INVESTIGATION OF RAPID METHODS FOR THE ASSESSMENT OF TRUE PURITY AND DRY SUBSTANCE IN FACTORY PRODUCT STREAMS
By J.D. SNOAD
LABORATORY analysis is an important element in maximising efficiency in the
factory. This paper describes investigations into alternative laboratory methods
for assessment of true purity and dry substance in pan products. The first
method described is for assessing true purity (TP) by measurement of electrical
conductivity (EC) at 27o brix. Investigations showed that the relationship
between EC at 27o brix and TP was linear under a given set of conditions,
allowing the use of EC to estimate TP. A comparison between TP analysis, and
assessment of TP by the EC method given showed a standard error of
prediction (SEP) of 0.83% purity, with 95% of results being within 1.5%
purity. As such, the method returned a more accurate reflection of the purity of
process materials than apparent purity methods, at the same time requiring a
lower level of analytical input and skill, as well as not requiring the use of lead
compounds. The second method described involves the assessment of dry
substance (DS) through adjustment of refractometer brix for purity. A
comparison of laboratory DS analysis to the predictions returned a SEP of
0.28% DS, with 95% of results within 0.52% DS. The methods described will
replace routine apparent purity and spindle brix measurement of pan products
in the Mulgrave Mill laboratory in 2005. Weekly analysis of TP using
conventional methods for assessing sucrose and DS will still be undertaken,
and the data used to ensure that prediction equations for assessing TP using EC
and DS by adjusted refractometer brix remain valid. The implementation of
these initiatives will mean that reasonable representations of the TP and DS in
pan products will be available in far shorter timeframes than available from
standard analytical methods. The laboratory results yielded will be a better
representation of the parameters being measured than those returned by
apparent purity and spindle brix analyses that these methods will replace. In
addition to these benefits, labour requirements in the laboratory will be
reduced, as will waste disposal and workplace health issues related to the use
of lead compounds.