This document discusses the structure and chemical composition of grapes. It describes the different parts of the grape cluster including the handle, tendril, and berries. The cluster reaches its final size at ripening and varies in shape depending on the length of the secondary nodes. The berries are attached to stalks, and the structure of the cluster depends on stalk length. The cluster represents 3-7% of the grape weight and is lower in sugars but richer in acids than other parts. The stalks contain high levels of phenolic compounds. The seeds, cuticle, and flesh all have distinct chemical compositions with varying levels of acids, salts, and polyphenols. Grapes contain antioxidants that provide health benefits such as heart protection, blood

1. Erasmus+ 2016-18
“Green Skills for Social Agriculture”
Structure and shape of the
grape
The grape consists of two sharply
different parts: the cluster that
represents the skeleton of the bunch,
and the actual fruit - grains.
The clusters are attached
to the nodes of the branch. This
part of the cluster is called the
handle, perhaps it is wrong if the
bunch is a single fruit. The
length of the handle and the
type of grape vary in the
different grape varieties. First,
a separate branch of the cluster
is a tendril. Often it is missing or dries and falls before flowering, sometimes it
turns into a small side cluster, as is the case in bunches
with aliform form (Petit Verdot), or develops in normal
cluster, as double clusters. The characteristic shape of
the cluster is determined by the shape of the secondary
nodes of the cluster, ending in the stalks, which are
nipples. For example, the bunch has a conical shape when
the base of the top nodes of the cluster becomes
shorter and smaller. The bunch is cylindrical, when the
branches have the same length.
The cluster reaches its final size when the grape
is ripened. At the beginning, it is very green. Although, it
loses part of chlorophyll, usually it stays green after
ripening the grapes. In some varieties, however, it turns
in (Malbec). The handle undergoes a maturation process

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at the same time the rod on which it is situated; it darkens
and dries the tissue and become hard, that is why the
separation of the clusters is difficult.
Berries are fastened on the stalk (bed). The
structure of the clusters depends on the length of the
stalk. If the stalks are long and slender the grains are
separated from each other and the clusters are loose. In
some varieties, conversely, stalks grow fat and remain
short. In this case, the clusters are concise and the grains -
compressed and flattened. The loose clusters are inherent
in the dessert varieties while wine grapes is in the most
compact clusters.
The following table indicates the percentage weight of various parts of
bunches before maturation and after that.
Also, pointed measurements made in 1893 by Girard and Linde concerning
the four varieties, as well as new data and Payne Maurier.
Mechanical construction of the cluster and the grain at maturing according
to Girard and Linde
Parts Before maturation Maturation
Grapes:
Cluster
Beans
10 to 20
80 to 90
2 to 4
96 to 98
Grains:
Meat
Cuticle
Seeds
65 to 80
15 to 24
5 to 9
75 to 85
15 to 20
3 to 6

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By Payne and Morier
Cabernet
Sauvignon
Merlo Malbek Petit Verdot
Parts of the grain:
Average weight g
Flesh,%
Zipper%
Pips%
1,32
74,4
19,8
5,8
1,62
78,8
16,4
4,8
1,60
82,9
14,2
2,9
1,83
76,0
21,0
3,0
Structure and chemical composition of the cluster
In a normally developed grape cluster
represents a 3 to 7% by weight. In spoiled or
affected by cutting grapes, this percentage can
be much larger. Bunches with small grains have
proportionally bigger cluster.
From a chemical point of view, the
cluster approach the leaves and mustache. It is
low in sugars, medium rich in free acidity and is
Cabernet
Sauvignon
Merlo Malbek Petit Verdot
Parts of the grape:
Bunch,%
Grains%
Parts of the grain:
Average weight g
Flesh,%
Zipper%
Pips%
2,9
97,1
1,22
87,4
8,7
3,9
2,7
97,3
1,65
88,4
7,9
3,7
2,4
97,6
2,70
91,0
6,5
2,5
1,7
98,3
1,37
87,6
6,9
5,5

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very rich in acids converted into salts, because it contains many mineral
substances. Cellular and juice has a high pH, over 4 clusters are particularly rich
in polyphenols. Contrary to general opinion insistence (soaking) of the clusters in
the production of red wine grapes Oron does not
cause increase and decrease the acidity of the wine
with significant increases in pH.
This table has a chemical composition of
clusters of four Bordolezki variety grown in the same
soil. Red varieties vary from white with higher
content of polyphenols.
Chemical composition of the cluster
(Leonyan, 1951)
Content of 1000 at maturation
The stalks are particularly rich in phenolic compounds. Indeed, by leaving
bunches of grape pulp the permanganate index
of red wine increases significantly. The
presence of leucocyanidin in red wines was
demonstrated by Ribera-Geyon. He has found
Proporti
-on
on
cluster,
%
pH Free
acids
Salt
s
Assembl
y
the
cations
Wine
acid
Apple
acid
Lemo
n
acid
Assem
bly
on
aniions
Solubl
e
polyph
enols
Sauvignon
Semillon
Cabernet
Sauvignon
Merlo
6,8
5,9
8,1
5,3
4,08
4,30
4,52
4,45
88
58
67
73
102
104
138
110
190
162
205
183
94
86
62
29
80
80
98
150
6
5
10
4
180
171
170
183
5,4
6,8
12,0
15,2

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that clusters give the wine around 1/3 of the
total leucocyanidin.
In 1910, Lasbordes proves that the tannin
in the vine and wine have the properties of
leucocyanidin. Rosenheim confirmed that in
1920.
Structure and chemical composition of the seeds
Grape must normally contains four
seeds originating from the four ovules found
in the ovary. Very often, the number of seeds
may be larger - when the ovary contains more
than four ovules. Almost always, however, the
number of seeds is less than - three, two and
one often due to lack of or damage to one or
more ovules.
Sometimes, due to improper fertilization, grains have no seeds or seeds
are smaller than normal. In such case, the not swollen grains remain small,
although they may ripen and accumulate more sugars.
This damage is called Milerandazh; if it is very common it
causes severe reduction of yield.
The absence of seeds in the grains is a
characteristic which is preferable in dessert varieties,
but also for the production of raisins. The lack of seeds
depends on the ability of grains of some varieties to
develop without being fertilized, or usually due to improper formation of the
ovules of all grains.
The development of seeds is essential for the size and the composition of
the grains. The weight of the grains is based on the number of seeds.

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Structure and chemical
composition of the cuticle
The cuticle consists of epidermis and several
layers of cells located underneath. It is
that part of the grain, which is
removed by crushing them. The
distinction is difficult. According to
Girardello Linde the skin represents 6
to 9% by weight of the grains. Cuticle
plays an important role in winemaking.
The cuticle consists of 6 to 10 layers
of cells. To the surface of the grain
cells are smaller but have a bold walls.
The internal cells are larger, but with
thinner walls. When the grain is cut it
shows that between the skin and the flesh there are not borders.
Chemical composition of the cuticles
Quanti
ty of
cuticles
,%
pH Free
acids
Related
acids
Assemb
ly
the
cations
Wine
acid
Apple
acid
Lemo
n
acid
Assem
bly
on
aniions
Soluble
polyphen
ols
Sauvignon
Semillon
Cabernet
Sauvignon
Merlo
14,0
21,0
19,6
16,2
4,15
4,30
4,05
3,79
94
67
80
55
148
116
90
65
242
183
170
120
99
64
79
80
132
110
75
40
9
3
4
3
240
177
158
123
2,6
3,4
6,8
6,4
The most characteristic skin substances are yellow and red pigments. They
appear in gray grape and maximize the volume reached at full maturity.

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Grapes healing effect and chemical composition
The flesh of the grape and the extract from its seeds contain powerful
antioxidants (proanthocyanidins and resveratrol). They are also insurmountable
barrier against harmful UV-rays of the sun. Therefore, grape oil is the main
ingredient in many sunscreen lotions.
Red grape cuticle contains resveratrol and its seeds together with certain
substances in grape seed extract protects
the body against the development of tumors.
Such effects have phytonutrients ellagic
acid and quercetin, which are also contained
in the fruit.
Grapes favors the prevention and treatment
of heart disease, thanks to that it contains
glucose. It is enough for the normal function
of the heart to take 200-300 grams of ripe
grapes per day. Glucose is a physiological
stimulator of the heart, supports the
processes of oxidation and metabolism.
Therefore, grape sugar participates in the
energy balance of the human body.
Again, the ingredient resveratrol in grapes
regulates blood sugar levels, which is
important for people prone to diabetes. An
important factor for prevention of the
disease is to maintain a normal body weight. The antioxidant resveratrol helps to
reduce excess fat
deposits in the body and
prevents re-deposition.

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The grapes increase resistance of the liver cells and it acts as an antidote.
Grapes has excellent properties for visually impaired. Regular consumption of
fruit limits the risk of vision loss associated with aging, known as macular
degeneration. Studies show that three servings a day reduce the risk of this
degeneration on average over 36 percent.
Grapes are strongly recommended for tuberculosis and other acute and chronic
diseases of the lung. It is better to be consumed by
asthmatics and people with chronic bronchitis. Grapes
clears the airways of mucus and phlegm.