Molasses decolorization

C. Raghukumar, C. Mohandass, S. Kamat and M.S. Shailaja, Simultaneous detoxification and decolorization of molasses spent wash by the immobilized white-rot fungus Flavodon flavus isolated from a marine habitat. Enz. Microbiol. Technol. 35 (2004) 197-202. 

Based on decolorization of standard blackscrap molasses relative to a reference with decoloring efficiency of 100. 

Quantitative measure of decolorizing capacity based on the change in color of molasses relates to adsorption of large molecules from a liquid. 

In evaluating the effect of pH, it is always well to examine for possible indicator action which could be misinterpreted as an adsorption effect. Many colors in agricultural and industrial products behave as acid-base indicators, in which case a change in pH may alter the hue or change the intensity of the color, e.g., the color of a molasses solution diminished by one-third in going from pH 9 to 4. When it is desired to compare decolorizations conducted at different pH levels, all filtrates should be adjusted to an identical pH when reading the residual color intensities. 

The molasses test, M-RE, is perhaps one of the most widely used tests, and in some earlier days was the only control test used in the manufacture of many brands of decolorizing carbons. At that time many assumed that when a batch of carbon attained a desired M-RE all adsorptive powers would be uniformly developed and based on a general absence of customer complaints such a conclusion seemed to be justified. Incidents in more recent years have led to a modification of that earlier view. It is now recognized that the M-RE does not mirror every mutation and deviation in the activation environment and some deviations that do not affect the M-RE can and do alter other adsorptive powers. Consequently, a carbon may have a satisfactory M-RE and still be deficient in certain other affinities that can be essential for the purification of a particular product. 

Dilute test solutions of molasses undergo chemical and biological changes that alter the adsorbability. Preservatives are of questionable utility in this. If kept in a refrigerator, a dilute molasses solution will usually be stable for 4 to 8 hours. When a new supply of molasses is procured, the stability of a diluted solution should be determined by making decolorizing tests with a standard carbon at hourly intervals. 

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