CARBOHYDRATE AND ACID COMPOSITION
OF FINNISH BERRIES

Maija-Liisa Salo and Kaija Suomi

Department of Animal Husbandry, University of Helsinki

Received January 26, 1972

Abstract. The study comprised six wild and seven cultivated berries grown in Finland,
one imported berry and the rhubarb. The samples were analysed for sugars, starch, hemi-
cel ulose polysaccharides, cellulose, crude lignin, titratable and total acidity and organic
salts, crude protein, crude fat and ash. Five berry species were furthermore analysed for
the amount and composition of seeds. The sugar content of the berries is some 35—55 per
cent of the dry matter, hemicellulose plus cellulose is 10—20 per cent, and crude lignin
3—lo per cent. A considerable proportion of the last two groups occurs in the seeds. The
total amount of plant acids varies within a range of 10—20 per cent, and 10—30 per cent
of the acids is in the form of salts. Titratable acid amounts to some 70—90 per cent of the
total acid content. Seed content and the composition ofseeds varies greatly. In some berries
seeds account for one-quarter of the dry matter, and seeds may have a fat content that is
nearly 30 per cent of the dry matter.

The main components in the dry matter of berries are carbohydrates, primarily
sugars, and non-volatile organic acid, i.e. plant acids. There is, however, little published
information on the composition of berries. Money and Christian (1950) quated analyt-
ical data of fruits, including many berry fruits. These data include total sugars and titra-
table acidity. Similar information is provided in Osborn’s (1964) table. Kuusi (1969)
has published certain parameters of Finnish berries though no carbohydrate values.
Like the above authors, she expresses the acidity as a simple titration result, the so-called
titratable acidity. Certain textbooks and tables of foodstuffs (e.g. Souci et al. 1962, Drews
1968) contain similar data on some berries. Whiting (1958) has studied the non-volatile
acids of some berries, determining both the titratable acid and total acid content.

The objective of the present study was to investigate the main composition of Finnish
berries. The samples were analysed for sugars, starch, hemicellulose, cellulose, crude
lignin, titratable and total acidity, organic salts, crude protein, crude fat and ash. Five
berry species were furthermore analysed for the amount and composition of seeds.

Materials and methods
Materials. The samples were obtained from Helsinki vegetable market and

food stores. The berries accepted for analysis were ripe, fresh and of good quality. The

https://www.c-info.fi/en/info/?token=_pGHwXebTamTs4Q5._q_sjHw211TVqipPDXQ1eA.I-sNfysFDiYGAJLgZPwKf-sF1qM9srguKF0dCfM-XXbkQKL2jrSiI2Hwa0eZbBU3WnTojfnLEIkPZM3477iN4PPYJHEVy8xscVNC5Qc8DLDAqWp3lb63td40h899RJzvD3TGcRb4BuavQ3kzi467Nndkgiavbn02kt8LpwAQNEkilz7_58KuAfpW_Ke7nw


69

only exception was the cloudberry which appeared to have been picked half-ripe and
had ripened in the dish. Berries of poor appearance were discarded from the samples.

From three berry species, two different samples were analysed. The sample blueberry
I represents the first ripe berries on the market, while blueberry II was picked three
weeks later. Samples I and II of strawberry and raspberry were obtained at a few days
interval. In addition to Finnish berries, also an imported berry, the Hungarian raspberry,
was investigated. Besides berries, also rhubarb was analysed.

Preparing of samples. All berries were »tailed» before weighing, and the
gooseberries also »topped». The hard berries were rinsed in water and dried with paper.
The rhubarb was peeled and chopped. The berries were crushed in a dish and the majority
of the samples was freeze-dried. Other samples were dried in a vacuum oven at 40°C.
No difference was noted between the two drying methods in the analysis, and the method
is therefore not indicated in the tables. The dried samples were ground with an IKA
analysis mill. A sieve mill is not suitable for this type of material.

A seed sample was prepared from five berry species, and the proportion of seed in
the dry matter was determined. Seeds were separated using a Top Drive macerater,
sieves and water.

Methods. The carbohydrates were determined by Salo’s (1965a) method. The
hemicellulose determination was, however, carried out directly on ethanol-extracted
residue. No starch was traced in the berries, and the occurence of tructosan was considered
so unlikely that it was not tested.

Titratable acidity, total acidity and organic salts were determined by the methods
of Salo and Kotilainen (1969). The only exception was that the cation determination
was carried out with flame spectrophotometry on a number of the samples, and with
atomic absorption spectrophotometry on the rest. The latter determination is faster since
cations can be determined directly from aqueous extraction.

Crude protein was determined by the Kjeldahl method. Crude fat was determined
by the conventional ether extraction method. The dry matter was determined by drying
at 100°C and the ash by incineration at 700 °C.

Results and discussion

Carbohydrates. Table 1 presents the carbohydrate contents of the berries.
Like all other analysis results of the present paper they are expressed as a percentage
of dry matter.

The results reveal, firstly, that sugars form the biggest dry matter group in berries.
The amount of sugars, monosaccharides and sucrose together, usually varies within the
range of 35—55 per cent. The bulk of the sugars is in the form ofmonosaccharides (glucose
and fructose). The fact that cloudberry has a lower sugar content than the other berries
was probably due to the sample having ripened in the dish. No starch was found in the
berries, not even in their seeds.

Berries have a relatively high content of hemicellulose, cellulose and lignin. A compa-
rison of the figures of Tables 4 and 5 shows that a considerable proportion of these cell-
wall substances derives from the seeds. Especially xylans and mannans belong to the seeds.
Seed plants usually have mannans only in traces (Salo 1965b), whereas mannose was



70

Table 1. Carbohydrate and lignin contents of berries, percentages of dry matter

Percentile distribution of hemi-
Mnnn- Hemicellulose „

.
Cellu- Crude cellulose sugars

sacha- Sucrose sugar uronic iose lienin i i u- i• ■
° ,u:>c «s""i galac- glu- man- arabi- xylosenaes anhydr. anhydr.

' ' tose cose nose nose

Wild berries
Strawberry 24.9 14.6 4.6
Blueberry I 43.2 0.0 6.3

» II 46.6 3.7 4.7
Raspberry 35.2 2.1 5.5
Cloudberry 23.0 0.0 9.2
Lingonberry 48.7 2.1 3.4
Cranberry 36.0 0.0 4.1

Cultivated berries
Strawberry »Ydun» 37.9 14.7 3.5

» »Senga Sengana» I 44.7 9.7 3.0
» » » II 38,3 20.1 2.5

Raspberry, Finnish
»Preussen» 26.5 6.4 5.9

» Hungarian I 43.3 5.4 5.0
» » II 37.9 8.4 5.2

Black currant »Bröd-
torp» 36.1 4.7 4.7

Red » »Punain.
hollantil.» 34.2 1.7 8.4

Gooseberry »Lepaan
punain.» 36.6 13.9 6.1

» »Houghton» 37.6 11.2 5.3

Rhubarb 9.8 3.5 5.7

6.8 4.9 6.0 20 10 + 30 40
5.5 5.6 4.9 20 10 + 20 50
5.0 4.0 5.1
5.4 7.8 8.0 15 15 + 20 50
9.4 13.9 10.2 10 10 + 10 70
4.7 3.6 3.8 20 10 + 50 20
5.4 4.8 8.1 25 10 + 45 20

5.7 4.8 4.9 25 10 + 35 30
6.6 3.6 2.9 20 5 + 50 25
7.4 2.7 2.8

6.5 8.0 9.2 20 10 20 50
5.3 6.9 7.3 20 10 20 50
5 2 7.4 7.2

6.5 2.8 7.2 15 15 30 20 20

5.9 4.5 10.2 15 10 35 20 20

5.0 3.1 5.8 20 5 35 35 5
5.6 2.8 7.2
7.0 10.3 3.8 50 10 15 25

found to form about two-thirds of the hemicellulose sugar units in the seeds of currants
and gooseberries. In the seeds of other berries mannose is replaced by xylose. The high
content of uronic acid, galactose and arabinose indicates that the hemicellulose of the
seedless part ofberries principally belongs to the pectin group. Crude lignin is surprisingly
abundant in many berries.

Rhubarb differs from berries on many points; as regards carbohydrates the most
essential difference is the low sugar content.

The papers mentioned in the introduction have assembled figures on total sugars,
indicating the mean, maximum and minimum values calculated on fresh weight. Com-
parison is difficult because also the dry matter contents are mean values ofseveral samples.
The only conclusion that can be drawn is that the sugar contents of the present study are

well within the variation ranges of the data quoted in the literature. No comparable
figures were found in the literature for carbohydrate groups other than the sugars.

Plant acids and organic salts. Table 2 supplies data on the acid
content of berries. The first column gives the so-called titratable acidity, i.e. the simple



Table
2.

Free
and
combined
acids
of

berries
per
1

g
dry

matter.

Acidity

Corrected
total_.
.

,

r.
„„

-r-,
~

mequiv.
Correc-

acidity

Water-sol.
cations,
mequiv.

Plant
acids,
tree
Titrat.

tions
ij

1

mequiv.
acids
acidity

titra-

.

as
citric

%

of
%

of

table
total
meqUIV

"
mel

uiv
-

acid
%

K+

Na+
Ca++
M
S

++

total
free
salts
total
total

Wild
berries Strawberry

1.44
1.94

0.04

1.90
12.2

0.31
0.00
0.11
0.12
0.54

1.40
0.50
74

74

Blueberry
I

1.00
1.38

0.02

1.36
8.7

0.17
0.00
0.07
0.06
0.30

1.08
0.28
79

72

II

1.18
1.42

0.03

1.39
8.9

0.19
0.00
0.06
0.04
0.29

1.13
0.26

81

83

Raspberry

1.46
1.77

0.06
1.71
10.9

0.29
0.00
0.06
0.10
0.45

1.32
0.39
77

82

Cloudberry

1.02
1.41

0.04
1.37

8.8

0.28
0.01
0.07
0.11
0.47

0.94
0.43
69

72

Lingonberry

1.64
1.86

0.02

1.84
11.8

0.13
0.01
0.09
0.04
0.27

1.59
0.25
86

88

Cranberry

2.88
3.13
0.01

3.12
20.0
0.14
0.00
0.09
0.04
0.27

2.86
0.26
92

92

Cultivated
berries Strawberry

»Ydun»

1.78
2.30
0.10
2.20

14.1

0.45
0.01
0.07
0.10
0.63

1.67
0.53
76

77

»Senga
S.»
I

1.53
2.16

0.08

2.08
13.3

0.50
0.01
0.07
0.14
0.72

1.44
0.64
69

71

II

1.51
2.06
0.05
2.01

12.9

0.50
0.01
0.07
0.09
0.69

1.39
0.62
69

73

Raspberry,
Finnish

2.29
2.71

0.06
2.65
17.0

0.36
0.00
0.07
0.14
0.57
2.14
0.51

81

85

Hungarian
I

1.14
1.42

0.08

1.34
8.6

0.24
0.01
0.08
0.09
0.42

1.00
0.34
75

80

II

1.23
1.52

0.08
1.44

9.2

0.16
0.01
0.06
0.07
0.30
1.22

0.22

85

81

Black
currant

2.56
3.05

0.09

2.96
18.9

0.40
0.01
0.10
0.09
0.60
2.45
0.51

83

84

R
ed

„

2.11
1.64

0.11

2.53
16.2

0.45
0.01
0.08
0.07
0.61

2.03
0.50

80

80

Gooseberry
»L.p.»

2.00
2.34
0.05

2.29
14.6

0.34
0.01
0.04
0.03
0.42

1.92
0.37

76

85

»H.»

2.38
2.73

0.04

2.69
17.2

0.28
0.01
0.08
0.06
0.43

2.30
0.39

86

87

Rhubarb

4.82
6.40

0.38

6.02
38.5

1.23
0.01
0.03
0.10

1.37

5.03
0.99
84

75

l
)

See
text

71



72

titration result of water extract. Column 2 shows the total acidity, i.e. the acid result
after salts had been converted into acid form by cation exchanger. The cation exchanger
also changes the possible inorganic salts into corresponding acids, and column 3 gives the
sum of the phosphate, chloride and nitrate corrections, mainly composed of phosphates.
The corrected total acidity is shown in the table both as equivalents and calculated as
citric acid. Berries, like plant materials in general, contain many organic acids. In berries
citric acid is found to predominate (Whiting 1958, Kushman & Ballinger 1968), whereas
malic acid predominates in rhubarb. Also oxalic acids occurs in rhubarb, but forms only
10—30 per cent of the total acid quantity. Furthermore, almost half of it is not soluble
in water (Blundstone & Dickinson 1964, Allison 1966).

Table 2 also shows the amounts of four water soluble cations, and the organic salt
quantities calculated on the basis of the sum of cations. The percentages reveal that the
majority of the acids in berries (some 70—90 per cent) is in free form. Furthermore it
can be seen that this figure is in agreement with the titratable acidity obtained by simple
alkaline titration. The titratable acidity suffices, therefore, for a relatively precise deter-
mination of the free acid quantity in berries. In vegetables and feeds the share of free
acid in total acid is much lower and less uniform (about 10—50 per cent) (Salo & Koti-
lainen 1969). For this reason also their titratable acidity/total acidity ratio varies within
wide limits.

Table 3. Dry matter content and the main groups of dry matter of berries

Percentages of dry matter
Dry Ratio

Other Total ,matter
„ . Crude Plant Crude Crude .... c , suB ar/

0/ Sugars carbo-
_

Ash deter- Seeds . ,/o
,

, lignin acids protein fat .
,

acid
hydrates ° r mined

Wild berries

Strawberry 15.5 39.5 16.3 6.0
Blueberry I 16.3 43.2 17.4 4.9

„ II 16.1 50.3 13.7 5.1
Raspberry 37.3 18.7 8.0
Cloudberry 16.5 23.0 32.5 10.2
Lingonberry 16.5 50.8 11.7 3.8
Cranberry 13.8 36.0 14.3 8.1

Cultivated harries
Strawberry »Y.» 11.0 52.6 14.0 4.9

»S.S.» I 11.3 54.4 13.2 2.9
II 10.2 58.4 12.6 2.8

Raspberry, Finnish 15.7 32.9 20.4 9.2
.Hungarian I 16.4 48.7 17.2 7.3

II 16.3 46.3 17.8 7.2
Black Currant 19.8 40.8 14.0 7.2
Red „ 16.8 35.9 18.8 10.2
Gooseberry »L.p.» 17.1 50.5 14.2 5.8

»H.» 19.0 43.8 13.7 7.2

Rhubarb 5.7 13.3 23.0 3.8

12.2 8.1 5.2 4.0 91.3 3.2
8.7 6.2 7.3 1.7 89.4 5.0
8.9 5.2 6.4 1.8 91.4 5.7

10.9 7.7 8.4 2.9 93.9 3.4
8.8 10.5 7.0 2.9 94.9 2.6

11.8 3.7 4.6 1.3 87.7 4.3
20.0 4.0 5.5 1.4 89.3 1.8

14.1 6.8 2.6 4.0 99.0 3.7
13.3 8.1 2.4 4.4 98.7 7.2 4.1
12.9 6.9 2.4 4.2 100.2 4.5
17.0 8.1 5.5 3.3 96.4 1.9
8.6 8.3 3.8 2.4 96.3 5.5
9.2 8.6 3.9 2.2 95.2 23.9 5.0

18.9 8.0 4.0 4.1 97.0 13.3 2.2
16.2 7.1 6.9 4.1 99.2 23.0 2.2
14.6 5.5 2.5 2.9 96.0 10.0 3.5
17.2 4.1 2.4 2.5 95.9 2.8

38.5 12.5 2.4 10.5 104.0 0.3



73

The acid content of most berries is of the order of 10—20 per cent of the dry matter.
Cranberry, currants, gooseberry and raspberry represent the highest acid content, cloud-
berry and blueberry the lowest. The only sample offoreign berries in the table, the Hun-
garian raspberry, differs essentially from the Finnish: its acid content is about half that
of the Finnish, while it has more sugar than the Finnish raspberry. The same finding
was recorded in a comparison ofFinnish and imported apples (Salo & Korhonen 1972).

It is difficult to compare the reports in the literature with the present results for the
reason already indicated for sugars. If a comparison of titratable acidity of fresh weight
is carried out, the mean values for the same berry species in Kuusi’s (1969) tables are

of the same magnitude as those now reported, excepting the lingonberry and cranberry
for which Kuusi quotes a higher acid content. In the tables of Money and Christian
(1950) and of Osborn (1964) the titratable acidity values are somewhat lower than the
present values. The same is true of rhubarb (Blundstone & Dickinson 1964, Allison
1966). Whiting (1958) determined both total acids and titratable acids for some of the
berry species included in the present study. His figures, on the whole, were also slightly
lower than the present values; the acid content of raspberry, however, was closer to the
Finnish than the Hungarian. The share of titratable acidity in total acidity was close to
that recorded in the present study.

General information on the composition of berries. Table 3
presents general information on the composition of berries.

The differences in cell-wall carbohydrates, lignin and protein contents are partly
due to differences in the seed content, as can be seen from Tables 4 and 5, and partly

Table 4. Composition of berry seeds

Composition of seeds % of dry matterSeeds
% of Hemicellulose

, Cellu- Crude- Plant Crude CrudearV Sugars sugar uronic , . ~ t
. r . Ash

lose lignin acids protein latmatter anhydr. anhydr.

Blackcurrant 13.3 4.7 19.7 5.0 7.4 20.1 1.5 25.6 28.9 4.6
Red currant 23.0 6.5 25.5 3.4 7.9 10.7 1.5 19.0 24.9 3.2
Gooseberry »Lepaan pun.» 10.0 4.9 24.5 4.7 7.6 18.2 1.6 21.8 24.9 3.6
Raspberry, Hungarian 23.9 1.1 14.1 5.5 24.2 25.5 1.3 7.7 8.2 2.0
Strawberry »Senga S.» 7.2 1.5 10.9 11.7 24.0 19.4 2.4

Table 5. Composition of the seedless part of berries, percentages of dry matter

HemicelluloseöeealCSS Ccllu- Crude Plant Crude
part Sugars sugar uronic . ~ ~

. ■ Ash
' ° lose hgnin acids protein
% anhydr. anhydr.

Blackcurrant 86.7 46.4 2.4 6.7 2.1 5.2 21.6 5.3 5.1
Red currant 77.0 44.7 3.2 6.6 3.5 10.0 20.6 3.5 4.4
Gooseberry 90.0 55.6 4.0 5.0 2.6 4.4 16.0 3.7 2.8
Raspberry, Hungarian 76.1 63.8 2.1 5.2 1.4 1.5 10.9 8.5 2.5
Strawberry »Senga S.» 92.8 58.5 2.4 3.0 1.3 7.2 4.6



74

to the structural differences of the berry species. The analysis results suggest that the seed
content is highest in cloudberry which, however, was not examined for seeds.

The differences in crude fat content are due to differences both in the seed content
of various berries and in the fat contents of the seeds (cf. Table 4). The fat values are
inaccurate, because e.g. citric and malic acid are dissolved in ether.

The last column shows the sugar/acid ratio. This figure reveals clearly the difference
between the Finnish and Hungarian raspberry. It also reveals the difference between
the berries and rhubarb.

It can furthermore be seen that the difference in composition between differentsamples
(I and II) of the same species are not great. The riper berries seem to contain some more
sugar and less protein than the less ripe ones, whereas no difference can be seen in the
acid contents.

The seeds. When berries are eaten a large quantity of seeds, up to a quarter of
the dry matter, is also eaten. In the human body the berry seeds escape digestion. Owing
to the high seed content the physiological calorie value of berries is lower than might be
expected from the chemical composition of the berries.

The seed content and composition of seeds was determined for five berry samples.
The dry matter content ofseeds was about 60—65 per cent. Table 4 shows the seed content
and their composition calculated on dry matter. A low content of sugar and acid is the
characteristic common to the seeds ofall five species. Otherwise the composition of seeds
varies a great deal from one species to another. The currants and gooseberries are alike:
the main component of the hemicellulose is mannan, in the other species it is xylan. No
starch occurs in seeds; the energy reserve consists of fat which in currant and gooseberry
seeds amounts to 25—30 per cent of dry matter. The seed residue obtained from currants
in the berry processing industry would make valuable animal feed owing to its high fat
and protein content, if drying and grinding the residue were an economic proposition.

Table 5 shows the composition of the seed!eis part ofberries, calculated by subtraction.
The sugar and acid contents are naturally higher compared with the whole-berry sample,
while the proportion of cell-wall components and mostly also that of protein has fallen.
In currants and gooseberries, the »tops» of the berries apparently raise the cell-wall
contstituent percentage of the seedless part. The crude fat content is not calculated because
the ether extract partly consists of substances other than lipids.

REFERENCES

Allison, R. M. 1966. Soluble oxalates, ascorbic and other contituents of rhubarb varieties. J. Sci.
Food Agric. 17:554—557.

Blundstone, H. A. W. & Dickinson, D. 1964. The chemistry of edible rhubarb. J. Sci. Food Agric.
15: 94—101.

Drews, H. 1968. Frishes Obst. Handbuch der Lebensmittelchemie. Bd. V/2. S. 1—75. Berlin—Heidel-
berg—New York.

Kushman, L. J. & Ballinger, W. E. 1968. Acid and sugar changes during ripening in Wolcott blue-
berries. Proc. Amer. Soc. horticult. Sci. 92: 290—295.

Kuusi, T. 1969. Kotimaisten marjojen kemiallisesta koostumuksesta ja tunnusluvuista. Valt. tekn. tutk.
lait. tied. IV. Kemia 100: 1—57.



75

Money, R. W. & Christian, W. A. 1950. Analytical data of some common fruits. J. Sci. Food. Agric.
1: B—l2.

Osborn, R. A. 1964. Fruits and fruit products. J. Ass. Off. Agric. Chem. 47: 1068—1086.
Salo, M.-L. 1965 a. Determination of carbohydrate fractions in animal foods and faeces. Acta Agr.

Fenn. 105: I—lo2.
Salo, M.-L. 1965 b. On the content of cell-wall constituents in various plant materials. J. Sci. Agric.

Soc. Finl. 37: 127—135.
Salo, M.-L. & Kotilainen, K. 1969. Determination of free and combined plant acids. J. Sci. Agric.

Soc. Finl. 41: 277—289.
Salo, M.-L. & Korhonen, I. 1972. Carbohydrate and acid composition of some apple varieties. J. Sci.

Agric. Sor. Finl. 44:63—67.
Souci, S. W., Fachmann, W. & Kraut, H. 1962. Die Zusammensetzung der Lebensmittel. Nährvvert-

Tabellen. Stuttgart.
Whiting, G. C. 1958. The non-volatile organic acids of some berry fruits. J. Sci. Food. Agric. 9: 244 —248.

SELOSTUS

SUOMALAISTEN MARJOJEN HIILIHYDRAATTI- JA HAPPOPITOISUUDESTA

Maija-Liisa Salo ja Kaija Suomi

Kotieläintieteen laitos, Helsingin yliopisto

Tutkimuksessa määritettiin kuudesta suomalaisesta luonnonmarjasta ja seitsemästä puutarhamarjasta,
yhdestä tuontimarjasta sekä raparperista sokerit, hemiselluloosahiilihydraatit, selluloosa, raakaligniini,
vapaana ja suolamuodossa esiintyvät kasvihapot, raakaproteiini, raakarasva ja tuhka. Viidestä marja-
lajista määritettiin lisäksi siementen osuus ja siementen koostumus. Analyysitulokset käyvät ilmi taulu-
koista.

Yleispiirteenä mainittakoon, että marjoissa on sokeria noin 35—55 % kuiva-aineesta, kettoainehiili-
hydraatteja 10—20 % ja raakaligniiniä 3—lo %. Huomattava osa kahdesta viimeksimainitusta ryhmästä
kuuluu siemeniin. Kasvihappojen kokonaismäärä liikkuu rajoissa 10—20 %. Hapoista 10—30 % on
suolamuodossa.

Tavanomainen raakarasvamääritys antaa liioitellun kuvan marjojen kaloriarvosta, sillä raakarasva
koostuu siementen lipideistä ja malto-osan orgaanisista hapoista.

Siemenpitoisuus ja siementen koostumus vaihtelee suuresti. Eräissä marjoissa siemeniä on neljäsosa
kuiva-aineesta. Siemenet saattavat sisältää rasvaa 30 % kuiva-aineesta.