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Sugars Sugar
Cane Sugar Beets Maple Sugar Palm Sugar Sorghum Syrup Misc.
Sugars Honey Starches
and Starch Products Sources of Commercial Starch Cornstarch Potato
Starch Wheat Starch Rice Starch Cassava Starch Arrowroot
Starch Sago Starch Starch Products Soluble
Starch Dextrin Glucose Industrial
Alcohol Nitrostarch Cellulose Products Paper
and Paper Industry Raw
Materials Wood Fibers Cotton and
Linen Minor
Paper Raw Materials Esparto Textile Fibers Paper Mulberry Misc Paper Sources Synthetic Fibers From Plant Products Cellulose Acetate Rayon Cuprammonium Rayon Nitrocellulose Rayon Viscose
Rayon Cellulose
Acetate Products Viscose
Products Products of Cellulose Hydrolysis Hemicellulose Cellulose
Nitrate Products Vegetable
Ivory Guncotton Pyroxylin |
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Sugars Green plants
manufacture sugars so that they all contain some quantity of sugar. However, much of the manufactured product
is used directly in plant metabolize that very little usually
accumulates. Storage sugars are found
in roots, as with beets, carrots, parsnips; in stems as in sugar cane,
sorghum, maize and the sugar maple; in flowers, such as in palm trees; in
bulbs like the onion; and in many fruits.
There are several kinds of sugar, principal among which are sucrose or
cane sugar, glucose or grape sugar and fructose or fruit sugar. They all seem to serve as a reserve food
supply for the plant. Humans
require sugar in their diet. It
constitutes a perfect food, as it is a form that can be readily assimilated
in the body. Its main value is as an
energy producer, and it is especially well adapted for use after heavy
exercise. A large industry has
developed in connection with the extraction of sugar from plant tissues,
purification and refining.
Additionally over 10 thousand different chemical derivatives have been
made. Sugar is an
especially valuable product derived from the plant world. Only wheat, maize, rice and potatoes
surpass it in importance. Yet there
are relatively few sources for this industry. Only the sugar cane, sugar beet, sugar maple, maize, sorghum
and several palms are commercial sources.
Sucrose is the type of sugar stored in all of these plant species. Most sugar is derived from Sugar Cane, Saccharum officinarum. It is a vigorous and rapid-growing
perennial grass reaching a height in cultivation of 8-12 ft and a diameter of
about 2 in. It grows in clumps with
bamboo like stems arising from large rootstalks and with very ornamental
feathery plumes of flowers. The stem
is solid with a tough rind and numerous fibrous strands, and contains about
80 percent juice, the sugar content of which varies considerably from area to
area and season to season. Commercial sugar cane is a cultivar
that is not known in the wild state.
The plant was most likely first domesticated in Southeastern Asia or
the East Indies from some wild ancestor from that region. By 327 B.C. it had become an important
crop in India. It reached Egypt in
641 A.D. and Spain in 755 A.D. Since
that time sugarcane has gradually been introduced into most humid tropical
and semitropical regions. The
Portuguese and Spaniards were great disseminators of the plant into the New
World. They carried it to Madeira in
1420 and to America by the beginning of the 16th Century. Within another 100 years it had spread all
over the West Indies, Central and South America. Sugar cane first arrived in the United States in Louisiana in
1741. The name “sugar” is derived
from Sanskrit “sarkara,” meaning gravel, and refers to the crude sugar, which
was the only kind known for centuries. Sugar cane
has been the principal export crop of the tropics and is unaffected by many
of the conditions that influence the growing of other crops. It will grow well in any moist hot region
where the average rainfall is 50 in. or more per year and where there is
abundant sunshine and where temperatures do not drop below 70 deg.
Fahrenheit. Backyard stands of sugar
cane are possible in colder climates, however. Cultivation styles vary considerably, but in general extensive,
flat, low-lying fields are utilized and these are plowed deeply. Cuttings of varying length made from the
upper joints of old canes propagate the sugar cane. These cuttings, known as seed, are placed in trenches and
nearly covered with soil. They begin
to sprout in about two weeks. When
the cane is grown for human consumption, the cuttings are usually placed in
holes. The crop has to be cultivated,
weeded and fertilized extensively during the first few months. It is harvested from 10-20 months after
sprouting. Harvest is 10-20 months
after sprouting. The sugar content is
carefully monitored and the canes are cut at just the right stage. This is usually when the flowers are
beginning to fade. The stems are cut
close to the ground because the lower end of the cane is richest in
sugar. Cane knives have been
ordinarily used in poorer countries.
The rhizomes normally give rise to two or three more crops, known as ratoons,
before another planting is required.
There have been up to 20 ratoon crops obtained, however. Cultivated
varieties today are usually hybrids of Saccharum
officinarum,
the “noble cane,” with other hardier species. Sometimes small
owners of a stand of sugar cane extracted their own sugar in a primitive
mill, but more often large “centrals” have been established which draw their
supply from a wide area. In the
milling process the canes are first carried to crushers where they are torn
into small pieces. They are then
passed through three sets of rollers.
In the first set 2/3rds of the juice is expressed. They are then sprayed with water to dilute
what sugar remains, and are passed through the second set. These rollers exerts a very high pressure
and remove nearly all of the moisture.
After passing through the last set the residue is almost dry. This bagasse, as it has been named, can be
used as a fuel for the mills, as a source of paper or wallboard because of
its fibrous nature. It also contains
a wax with some commercial value. The juice
that flows from the mill is a dark-grayish sweet liquid full of
impurities. It contains sucrose, and
other sugars, together with proteins, gums, acids, coloring materials, soil
and pieces of cane. The purification
of the sugar involves the separation of the insoluble materials and the
precipitation of the soluble nonsugars.
The juice is first strained or filtered to remove the solid
particles. It is then heated to
coagulate the proteins, a process which is aided by the addition of
sulfur. Lime is then added to
neutralize the acids present, to prevent the conversion of sucrose into lower
carbon sugars and to precipitate some of the substances in solution. These are removed by a series of filter
bags or a filter press. Carbon
dioxide may be added to aid in the process.
The chemical processes involved in the purification of sugar are under
constant supervision. The juice is
now clear and dark colored and ready for concentration. It is boiled down to a syrup of such
density that the sugar crystallizes out.
This operation is done in open kettles or vacuum pans. The resulting sticky mass is known as
massecuite. It is placed in hogsheads
with perforated bottoms. The juice
slowly percolates through the holes leaving the crystals of sugar
behind. The juice constitutes the
familiar molasses of commerce. In
modern refineries the massecuite is centrifuged with the molasses passing out
through fine perforations. The raw or
crude sugar thus obtained is brown in color and 96 percent pure. Besides the
bagasse, by-products of value are molasses, which is used in cooking and
candy making. It is also used in the
manufacture of rum and industrial alcohol.
The better grades of molasses are obtained when the cruder methods of
sugar milling are employed, for in such cases the sugar content of the
molasses is higher. A mixture of
bagasse and molasses, known as molascuit, is a valuable cattle feed. Refining is
the final stage of sugar preparation for markets. This is usually done in factories located in seacoast areas of
the United States and Europe. The
process involves washing to remove the film of dirt from around the crystals
of crude sugar, dissolving the sugar in hot water, the removal of any
mechanical impurities by filtering through cloth, decoloring by passing
through bone black, recrystallization by boiling, and the removal of the
liquids from the granulated sugar by centrifuging or other means. A hundred pounds of raw sugar usually
yields 93 lb. of refined sugar and three-quarter gallon of refined
molasses. The granulated sugar is
washed, dried, screened, and packed.
Loaf, cube and domino sugars are made by treating granulated sugar
with a warm concentrated sugar solution and pressing it into molds. Loafsugar is often sawed into blocks,
strips or other forms. Powdered sugar
is made from loafsugar or imperfect pieces of other types by grinding,
bolting and mixing with starch to prevent lumping. The refining of sugar is a very old process and was probably
first done in North Africa. The first
type of refined sugar was the sugar loaf, which appeared in England in 1310
and was familiar in America until late in the 19th Century. A marketable syrup has
also been made from sugar cane by clarifying the juice and merely evaporating
it to a consistency where the water content is 25-30 percent. This is sometimes called Golden Syrup. India led the
production of cane sugar in 1947, raising about 25 percent of the world’s
crop. Cuba, Brazil, Puerto Rico and
other islands of the West Indies and Australia followed in the order
names. In the United States
Louisiana, Florida and Texas produce most of the sugar. The highest yields per acre have been
recorded in Mauritius. <bot335> Bananas (Musa sapientum )-fruit; fiber, Sugar Cane (Saccharum
officinarum) Costa Rica Sugar beet, Beta vulgaris, is another important
source of sugar. It was derived from
the wild B. maritima, which is still found wild on European
seacoasts. There were times when beet
sugar equaled or even exceeded that of cane sugar. However, by the 21st Century only about one-third as much beet
sugar as cane sugar was being produced. Although
sugar beet was known since before the Christian era it was not used as a
source of sugar until modern times.
The leaves are edible as a substitute for spinach and the cooked beet
serves as a delicious vegetable. The
occurrence of sugar in the tubers was first noted in 1590 but Maregraf in
1747 first realized its possibilities.
The industry formally began around 1800 in both Germany and
France. Napoleon promoted the use of
it as an embargo against British importations. He was ridiculed because of this and a famous cartoon pictured
him dipping a sugar beet into his coffee.
Another cartoon showed him offering one to his small son, the King of
Rome, with the caption, “Suck dear, suck, your father says it’s sugar” (Hill
1952). Subsequently interest in sugar
beets decreased, but it was again revived in France around 1829 and in
Germany in 1935. Since then it has
been a crop of increasing importance in many European countries. Although earlier attempts were made, the
beet industry did not truly begin in the United States until 1879. Sugar beet is
a white-rooted biennial that grows best in regions where summer temperatures
range around 70 deg. Fahrenheit. It
produces well in irrigated portions of the southwestern United States during
winter months. Almost any good soil
is suitable for this plant’s growth.
Plants are frown from seed and must be thinned until they are from
8-10 in. apart. Thorough weeding and
deep cultivation are required. The
crop is easily machine cultivated and harvesting, so is less expensive to
raise than sugar cane. In temperate
climates the seeds are sown inn April and the roots are allowed to remain in
the ground until October because the sugar content increases in that
position. The beets are pulled before
the ground hardens and the tops are removed to prevent loss of sugar after
which they are stored. The finest
plants are saved for seed, which has led to a gradual improvement, by
selection. Extraction of the juice is a simpler
process than for sugar cane because the roots are soft and pulpy. Earlier they were rasped to a pulp and the
juice squeezed out in bags, but then a diffusion process was used. The roots are cleaned, cut into thin
strips and heated in running water in a series of tanks. About 97 percent of the sugar can be
extracted in this manner. The waste
beet pulp is removed and a process known as carbonation precipitates the
insoluble impurities in the raw juice out.
For this the raw juice is treated with lime, which coagulates some of
the nonsugars, and carbon dioxide, which precipitates calcium carbonate. This settles out along with the impurities
and the purified juice is separated out by filtration. The process is repeated several times
during which sulfur dioxide is added to adjust the alkalinity. A clear liquid is left after filtration,
which is concentrated, crystallized and centrifuged just as with cane sugar. The massecuite is reboiled several
times. It is difficult to
differentiate between raw beet sugar and raw cane sugar for they are for all
practical purposes identical in composition and appearance. By-products of the industry include the
green tops, which are used for cattle feed and fertilizers; the wet or dried
pulp, which is a valuable cattle and sheep feed; the filter cake, which is
used as a manure; and the molasses, which is used for stock feeding or for
industrial alcohol. Central Europe
has produced most of the beet sugar, while in the United States California,
Colorado and Idaho are the principal states that grow this crop. It might be noted that in the manufacture
of rum in Europe, the flavor when the rum is derived from beet sugar differs
substantially from that prepared from sugar cane. The former tends to be much more aromatic and has a distinctly
unique taste
<bot701> Sugar beet roots (Beta vulgaris) [Mediterranean] The sap of maple trees is used in
making syrup and sugar. The area is
confined to northeastern North America and was discovered and developed by
the Amerindians. Although several species of maple
have a sweet sap, the most important is the Sugar
Maple, Acer
saccharum, and the Black
Maple, A. nigrum. The sugar maple is a prominent tree in the
northern part of the eastern deciduous forest zone. It reproduces naturally and lives to an age of 300-400
years. The red and silver maples give
a comparatively small yield and are not of commercial interest. The sap begins to flow about the middle of
March and continues for about a month.
This is a period of warm, sunny days and cold nights. The best flow comes when the temperature
reaches 25 deg. Fahrenheit at night and 55 deg. Fahrenheit during the
day. The preferred location for
tapping is the first three inches of sapwood, about 4.5 ft. above the ground. Amerindians made incisions in the
bark or large roots and conveyed the sap by reeds or curved pieces of bark
into clay or bark receptacles. They
boiled down the sap by dropping hot stones into it and converted the sap into
sugar by letting it freeze and skimming off the ice. European settlers were quick to adopt the
procedure and they added many improvements, eventually tapping with a 1-inch
auger and using spiles to convey the sap into containers. They evaporated the sap in the open in
large kettles so the sugar had many impurities. The dark-brown sap was stored and later converted into
sugar. This involved the famous
sugaring-off, a process in which the syrup was boiled until it became waxy
and the container was then dropped into snow. It was then poured into molds, where it immediately
crystallized. Such simple methods are
persisted for domestic use. Commercial production further
advanced the technique. Modern
evaporators have replaced the furnaces and oiling pans of earlier times. These are able to convert from 25-400 gallons
of sap into syrup in one hour. Great
improvements have also been made in cleanliness and in the methods of
collecting and transporting the sap.
Such large operations involve from 100-1,000 trees. A well-managed sugarbush has about 70
trees to the acre, which allows room for the development of individual trees. The maple-sugar industry reached
its peak in 1869 when 45-million pounds were produced. With the advent of cane sugar it ceased to
be an important commodity. Today the
product is very pure and the demand is increasing for the syrup
especially. Southeastern Canada is
the leading producer while in the United States Vermont, New York, Ohio,
Michigan and Wisconsin produce small amounts. <bot700> Maple (Acer saccharum) tapping in February [NE North America] Several species of palm provide a fourth source of commercial
sugar all of which is only available in the tropics and subtropics. The species utilized are the Wild Date, Phoenix sylvestris, the Palmyra Palm, Borassus flabellifer, the Coconut, Cocos nucifera, the Toddy Palm, Caryota urens, and the Gomuti Palm, Arenya pinnata. Some of the oil palms also yield
sugar. The date palm is tapped
similar to that of a maple and the sap is obtained from the tender upper
portion of the stem. In the other
palm species the sap is secured from the unopened inflorescences. Usually the tip of these is cut off and
the sap oozes out and is collected in various containers. The yield of this sweet juice, known as
toddy, amounts to 3-4 quarts per day for a period of several months. The sap has a sugar content of about 14
percent. It is boiled down to a
syrupy consistency and poured into leaves to cool and then hardens into the
crude sugar known as jaggary. Some of
this has reached European markets.
Three quarts of juice yield about one pound of sugar. The toddy is often fermented to make the
beverage known as arrack. The palm
sugar industry is very old in India where over 100,000 tons were still being
produced yearly by the mid 1900’s. The stem of the Sweet Sorghum, Sorghum vulgare var.
saccharatum,
contains a juice that is used in making syrup. To differentiate between a true syrup and a molasses it is
necessary to realize that syrup is the product obtained by merely evaporating
the original plant juice so that all the sugar is present. On the other hand, molasses is the residue
left after a juice has been concentrated to a point where much of the sugar
has crystallized out and been removed.
The sweet sorghum or sorgo is a wild plant of the tropics and
subtropics which ahs long been cultivated in many parts of the world. The juice is a poor source of sugar, but
yields nutritious and wholesome syrup.
The stems are easily crushed and the juice is evaporated in shallow
pans. On the average about 11-million
gallons were being made in the United States by the mid 1950’s. Similar syrup has also been made from
sugar cane by clarifying the juice and evaporating it to a consistency where
the water content is 25-30 percent. Agave Syrup & Sugar As a biproduct
of the Tequila Industry, sugars are derived from leaves of the Agave
plant. There is a slight bitter taste
to these sugars, however. This sugar is also
known as dextrose or grape sugar. It
is present in small amounts in many of the organs of higher plants and is
especially characteristic of fruits.
However, commercial glucose is prepared from starch. Also known as levulose, this fruit
sugar is present in many fruits together with glucose. It is somewhat sweeter than cane sugar and
is valuable because diabetics can consume it. Commercial fructose is prepared from inulin, a polysaccharide
that occurs in the tubers of the Dahlia, Dahlia pinnata, the Jerusalem
artichoke (=
sunchoke), Helianthus
tuberosus,
and some other plants Mannose does not occur free in
nature so that it must be obtained by hydrolysis from several complex compounds. It is readily oxidized from the juice of
the Manna
Ash, Fraxinus
ornus, a
tree in Sicily and southern Europe.
The juice oozes from slits made in the bark and dries into a very
sweet flakelike material known as manna.
Its use is primarily in medicine. Maltose is
also rarely found in a free state in plants, but is easily produced from
starch through the activity of the enzyme diastase. It is used primarily in the brewing industry. Maltose syrup is sometimes used as a
substitute for glucose and in medicine.
Maltose that is obtained from rice starch has been used in Japan as a
flavoring for over 2,000 years. Flowers that are attractive, such
as roses, hibiscus, etc., usually produce a sweet substance called
nectar. This serves to attract
various insects that are necessary for pollination of the plant. Nectar is composed mainly of sucrose with
some fructose and glucose. It is used
as food by bees, and some of it, after partial digestion, is converted into
honey and stored for future use.
During this process the sucrose is changed to an invert sugar, which
is a mixture of fructose and glucose.
Honey contains 70-75 percent invert sugar along with proteins, mineral
salts and water. The sugar has a
tendency to crystallize out. Honey
was most likely the first sweetening substance used by humans. Beekeeping is one of the very oldest
industries. The flavor and quality of
honey vary depending on the source of the nectar. Flowers that contain essential oils impart a typical
taste. The bees favor certain plants
and these are often cultivated near the apiaries. Clover, Alfalfa, buckwheat, lindens and some of the mints and
citrus are among the favorites. Honey
is an excellent food for it is almost pure sugar. It is also used in medicine, in the tobacco industry and in the
manufacture of a fermented beverage called mead. The best quality honey is derived from the Tupelo tree in SE
United States and from wild plant sources in southern Mexico and Central
America. <bot750> Sea Grape (Coccoloba uvifera
Jacq.) (fruit; ornamental; wood products; red dye;
honey; treat fevers) [Neotropics] One of the most important and
widely available vegetable products, starch constitutes the principal type of
reserve food for green plants. It is
a complex carbohydrate. It is stored
in thin-walled cells in the form of grains.
There are several types of starch that differ in the size and shape of
the grains and other physical and microscopic characteristics. Important sources of starch are the cereal
grains and underground tubers, although nuts, legumes and other plant organs
may contain substantial amounts.
Besides being a staple food for animals and humans, it also has many
industrial applications. Soluble starch is a form that is
used in the textile industry to strengthen the fibers and cement the loose
ends thus making a thread that is smoother and easier to weave. It also gives a finish to the end product. It serves as a mordant in calico printing,
a thickener for the colors. Starch is
also used as a sizing agent in paper industry, in laundry work, in medicine,
in the preparation of toilet powders, as a binding for china clay and as a
source of many other products. Relatively
few plants are used for the commercial production of starch. The main ones are potato, maize, wheat,
rice, cassava, arrowroot and sago. Maize or
Indian corn is the source of over 80 percent of the starch that is made in the
United States. The grains are soaked
in warm water with a small amount of sulfurous acid to loosen the
intercellular tissue and prevent fermentation. Then the corn is ground so as not to injure the embryos. The ground material is placed in germ
separators where the embryos are removed.
The starch material is then ground very fine and is either passed
through sieves of bolting cloth or is washed in perforated cylinders to
remove the bran. The resulting milky
liquid is run onto slightly inclined tables where the starch grains settle
out and the remaining material flows off.
The starch is later collected and dried in kilns and is then ready for
the market. The best grades of
cornstarch are used for food while inferior grades are for laundry starch and
sizing and as a basis for glucose. Cull potatoes are utilized for
making starch. These are washed and
reduced to a pulp in graters or rasping machines. The resulting paste is passed through sieves to remove fibrous
matter. After washing the solid
starch is separated by sedimentation, the use of inclined tables, or
centrifuging, and is then dried.
Potato starch finds uses in the textile industry and as a source of
glucose, dextrin and industrial alcohol.
Europe is the principal producer. The oldest
commercial sources of starch were from wheat. It was known to the Greeks and was widely used in Europe in the
16th Century in connection with the linen industry. The gluten in wheat makes the removal of the starch a difficult
process. It is accomplished by
extraction with water or by the partial fermentation of the grain. Wheat starch is used mostly in the textile
industry. Rice grains
that are broken or imperfect are used for making rice starch. These are softened by treating with
caustic soda and are then washed, ground and passed through fine sieves. More alkali is added and after a time the
starch settles out as a sediment.
This is removed, washed and dried.
Occasionally dilute hydrochloric acid is used to free the grains. Rice starch has found use in laundry and
for sizing. Cassava flour and tapioca are used
in industry mainly as sizing materials and as the source of certain starch
products. The tubers of several tropical
plants provide a source for arrowroot starch. West
Indian arrowroot is from Maranta arundinacea. Florida arrowroot is
from Zamia
floridana. Queensland arrowroot is from Canna edulis, and East Indian arrowroot
from Curcuma angustifolia. The tubers of these plants are peeled,
washed and crushed and the pulp passed through perforated cylinders. A stream of water carries the starch into
tanks where it settles out. Arrowroot
starch is easily digested and thus is valuable as a food for children and
invalids. There is little use in
industry. The stems of the Sago {alm, Metoxylon sagu, contain starch. Cultivation is in Malaya and
Indonesia. The flowers appear when
the trees are about 15 years old and just prior to this time the stems store
up a large amount of starch. The
trees are felled and the starch pith is removed. This is ground up, mixed with water and strained through a
coarse sieve. The starch is freed
from the water by sedimentation and washed and dried. This is known as sago flour. Commercial sago is prepared from this by
making a paste and rubbing it through a sieve in order to cause
granulation. The product is dried in
the sun or in ovens and appears as hard shiny grains, known as pearl
sago. Both sago starch and pearl sago
are used almost entirely for human consumption. Starch grains are insoluble in
cold water but they readily swell in hot water until they burst to form a
thin, almost clear solution or paste.
This soluble starch has been used for finishing textiles and in the
paper industry. When starch is heated or treated
with dilute acids or enzymes it becomes converted into a tasteless, white,
amorphous solid known as dextrin or British Gum. Dextrin possesses adhesive properties and has been used as
substitutes for mucilage, glue and natural gums. Bread loaves brushed with dextrin aids in crust formation. In steel manufacture, the sand for the
cores used in casting is held together with dextrin. Other uses include cloth printing, glazing
cards and paper and making pasteboard. When starch
is treated with dilute acids for a long time it becomes more completely
hydrolyzed and is converted into glucose sugar. Often the same factory that extracts the starch also converts
it into glucose. This operation is
done in large copper boilers under pressure.
About six pounds of dilute hydrochloric or sulfuric acid are used for
each 10,000 pounds of starch. After
all the starch has been converted, the free acids are neutralized with
caustic soda. The liquid is then
decolorized with boneblack and concentrated into thick syrup. One of the common brands of corn syrup is
“Karo.” Glucose may be considered as
an inferior substitute for cane sugar.
However, it is an excellent food material. Its use is in table syrup, for sweetening, in candies, jellies
and other kinds of cooking. It is
often mixed with maple syrup, brown sugar, honey or molasses it is used for
making vinegar and in brewing. Starch is the
source of an enormous quantity of industrial alcohol. Maize and potatoes constitute the chief
sources, although the other starches and even cellulose, various products of
the sugar industry and fruit juice may be utilized. The process converts the starch into sugar by means of diastase
and the fermentation of the sugar by yeasts to yield alcohol. The operations are carried out under
different conditions from those followed in making alcoholic beverages. When fermentation has stopped, the alcohol
is extracted from the mash by fractional distillation. The alcohol thus formed as a result of the
fermentation of sugar is known as ethyl alcohol, as distinguished from methyl
or wood alcohol, a product of the destructive distillation of wood. To render it unpalatable, ethyl alcohol is
often “denatured:” by adding methyl alcohol or other substances. Industrial alcohol is the most important
and most widely used solvent and is the basic material in the manufacture of
hundreds of products. It is also used
in medicine, pharmacy and other industries. Starch and cellulose are
chemically very similar products. Cellulose
reacts with nitric acid to form nitrocellulose while starch yields nitro
starch. Nitrostarch is a very safe
explosive if the ingredients are absolutely pure. Tapioca starch was originally imported for this purpose but
during World War I cornstarch was used as a source. The most
complex of the carbohydrates, cellulose is present in the cell walls of all
plants. Because of their strength,
cells with thick walls have been used in various industries. Besides the natural product being used in
the textile industry, artificial fibers are derived directly from cellulose
as well as countless other products.
Cellulose chemistry is an important phase of organic chemistry. Cotton, a very pure form of
cellulose, has been used for a very long time in the production of artificial
fibers and other cellulose products.
Wood is another very available source. When certain woods are treated with concentrated acids or
alkalis, the bond between the wood fibers and the lignin, which cements them
together, is broken, and the fibers, which are pure cellulose, can be
removed. These fibers may then be
reorganized as paper, or they may be treated further chemically. If the chemical treatment merely causes
the dissolution of the fiber into its component molecules, these molecules
may be synthesized into artificial fibers or converted into cellulose
plastics. But if the molecules
themselves are broken down, their component elements, carbon, hydrogen and
oxygen, may be recombined to form wood sugar. Thereafter the wood sugar may be transformed into yeast or
alcohol and thus become available for food or as the raw material for
numerous industrial products. A very
important use of cellulose is in the manufacture of paper, a very old
industry. The word “paper” comes from
the Latin “papyrus” the name of a sedge, the pith of which was used for paper
in 2400 B.C. Egypt. However paper was
first made in China. The industry
spread from China to India, Persia and Arabia and then through Spain to other
European countries. The first paper
mill in the United States was in 1690 at Philadelphia. The
papermaking value of the various fibers depends on the amount, nature,
softness and pliability of the cellulose present in the cell walls. This cellulose may occur alone or in
combination with lignin or pectin.
Wood fibers, cotton and linen are the principal raw materials. Wood began being used in the paper
industry from about 1850. Today wood
has largely replaced the other fibers and furnishes over 90 percent of all
the paper manufactured in the Untied States. Spruce is a very important source
of wood pulp and has furnished about 30 percent of the total supply. It is ideal because it has all the
requirements of a good pulpwood. The
fibers are long and strong with a maximum content of cellulose. The wood is almost free from resins, gums
and tannins; and it is light colored, sound and usually free from
defects. Red spruce, Picea rubens, White spruce, P. glauca and Sitka spruce, P. sitchensis, are the main species The Southern yellow pine, Pinus australis, is another important
pulpwood. The eastern hemlock, Tsuga
canadensis, is a main species in the Lake States while the Western hemlock, T. heterophylla is important on the
Pacific Coast. Other species include Aspen, Populus grandidentata and P. tremuloides, and Balsam fir, Abies balsamea. Of lesser importance are Jack pine, Pinus banksiana, Tamarack, Larix laricina, White fir, Abies concolor, and several hardwoods
among which are the Beech, Fagus grandifolia, Sugar maple, Acer saccharum, and Birch, Betula lutea. Sawmill waste is also an increasingly
valuable source of wood pulp. Up to the
middle of the 19th Century rags of cotton and linen were the only source of
paper, and they are still used for making the finest grades. Cotton fibers have a high felting power
and a high cellulose content of about 91 percent. Rags and raw cotton in the form of fuzz or linters are
utilized. Flax fibers, that comprise
linen, contain 82 percent of pectocellulose and yield a paper of great
strength, closeness of texture and durability. Textile waste may also be used. In the preparation of rag pulp the material is sorted, cut into
small pieces and freed from dust. It
is then boiled in caustic soda to remove the grease, dyes and other
impurities and it is washed until perfectly clean. The resulting pulp is used directly in papermaking. Esparto grass, Stipa tenacissima, is important in Great
Britain. The plant is native to
Northern Africa where it flourishes in dry, sandy and rocky coastal
regions. The tufted wiry stems are
plucked and pressed into bales for shipment.
Esparto is converted into pulp by heating in a caustic coda solution
under pressure. Although the cellulose
content is only 48 percent, the fiber has great flexibility and felting power. It yields an opaque, soft, light paper of
uniform grade. The finest printing
papers in England have been made from esparto, either entirely or in a
mixture. Another grass, Lygeum spartum, is also used. There are
other textile fibers other than cotton and flax that have been used as
sources for paper. The waste material
of the jute and hemp industry, in the form of old ropes, sacking, sailcloth,
etc. was once used extensively for making strong and tough papers. Jute and jute butts were used mainly for
wrapping paper, envelopes, cable insulation, while hemp, after bleaching,
yielded ledger and bank-note paper.
Manila hemp was an important source of envelopes and wrapping paper. Ramie, sisal, sunn hemp, New Zealand hemp,
coir and other fibers have been utilized.
The bast fibers of the paper
mulberry are very strong and have been used in Japan for paper lanterns and
umbrellas and as paper for writing.
The fiber is scraped, soaked and beaten, after which it is mixed with
mucilage and spread on frames to dry.
When treated with oil this paper becomes strong enough to serve as a
substitute for leather or cloth. There are many other sources for
making paper than what has been noted previously. For example, stems of rye, barley, wheat, oats, rice and other
grasses are used for low-grade paper, strawboard, pasteboard and
cardboard. These plants have fibers
with low cellulose content and are too short and small to have much tensile
strength. Thus, they are mixed with
other fibers. Sugarcane bagasse,
cornstalks, and waste paper have been developed as sources of paper. Banana fiber, tree bark, rushes, weeds,
broomroot, licorice, cotton and tobacco stalks, beet pulp waste and peat have
been used somewhat. Recycled paper is
extensively used to make other paper products. In the Orient bamboo fiber is an important
source of paper. The Papyrus, Cyperus papyrus, Baobab, Adansonia
digitata, and Daphne cannobina are used in Africa and
India. Rice paper of Japan and China is
made principally from Tetrapanax papyriferum, Edgeworthia tomentosa or Wickstroemia canescens. Synthetic Fibers From Plant Products Hill (1952)
wrote that since the Middle Ages until modern time there have been many
schemes to make artificial silk and other fabrics. In 1880 Count de Chardonnet made the first artificial fiber,
and a few years later the first artificial silk. Later factories were established for making the product. At the outset this new material was
handicapped by its name for the public considered it only as an imitation or
a substitute. This condition existed
as late as 1908. Today it is
understood that all the artificial fibers constitute entirely new products
with valuable characteristics and properties of their own. The raw material of the rayon
industry is high-polymer alpha cellulose, prepared in a pure form from wood
pulp or cotton linters. Purification
is accomplished by the elimination of mechanical impurities through air
separation and then cooking in a 3.5 percent sodium hydroxide solution. This removes all the other organic
substances. The pure cellulose fibers
that remain are bleached, washed and dried.
The next step is to dissolve the cellulose by various solvents thus
rendering it sufficiently liquid so that it can be squirted in a fine
jet. The solution is then forced by
pressure through minute perforations in glass or platinum, and emerges from these
“spinnerets” in thin streams. The streams
are coagulated into fine, almost invisible filaments in different ways. The solvents are removed and the filaments
are caught up by revolving reels and twisted into threads suitable for
spinning. The threads are washed,
bleached and dried. In the viscose,
nitrocellulosee, and euprammonium processes the final product is an almost
pure cellulose fiber known as regenerated
cellulose. This is chemically identical with the
cellulose in cotton, but it differs in itss mechanical properties. The product of the acetate process is a
cellulose ester, cellulose acetate. This differs from regenerated cellulose in
both its chemical and physical properties. Several kinds of rayon are Viscose Rayon, Cellulose
Acetate Rayon, Cuprammonium Rayon and Nitrocellulose Rayon. Treatment
with concentrated nitric acid in the presence of sulfuric acid causes
cellulose to change into several types of cellulose nitrate. These differ according to which
concentration of nitric acid was used and the consequent degree of nitration
as well as the temperature and the duration of the action. The higher cellulose nitrates are called
guncotton, or in error nitrocellulose.
The lower nitrates constitute pyroxylin, or collodion cotton. This is made
from cotton linters during which process the cellulose is completely
nitrated. It is used as an ingredient
of many high explosives. Cordite,
e.g., is a combination of guncottton and nitroglycerin, while smokeless powder
is made from a mixture of guncotton and the lower nitrates. Guncotton is one of the safest of
explosives to handle when properly manufactured. A partial
nitration of cellulose produces pyroxylin.
This is carried out under different conditions from those, which
result in the formation of guncotton.
In modern photography the films often consist of pyroxylin coated with
gelatin. It is used in the rayon
industry. However, its chief value is
that it is soluble in a variety of solvents and yields many useful products,
such as celluloid and other plastics, collodion, artificial fabrics and
varnishes. Industrial
uses include as a substitute for cellulose nitrate in the film industry
because it is not very flammable.
Resultant films are more brittle and expensive, however. It is also used for goggles, gas masks,
automobile windows, artificial fabrics, index cards, airplane varnish, etc. Cellophane is
a viscose product. Forcing crude
viscose through tiny slits rather than perforations makes this. It coagulates into a thin transparent film
only one-thousandths of an inch in thickness. Such viscose files are used for numerous poses even for sausage
casings. Viscose fibers have replaced
cotton in Welsbach mantles. Products of Cellulose
Hydrolysis When
cellulose is completely hydrolyzed in a process of saccharification this
ultimately results in the conversion of the cellulose into wood sugar that in
its turn yields alcohol and yeast. It
is a complement to the manufacture of paper pulp from wood. Under usual
processes of pulp making one ton of wood is converted to one-half ton of pulp
and enough wood sugar to yield 10-12 gallons of alcohol. Doubling the cooking time produces an
edible starchy material that is an excellent cattle feed, and sufficient
sugar to furnish 20 gal. of alcohol is obtained. Under a still longer cooking time all of the cellulose can be
converted into sugar with an eventual production of 60-80 gal. of alcohol. Regarding the
kinds of wood sugar that are produced, conifers yield glucose, pentose, and
mannose; hardwoods glucose and pentose.
These sugars are useful because they can be readily fermented. Glucose and
mannose, which comprise about 2/3rds of the wood sugar, are converted into
ethyl alcohol by the action of ordinary yeast. This industrial alcohol has a wide range of uses. Pentose sugars are not fermentable into
alcohol, but they can be converted, through the activity of a bacterium, Torulopsis
utilis,
into Torula yeast, and edible substance with a 50 percent protein
content. One ton of pulp will yield
from 40-100 lbs. of yeast. Cellulose
hydrolysis can play an increasing role in a well-organized system of forest
utilization as it eliminates much of the waste. Small pieces of wood, chips, sawdust, wood flour and sawmill
waste can all be used effectively Many tropical plants have seeds that
are very thick, hard and have heavy walls consisting of hemicellulose. This is a modification of ordinary
cellulose and constitutes a supply of reserve food for the plant. In young seeds the endosperm consists of a
milky juice, but as the seeds mature this fluid is replaced by the harder
material. hemicellulose cannot be
used by animals as food. However, it
does provide vegetable ivory of commerce. The Ivory-nut or Tagua
Palm, Phytelephas macrocarpa, of the Neotropics is
the main source of vegetable ivory.
The palm is a low-growing tree typically on riverbanks from Panama to
Peru. The drupes like fruits have
from 6-9 bony seeds with a thin brown layer on the outside and a very hard
and durable endosperm. The natives
collect the seeds that are shipped to Europe and the United States. Ecuador is the main exporter. This ivory may be carved and shaped into
various objects, so it serves as a substitute for true ivory in the
manufacture of buttons, poker chips, knobs, chessmen, dice, inlays, etc. Several species of palms in Africa
and Polynesia and Neotropical America have seeds of similar
constituency. With the exception of Metroxylon amicarum of the Caroline
Islands, these are not important in commerce. |
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