had a tenden-
cy to yield higher glucose and fructose con-
tents and a higher total sugar content than did
fertilized treatments on the average.

The glucose, fructose and total sugar con-
tents were higher in 1985 than in 1986. With
a few exceptions, the sucrose content was
higher in 1986. The weather was more
favourable in 1986 than in 1985; both the
mean day temperature and the number of sun-
shine hours in June and July were higher in
1986 than in 1985 (Evers 1988). Yield and dry
matter contents were higher in 1986 than in
1985 (Evers 1988). Thus the glucose, fructose
and total sugar contents seemed to be higher
in the unfavourable year of 1985 and in un-
fertilized treatments as compared to the more
favourable year of 1986 and to fertilized treat-
ments. It is obvious that more photosynthates
were produced in the more favourable year of
1986 and in fertilized treatments, but that
greater amounts of photosynthates were used
for phytomass production, leaving less sugars
to fill the storage cells. Consequently the glu-
cose, fructose and total sugar contents are
hypothesized to be related to growth.

Glucose Fructose Sucrose Total Taste Texture
sugars

im
ilucose 1 0.84* 1 n.s. n.s. n.s. n.s.

Fructose 1 n.s. n.s. n.s. n.s.
Sucrose 1 0.87* n.s. n.s.
Total sugars 1 n.s. n.s.
Taste 1 n.s.
Texture 1
1986
Glucose 1 o.97*** —o.4B** 0.37* n.s. n.s.
Fructose 1 —o.s2*** 0.32* n.s. n.s.
Sucrose 1 o.63*** n.s. n.s.
Total sugars 1 n.s. n.s.
Taste 1 o.sl***
Texture 1

1195



In the present study, the total sugar content
for all treatments was on the average 7.8 %

of fresh weight in 1985 and 6.7 % in 1986.
These values were higher than reported by
Habben (1972), Dracland (1978) and Bajaj et
al. (1980), and on same level as thosereported
by Phan & Hsu (1973), Fritz & Habben (1975),
and Nilsson (1979, 1987). The reasons for the
different total sugar levels reported in differ-
ent studies are probably both genetic and en-
vironmental, and they ought to be examined
in relation to growth.

The superiority order of the treatments was
similar when the calculated total sugar value
was compared with the calculated value for
the sweetness of sugars. This indicates that all
treatments produced roughly similar propor-
tional amounts of glucose, fructose and su-
crose.

Taste and texture

The flavour of raw carrots is influenced by
genotype and environment (Simon et al.
1982). Sugars and volatile terpenoids are the
two major components of carrot flavour
(Freeman & Simon 1983), but carrot aroma is
very complex, and is affected by many com-
pounds (Simon 1985). In the present study, in
both years, NPK fertirrigations without basic
fertilization produced better taste than did
placement fertilization. On the other hand
placement fertilization had a tendency to in-
crease the glucose content as compared to
NPK fertirrigations, but no correlation was
found between glucose content and taste. Be-
cause no earlier research could be found on
this subject, it would be a very interesting top-
ic of further study, using different varieties
and different environmental conditions. Two
aspects are interesting; why did NPK fertirri-
gations without basic fertilization have a
favourable effect on taste, and why did place-
ment fertilization have a negative effect on
taste?

The taste and texture results obtained in this
study should be considered to be indicative
only, because the taste panel evaluated ten

samples, one for each treatment; thus there
were no replicates. The taste panel comprised
only ten people, and each taster evaluated two
carrots; thus 20 carrots were evaluated per
treatment. The range of variation in taste and
texture scores between individual tasters was
great. This may be due to differences between
tasters or due to great variation between in-
dividual carrots. The variation would have
been smaller had all tasters evaluated carrot
pieces cut from the same carrots, but in this
case less carrots could have been studied. If
there had been a great variation between in-
dividual carrots, it would not have been no-
ticed.

Carrots from organic cultivation

The sugar content of organically cultivated
carrots was on the same level as that of the
carrots grown during the fertilization experi-
ment. This is in agreement with the fact that
sugar content is, to a large extent, genetically
controlled. Environmental variation is not as
remarkable as genetic variation (Simon et al.
1982). The negative results of the sensory
evaluation should give rise to closer study,
performed by analyzing the aroma compo-
nents of organically cultivated carrots.

In conclusion

No statistically significant differences (at
the level of p<0.05) in sugar contents were
found between fertilization practices. This is
in agreement with the study of Simon et al.
(1982), where genotypic variation was highly
significant in reducing sugars, sucrose, and to-
tal sugars, the influence of soil and climate be-
ing slight as compared to the genetic influence.
In the present investigation, in 1986, unferti-
lized treatments produced a higher total sugar
content than did fertilized treatments, on the
average, and the total sugar content was
higher in less favourable year of 1985 than in
1986, on the average, for all treatments. Thus
it can be hypothesized that because the total
phytomass production was greater in fertilized
treatments and in 1986 (Evers 1988); conse-

120



quently more photosynthates were used for
phytomass production, leaving less sugars for
the storage organ. The taste and texture results
obtained in this study should be considered to
be indicative only.

References

Bajaj, K.L., Kaur, G. & Sukhija, B.S. 1980. Chemical
composition and some plant characteristics in rela-
tion to quality of some promising cultivars of carrot
(Daucus carota L.). Qual. Plant. PI. Foods Hum.
Nutr. 30: 97—107.

Balvoll, G., Apeland, J. & Auranaune, J. 1976. Kje-
misk samansetnad og organoleptiskkvalitet hjä gul-
rot frä sor- og nord-Noreg. Forskn. Förs. Landbr.
56: 327—337.

Barnes, W.C. 1936. Effects of some environmental fac-
tors on growth and color of carrots. Cornell Univ.
Agric. Exp. Stn. Mem. 186: 2—36.

Draoland, S. 1978. Nitrogen- og vassbehov hos gulrot.
Forskn. Förs. Landbr. 29: 139—159.

Evers, A-M. 1988 Effects of different fertilization prac-
tices on the growth, yield and dry matter content of
carrot. J. Agric. Sci. Finl. 60: 135—152.

Freeman, R.E. & Simon, P.W. 1983. Evidence for sim-
ple genetic control of sugar type in carrot (Daucus
carota L.). J. Amer. Soc. Hort. Sci. 108: 50—54.

Fritz, D. & Habben, J. 1975. Determination of ripeness
of carrots (Daucus carota L.). Acta Hort. 52:
231—238.

Gallagher, P.A. 1966. The effect ofpotassium on yield
and quality of carrots. Proc. 8. Intern. Potash Inst.
Congr. Brussel, p. 257—263.

Habben, J. 1972. Einfluss von Diingung und Standort
auf die Bildung wertgebender Inhaltsstoffe in Möhren
(Daucus carota L.). Diss. Techn. Univ. Miinchen.

Härdh, J.E. 1975. Der einfluss der umwelt nördlicher
breitengrade auf die qualität der gemiise. Qual. Plant.
25: 43—56.

Hyvönen, L., Kurkela, R., Koivistoinen, P. & Ala-
Kulju, M-L. 1978. The relative sweetness of fruc-
tose, glucose and xylitol in acid solutions at different
temperatures. Lebensm. Wiss. Technol. 11: 11 —l4.

Kelm, W. 1985. Einsatz vom zuckersorten, zuckerarten
und kunstlichen sußstoffen fiir alkoholfreie er-

Acknowledgements. My thanks are due to Ms. Oili
Uusitalo for her excellent technical assistance with the ex-
periments and sugar analyses and to Börje Björkqvist,
M.Sc., for his expertise in sugar analysis. 1 am grateful
to the Academy of Finland and to Kemira Oy for finan-
cial support.

frischungsgetränke. Getränkeindustrie 39: 13—18.
Martens, M., Rosenfeld, H.J. & Russwurm, H., Jr.

1985, Predicting sensory quality of carrots from chem-
ical, physical and agronomical variables: a multivar-
iate study. Acta Agric. Scand. 35: 407—420.

Nilsson, T. 1979. Avkastning, lagringsförmäga, kvalitet
och kemisk sammansättning hos möröt, vitkäl och
purjo vid konventionell och organisk gödsling. Inst.
Trädg. Vet. Rapp. 7: 3—52.
1987. Growth and chemical composition of carrots as
influenced by the time of sowingand harvest. J. Agric.
Sci. Camb. 108: 459—468.

Phan, C.T. & Hsu, H. 1973. Physical and chemical
changes occuring in the carrot root during growth.
Can. J. PI. Sci. 53; 629—634.

Schwarzenbach, R. 1976. A chemically bonded station-
ary phase for carbohydrate analysis in liquid chro-
matography. J. Chromatogr. 117: 206—210.

Simon, P.W. 1985. Carrot flavor: effects of genotype,
growing conditions, storage and processing. In:
“Evaluation of qualityof fruits and vegetables”. (Ed.
H.E. Pattee), p. 315—328. Westport, Connecticut.

Simon, P.W., Peterson, C.E. & Lindsay, R.C. 1980 a.
Genetic and environmental influences on carrot flavor.
J. Amer. Soc. Hort. Sei. 105: 416—420.

—, Peterson, C.E. & Lindsay, R.C. 1980 b. Correla-
tionsbetween sensory and objective parameters of car-
rot flavor. J. Agric. Food. Chem. 28: 559—562.

—, Peterson, C.E. & Lindsay, R.C. 1982. Genotype,
soil and climate effects on sensory and objective com-
ponents of carrot flavor. J. Amer. Soc. Hoit. Sei. 107:
644—648.

Steel, R.G.D. & Torrie, J.H. 1980. Principles and
procedures of statistics. A biometrical approach. 633
p. 2nd Ed. Tokyo.

Ms received March 16, 89

121



SELOSTUS

Lannoitusmenetelmien vaikutus porkkanan
glukoosi-, fruktoosi- ja sakkaroosi-
pitoisuuksiin sekä makuun ja rakenteeseen

Aino-Maija Evers
Kemira Oy, Espoon tutkimuskeskus
Luoteisrinne 2, 02270 Espoo

Eri lannoitusmenetelmien vaikutusta porkkanan ‘Nan-
tes Duke Notabene 370 Sv’ sokeripitoisuuksiin sekä ma-
kuun ja rakenteeseen tutkittiin vuosina 1985 ja 1986. Kent-
täkokeissa Kotkaniemen koetilalla Vihdissä oli vertailta-
vina lannoitusmenetelminä sijoitus- ja pintalannoitus
(ilman kastelua jakastelun kera), NPK kastelulannoitus
ja NPK kastelulannoitus, jossa puolet ravinteista annet-
tiin sijoittaen keväällä, sekä koejäsen, jossa P ja K an-
nettiin sijoittaen keväällä ja N kastelulannoituksena kas-
vukaudella. Kokeessa verrattiin myös ravinteiden kerta-
levitystä jaksotettuunravinteiden antoon. Näytteet soke-
rimäärityksiin ja maun ja rakenteen aistinvaraiseen ar-
viointiin kerättiin sadonkorjuun yhteydessä.Tulokset ana-
lysoitiin tilastollisesti kontrastianalyysillä, japarametrien
väliset korrelaatiot laskettiin.

Lannoitus (verrattuna lannoittamattomaan) ja lannoi-
tustavat eivät vaikuttaneet lainkaan sakkaroosipitoisuu-
teenkumpanakaan vuonna. Sakkaroosipitoisuus oli kor-
keampi kasvuoloiltaan suotuisampana vuonna 1986. Sen
sijaan glukoosi-, fruktoosi- ja kokonaissokeripitoisuudet
olivat korkeammat epäedullisempana vuonna 1985 kuin
vuonna 1986. Glukoosi- ja fruktoosipitoisuudet olivat

suuntaa-antavasti korkeammat (p<0.08) ja kokonaisso-
keripitoisuus oli korkeampi (p =0.03) vuonna 1986 lan-
noittamattomissa koejäsenissä kuin lannoitetuissa koe-
jäsenissä. Koska aiemmassa tutkimuksessa (Evers 1988)
on todettu, että kokonaisfytomassan tuotto oli suurem-
pi 1986, tässä tutkimuksessa päädyttiin hypoteesiin, että
porkkanan sokeripitoisuutta tulee tarkastella suhteessa
kasvuun. Edullisissa kasvuoloissa yhteyttämistuotteita
muodotuu enemmän, muttakoska huomattava osa niis-
tä kuluu fytomassan tuottoon, jää vähemmän yhteyttä-
mistuotteita eli sokereita sellaisenaan varastoelimeen. Ko-
konaissokeripitoisuudetkoko aineiston keskiarvoina oli-
vat 7.8 % ja 6.7 % vuosina 1985 ja 1986. Aistinvaraisen
arvioinnin suuntaa-antavat tulokset osoittivat, että NPK-
kastelulannoituksen saaneiden porkkanoiden maku oli
kumpanakin vuonna parempi kuin sijoituslannoituksen
saaneissa porkkanoissa, mutta koejäsenten väliset erot oli-
vat pienet. Kahden orgaanisesti viljellyn havaintoaineis-
ton porkkanoiden sokeripitoisuudetja rakenne olivat sa-
mansuuruiset kuin vastaavat arvot lannoituskokeessa,
mutta orgaanisesti viljellyt porkkanat eivät maistuneet
yhtä hyvältä.

122