Colorants from molasses

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

Rum is produced from the fermentation of molasses. After distillation, it is aged from 5 to 7 years. Rum gets its color from the oaken cask in which it is aged and from caramel added before aging. Some light rums are rapidly fermented with cultured yeast and aged from 1 to 4 years. 

Caramel. Officially, the color additive caramel is the dark brown Hquid or soHd material resulting from the carefully controlled heat treatment of the following food-grade carbohydrates dextrose, invert sugar, lactose, malt symp, molasses, starch hydrolysates and fractions thereof, or sucrose. Practically speaking, caramel is burned sugar. 

Molasses is the viscous, dark-colored material that remains when no more sugar can be economically extracted by crystallization. Beet molasses is generally high in sucrose, 60 percent dry basis, and represents considerable value. Sugar is routinely recovered from beet molasses by various ion exclusion chromatographic systems. 

The observations from the reactions of amino acids with mono- and di-saccharides have been logically employed for caramelization of molasses. A strong color, stable to tannin, sodium chloride, and alcohol was obtained at pH 9 with glycine or L-lysine as the catalyst. ... 

These chemical reactions and tests for caramel are complemented by a group of physical methods based on size-exclusion chromatography. These methods may be applied for the detection of caramel in beverages, beer, and wine. Caramel may be detected in bread and in various slightly colored products from the sugar industry (raw sugar, molasses, sugar syrups, and the like). Spectral methods are most useful for these purposes. 

A mash is made up of diluted molasses containing about 25 to 30 per cent sugar and skimmings (sometimes juice is added). Dunder is also added. This is the name given to the spent liquor from the stills and has the color and consistency of pea-soup. It contains mineral salts, coagulated albuminoids and soluble nitrogenous substances and not only stimulates fermentation but increases yield and has a distinct influence on taste and flavor. 

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. 

Although similar methods of activation give similar isothermal slopes, the converse does not necessarily follow, and one should not conclude that two carbons were produced by the same method because the isothermal slopes are found to be parallel under a single set of conditions. Thus, the isotherms for molasses color with carbons L and M were found to be almost identical at 25° C, but were dissimilar when the adsorption was conducted at 95° C (Table 9 5). Here, although two carbons have a similar slope at 25° C, the same type of surface is not present on both carbons, as is revealed by the different response to temperature. From a practical point of view, the different response to temperature emphasizes the fact that industrial studies of adsorptive power should be conducted at the temperature to be employed in the process. 

Batches of molasses obtained from different sources will vary considerably in depth of color and in the ease with which the color bodies are adsorbed. Because of this, it is not practical to state the concentrations of molasses to be used in preparing the stock solution. Depending upon the type of molasses, somewhere between 20 and 60 grams of molasses per liter of solution will be suitable. 

As in the case of molasses, the color of different samples of caramel varies in intensity. Usually 4 to 6 grams of caramel per liter of water will give a satisfactory solution. The method of buffering the solution and the procedure for conducting the test parallel those used for molasses. During the early development of carbons for the treatment of liquids, this test was extensively used. Since then, it has been found that the test has very little relation to the removal of impurities from most industrial solutions and is seldom used now. 

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