INVESTIGATION OF RAPID METHODS FOR THE ASSESSMENT OF TRUE PURITY AND DRY SUBSTANCE IN FACTORY PRODUCT STREAMS

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.