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GB/T 12496.9-2015 English PDF (GBT12496.9-2015)

GB/T 12496.9-2015 English PDF (GBT12496.9-2015)

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GB/T 12496.9-2015: Test methods of wooden activated carbon -- Determination of decolorization of caramel

This Standard specifies the test method for the decolorization ratio of caramel pigments by wood activated carbon. This Standard is applicable to the determination of the decolorization ratio of caramel by various types of activated carbon for decolorization.
GB/T 12496.9-2015
NATIONAL STANDARD OF THE
PEOPLE REPUBLIC OF CHINA
ICS 65.020
B 73
Replacing GB/T 12496.9-1999
Test Methods of Wooden Activated Carbon -
Determination of Decolorization of Caramel
ISSUED ON: JULY 03, 2015
IMPLEMENTED ON: NOVEMBER 02, 2015
Issued by: General Administration of Quality Supervision, Inspection and Quarantine;
Standardization Administration of PRC.
Table of Contents
Foreword ... 3
1 Scope ... 4
2 Normative References ... 4
3 Method Summary ... 4
4 Main Instruments ... 4
5 Main Reagents ... 5
6 Preparation and Identification of caramel Liquid ... 5
7 Operation Procedures ... 7
8 Expression of Caramel Decolorization Results ... 8
Test Methods of Wooden Activated Carbon -
Determination of Decolorization of Caramel
1 Scope
This Standard specifies the test method for the decolorization ratio of caramel pigments by wood activated carbon.
This Standard is applicable to the determination of the decolorization ratio of caramel by various types of activated carbon for decolorization.
2 Normative References
The following documents are essential to the application of this document. For the dated documents, only the versions with the dates indicated are applicable to this document; for the undated documents, only the latest version (including all the amendments) are applicable to this document.
GB/T 6682-2008 Water for Analytical Laboratory Use - Specification and Test Methods
GB/T 9721-2006 Chemical Reagent - General Rules for the Molecular Absorption Spectrophotometry (Ultraviolet and Visible)
3 Method Summary
The sample and caramel are mixed and absorbed, then filtered; and use a spectrophotometer to measure the absorbance of the filtrate.
4 Main Instruments
4.1 1000mL three-neck flask.
4.2 Electric mixer (variable speed).
4.3 Glass thermometer (scale 0??C ~ 200??C).
sodium carbonate dissolved in 50mL of water) to the three-neck flask; and keep stirring until the foam disappears. Pour out after identifying it is qualified; store it into the bottle with the ground stopper; and place in the dark; the use period is one month. If it is stored in the refrigerator, store it at -1??C ~ 5??C, the use period is one year. NOTE: For Sugar-A, the preparation temperature of sugar solution is (125??1) ??C; for Sugar-B, it is (118??1) ??C, which is the temperature under standard state. If the altitude changes, the holding time shall be adjusted appropriately.
6.1.2 Identification of Method-A caramel stock solution
Take 0.833g of caramel stock solution; add water to dissolve and make constant volume to 500mL. Then use the spectrophotometer to measure the absorbance in a cuvette with a wavelength of 426nm and a light path length of 1cm; and the absorbance difference with the potassium dichromate color standard solution I under the same conditions shall be no greater than ??0.03. If the absorbance exceeds the above provisions, add a little water to the original solution or evaporate a little water to achieve the specified absorbance.
6.2 Method-B caramel
6.2.1 Preparation of Method-B caramel stock solution
Take 250g of anhydrous glucose; place it in a 1000mL three-neck flask; add 250mL of water; install an electric mixer and thermometer; and open the other neck. Place the flask in a glycerin bath (the glycerin may be heated in advance), so that the level of the sugar liquid in the flask is consistent with the level of the glycerin bath. After all the sugar is dissolved, start the mixer to raise the temperature of the oil bath and keep it at (145??5) ??C. When the sugar liquid began to boil, sequentially add 5.0g of anhydrous sodium carbonate and continuously mix; maintain the uniform temperature-rise rate. Within 25min~30min, the addition of anhydrous sodium carbonate shall be completed; and raise the temperature of the sugar solution evenly to (118??1) ??C; keep at this temperature for 30min (the temperature of the oil bath shall be appropriately reduced during the heat preservation). If the temperature of sugar solution exceeds the specified temperature, a little cold water may be added dropwise. After the heat preservation is completed, remove the heating device; slowly add 50 mL of sodium carbonate solution (5.0g of anhydrous sodium carbonate dissolved in 50mL of water) to the three-neck flask; and keep stirring until the foam reduces. Pour out after identifying it is qualified; store it into the bottle with the ground stopper; and place in the dark; the use period is one month. If it is stored in the refrigerator, store it at -1??C ~ 5??C, the use period is one year.
NOTE: For Sugar-A, the preparation temperature of sugar solution is (125??1) ??C; for Sugar-B, it is (118??1) ??C, which is the temperature under standard state. If the altitude changes, the holding time shall be adjusted appropriately.
6.2.2 Identification of Method-B caramel stock solution
Take 1.00g (accurate to 0.01g) of caramel stock solution; add water to dissolve and make constant volume to 500mL. Then use the spectrophotometer to measure the absorbance in a cuvette with a wavelength of 426nm and a light path length of 1cm; and the absorbance difference with the potassium dichromate color standard solution I under the same conditions shall be no greater than ??0.03. If the absorbance exceeds the above provisions, add a little water to the original solution or evaporate a little water to achieve the specified absorbance.
6.3 Potassium dichromate color standard solution
6.3.1 Potassium dichromate color standard solution I
The potassium dichromate is ground in a mortar; and place it in an electric drying oven adjusted to (115??5) ??C to dry to constant weight. Take 0.420g; add water to dissolve and transfer to a 1000mL volumetric flask to make constant volume.
6.3.2 Potassium dichromate color standard solution II
The potassium dichromate is ground in a mortar; and place it in an electric drying oven adjusted to (115??5) ??C to dry to constant weight. Take 0.325g, dissolve it with water and transfer to a 1000mL volumetric flask to make constant volume.
6.4 Preparation of caramel test solution
Take 17.00g (accurate to 0.01g) of the certified caramel stock solution of Method A or Method B; dissolve it with water and transfer to a 500mL volumetric flask to make constant volume. After preparation, use it on the same day; or store it in the refrigerator at -1??C ~ 5??C; the period of use is 3 months. Test solution preparation may be reduced or increased in proportion.
7 Operation Procedures
7.1 Method-A caramel decolorization
Take 0.400g (accurate to 1mg) of the dried sample crushed to a particle size ???71??m (through a 200-mesh sieve); place it in a 100mL conical flask with a stopper; add 25mL of caramel test solution by a pipette; and shake it slightly to wet the sample. Cover the glass stopper and insert a filter paper strip about 1cm wide between the glass stopper and the bottle mouth to maintain a slight gap between the glass stopper and the bottle mouth. Place the flask in a boiling water bath and heat for 30 min (shake the flask once every 5min); take out and cool it; then filter it by the 12.5cm-diameter medium-speed qualitative filter paper. After discarding about 5mL of the initial filtrate, the remaining liquid is transferred into a cuvette with 1cm light path; use a spectrophotometer to

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