Hygroscopic water in sugarcane : final report 114
Date
1990Metadata
Show full item recordAbstract
At the 1989 Workshop on Cane Analysis conducted by the Sugar
Research Council it emerged that the best technical method of cane
analysis for the Australian industry was the direct cane analysis
method (DCA) employing the wet disintegrator technique. This
method involves comminuting a sample of prepared cane with a
weighed amount of water and then analysing the resultant liquid
extract. The analysis of cane is determined by calculation, making
allowance for the degree of dilution by the added water. This
calculation also makes allowance for some water in sugar cane which
is not available for solution of the dissolved substances in juice.
This water is commonly referred to as bound water or hygroscopic
water. The usual calculations with DCA involve the use of a value for
hygroscopic water of 25 percent of the fibre percentage. The
origin of this 25 percent figure cannot be determined but it is
believed that it came about at the time of the method's development
when it represented an approximate average of the data available at
the time. Because early data showed a wide range of values
reflecting possibly variations from one type of cane to the next
and analytical errors, it was decided to attempt the rigorous
determination of hygroscopic water in sugar cane with the benefit
of today's better analytical instruments. The author has found the same difficulties that were
experienced by the earlier Horkers but an attempt has been made to
show how much the variability in results can be attributed to the
many causes. We think that the traditional 25 percent of fibre
figure may be a little high for today's canes especially
considering that the fibre as determined by traditional methods
includes 1-2 percentage units of dirt. The hygroscopic water
associated with dirt is much lower than that for true cane fibre.
A more realistic value would probably lie between 15 and 20 percent
of fibre.