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ItisACQUI |
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THE GRAPE |
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The
bunch of grapes is made up by a grape stalk and grapes. The grape stalk is
the branched central axis where the grapes insert themselves. It contains
thready substances such as lignin and cellulose, pectines, resines and
tannines. The
grapes is made up of the peel that has got an internal and an external part,
both are composed of flattened cells. On teh grape’s external surface there
is a waxen substance, known as bloom, that keeps the chemical balance. This
substance appears in the period of maturation and it regulates gasiform and
water exchanges between the external and internal enviroment. There are other
substance with waxen structure, such as alcohol esters and heavy acids. The
bloom arranges itself in a small masses that permit a little permeability. In
the squashed cells below there are also dyestuffs and aromatic substances that
give grapes and must, their particular smell. The peels are extremly rich of
mineral elements. The
most internal part of the grape is the pulp. This is the most important part
from a commercial point of view. It contains more sugars than the other part:
glucose and fructose. The acids are organic: in particular tartaric, malic
and citric acid. There are also proteins and other nitrogenous and even
inorganic substances (like the ammonium ion). Wine
grapes have one or more grapes seeds (pips) that contain polyhydric phenols
and fat substances. They are extracted to have grapes seed’s oil and are last
discarded. |
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