Spectrophotometric Studies on Refined Sugars in Solution

Color evaluation in the cane sugar industry

“…Zerban and his associates [5,6] have specified the colors of a variety of raw and refined sugars by use of the coordinate luminous transmittancy (also called brightness), and two other coordinates to describe the chromaticity, namely, the purity and the dominant wavelength. They found that the dominant wavelength varied only slightly (573 to 578 m,u) , which indicated that only one variable was sufficient to define the chromaticity of [7].…”

“…The concentration of total solids and the cell depths must b e adjusted to equality before comparisons among various products can be made. Zerban and his associates, following the work of P eters and Phelps, proposed that the visual appearance of solutions of refined [5] and raw [6] sugars be quantitatively m easured by the single value of the attenuancy index (-log t ) at 560 m,u, where t is the transmittancy at unit depth and solids concentration. As the spectrophotometric data at 420 m,u and at 560 m,u were given in these publications, it was possible to determine t:..ENBS from the color chart.…”

Recent Developments in White Sugar Colorimetry

“…The use of a wave length of 560 mg instead of 420 mg might permit better correlation with newly proposed methods for dark sugars ( 13) and better agreement with visual observations (14). However, at 420 mg, differences in white sugar colors are magnified, and wave lengths in this region of the spectrum have therefore been used by many laboratories for some years (Table I).…”

Calculation of Integral Attenuation Index between 400 and 700 Millimicrons and of Corresponding Wave Length for Filtered Raw Sugar Solutions

“…In this sense color may be expressed in terms of luminance (photometric brightness), excitation purity, and dominant wave length. In previous work by the writers and associates (7, 8) on Filter-Cel-filtered solutions of refined and later of raw sugars, the wave lengths chosen in the computation of the trichromatic coefficients were those given by Hardy (2) in his method of color determination on the basis of ten selected wave lengths for each primary. All of these are in the range of 422.2 to 646.2-that is, in the visible range between 400 and 700 µ.…”