Sugarcane grows in all tropical and subtropical countries. Sucrose as a commercial product is produced in many forms worldwide. Sugar was first manufactured from sugarcane in India, and its manufacture has spread from there throughout the world. The manufacture of sugar for human consumption has been characterized from time immemorial by the transformation of the collected juice of sugar bearing plants, after some kind of purification of the juice, to a concentrated solid or semi solid product that could be packed, kept in containers and which had a high degree of keep ability. The efficiency with which juice can be extracted from the cane is limited by the technology used. Sugarcane processing is focused on the production of cane sugar (sucrose) from sugarcane. The yield of sugar & Jaggery from sugar cane depends mostly on the quality of the cane and the efficiency of the extraction of juice. Other products of the processing include bagasse, molasses, and filter cake. Sugarcane is known to be a heavy consumer of synthetic fertilizers, irrigation water, micronutrients and organic carbon. Molasses is produced in two forms: inedible for humans (blackstrap) or as edible syrup. Blackstrap molasses is used primarily as an animal feed additive but also is used to produce ethanol, compressed yeast, citric acid, and rum. Edible molasses syrups are often blended with maple syrup, invert sugars, or corn syrup. Cleanliness is vital to the whole process of sugar manufacturing. The biological software is an important biotechnical input in sugarcane cultivation. The use of these products will encourage organic farming and sustainable agriculture.
The book comprehensively deals with the manufacture of sugar from sugarcane and its by-products (Ethyl Alcohol, Ethyl Acetate, Acetic Anhydride, By Product of Alcohol, Press mud and Sugar Alcohols), together with the description of machinery, analysis of sugar syrup, molasses and many more. Some of the fundamentals of the book are improvement of sugar cane cultivation, manufacture of Gur (Jaggery), cane sugar refining: decolourization with absorbent, crystallization of juice, exhaustibility of molasses, colour of sugar cane juice, analysis of the syrup, massecuites and molasses bagasse and its uses, microprocessor based electronic instrumentation and control system for modernisation of the sugar industry, etc.
Research scholars, professional students, scientists, new entrepreneurs, sugar technologists and present manufacturers will find valuable educational material and wider knowledge of the subject in this book. Comprehensive in scope, the book provides solutions that are directly applicable to the manufacturing technology of sugar from sugarcane plant.
of Gur (Jaggery)
raw material Gur is manufactured in India from
sugarcane juice and sweet juices of palmyra and date-palm trees. The
proportion of Gur produced is from sugarcane juice.
sugarcane (Saccharum officinarum) is a well-known
perennial plant of the grass family and its cultivation is confined to
warmer regions of the earth. The sugarcane looks like a thin bamboo and
up of root, root stock, the stalk, the leaves and the inflorescence.
is the portion crushed for the extraction of juice. It is a cylinder,
of which are formed by a hard outer tissue called the rind and the
being filled with a soft cellular structure, the pith consisting of
(parenchyma) which serve to store the juice. The cylinder is subdivided
number of smaller cylinders by transverse partitions, namely the nodes.
material, of which the rind is made, is of a hard woody nature and
impurer juice which may be termed as rind-juice. The pith is of a
and contains a purer juice which may be called pith-juice. Broadly
the sugarcane is divided into juice and fibre, the latter term
everything which is not water or which is insoluble in water. The
therefore, is made up of rind-tissue and pith-tissue and the juice is
of rind-juice and pith-juice. The composition of cane Varies with
climatic and soil condition in which it is grown and with variety and
maturity. The average composition in India may be taken to be as
Juice 85% cane
Fibre 15% cane
The cane is harvested when it is fully ripe. The period
which the sugarcane takes to attain ripeness or maturity depends upon
climate and rainfall of the region in which it is grown, on the variety
sugarcane and on whether it is a plant crop or ratoox crop. It is
to 12 months* for sali cane and 16 to 18 months** for Adsali cane in
When the cane is fully ripe the reducing sugar content is minimum or
and the purity of juice is the highest. Arrowing and flowering of
marks the end of the vegetative period of growth. After the cane has
further formation of sugar takes place in the plant but an elaboration
already formed obtains with an increase in the sugar content and
time to which cane can be left standing after arrowing is variable and
dependent upon variety and climate, but arrowing should be regarded as
unfavourable sign since vegatative growth having ceased the cane is
to die off than if it had not arrowed. Ratoon crop (peri) ripens
the plant crop (Naulaf) but its yield is less than that of the plant
simple though rough method of ascertaining the maturity
of cane is to test the brix (specific gravity) of juice tapped from top
and botton half of the cane by means of a Hand Refractomer. Where the
top and bottom brixes is very near unity the cane may be regarded as
practice with cultivators in Northern India is to
start harvesting operations soon after Deothan Ekadashi i.e. sometime
middle of November when the cane is believed to have ripened.
This process consists of cutting off the cane from the
ground, stripping off the Leaves and removing the tops. The cane should
as close to the ground as possible as the bottom most portion is the
sugar. The topping should be done just above the highest coloured
the manufacture of Gur it would be better to remove the top two or
below the top most joint as these joints are of lower sucrose and
glucose content than the rest of the stalk.
is done in India almost entirely by manual
labour and no mechanical means are employed. The tool used for the
purpose is a
broad-bladed knife, a pick axe spade or a sickle. The green tops are
feeding the cattle or if the topped portion have a few nodes it may be
dry leaves are left in the field to be collected and
tied into bundles and carried to the boiling shed to be used as fuel or
thatch huts or to spread as litter in cattlesheds.
the stock of canes cut is sufficient to feed the
crushers for a day, they are tied in bundles and carried to the crusher
in head-loads or in carts or in trucks.
cutting the cane begins to lose weight through
evaporation and simultaneously a loss of sugar takes place due to
The rate of loss of weight and sugar will depend upon the prevailing
temperature and humidity. For this reason it is essential to crush the
Gur manufacture as soon after cutting as possible.
It should preferably
be crushed within twenty-four hours of harvesting.
main operations are involved in the manufacture of Gur,
viz. (1) Extraction of juice from sugarcane (2)
Purification of juice
and (3) Concentration of juice into Gur.
equipment used for the purpose consists of a crusher
or a number of crushers for the extraction of juice from sugarcane and
a pan or
set of pans heated over a furnace. The combined equipment consisting of
furnace with pans fixed on it is termed in Hindi as BEL.
The process of
clarification of juice and its concentration is carried out in the Bel.
very remote times crushing has been the mode
generally practised for the extraction of juice from sugarcane. The
method of crushing cane in India for the manufacture of Gur
bruising or grinding bits of cane in a mortar by means of a wooden
by bullocks or camels. Mills used to be made by cutting down standing
about two feet above the ground level and utilising the two feet stump
mortar and cut-out trunk as the pestle. Such trees were however not
at all times and places and so later on the mortar was made of stone. A
will with a wooden pestle.
of cane in a pestle and mortar being a very
crude and inefficient device it was followed by the crushing cane
wooden or iron rollers fitted close to one another vertically or
The two-roller mills were later on substituted by three-roller mills
are now in general use in India by those who make Gur. Three-roller
crushers driven by bullock power are employed by cultivators for
crushing and the three-roller (horizontal) power-driven crushers are
by big farm owners who have to deal with larger quantities of cane.
sketch shows a vertical three-roller bullock-driven
crusher and its component parts.
of the various parts of the crushers
bolts and nuts
19. 5/8² “ “ “
20. 1/2² “ “ “
21. 1/4² “ “ “
for iron standards
10. Cover crescent
11. Two Blocks
12. Wood Bushings
13. Oil Box
14. Pivot ring
sizes of these crushers vary from make to make and
generally range between 7²
in diameter or height for major
rolls and somewhat smaller diamensions for the minor rolls. The
depending upon the size of crusher and quality of cane and range
between 2 mds
& 4.5 mds. of
cane per hour. Juice extraction
varies from 50 to 70 per cent. cane.
horizontal mills are generally in use though
vertical three-roller crushers (Kolhus) driven by mechanical power are
with a three-roller horizontal power crusher and Photo No.4 a
vertical power-driven Kolhu.
capacities of power crushers (horizontal type) vary
from 15 to 55 mds. cane per hour according to their size and juice
from 64 to 72 per cent. cane. The power requirement varies from 5 to 25
according to size.
quantity of juice expressed out from cane depends
upon the quality of cane, design features of the crusher and the
cane into the crusher and the pull applied by the bullocks. A fresh
lower percentage of fibre will naturally give more juice than a dried
having higher percentage of fibre. The design features, such as roller
(distance apart of rollers), and the type and size of groovings of
also the quality of roller material and rigidity of construction have a
profound influence on extraction. From the Gur manufacturer’s point of
cane should be of low fibre, soft and light-coloured and rich in
cane juice is an opaque liquid varying in colour from
grey to dark green according to the colour of cane from which it is
It contains in solution all the soluble constituents of cane, viz,
reducing sugar, salts, organic acids etc., and besides air it carries
suspension gums, fine bagasse fibre, wax and clay and colouring matter
The proportion of the different constituents varies depending upon
age of cane, nature of soil, manures applied and climate in which cane
grown. In the cane, main figures for sucrose and reducing sugars show
greatest differences while the other elements do not vary much in sound
ripe canes. The proportion is somewhat as follows:-
70 to 72
12.5 to 17.5
11 to 14
6. Fat and wax
7. Pectin (gums)
8. Organic acids
clarification of juice
turbid viscous juice from the mills is not fit to be
worked up into an edible material without clarification. The course
particles of fibre may therefore first be removed by straining and the
and gummy constituents and fine particles of fibre by coagulation. As
is very liable to inversion and fermentation due to the action of
micro-organisms it is very necessary to boil the juice immediately
after it is
expressed from cane whereby the albuminoids are also coagulated and
of micro-orgamisms is checked. The aim of clarification is to prevent
non-sugars being formed again in the juice and next to remove as far as
possible al objectionable matter which may be present. A further
to prevent charring or overheating during the concentration of juice.
therefore is to make juice clear as well as to make it light in colour.
first object is achieved by coagulating the colloidal impurities
insoluble matter held in suspension by the colloidal constituents is
thrown down or rises to the surface leaving the juice clear.
the means that may be adopted for the
flocculation of colloids the following may be mentioned (i) addition of
electrolyte, (ii) action of electric current, (iii) change in the
solution, (iv) elevation of temperature, (v) addition of vegetable
which coagulate on heating and entangle suspended impurities and (vi)
by surface-attraction using flocculent materials.
the process of manufacture of Gur from cane
juice the fourth method alone or a combination of the fourth and the
methods is generally employed. These Methods are further combined with
third or the sixth mehtod or with both when a very good quality of Gur
is desired. The actual procedure is as follows:-
the furnace has been sufficiently heated juice is
filtered into the pan of the Bel and heated up
slowly to the boiling
temperature. Care is taken not to boil it over. In the course of this
the scum appears on the surface of the juice and accumulates to the
the pan. This is removed by means of a perforated ladle. When vegetable
mucilages are used as clarificants of flocculants they are added when
temperature of juice has risen to the boiling point and the cracking of
scum layer on the top has well advanced and not before. With fall in
temperature, which follows, any separable particles still contained in
juice are set over and ascend to the top, whence they are easily
the thick layer of the scum.
it is found that the waves of impurities do not
continually travel from the south to the north side of the pan it
concluded that the fault lies in the construction of the furnace. The Nikhar
or the clarifying pan should receive the heat at the southern end and
boiling must not be allowed to originate except in that part of the
much emphasis cannot be laid on the necessity of faithfully observing
important rule as neglect to do so would result in bad clarification
defective quality of Gur.
a fairly clear liquor has been obtained Sajji
water may be added taking care not to exceed the dose. If this is done
should be checked for a while otherwise violent ebullition would take
the juice may boil over.
the above case no chemical change takes place. The
clarification of juice can however be affected by effecting a change in
reaction of the juice. Cane juice being acidic initially (acidity
according to the maturity, freshness or staleness of cane) the chemical
or the change in the reaction of the juice can be brought about by the
of heat and alkalies such as Sajji and lime water.
This change in
reaction would also effect flocculation and result in the production of
coagulated scums rising to the surface whence they may be ladled out.
scums which are ladled out are transferred into a
strainer which is usually made of a coarse cloth spread into a basket
an earthen pot into which the juice entrained with scum will filter
clarification process may be considered complete when
no more scums are formed and the juice is clear and the foams formed
clarificants used may be divided into two classes,
viz. (i) vegetable clarificants and (ii) chemical clarificants.
The vegetable clarificants. The principal
vegetable clarifying agents used in the manufacture of Gur
juice are Deola (Hibiscus Ficulneus), Bhindi
Esculentus), bark of Semal tree (Bombax
Malabaricum), bark of Phalsa
tree (Grewia Asiatica), and Sukhlai (Kydia
Calycina). The method of
preparing and using them is described below:-
The freshly cut green lower portions of the stem and a
part of roots of the Deola plant are well pounded
in water and rubbed
between the hands with the addition of more water.
mucilaginous colourless liquid having a thick
consistency is produced. This extract is added to the juice in the
pan at the time when the juice is about to boil. The exact point is
the following way:-
first green scums begin to come up to the surface and
a hissing sound is heard from the heated juice in the clarifying pan.
sound gradually becomes less and less audible as the temperature of
higher up. Before the sound stops the requisite quantity of extract is
in the juice. The extract contains vegetable albumins, which coagulate
heating, entangle the suspended and colloidal impurities and bring them
the surface, where they are skimmed off. In order to reduce vigorous
while skimming cold water is occasionally sprinkled on the juice. The
first are dark green in colour and are known as Dhandoi or
But towards the completion of clarification these are like white froth
called Chandoi. If the scums appear to be still
dirty at this stage it
means that the juice requires a further dose of clarificant which is
though sparingly till the froth rising to the surface is perfectly
It is used just in the same way as
Deola (Hibiscus Ficulneus) above.
of several Tree (Bombax MalaBaricuns):- The green
barks of the tree are pounded in water, rubbed between the hands and
mucilaginous liquid extracted. The extract is used for the
juice in the same way as that of Deola.
Of Phalsa (Grewia Asiatica).
The green bark of the tree is used
in the same way as that of the Semal tree.
The dry barks of Kydia Calycina are
soaked in water for some time before the mucilaginous liquid is
the same way as that of other clarificants and the manner of using it
The chemical clarificants. The chemical
clarificants used in the manufacture of Gur are:-
2. Sodium carbonate
3. Sodium bicarbonate
of these chemicals such as sodium carbonate, sodium
bicarbonate, Sajji and lime water can be used with
advantage in the
manufacture of Gur from inferior canes such as
lodged cane, diseased
cane or canes of over-luxuriant growth. They help in solidification of Gur,
but impart dark colour to the finished product.
Lime water. Saturated lime water, which is
quite clear, is added to the juice after clarification with Deola. Lime
is of special advantage whilst treating the juice from inferior canes.
treatment helps in solidification of the resulting Gur very
It should be used in moderate quantity which is judged by experience.
water is employed in an excessive quantity the colour of the Gur
dark though the crystals will be stronger. If the juice is limed to the
of neutrality of there about the Gur produced is
Sodium carbonate. This chemical is also used
after clarification of juice with Deola. This
minimises the effect of
aoids during boiling and improves the keeping quality of Gur.
carbonate should be used only when Gur is to be
made from inferior
quality canes. It should also be used in moderate quantity.
Sodium bicarbonate. It is added in the Chak
churning the cooled concentrated mass. It improves the colour of the Gur
but the effect is temporary. The Gur acquires its
real colour after some
days. So there is no advantage in adding sodium bicarbonate. Rather it
disadvantage that it increases the cost of manufacture.
Sajji. It is commonly used in manufacture of Rab
but it is also used in manufacture of Gur when Gur
is made from
unripe cane or canes of the inferior type. Sajji
contains about 50 per
cent of sodium carbonate, 6.4 per cent of sodium sulphate and 4.5 of
chloride and being cheaper than sodium carbonate it is used in place of
carbonate to partially neutralise the acidity of the juice.
solution of Sajji in water is prepared and is
boiled before use. The Sajji solution is added to
the boiling juice
after clarification with Deola. A copious evolution
of carbon dioxide
takes place, and the heavy froth which forms, consists chiefly of gummy
impurities of the juice which are skimmed off. A strong smell of
dioxide is also noticed, due probably to the breaking up and reduction
sulphates. The sulphur dioxide exercises a bleaching action on the
juice. But Sajji
spoils the taste of the finished product even if it is used in small
Super-phosphate. Superphosphate added to the
juice clarified in the usual way with the extract of Deola
gives to the Gur a golden colour but the
crystalline structure for which
the Gur is valued is lacking, more so with
increased amount of
superphosphate. The drop in purity of the Gur from
that of the juice
increases with addition of superphosphate. This is due to the increase
natural acidity of juice. When that juice is heated inversion occurs
in temperature and the quality of
Alum. Alum is used as a clarificant in some
parts of Bengal. Alum used along with the extract of Deola
good clarification, but the juice has to be subsequently neutralised
or lime water. Where Gur is made in lump form, no
useful purpose is
served by using this chemical. If the juice treated with alum is
with soda or lime water, colour of the finished product is affected and
neutralisation is not done after alum clarification the crystalline
of the Gur is affected. It should be used only in
those parts of the
country where Gur is made in semi-liquid form as in
Bengal. In that case
neutralisation of juice after Deola and alum
clarification is not
of Cream Jaggery
colour of Gur usually ranges from yellowish to
dark brown. The lighter the colour of Gur the
better is its quality. In
order to improve the colour special treatment has to be given utilising
principle of surface-attraction. A process has been evolved for making Gur
directly from juice yielding a creamy white product. This Gur
termed cream jaggery.
of the process of manufacture of cream jaggery
are given below:-
process of manufacture of cream jaggery was evolved
by the Indian council or Agricultural Research, New Delhi. The Gur
produced by this process is of good quality and has cream colour. It is
superior to ordinary Gur. Due to its fancy colour
there is great demand
for it. Manufacture of this type of Gur was started
first in the western
part of U.P. But now it is gaining popularity in other parts of the
juice from the cane mill is strained through a coarse
Garaha cloth or a wire netting of five mesh before
filling it in the pan
of a Bel. The juice is then heated to boiling point
and clarified with Deola
in the usual way. When clarification is complete it is treated with
carbon to remove colouring matters from it. Treatment of juice with
carbon is done in two ways - one is called the filtration process and
the settling process.
The filtration process.
In this process juice after
clarification with deola is passes through a layer of activated carbon
percolator. Percolator is a conical bucket with perforated bottom. It
G.I. Sheet and is placed on an angle iron stand. Design
of a percolator of 16²
top dia. x 10²
bottom dia. x
high is given in the Drawing No. 1. The size and number
of percolators depend upon the quantity of juice to be treated daily.
is filled in the percolator after placing a thin
pad of cotton-wool on the perforated bottom. A small wooden disc is
the layer of carbon so that it may not be disturbed when the juice is
over it. Before passing clear juice the carbon is washed with hot water.
quantity of carbon required for complete
decolourisation of juice depends upon the quality of the carbon and the
to be treated with a fairly good quality of carbon - it is 2.5% on
the percolator is ready a clean bucket is placed
under it to receive the decolourised juice. The clear juice from the Bel
is then filled in the percolator slowly. In the beginning, juice coming
from the percolator brings with it fine particles of carbon. Such juice
again passed through the percolator. The juice is examined from time to
means of a test tube and when brilliant juice, free from carbon
starts coming out it is received in the bucket and transferred into the
concentrating pan of the Bel. When sufficient
quantity of decolourised
juice has been colected in the pan it is concentrated and converted
process of decolourisation of juice is suitable for
small scale work. It works efficiently only with coarser carbons and
easily adopted in the case of more efficient but finer carbons
available in the
The settling process.
This process is suitable for both
small scale as well as large scale work. It was evolved at the Sugar
& Testing Station, Rilari. In this process activated carbon is
directly to the juice in the boiling pan. The raw juice after straining
heated and clarified with Deola in the usual way.
Requisite quantity of
activated carbon (2.5% on juice in normal cases) is added to the
in the pan and thoroughly mixed by stirring with a wooden Ghota
about ten minutes for complete action. Paddy husk carbon, which is of a
variety is to be powdered fine before use. Milk (whole or skimmed)
about four times with water is added to the juice. After a couple of
spongy mass of carbon particles rises to the surface and is removed
ladle (Pauna). The process of adding diluted milk
followed by skimming
is repeated a few times until the treated juice when taken in a glass
settles down quickly leaving a transparent layer of juice. In this way
portion of light carbon is eliminated from the juice. The juice is then
transferred to a rectangular settling tank made of G.I. Sheet. After
the juice to settle for 20 to 30 minutes the upper cock is opened and
juice is allowed to discharge into the next pan of the Bel.
stops coming out from the upper cock the lower cock is opened. The
quantity of juice with carbon left over at the bottom of the settling
the scums are Filtered and washed in bag filters. The filtrate is mixed
boiled with clear decolourised juice received from settling tanks.
settled juice still contains some suspended particles
of fine carbon which are easily removed by further sprinkling diluted
skimming. The juice now possesses a colourless sparkling appearance and
from carbon particles. Afte this stage, all further contamination of
with carbon is to be carefully avoided. The transparent juice is
in the usual manner for making Gur.
cost of manufacture of cream jaggery and that of
ordinary Gur is given in the Table No. 12 as
supplied by the
Agricultural Research Station Anakapalli. It will be observed from the
that the cost of manufacture of one 1b. of cream jaggery is 10.16 Pies
against 4.19 Pies of ordinary Gur. Thus for
producing cream jaggery an
additional expenditure Per of only 5.97 pies per 1b. is incurred. This
additional expenditure maund of Gur comes to Rs.
Gur is prepared for refining purposes. It cannot
be consumed directly due to its unpleasant taste. But it contains
percentage of sugar in it and would fetch better price than ordinary Gur
in the refineries.
the manufacture of ordinary Gur there is much
destruction of sugar during boiling of juice. The finished product is
of poor quality. The two most important causes responsible for the poor
of Gur are (i) inversion due to acidity and high
temperature and (ii)
caramelisation due to concentration at high temperature. In order to
loss of sugar due to inversion caused by boiling an acidic juice at
temperature for a long time the juice is neturalised before boiling,
produced from the juice thus neutralised is called Neutral Gur.
process or manufacture of neutral Gur differs
slightly from the process of making ordinary Gur
and is given below.
Gur can be prepared in any Bel.
a three pan furnace is more suitable for this work. In such a Bel
pan is utillised for storing and heating of raw juice, the second for
clarification and neutralisation of juice and the third for
small scale work Bilari Bel No. 1 is the most
suitable Bel for
this Purpose and for large scale work the meerut Bel
can be used.
sucrate is used for the neutralisation of juice. It
is prepared in the following way:-
lime is first slaked in a small quantity of water
and when it is completely slaked more water is added so that the total
of water added in two stages is about 5 times the quantity of lime by
If the quantity of lime is good the milk of lime will be approximately
The milk of lime thus prepared is strained through a wire gauge of
mesh and through a course Garaha cloth and is then
mixed with cold raw
juice to prepare lime sucrate. To 100 parts of raw juice 18 parts
upon the quality of lime and juice) of milk of lime are added and after
stirring vigorously the mixture is allowed to settle. The clear
liquid is decanted and is ready for use.
juice and boiling
juice from cane mill after proper straining is filled
in the pan or pans of the Bel and the furnace is
fired. When the juice
temperature reaches to cracking point Deola
mucilage is added and the
juice is clarified in the usual way. After the clarification of juice
complete freshly prepared sucrate of lime is added in requisite
the pH of juice comes to 6.8 to 7.0. The Ph of juice is Frequently
means of Bronco Thymol Blue Paper. When this (BTB)
paper gives a faint
blue tint the pH of 6.8 to 7.0 is indicated. In the begining some
felt in detecting the exact shade. The best course is to moisten one
end of a
strip of BTB paper with normal saliva and to match the shade obtained
obtained by dipping the BTB paper in neutralised juice. The juice is
boiled vigorously. The scums formed at the surface of the juice are
means of a ladle from time to time. If a multiple pan furnace is
making neutral Gur, clarification and
neutralisation is carried out in
the second pan as the juice comes to the Nikhar stage. The further process
of boiling and
concentration of the neutralised juice to Gur is
similar to that of
preparing ordinary Gur.
to neutralisation of juice the quality of Gur
is much improved. Comparative results obtained by the ordinary process
neutralisation method using the same quality of juice in the two
shown in Table 13. It will be seen from these results that the nett
of neutral Gur is 8.15 units higher than that of
cost of manufacture of neutral Gur is only
about 8 pies more per mol. of Gur as compared to
the cost of ordinary Gur.
This is due to the use of lime for the preparation of lime sucrate.
all other items of cost are the same as in the manufacture of ordinary Gur.
The higher purity of neutral Gur possessing better
however more than counter balances the increased cost.
manufacturing neutral Gur
refineries purchase Gur on nett rendement
basis according to a sliding scale. Generally a flat rate is paid for Gur
having nett rendement between 40 and 45. If the value is below 40 the Gur
is rejected and for each degree rise in the nett rendement value above
supplier gets more price. In pre-war times, it used to be generally one
more for each degree rise. The supplier of Gur
would thus receive from
the refineries eight annas more per maund of neutral Gur
than for the
ordinary Gur. Deducting the extra expenditure of a
pies, he would get
annas seven and four pies more per md. of Gur.
refineries, on the other hand, get much better raw
material which in addition to increasing the recovery would lower the
production of sugar. The extra payment made by the refinery would
only a fraction of the increased return accruing from a better raw
of Molassine Gur
the Khandsari system of sugar making two straight
boilings are generally practised. The cane juice is boiled to first Rab
the molasses from first Rab is
boiled for obtaining second sugar and exhaust molasses. During normal times a major
portion of this molasses
for want of adequate utilisation is not easily saleable at a fair price
to give a good return to the Khandsari. Under such
molasses is converted into Gur. As the sugar per
cent in exhaust
molasses is very low Gur prepared from it does not
solidify. To make
solid Gur from molasses it is prepared from
molasses obtained after
curing first Rab.In this case manufacture of 2nd
sugar and exhaust
molasses is eliminated and the Khandsari is saved
from the problem of
disposing of its exhaust molasses.
manufacture of molassine Gur
the first Rab is fully matured it is purged
in centrifugal machines. The first light and heavy molasses obtained
are mixed together and diluted with a little water to dissolve the
of sugar present in it. The diluted molasses is then boiled without any
to 122°C. When it reaches the desired consistency it is transferred to
where it is cooled and solidified in the usual way.
molassine Gur prepared in this way is of
ordinary quality and does not fetch good price in the market. Better
molassine Gur may be prepared from:-
obtained from partially crystallized
molasses by mixing clarified juice.
(iii) First molasses using Khandsari
Manufacture of molassine Gur from exhaust molasses by mixing clarified
weighed amount of cane juice is taken in a flat
bottomed pan furnace and clarified with Deola
Mucilage in the usual way.
Skimmed exhaust molasses equal to one third the weight of cane juice is
mixed with the clarified juice. The mixture is boiled to Gur
ordinary way. The molassine Gur thus prepared is
and good in taste. It can be distinguished with difficulty from the
quality Gur sold in the market. It will be seen
from the data given in
the table below that the purity of the Gur prepared
from exhaust Khandsari
molasses alone is 55.73 while that of Gur
prepared from clarified
cane juice and exhaust molasses, mixed with proportion or 3 : 1, is
over 9 units higher. Leaving aside the chemical composition of this Gur,
it compares favourable with the ordinary Gur
available in the market.
But owing to the increase in the impurities due to the addition of
keeping quality during rainy season is comparatively poor.
(iii) Manufacture of
molassine Gur from first
molasses using Khandsari sugar
first molasses is diluted with an equal quantity of
water and then the diluted molasses is boiled in the same way as the
is boiled for making Gur. During the course of
boiling, a solution of
sodium bicarbonate is sprinkled, two or three times, on the boiling
the Gur is ready, the pan is removed from the
furnace for cooling for
about ten minutes. When the temperature of the mass comes down to about
small quantity of powdered Khandsari Sugar is
sprinkled over it and the
whole mass is thoroughly mixed. The process is repeated three times
temperature of the mass goes down to about 75°C. The semi-liquid mass
transferred to Gur moulds or frames. About three Chattaks
powdered Khandsari sugar is required for making one
maund of molassine Gur.
This process, which has been developed at the Patna Agricultural farm,
ensures a crystalline structure to the Gur, (b)
reduces considerably the
stickiness of the product, (c) helps rapid solidification of Gur
improves the keeping quality of Gur. The yield of
on cane is 4 to 5 per cent., while on molasses it is 58 to 64 per cent.
molassine Gur in Bombay
the Bombay Presidency the purity of cane juice is
usually much higher and hence the manufacture of molassine Gur From
Molasses alone is always possible. This Gur is of fairly good quality
fetches about 75 to 80% of the price realised for the first quality of Gur.
The process of manufacturing molassine Gur as
worked out by the
Agricultural Department of the Bombay Govt. is described below:-
order to dissolve the false grain of sugar it is
necessary to add water to the first molasses. In the beginning of the
when the brix of cane juice is only about 16, addition of fresh juice
proportion of 1 : 5 (one part of juice and five parts of molasses) is
necessary. Later on as the brix of juice increases to 18° it is not
to add any fresh juice to molasses. In the latter case the proportion
to molasses is one part of molasses and two parts of fresh clear water.
addition of water the dilution is brought to 65° to 70° and is
bring about clarification. The impurities of the diluted molasses get a
chance to come up to the surface and are then easily removed. During
boiling of the molasses, a solution of sodium bicarbonate in water is
after the removal of scum. This helps the impurities still remaining to
frothing in the form of white scums which are removed with the ladle.
boiling temperature of the molasses is to be kept to 122° C to 125° C,
the proper strike. The pan containing the concentrated mass is then
from the furnace and the contents are poured into the cooling pan.
operations are the same as followed for making Gur in
the usual way.
This Molassine Gur is only a little inferior to Gur made from fresh
its yield is much higher than that obtained in Northern India.
seer of Gaozaban and 1/4 seer of black Sajji
steeped in 6 seers of water in a bucket for 24 hours. The mass after
rubbed between the hands is strained through fine muslin cloth. The
mass is again put in 3 seers of water well rubbed and restrained. To
strained liquids 1 drum of alum is added and this is boiled till the
reduced to 1/4th. 3 ozs. of this liquid is added to a charge 2.5 mds.
in the pan after the scums have been removed. On its addition the scums
rise to the surface are again removed. The clarified juice is then
boiled to Gur
in the usual way.
order to study the quality of Gur that is
produced by this process comparatively, Gur was
also made from the same
quality of juice by the usual Deola clarification.
In appearance, the
colour of Gur produced by Deola
clarification was lighter than
that of Gaozaban.
is manufactured in the districts of Saharanpur and
Dehradun. The process of manufacture for this form of Gur
is the same as
that for Chaku Minjha Gur except that in this case
only a single layer
of cooled mass is spread over the hessian cloth in the Adda.
mass has cooled it is cut with knives into oblong bits and collected in
baskets. Some times the Andarki Gur is spiced with
roots, cloves, cardamoms and shredded Copra. These
are added to the
boiling juice after clarification.
is a kind of raw sugar directly consumed or used by Halwais
for the manufacture of inferior kinds of sweets. The process of
and boiling is similar to that of Gur except the
boiling is continued a
little longer than in case of Bheli Gur. When the
boiling mass attains
the proper consistency which is at a temperature of 120° C, the
emptied in earthen Chaks and allowed to cool. When
the mass has cooled
down somewhat soda dissolved in a little water is sprinkled over it and
mass well kneaded with Khurpies until it has
required a pale yellow
colour. The mass is then made into a conical lump and removed to next Chak
to cool down further. After 15–20 minutes the mass is rubbed violently
the hands till the powdered Gur (Shakkar)
is ready. The quantity
of soda is about 30 gms. per 24 seers of the boiled mass. In order to
decolorise the Shakkar and give it a good
appearance Blankit (Sodium
Hydrosulphite) is also used. The blankit is added in two stages. It is
added with a little soda when the juice is boiling in the pan after
clarification. In the 2nd stage it is added dissolved along with soda
cooled mass in the earthen Chak. The quantity of
blankit added is about
half that of the soda. The Shakkar so produced is
pale yellow in
appearance, and its taste is somewhat different.
Bagasse and its Uses
product of Milling
by-product of residue of milling cane is bagasse (in
British Commonwealth areas megass), the woody fiber of the cane with
residual juice and the moisture remaining from the imbibition water. In
practice, about one-half is fiber, the other half water and soluble solids, with variations
resulting from the
milling procedures and the variety and quality of the cane.
great majority of the bagasse produced, amounting to
one-fourth of all
the cane ground in the
world, supplies the fuel for the generation of steam in the raw
Because of electrification and other means of fuel economy most modern
factories have an excess of bagasse
during the regular grinding season. The handling of this excess
problem because of the bulk of the material. Baling is resorted to in
areas so that less storage volume is needed. Rehandling for locomotive
domestic usage, and the like is facilitated by briquetting, sometimes
figures by Tromp and others, Hugot takes the average
bulk weight of bagasse as 12.5 lb. per cu. ft. when stacked, 7.5 lb.
Value of Bagasse
fuel value of dry bagasse shows surprising uniformity
throughout the world. Numerous calorimeter combustion tests in Cuba,
Hawaii, Puerto Rico, Natal, and Australia give Btu. values between 8200
8400 (4550 to 4660 cal.) Investigations of the fuel values of the newer
canes in several of these countries corroborate these figures. The
8350 Btu. per lb. of ash -free dry bagasse (4640
cal. per kg.) falls
within the limits of error of sampling and analysis, but bagasse is not
ash-free so the average figure chosen is not too important. The actual
value of bagasse burned upon the grates depends on the moisture
requires heat units to evaporate it. Other variables are the stack
and the excess air drawn through the grates the must be heated. The
present in the fuel forms water that also absorbs part of the heat
bagasse fibre has been analyzed by various
investigators with average figures of carbon 47.0, hydrogen 6.5, oxygen
ash and undetermined 2.5 per cent. Hugot tabulates the results of ten
analyses that indicate the variations.
figures represent the actual number of Btu’s
available at the burners with conditions of excess air, stack
moisture as indicated.
excess air actually used may be arrived at by determining the CO2
gases (now generally determined automatically). The curve given in Fig.
shows the relationship between CO2 by volume and percentage of
excess air as well
as the volume of gases produced.
hundred per cent excess air was formerly taken as good average
However, with modern installations this has been reduced, so that 50
is closer to the average for good furnaces, and 25 per cent is the
average for spreader stokers. The heat lost in stack gases is a
function of the
excess air and the temperature of the stack gases
Feed to Boilers
bagasse is carried directly from the mills to the
boilers by carriers of the drag type and is fed to the boilers
The simplest mechanical device consists of a hopper fitted with a
counterbalanced trap door. Rotary feeders are mechanically driven drums
seal the opening at all times while revolving and delivering the
bagasse to the
devices regulating the quantity of bagasse fed
to the boilers have become quite common in recent installations.
drives operating in conjunction with automatic combustion-control
maintain uniform feed rate, proper air-fuel ratio, and improved boiler
drying of the bagasse by the waste heat in
chimney gases to increase the net Fuel value has been advocated by many
actually practiced in a few small plants in some European colonies. It
many mechanical difficulties, together with considerable danger of fire
the air admitted to the furnace for combustion
purposes will effect as great a saving as drying the bagasse and
simpler equipment. The simplest of the air preheaters are of the
in which the flue gases pass
tubes and the air to be heated circulates around
the tubes. (A preheater of this type is shown in Fig. 23.7) Practically
modern installations include preheaters.
earliest furnaces for burning green bagasse were
introduced almost simultaneously in 1886, first in Louisiana, then in
Samuel Fiske and Frederick Cook. Fiske’s furnace had
horizontal grate bars on which the bagasse
burned. Cook’s furnace was of the hearth type. Both used forced draft.
step-grate furnace, consisting of horizontal grate bars, resembles a
down which the bagasse falls as it burns, the ash being collected on a
flat grate at the bottom. Air passes between the grate bars and through
burning bagasse blanket. The grate or hearth types have been generally
in the West Indies, and the stepgrate in Hawaii, the Philippines, and
Australia; but Hugot says that the stepgrate is giving
way in most areas to hearth-type furnaces.
tendencies are toward much larger furnace volumes
to ensure high furnace temperatures. With modern furnace design
2300° F. are the rule , as contrasted with 1700° F. in older
furnaces have suspended flat tops (so-called flat
arches) which, besides having many
advantages of construction, distribute the hot gases to
the boiler more
evenly than the circular brick arch formerly used. Another important
the mixing wall, above the bridge wall, which directs the gases at the
the furnace downward to promote mixing and prevents stratification of
gases, thereby aiding in securing complete combustion. The use of
also aids in mixing the gases and avoiding stratification. The downward
of the roof reflects the heat back on the fuel bed, promoting the
drying of the
improvements in furnace design that have received
wide acceptance are the Ward single-pass furnace and the Detrick-Dennis
construction. The Ward single-pass furnace in connection with a
boiler, consists of a cast-iron hearth
with a bottle-shaped furnace, from which the name has been
is admitted at the lower rim of the hearth, and secondary air is
tuyeres at the bottleneck. Because of the contraction and expansion of
combustion gases a torch effect results. No combustion chamber is
the multiple hearths need to be cleaned only once a day, according to
conditions. Recent installations include hydraulic devices for dumping
Detrick-Dennis Multi-Cell furnace usually consists of
four high round cells each with a restricted throat on top, set beneath
boiler radiant surfaces. The cells are equipped with tuyeres in their
side walls for the introduction of primary air. Tangential air
several points higher up produces a cyclonic action which provides an
mixture of air and fuel. This whirling mixture sorts out the fine
From the incoming bagasse fed into the cells From above the throat
These fines are carried into the upper furnace chamber and burned in
suspension. The resultant coarse bagasse relieved of the blinding
effect of the
fines, dries and burns at an accelerated rate.
larger boiler furnace chamber above the cells acts as
an expansion chamber to provide low vertical velocity for burning
particles, resulting in little carry-over of unburned carbon particles.
cleanouts are required as often as in any other method of cell burning
equivalent hearth area, but by
the individual cell cleanouts at least 30 minutes apart, full steam
the other three cells may be maintained. Some installations have
operated dumping hearths above the boiler room floor under each cell.
The most marked advance in bagasse burning in the past
15 years has been the growing use of spreader stokers, particularly in
connection with boilers of large capacity. The method of feeding the
constitutes the original features of the spreader stoker. The bagasse
discharges through a chute at the bottom of which a blast of air throws
bagasse particles from a distributor plate into the furnace. The finer
particles dry and burn as they fall through the air and the coarser
burns on the grate. Spreader-stoker installations generally employ
manual-dumping grates for boilers of less than 40,000 lb. Steam per
whereas units above 70,000 lb. Steam per hr. have continuous mechanical
discharge of ashes. Boilers from 40,000 to 70,000 lb steam capacity per
use ash-removal methods of either style. The spreader stoker with
feed regulation and automatic combustion controls permits bagasse
the burning of any waste fuel, at higher combustion rates and improved
efficiencies not possible with older-type furnaces. The ease of ash
the economical brick work made possible by the lack of arches and
furnaces are other advantages cited by Hugot. Spreader-stoker
been introduced primarily for other waste fuels, such as bark and wood
and have later been adapted to bagasse burning, in contrast to earlier
especially designed for bagasse.
annotated bibliography on the commercial utilization
of bagasse compiled for Sugar Research Foundation includes all
July 1951. The interest in bagasse as a raw material for commercial
evident from the 541 items in this compilation. Additional references
found in “A Century of Utilization and Fundamental Work of Sugar Cane
by Srinivasan and Pathak.
on the manufacture of paper from bagasse extend
back nearly 100 years but full commercial success was achieved only
past 25 years by the W.R. Grace Company in Peru. In the interval, this
factory in connection with Paramonga Sugar Factory has supplied the
part of the paper products required by the Peruvian market. Almost
of paper from corrugated medium to white bond is manufactured,
representatives of the Grace Company with annual production approaching
metric tons. Similar paper mills have been established in Puerto Rico
Colombia, using the PEADCO process as in Peru.
second successful process, utilizing soda, developed by
Valentine Sugar Company in Louisiana, started in 1953 on a commercial
The annual out put has now reached 25,000 tons of fine writing and bond
Bagasse paper mills are in operation in the Argentine, the Philippines,
and Spain besides the ones mentioned in Peru, Puerto Rico, Colombia and
and Insulating Board
for the manufacture of building and insulating
board, inaugurated by the Celotex Company in Louisiana in 1922, has
its use as fuel in about one-fourth of Louisiana mills. Bagasse from
is baled and stored in large piles under roofing paper. The process
shredding and cooking, which removes the resins, waxes, and
renders the fibers tough and flexible. From the cooker and washer the
goes through paper-mill refiners to separate the fiber bundles, after
waterproofing and termiteproofing chemicals are added. The board forms
process known in pulp handling as “felting,” the strength of the board
due solely to the interweaving and entangling of the fiber. As the wet
comes from the forming machine it is fed into a continuous hot-air
which it emerges finished in a continuous sheet 12 ft. wide, cut by
convenient sizes. The board is made in several forms and thickness, and
special tile about 1 in. thick and 12 in. square is drilled with 441
holes as a
sound absorbent or sound deadener.
processes are in operation in Hawaii and
Australia with some modifications. The Australian factories, because of
rising cost of coal in wartime, found it advisable to use an admixture
made from low grade eucalyptus trees, rather than all bagasse. Their
material production more than doubled between 1940 and 1555. A
factory to produce hard board (as contrasted with the soft-style board
presently made) in Louisiana will employ resins to cement the fibre
the first operation of this type using bagasse as a base.
to utilize the finer portions of bagasse for the
production of alpha-cellulose, to be used as a basis for rayon, high
explosives, etc., have not met with the commercial success that the
of paper and wallboard has. De la Rosa described the production of a
alpha-cellulose of 97 per cent purity at Central Tuinucu, Cuba, but his
articles indicate that the commercial venture was discontinued. The
involved digestion with SO2 at 110° C. and
then with 10 per cent caustic soda at 140° C., followed by bleaching
hypochlorite. Laboratory studies in Hawaii, using nitric acid
high-grade alpha-cellulose pulp D.F.J. Lynch and others made a detailed
of pulping bagasse and other fibrous materials with nitric acid,
separation of the pith by gravity separators
of the type used for bone char has been practiced. Lathrop says that in
manufactures of Celotex a certain amount of the pith is washed out of
fibre, which is collected, washed, and dried. The annual yield is
thousand tons of an extremely light, porous product sold to the
Mulch and Cattle Bedding
Louisiana operation involves separation of the
bagasse into various fractions according to particle size. The bagasse
mill loses about 40 per cent moisture in passing through gas-fired Heil
at 1400° F. The dehydrated bagasse goes to Roten screens and divides
fractions. The coarsest fraction serves as a horticultural mulch; the
fraction (also Fibrous) is used for chicken litter and cattle bedding. The finest
fraction, the pith, is
further separated by the gravity separator mentioned above, yielding
fractions: a fairly high-test alpha-cellulose for explosives
manufacture, and a
coarser fraction used as roughage in a feed mix with molasses.
successful venture in bagasse utilization credited to
the Valentine Sugar company of Louisiana is the production of various
from the lignin in bagasse. First worked out as pilot-plant operations
government laboratories, the process was commercially perfected at
about 1950. The products, sold under the general trade name Valite, are
thermoplastic and thermosetting wheel suited for the manufacture of
records. Several articles by T.R. Mc Elhinney and colleagues cited in
annotated bibliography describe the various uses to which the bagasse
may be put, such as varnishes, laminates and low-cost molding material.
Products from Bagasse
subject for patents is activated carbons from bagasse, but none of the
present-day carbons uses bagasse
base material. The production of furfural from bagasse, by
same methods as those using corn
a base, has also been the subject of several
patents and has
resulted in commercial production in Dominican Republic under American
and Reducing Sugars
crystals are hard and anhydrous and belong to the
mono-clinic system, characterised by three axes of unequal length.
density is equal to 1.606 g/cm3.
Impurities have a remarkable
influence on the formation of the crystals.
is very soluble in water and in dilute ordinary
alcohol. It is insoluble in chloroform, in cold absolute alcohol, ether
solubility of pure sucrose in water increases with
the rise in temperature of the solution as indicated below.
pure sucrose solutions the boiling point elevation can
be used as an index of the concentration of the sucrose solution at a given absolute
pure sucrose is dissolved in water, sucrose hydrate
is formed. 1 molecule of sucrose in diluted solution is hydrated by not
than 4 molecules of water. Other consider that the formation of
hydrates in the
range of 60-120°C is not so much influenced by temperature as by
With increasing concentration, the degree of hydration falls between 60
per cent and increases between 80 and 60 per cent.
solubility of sucrose in water is modified by the
presence of other substances. In general salts in lower concentration
at up to
about 40°C have the effect of lowering the solubility of the sucrose
(salting-out M effect), while in higher concentrations of salt (except
case of calcium salts) the solubility increases. Solubility of sucrose
impure solution is influenced by temperature, composition of the
and its concentration. It is supposed that the increase of solubility
sucrose is due to the development of addition compounds of salt and
and this is one of the several hypotheses put forward for the formation
molasses. The higher solubility of calcium oxide in a solution of
compared with the solubility in pure water is due to the formation of
compounds of sucrose and calcium oxide : at 12°C only 0.137 g of
are dissolved in 100 g of solution without sucrose, while in a solution
containing 29.2 g of sucrose 8.5 g of calcium oxide are dissolved, that
say 62 times more. Soluble and insoluble compounds of sucrose and lime
destroyed even by weak acids.
specific gravity varies from 1.033 to 1.106 according
to concentration. The density of the sugar solution is determined in
by Brix and Beaume spindles or Balling saccharimeter.
ray of light bends (refracts) if passed through sucrose
solution. The refractive index, as it is called, is measured with a
refractometer and varies with concentration of the solution under
the length of the column of liquid, the nature of light and the
having a fixed length of column of liquid, standard temperature and
light, the rotation then becomes a function
of the concentration
of the sugar in solution.
acids on sucrose solution
inversion of sucrose is much more rapid when the solution
is made slightly acidic. The acid acts as a catalyst and remains
rate of inversion gets accelerated with increase in temperature.
rate of inversion has been studied by Ostwald who
established the following laws. The rate of inversion depends upon:
The strength, nature of acid and the temperature of
Time during which the acid acts.
Proportional to the active mass of sucrose (k) if
temperature and concentration of acid remain unchanged.
20% sugar solution inverts twice as fast as a 10%
solution. This can be represented mathematically as under.
of inversion = k (a –x),
integration between 0 and x limits,
log = k
‘k’ is a specific reaction rate constant and is
different for different acids; ‘a’ denotes original amount of sugar
‘x’ denotes quantity of sugar inverted in time ‘t’ after the
40– (–12) = 52°
minutes = 30°
amount of sugar inverted = X = (40–30) = 10
= 1/60 log =
inversion of sucrose is combined with a reversal of
the optical activity. If pure sucrose is treated with dilute acid under
conditions, then the optical rotation recedes from + 100° S to – 33°C,
the decrease in the rotation value amounts to 133°S (inversion).
Invert sugar itself has no inverting power.
acids effect a more complete decomposition
of sucrose in solution, especially when heat is applied. The
sulphuric acid removes elements of water from solid sucrose molecules,
a black mass of carbon.
of cane juice:
It has been found that free acids alone even in traces
rapidly invert pure sucrose solution, but this is not so in the case of
in cane juice as expressed from mills.
reason for this is the inhibitory effect of the
neutral salts of weak acids present in cane juice. The hydrolysing
mineral acids is replaced by weaker organic acids and so very weak acid
can be worked for sometime and heated under vacuum upto a temperature
of 90 to
95°C without much fear of ‘inversion’. The allowable acidity (due to
acids) will depend upon the quantity of neutral salts present in the
acids on sugar solutions
acids posses weak inverting power because of
their small dissociation constant.
states that if the ‘inverting power’ of
hydrochloric acid is taken as 100, that of formic acid is only 1.5, of
acid 1; and of acetic acid only 0.5.
alkalies (lime) and alkaline earths
alkalies such as calcium, potassium and sodium
hydroxides do not decompose sucrose (cane sugar) even on boiling and
for their neutralization just as much acid as corresponds to the amount
base present in the compound.
alkalies decompose sucrose into lactic,
formic, acetic and humic acids which combine with the base present to
salts. Barium and strontium (alkaline earth elements) likewise form
saccharates, with varying quantities of the base.
moderately concentrated alkalies unite with sucrose,
even in cold, readily forming soluble compounds having an alkaline
forms three well-known compounds called
‘saccharates’ with varying quantities of the base, viz.
first two are soluble in water but the third is practically insoluble.
boiling, the mono and the disacchartaes change into insoluble
of mono and dicalcium saccharates on being heated consequently become
turbid. The following reaction takes place:
dioxide is introduced into a heavily limed solution of sucrose (a
mono-, di- and trisaccharates), the gas is at first almost completely
but soon the mass becomes gelatinous and viscous, so that the carbon
only partly absorbed, the remainder escaping free. The gelatinous and
compound formed is called ‘calcium hydro-sucrocarbonate’ presumably of
following formula :
gassing of carbon dioxide, the viscous liquid will gradually become
in which case the hydro-sucrocarbonate of calcium breaks up into
calcium carbonate which precipitates and the carbon dioxide gets
absorbed until the point of neutrality is reached. Finally, a stage is
when all the three sacharates without distinction decompose on
carbon dioxide into free sucrose and calcium carbonate. Upon this
principle of carbonation is chiefly based.
readily oxidised and is, therefore, not affected by free oxygen or
Nitric acid oxidises sucrose first to saccharic acid and afterwards to
tartaric, oxalic and uric acids. Sucrose does not reduce Fehling’s
differs from reducing sugars in this respect.
contains different enzymes which have specific
action. The sucrose is first decomposed into reducing sugars and then
alcohol and carbon dioxide and finally into glycerine and non-volatile