It is a small tree with a
smooth, grayish-brown bark and branches that spread into a fairly regular
hemisphere. The oval, alternate, evergreen leaves, 3 to 4 inches long,
have sometimes a spine in the axil. They are glossy, dark green on the
upper side, paler beneath. The calyx is cup-shaped and the thick, fleshy
petals, five in number, are intensely white, and curl back.
The fruit is earth-shaped,
a little rougher and darker than the common, sweet orange: the flowers are
more strongly scented and the glands in the rind are concave instead of
convex.
The first mention of
oranges appears in the writings of Arabs, the time and manner of their
first cultivation in Europe being uncertain.
The small, immature fruits
are sometimes used under the name of Orange berries for flavoring Curaçoa.
They are the size of a cherry and dark grayish-brown in color. Formerly
an essence was extracted from them.
The peel is used both fresh
and dried. Much is imported from Malta, cut more thinly than that prepared
in England.
In Grasse the blossoms are
candied in large quantities.
Oil of petit grain is made
from the leaves and young shoots.
The volatile oil of the
bitter Orange peel is known as Oil of Bigarade, and Sweet Orange oil as
Oil of Portugal. For methods of extraction, see
LEMON.
Orange oil is one of the
most difficult to preserve, the most satisfactory method being to add 10
per cent of its volume of olive oil.
The flowers yield by
distillation an essential oil known as 'Neroli,' which forms one of the
chief constituents of Eau-de-Cologne. A pomade and an oil are also
obtained from them by maceration.
The oil from Sweet Orange
blossoms is found in commerce under the name of 'Neroli petalae.' Being
far less fragrant it only fetches half the price of neroli oil and on that
account is frequently used to adulterate the true neroli oil.
The largest Bigarade-tree
plantations are to be found in the South of France, in Calabria and in
Sicily. The centre of the industry of neroli oil is the South of France,
where the bitter Orange is extensively cultivated for that purpose alone.
The tree requires a dry soil with a southern aspect. It bears flowers
three years after grafting, increasing every year until it reaches its
maximum, when it is about twenty years old. The quantity depends on the
age and situation, a full-grown tree yielding on an average 50 to 60 lb.
of blossoms. One hundred Orange trees, at the age of ten years, will
occupy nearly an acre of land, and will produce during the season about
2,200 lb. of Orange flowers. The flowering season is in May and the
flowers are gathered two or three times a week, after sunrise. When the
autumn is mild and atmospheric conditions are favourable, flowering takes
place in October, and this supplementary harvest lasts until January, or
till a frosty morning stops the flowering. These autumn flowers have much
less perfume than those of the spring and the custom is to value them at
only one-half the price of May flowers. The Bitter Orange and Edible
Orange trees bear a great resemblance to each other, but their leaf-stalks
show a marked difference, that of the Bitter Orange being broadened out in
the shape of a heart. The yield of oil is greatly influenced by the
temperature and atmospheric conditions prevailing at the time of
gathering. In warm weather it may amount to as much as 1,400 grams per 100
kilogrammes of flowers, but under adverse conditions, such as damp, cool
and changeable weather, considerable diminution is experienced. Generally
the largest yields are obtained at the end of the flowering season, on
account of the warmer temperature.
The method most followed
for extraction of the oil is by distillation, which yields a higher
percentage of oil from the flowers than maceration or absorption in fats
and volatile solvents. The flowers are distilled immediately after
gathering, the essential oil rising to the surface of the distillate is
drawn off, while the aqueous portion is sold as 'Orange Flower Water.'
Orange flower water is being increasingly used in France by biscuit-makers
to give crispness to their products, and some of the English
biscuit-makers have also adopted it for this purpose.
There is a marked
difference in the scent of the oils obtained by the different processes.
Neroli obtained by distillation has quite a different odor from the fresh
Orange flower; the oils obtained by solvents and by maceration and
enfleurage are truest to the scent of the natural flower. From 100
kilogrammes of flowers 1,000 grams of oil are obtained; by volatile
solvents, 600 grams; by maceration, 400 grams; and by enfleurage, only
about 100 grams of oil.
Orange Flower Oil as
obtained from pomatum, slightly modified with other extracts, can be
employed to make 'Sweet Pea' and 'Magnolia' perfumes, the natural odours
of which it slightly resembles.
The use of Orange-blossom
as a bridal decoration is neither long-established nor indigenous, as it
was introduced into this country from France only about a hundred years
ago.
The peel of var. Bigaradia contains volatile oil,
three glucosides, hesperidin, isohesperidin, an amorphous bitter
principle, Aurantiamarin, aurantiamaric acid, resin, etc.
The ethyl ether of -naphthol,
under the name of nerolin, is an artificial oil of neroli, said to be ten
times as strong.
- Oil of Orange Flowers
is:
- 'soluble in an equal
volume of alcohol, the solution having a violet fluorescence and a
neutral reaction to litmus paper. The specific gravity is 0.868 to 0.880
at 25 degrees C. (77 degrees F.). When agitated with a concentrated
solution of sodium bisulphate it assumes a permanent purple-red colour.'
It must not be colored by
sulphuretted hydrogen.
Oil of Sweet Orange Peel
contains at least 90 per cent o-limonene, the remaining 10 per cent being
the odorous constituents, citral, citronellal, etc. It is a yellow liquid
with the specific gravity 0.842 to 0.846 at 25 degrees C. (77 degrees F.).
Oil of Bitter Orange Peel,
a pale yellow liquid, is soluble in four volumes of alcohol, the solution
being neutral to litmus paper. The specific gravity is 0.842 to 0.848 at
25 degrees C. (77 degrees F.). The odor is more delicate than that of the
Sweet Orange.
Fuming nitric acid gives a
dark green color to sweet peel and a brown to the bitter.
The oil is used chiefly as a flavoring agent, but
may be used in the same way as oil of turpentine in chronic bronchitis. It
is non-irritant to the kidneys and pleasant to take.
On the Continent an
infusion of dried flowers is used as a mild nervous stimulant.
The powdered Bitter Orange
peel should be dried over freshly-burnt lime. For flavoring, the sweet
peel is better, and as a tonic, that of the Seville or Bigaradia is
preferred.
A syrup and an elixir are
used for flavoring, and a wine as a vehicle for medicines.
The compound wine is too
dangerous as an intoxicant, being mixed with absinthium, to be recommended
as a tonic.
