Some standard content:
National Standard of the People's Republic of China
Food additive
Citric acid
Food additive
Citric acid
UdC 661.734.1
GB 1987-86
Replaces GB 1987--80
This standard applies to citric acid obtained by fermentation of starch and sugar raw materials and is used as an acidulant in food processing. Chemical name: 2-hydroxy-1,2,3-propanetricarboxylic acid Formula: CHO,·H,O
CH, -CoOH
Structural formula:
1 Technical requirements
HO- C-COOH- H,O
CH, - COOH
1.1 Sensory requirements: Colorless translucent crystals, or white granules, or white crystalline powder. 1.2 Physical and chemical requirements: See the table below.
Indicator name
Citric acid (in C.HO,·H,O), %Sulfate (in SO), %
Oxalate (in C,0), %
Heavy metal (in Pb), %
Chloride (in CI), %
Iron (Fe) %
Arsenic (As), %
Sulfated ash, %
Easily carbonizable matter
2 Test method
2.1 Identification
2.1.1 Reagents and solutions
2.1.1.1. Sulfuric acid (GB625-77).
Published by the National Bureau of Standards on August 26, 1986
Conforms to the regulations
Conforms to the regulations
Not deeper than the standard
Implemented on June 1, 1987
GB 1987-86
2.1.1.2 Mercuric sulfate: Weigh 5g yellow mercuric oxide (HG31069-77), add 40ml water, slowly add 20ml sulfuric acid, stir while adding, then add 40ml water and stir to dissolve. 2.1.1.3 Potassium permanganate (GB643-77): 0.1N solution. Calcium chloride: 7.5% (W/V) solution.
Acetic acid (GB676-78).
Hydrochloric acid (GB 622-77): 24% (W/W) solution. 2.1.1.63
2.1.1.7 Sodium hydroxide (GB629-81): 4.3% (W/V) solution. Silver nitrate (GB670-77): 0.1N solution. 2.1.1.8wwW.bzxz.Net
2.1.1.9 Ammonia water (GB 631-77): 40% (W/W) solution. 2.1.2 Determination procedure
2.1.2.1 Take a small amount of sample and burn it with direct fire. It will slowly decompose, but no caramel odor will occur. 2.1.2.2 The sample solution is adjusted to neutral with 4.3% sodium hydroxide solution, and then add mercuric sulfate solution and heat to boiling. Then add 1 drop of 0.1N potassium permanganate solution and shake. The purple color will disappear and a white precipitate will be produced. 2.1.2.3 The sample solution was adjusted to neutrality with 4.3% sodium hydroxide solution, and an excess of 7.5% calcium chloride solution was added. There was no change when it was cooled, but a white granular precipitate was generated when it was boiled. 4.3% sodium hydroxide solution was added to one part, and the precipitate did not dissolve. 24% hydrochloric acid was added to the other part, and it dissolved.
2.1.2.4 The sample solution was adjusted to neutrality with 4.3% sodium hydroxide solution, and an excess of 0.1N silver nitrate solution was added, and a white precipitate was generated. The white precipitate can be dissolved in nitric acid or 40% ammonia solution. Take the ammonia solution in a test tube, heat it to 60-70℃ in a water bath, and connect the tube to a silver mirror that does not show.
2.2 Determination of citric acid (CHO,·HzO) content 2.2.1 Trial preparation and solution
2.2.1.1 Phenolphthalein: Prepare according to GB604-77 "Indicator pH Color Range Determination Method". 2.2.1.2 Sodium hydroxide (GB629-81): 1N standard solution, prepared according to GB601-77 "Chemical Reagent Standard Solution Preparation Method".
2.2.2 Determination Procedure
Weigh 1.5g of sample (accurate to 0.0002g), add 40ml of freshly boiled cold water, and dissolve. Add 3 drops of 1% phenol indicator, and titrate with 1N sodium hydroxide standard solution until it turns slightly red. 2.2.3 Calculation
_ V×CX 0. 064 04 × 100
m(1 - 0. 085 66)
Wherein: X——the base content of citric acid in water (calculated as anhydrous)%; V—the volume of sodium hydroxide standard solution consumed for titrating the sample, ml; C—the concentration of sodium hydroxide standard solution, mol/L; m—the mass of sample, B; 0.06404—the mass of citric acid in grams equivalent to 1 ml of sodium hydroxide standard solution [CNaOH=1.000mol/L]; 0.08566—the theoretical base content of CH2O3 (in H), that is, 18/210.14. 2.3 Determination of sulfate (calculated as SO-) content 2.3.1 Reagents and solutions
2.3.1.1 Sodium hydroxide (GB629-81): 4% (W/V) solution. 2.3.1.2 Hydrochloric acid (GB 622-77): 24% (W/W) solution. 2.3.1.3 Barium chloride (GB 652-78): 25% (W/V) solution. 2.3.1.4 Sulfate standard solution: Each ml contains 0.1 mg SO3, prepared according to GB602-77 "Preparation Method of Standard Solution of Chemical Reagent Impurities".
2.3.2 Determination Procedure
Weigh 1g of sample (accurate to 0.01g), pour into a 50ml Nessler colorimetric tube, add appropriate amount of water to dilute to 25ml, add 1ml24% hydrochloric acid solution, place in a 30-35℃ water bath, keep warm for 10min, then add 3ml25% barium chloride solution, shake well, and leave for 10min. Compare with the special standard tube, and its turbidity shall not be lower than that of the standard tube. GB 198786
Preparation of standard tube: Pipette 3 ml of sulfate standard solution and do the same treatment as the sample tube. 2.4 Determination of oxalate content
2.4.1 Reagents and solutions
2.4.1.1 Hydrochloric acid (GB 622-77): 38% (W/W) solution; 2.4.1.2 Hydrochloric acid benzoate (HG3-1112-77): 1% (W/V) solution. 2.4.1.3 Potassium ferrocyanide (GB644-77): 5% (W/V) solution. 2.4.1.4 Oxalic acid (HG 3-988--76): 0.005% (W/V) solution. 2.4.1.5 Arsenic-free metallic zinc (GB230480). 2.4.2 Determination Procedures
Weigh 0.4g of sample (accurate to 0.01g), dissolve in 4ml of water, add 3ml of 38% hydrochloric acid and 1g of zinc granules, boil for 1min, let stand for 2min, then pour out the clear solution and add it to a test tube containing 0.25ml of 1% hydrochloric acid benzene solution, and heat to boiling. After cooling, pour it into a graduated cylinder, add an equal volume of 38% hydrochloric acid and 0.25ml of 15% potassium ferricyanide solution, vibrate, let stand for 30min, and visually compare it with the standard tube. The pink color produced should not be darker than that of the standard tube. Preparation of standard tube: Pipette 4ml of 0.005% oxalic acid solution and do the same treatment as the sample tube. 2.5 Determination of barium salts
2.5.1 Reagents and solutions
2.5.1.1 Sodium hydroxide (GB629-81): 2M solution. 2.5.1.2 Sulfuric acid (GB 625-77): 1M solution. 2.5.1.3 Citric acid sample solution: Weigh 5g of the sample (accurate to 0.01g), dissolve it in 39ml 2M sodium hydroxide solution, and dilute it to 50ml with water.
2.5.2 Determination procedure
Pipette 5ml of citric acid sample solution into a colorimetric tube, add 1M sulfuric acid to adjust the pH to 2. Leave it for 1 hour, and visually compare it with another colorimetric tube containing citric acid sample solution but without sulfuric acid. The turbidity of the colorimetric tube shall not exceed that of the latter. 2.6 Determination of calcium salts
2.6.1 Reagents and solutions
2.6.1.1 95% Z alcohol (GB 679--80). 2.6.1.2 Calcium carbonate (HG 3-1066-77). 2.6.1.3 Acetic acid (GB 676-78): 6 M solution. 2.6.1.4 Calcium ethanol standard solution (containing 100 ppm calcium): weigh 2.5 g of dried calcium carbonate in 12 ml of 6 M acetic acid, dilute to 1000 ml with water (calcium solution A). Take 100 ml from it and dilute to 1000 ml with 95% ethanol solution. 2.6.1.5 Calcium standard solution (containing 10 ppm calcium): take 10 ml of the calcium solution prepared above and dilute to 1000 ml with water. 2.6.1.6 Ammonium oxalate (HG3-976-81): 4% (W/V) solution. 2.6.1.7 Acetic acid (GB 676-78): 2 M solution. 2.6.2 Determination procedure
Pipette 0.2 ml calcium ethanol standard solution and 1 ml 4% ammonium oxalate solution into a colorimetric tube. After 1 minute, add 1 ml 2M acetic acid and 15 ml sample solution (5 ml citric acid sample solution plus 10 ml water), shake well, and place it for 15 minutes. Compare with the standard tube. Its turbidity shall not exceed that of the standard tube.
Preparation of standard tube: Pipette 1 ml 4% ammonium oxalate solution and 10 ml calcium standard solution into a colorimetric tube, add 1 ml 2M acetic acid solution and 5 ml water, shake well, and place it with the sample tube for 15 minutes before colorimetric comparison. 2.7 Determination of heavy metal (in terms of Pb) content 2.7.1 Reagents and solutions
2.7.1.1 Sodium hydroxide (GB629-81): 1M solution. 2.7.1.2 Propylene glycol (glycerol) (GB687-77). 154
GB 1987-86
2.7.1.3 Thioacetamide reagent: Take 1 ml of sodium hydroxide solution (15 ml of 1M sodium hydroxide solution plus 5 ml of water), add 20 ml of glycerol and 0.2 ml of 4% (W/V) thioacetamide solution, mix well, heat in a boiling water bath for 20 seconds, and use immediately after cooling. 2.7.1.4 Ammonium acetate buffer solution: Weigh 2.5 g of ammonium acetate (HGB3076-59), dissolve it in 25 ml of water, adjust the pH to 3.5 with 2M hydrochloric acid (GB622-77) solution, and dilute to 100 ml with water. 2.7.1.5 Lead standard solution (containing 0.5ppm lead): Weigh 0.4g lead nitrate (GB601-77), add 2ml 65% nitric acid (GB626-78) solution, and dilute to 250ml with water. Draw 1ml from it and dilute to 100ml with water. Draw 5ml from it and dilute to 100ml with water.
2.7.2 Determination procedure
Draw 10ml citric acid sample solution (2.5.1.3) into a colorimetric tube, add 1.0ml thioacetamide solution and 2ml pH3.5 ammonium acetate buffer solution, shake well, and let stand for 2min. Visually compare with the standard tube. Its color should not be darker than that of the standard tube. Preparation of standard tube: Draw 10ml lead standard solution and do the same treatment as the sample tube. 2.8 Determination of chloride (in terms of CI) content 2.6.1 Reagents and solutions
2.8.1.1 Nitric acid (GB 62678): 2M solution. 2.B.1.2 Silver nitrate (GB670-77): 0.1M solution. 2.8.1.3 Sodium chloride (GB1266--77). 2.8.1.4 Chloride standard solution (containing 10ppm chlorine): weigh 0.33g of sodium chloride burned to constant weight at 500-600℃, dissolve it in water and dilute to 1000ml. Take 5ml from it and dilute to 100ml with water. 2.8.2 Determination procedure
Take 10ml of citric acid sample solution (2.5.1.3) into a colorimetric tube, dilute to 15ml with water, then add 1ml of 2M nitric acid solution, and immediately add 1ml of 0.1M silver nitrate solution. Keep it away from light for 2 minutes, and compare the turbidity with the standard tube visually against a black background. The turbidity of the milk shall not exceed that of the standard tube.
Preparation of standard tube: Pipette 10ml of chloride standard solution, add 5ml of water, and do the same treatment as the sample tube. 2.9 Determination of iron (Fe) content
2.9.1 Reagents and solutions
2.9.1.1 Hydrochloric acid (GB 622--77): 24% (W/W) solution. 2.9.1.2 Ammonium persulfate (GB 655--77): -1% (W/V) solution. 2.9.1.3 Ammonium thiocyanate (GB 660-78): 8% (W/V) solution. Iron standard solution (containing 10ppm iron): 1ml contains 0.01mg of iron. After preparing according to GB602-77, accurately dilute 102.9.1.4
times before use.
n-Butanol (HG 3-1012-76).
2.9.2 Determination procedure
Weigh 1g of sample (accurate to 0.01g), dissolve it with 35ml of water, add 3ml of 24% hydrochloric acid, 3ml of 1% ammonium persulfate solution and 3ml of 8% ammonium thiocyanate solution, and then add appropriate amount of water to dilute to 50ml, shake well. Add 20ml of n-butanol, shake, and let stand. Visually compare the alcohol layer with the standard tube solution made by the same method with 1ml of standard iron solution. Its color shall not be darker than that of the standard tube. 2.10 Determination of arsenic (As) content
2.10.1 Reagents and solutions
2.10.1.1 Hydrochloric acid (GB 622-77).
Potassium iodide (GB1272-77): 15% (W/V) solution. 2.10.1.2
Stannoic chloride (GB638-78): 40% (W/V) hydrochloric acid solution. 2.10.1.3
Arsenic-free metallic zinc (GB2304-80).
Lead acetate cotton: prepared according to GB603-77. 2.10.1.5
Mercuric bromide test paper: prepared according to GB603-77. Arsenic standard solution: 1ml contains 0.001mg, after preparing according to GB602-77, accurately dilute 100 times for use. 165
2.10.2 Determination Procedure
GB 1987—86
Weigh 2g of sample (accurate to 0.1g), place in an arsenic determination bottle, add 23ml of water, 5ml of hydrochloric acid, 5ml of 15% potassium iodide solution and 5 drops of 40% stannous chloride hydrochloric acid solution, and shake well. Place at room temperature for 10 minutes, add 2g of arsenic-free zinc particles, immediately plug the arsenic determination tube filled with lead acetate cotton and mercuric bromide test paper, and place it in a dark place at 25-30℃ for 1 hour. The color spot presented by the mercuric bromide test paper shall not be darker than the standard color. The standard color is to take 2.0ml of arsenic standard solution and do the same treatment as the sample at the same time. 2.11 Sulfate ash
2.11.1 Determination Procedure
Weigh 2g of sample (accurate to 0.0002g) in a crucible that has been burned to constant weight, slowly heat until the black carbon particles disappear, and cool. Add 0.5-1.0ml sulfuric acid to moisten it, heat at low temperature until the sulfuric acid smoke is completely removed, and then place it at 700-800℃ for burning. Move it to a dryer to cool, weigh it accurately, and then burn it at 700-800℃ until it reaches constant weight. 2.11.2 Calculation
(Gr-G2)
Sulfate ash (%) =
Where: G,—weight after burning, g
G2—empty crucible weight, g
G——total weight of sample plus empty crucible, g.
2.12 Determination of easily carbonizable substances
2.12.1 Reagents and solutions
2.12.1.1 Hydrochloric acid (GB622-77): 32% solution. G-G2
￥100·
2.12.1.2 Cobalt chloride (CoC1·6HO) (GB1270-77): 5.95% cobalt chloride solution. Weigh 5.95g cobalt chloride, dissolve it in 1 part of 32% hydrochloric acid solution and 39 parts of water, and make up to 100ml. 2.12.1.3 Ferrous chloride (HG3-1085-77): 4.5% solution. Weigh 4.5g ferric chloride, dissolve it in 1 part of 32% hydrochloric acid solution and 39 parts of water, and make up to 100ml. 2.12.1.4 Color limit standard solution: Pipette 0.6ml cobalt chloride solution and 5.4ml ferric chloride solution and mix them. 2.12.1.5 Sulfuric acid (GB625-77): 95% solution. 2.12.2 Determination Procedures
Weigh 0.25g of sample (accurate to 0.01g), add 5ml of 95% sulfuric acid solution preheated to 90℃. Heat in a 90℃ hot water bath in the dark for 1min, then take out and spread evenly. Continue to heat in a 90℃ water bath for 1h, take out and cool to room temperature (preferably in cold water). Compare with the color limit standard solution. Its color shall not be darker than the standard.
3 Inspection Rules
3.1 Citric acid shall be inspected by the technical inspection department of the manufacturer. The manufacturer shall ensure that all citric acid shipped out of the factory meets the requirements of this standard. Each batch of products shipped out of the factory shall be accompanied by a quality certificate. The certificate includes the manufacturer's name, product name, batch number, date of shipment, product net weight, product quality and this standard number. 3.2 The weight of each batch shall not exceed the daily output of the manufacturer. 3.3 The user may verify whether the quality of the received products meets the requirements of this standard in accordance with the inspection rules and test methods of this standard.
3.4 Sampling method: Samples should be selected from 10% of each batch of packaging, and the number of small batches should not be less than 3 packages. From the selected packages, use a sampling needle or other sampling tool to extend into three-quarters of each package and take out a sample of no less than 100g. The total sample weight of each batch should not be less than 2kg. Mix the selected samples quickly, divide them into quarters, and send them to the laboratory for analysis. 3.5 If one of the indicators in the test results does not meet the requirements of this standard, samples should be taken from twice the amount of packaging for re-testing. Even if only one item in the re-test results does not meet the requirements of this standard, the entire batch will be unqualified. 3.6 When the supply and demand parties have objections to the quality of the product, they shall be handled in accordance with the "Food Hygiene Law of the People's Republic of China (Trial)". 166
, Packaging, marking, transportation, storage and safety GB1987-86
4.1 Citric acid products are packed in polyethylene lined food bags and double-layer kraft paper bags, with sacks or woven bags as outer bags. The net weight of each bag is divided into 25kg and 50kg, with an allowable error of ±0.5kg. 4.2 Each batch of products should be accompanied by a quality certificate. 4.3 The outer sack or woven bag of each bag should indicate the name of the manufacturer, food additive citric acid, production date, batch number and net weight.
4. This product should be protected from rain, moisture and sunlight during transportation. It should be stored in a cool, dry warehouse and should not be piled up in the open air. 4.5 This product should not be mixed, transported, or piled up with toxic, odorous, colored powders or alkaline substances during storage and transportation. Additional remarks:
This standard was proposed by the Ministry of Light Industry of the People's Republic of China and is under the jurisdiction of the Food Fermentation Industry Science Research Institute of the Ministry of Light Industry. This standard was drafted by Shanghai New Fermentation Plant and Guangdong Provincial Health and Epidemic Prevention Station. The main drafters of this standard are Xing Xuejie and Chen Zhentao. 167
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