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This standard replaces GB 6782-2009 Food Additive - Sodium Citrate.
The following main change has been made with respect to GB 6782-2009:
——The standard name is revised as National Food Safety Standard - Food Additive - Sodium Citrate.
National Food Safety Standard
Food Additive - Sodium Citrate
1 Scope
This standard is applicable to food additive, sodium citrate, which is obtained by fermenting and purifying from starchiness or sugariness.
2 Chemical Name, Molecular Formula, Structural Formula and Relative Molecular Mass
2.1 Chemical name
2-hydroxy-1,2,3-propanetricarboxylic acid trisodium salt
2.2 Molecular formula
C6H5Na3O7•2H2O
2.3 Structural formula
2.4 Relative molecular mass
294.10 (as per 2007 international relative atomic mass)
3 Technical Requirements
3.1 Sensory requirements
Sensory requirements shall be in accordance with those specified in Table 1.
Table 1 Sensory Requirements
Item Requirement Inspection method
Color and lustre White or colorless Put a proper amount of specimen into a clean and dry white porcelain dish, and observe its color and lustre as well as state under natural light.
State Crystalloid particles or powder a
Odor and taste Odorless and salty
a It may slightly deliquesce in moist air and slightly weather in hot air.
3.2 Physical and chemical indexes
Physical and chemical indexes shall be in accordance with those specified in Table 2.
Table 2 Physical and Chemical Indexes
Item Index Inspection method
Content of sodium citrate (calculated by dry matter), ω/% ≥ 99.0~100.5 A.3 of Annex A
Luminous transmittance/% ≥ 95.0 A.4 of Annex A
Moisture content, ω/% ≤ 10.0~13.0 A.5 of Annex A
pH Pass the test A.6 of Annex A
Sulfate, ω/% ≤ 0.01 A.7 of Annex A
Iron salt/(mg/kg) ≤ 5.0 A.8 of Annex A
Oxalate, ω/% ≤ 0.01 A.9 of Annex A
Calcium salt, ω/% ≤ 0.02 A.10 of Annex A
Readily carbonizable substance ≤ 1.0 A.11 of Annex A
Chloride, ω/% ≤ 0.005 A.12 of Annex A
Lead (Pb)/(mg/kg) ≤ 2.0 GB 5009.12
Arsenic (As)/(mg/kg) ≤ 1.0 GB 5009.11
Water insolubles Pass the test A.13 of Annex A
Annex A
Inspection Methods
A.1 General requirements
Unless otherwise specified, analytically pure reagents and Grade 3 water (specified in GB/T 6682) shall be used in this standard; if there is no requirement, standard solutions, impurity standard solutions, preparations and products used in test shall be prepared according to the requirements of GB/T 601, GB/T 602 and GB/T 603. Solutions used in the test are all aqueous solution, unless other solvents are indicated to be used for preparation.
A.2 Identification test
A.2.1 Solubility
Soluble in water and insoluble in ethanol.
A.2.2 Reagents and materials
A.2.2.1 Sulfuric acid solution: 5%.
A.2.2.2 Mercury sulfate solution: weigh 5g of mercuric oxides, add 40mL of water firstly, then 20mL of concentrated sulfuric acid slowly, stir while adding, then add another 40mL of water and stir to make it dissolve.
A.2.2.3 Potassium permanganate solution: .
A.2.2.4 Hydrochloric acid solution: 5%.
A.2.2.5 Pyridine - acetic anhydride (3+1).
A.2.2.6 Solution of sodium citrate specimen: 5g/L.
A.2.3 Analytical procedures
A.2.3.1 Put a small amount of specimen into a 25mL crucible and ignite directly with fire to decompose it slowly, but no caramel smell is allowed.
A.2.3.2 Take 2mL of specimen solution, add several drops of sulfuric acid solution, boil it, then add several drops of potassium permanganate solution, shake it and the purple disappears; add one drop of mercury sulfate solution and white precipitate is generated.
A.2.3.3 Take 5mL of specimen solution and add about 5mL of pyridine - acetic anhydride solution and thus the solution changing from yellow to red or purple is generated.
A.2.3.4 Take platinum wire and dip it with hydrochloric acid, then dipped with specimen, burn it in colorless flame, and the flame becomes yellow.
A.3 Determination of sodium citrate content (calculated by dry matter)
A.3.1 Apparatuses
A.3.1.1 Conical flask: 150mL.
A.3.1.2 Acid burette.
A.3.2 Reagents and solutions
A.3.2.1 Perchloric acid standard titration solution: c(HClO4)=0.1mol/L.
A.3.2.2 Crystal violet indicator liquid: 10g/L.
A.3.2.3 Glacial acetic acid.
A.3.2.4 Acetic anhydride.
A.3.3 Analytical procedures
Accurately weigh 0.15g of sodium citrate after drying (at 105℃±2℃ for 2h), add 20mL of glacial acetic acid, heat them until they are dissolved; after the solution is cooled, add 10mL of acetic anhydride and titrate with 0.1mol/L perchloric acid. Use two drops of acetic acid - crystal violet as indicator, the solution color turns from purple to blue and to green finally, which is the end point. Carry out blank test with the same method, make necessary correction and calculate the content by dry matter.
Foreword i
1 Scope
2 Chemical Name, Molecular Formula, Structural Formula and Relative Molecular Mass
3 Technical Requirements
Annex A Inspection Methods
