color definitation

B. GENERAL TESTS

Color Value Test

The Color Value Test is designed to measure the concentration (Color Value) of a coloring matter in a food color by determining absorbance. In general, the color value is expressed as the figure (E1cm), when the absorbance of a food color solution is determined at the wavelenth of maximum absorption in visible light region and calculated in terms of the absorbance of a 10% w/v solution.

Procedure Unless otherwise specified, proceed as directed below. When determining an absorbance, adjust the test solution so that the absorbance of the test solution can fall in a range of 0.3󰊵0.7.

Unless otherwise specified, weigh accurately the amount of sample given in the table below that corresponds to the color value indicated, transfer to a measuring flask, dissolve in about 10 ml of the specified solvent, and add the solvent to make exactly 100 ml. Centrifuge or filter it, if necessary and use this solution as the sample solution. Dilute the solution in a dilution factor given in the same table if necessary and use this solution as the test solution.

Unless otherwise specified, determine the absorbance (A) at the specified wavelength in 1-cm cell with the solvent used for preparing the test solution as a blank. Calculate the color value by the formula below. Determination of the color value should be done promptly after the preparation of the test solution to avoid the influence of fading after preparation.

10%

Colorvalue=

10×F×A

amountofsample(g)

where A = Absorbance of test solution

F = Dilution factor of test solution used to adjust the absorbance so that it can fall in a range of 0.3󰊵0.7.

If the color value exceeds the maximum value in the above table, adjust the dilu-tion factor before determination.

B. GENERAL TESTS

Color Concentration for volume (ml)

Absorbance Dilution method F

value measurement (%) of dilution 0.25g󰋠100ml 20 0.025 0.5 50 0.10 100 0.05 200 0.03 400 0.015 500 0.01 700 0.01 0.1g󰋠100ml 0.5 0.5g󰋠100ml󰋠10ml󰋠100ml 0.5 0.6g󰋠100ml󰋠5ml󰋠100ml 0.6 0.3g󰋠100ml󰋠5ml󰋠100ml 0.6 0.2g󰋠100ml󰋠5ml󰋠100ml 0.5 0.2g󰋠100ml󰋠5ml󰋠100ml 0.7 100 1 100 1 1,000 10 2,000 20 2,000 20 2,000 20 2,000 20 4,000 40 4,000 40 5,000 50 10,000 100 10,000 100 10,000 100 0.25g󰋠100ml󰋠5ml󰋠200ml 800 0.00625 0.5 900 0.005 1,000 0.006 1,500 0.004 2,000 0.003 2,500 0.002 0.2g󰋠100ml󰋠5ml󰋠200ml 0.45 0.6 0.3g󰋠100ml󰋠5ml󰋠250ml

0.6 0.4g󰋠100ml󰋠5ml󰋠50ml󰋠5ml󰋠50ml 0.6 0.3g󰋠100ml󰋠5ml󰋠50ml󰋠5ml󰋠50ml 0.5 0.2g󰋠100ml󰋠5ml󰋠50ml󰋠5ml󰋠50ml