Some standard content:
National Standard of the People's Republic of China
GB 18186-2000
Brewed Soy Sauce
Fermented Soy Sauce
2000-09-01 Issued
State Administration of Quality and Technical Supervision
2001-09-01
GB18186-2000
Chapter 8 and Article 5.3.2 of this standard are mandatory, and the rest are recommended. This standard is formulated on the basis of ZBX66012-1987 "Quality Standard for High-Salt Dilute Fermented Soy Sauce", ZBX66013-1987 "Low-Salt Solid Fermented Soy Sauce" and ZBX66014-1987 "Test Method for Low-Salt Solid Fermented Soy Sauce". The sanitary indicators of this standard are consistent with GB2717-1996 "Soy Sauce Hygiene Standard". This standard is proposed by the State Bureau of Domestic Trade. The main drafting unit of this standard is Shijiazhuang Zhenji Brewing Group Co., Ltd. The main drafters of this standard are Zhang Lin, Lu Zhaoyuan, Li Shuanqin and Li Yue. The China Condiment Association is entrusted with the interpretation of this standard. 52
1 Scope
National Standard of the People's Republic of China
Fermented soy sauce
Fermented soy sauce
GB18186-2000
This standard specifies the definition, product classification, technical requirements, test methods, inspection rules and labeling, packaging, transportation and storage requirements of brewed soy sauce.
This standard applies to brewed soy sauce referred to in Chapter 3. 2 Referenced standards
The provisions contained in the following standards constitute the provisions of this standard through reference in this standard. When this standard is published, the versions shown are valid. All standards are subject to revision, and parties using this standard should explore the possibility of using the latest versions of the following standards. GB/T601-1988 Preparation of standard solutions for titration analysis (volume analysis) of chemical reagents. GB2715-1981 Hygienic standard for grain
GB2717-1996 Hygienic standard for soy sauce
GB2760—1996
6 Hygienic standard for the use of food additives
GB4789.22-1994 Microbiological examination of food hygiene and inspection of condiments GB/T5009.39—1996 Analytical method for hygienic standard for soy sauce GB 5461—2000
GB5749-1985
Edible salt
Drinking water standards
GB/T6682—1992
GB7718-—1984
3 Definitions
Specifications and test methods for water used in analytical laboratories General standard for food labeling
This standard adopts the following definitions.
Fermented soy sauce
Liquid condiment with special color, aroma and taste made from soybean and/or defatted soybean, wheat and/or bran through microbial fermentation.
4 Product classification
It is divided into two categories according to the fermentation process.
High-salt dilute fermented soy sauce (including solid dilute fermented soy sauce) Approved by the State Administration of Quality and Technical Supervision in 2000-09-01 GB18186-2000
Implemented in 2001-09-01
Soy sauce made from soybean and/or defatted soybean, wheat and/or wheat flour, which is steamed, koji-made with Aspergillus, mixed with salt water to make dilute, and then fermented.
4.2 Low-salt solid fermented soy sauce
Soy sauce made from defatted soybeans and wheat bran, which are steamed, koji-made with Aspergillus, and then mixed with salt water to form solid soy sauce, which is then fermented.
5 Technical requirements
5.1 Main raw materials and auxiliary materials
5.1.1 Soybeans, defatted soybeans, wheat, wheat flour, bran: should comply with the provisions of GB2715. 5.1.2 Brewing water: should comply with the provisions of GB5749. 5.1.3 Edible salt: should comply with the provisions of GB5461. 5.1.4 Food additives: Food additives permitted for use in GB2760 should be used, and should also comply with the corresponding product standards for food additives.
5.2 Sensory properties
The sensory properties shall comply with the requirements of Table 1
High-salt diluted fermented soy sauce (including solid diluted fermented soy sauce) Special grade
Reddish brown or light reddish brown
Color, bright color, with
strong
sauce aroma and
ester aroma
Stronger
sauce aroma
and ester aroma
Taste delicious, mellow, fresh,
salty, sweet and palatable
5.3 Physical and chemical standards
Reddish brown or light reddish brown
With sauce aroma and ester aroma||tt| |Delicious taste,
Just right salty and sweet
Just right salty
Low-salt solid-state fermented soy sauce
Bright
dark reddish-brown
color, glossy
strong
rich
flavor of sauce, all
good smell
Delicious taste,
mellow, salty
palatable
Reddish-brown
or brown
color, with
relative
bad
flavor of sauce, palatable
Soluble salt-free solids, total nitrogen and amino acid nitrogen should conform to the requirements of Table 2. 5.3.1
Soluble salt-free solids,
g/100mL
Total nitrogen (calculated as nitrogen), g/100mL≥
Amino acid nitrogen (calculated as nitrogen),
g/100mL
High-salt diluted fermented soy sauce (including solid diluted
fermented soy sauce)
GB18186—2000
Reddish brown
or brownish brown
Bad smell
Tasteful
Brownish brown
Slightly with sauce
fragrant, all
Good smell
Fresh and salty
Low-salt solid fermented soy sauce
The content of ammonium salt (calculated as nitrogen) shall not exceed 30% of the content of amino acid nitrogen. 5.4 Hygiene standards
Should comply with the provisions of GB2717.
6 Test methods
All reagents used are analytically pure, and the experimental water should comply with the third-grade water specifications in GB/T6682. 6.1. Sensory properties
Tested in accordance with Chapter 3 of GB/T5009.39-1996. 6.2 Soluble salt-free solids.
The content of soluble salt-free solids in the sample is calculated according to formula (1): X=X2-X
Where: X is the content of soluble salt-free solids in the sample, g/100mL; X2
is the content of soluble total solids in the sample, g/100mL; and the content of sodium chloride in the sample, g/100mL. 6.2.1 Determination of total soluble solids
a) Analytical balance: sensitivity 0.1mg;
b) Electric constant temperature drying oven;
c) Pipette;
d) Weighing bottle: Φ25mm.
6.2.1.2 Preparation of test solution
After shaking the sample thoroughly, filter it with dry filter paper into a dry 250mL conical flask for later use. 6.2.1.3 Analysis steps
Pipette 10.00mL of the test solution (6.2.1.2) into a 100mL volumetric flask, dilute to the mark with water, and shake well. (1)
Pipette 5.00mL of the above diluted solution into a weighing bottle that has been dried to constant weight, transfer it into an electric constant temperature drying oven at (103±2)℃, and place the bottle cap obliquely on the side of the bottle. After 4 hours, cover the bottle cap, take it out, move it into a dryer, cool it to room temperature (about 0.5 hours), and weigh it. Bake it for another 0.5 hours, cool it, and weigh it until the difference between the two weighings does not exceed 1 mg, which is the constant weight. 6.2.1.4 Calculation
The content of soluble total solids in the sample is calculated according to formula (2): X2=
Where: X2
The content of soluble total solids in the sample, g/100mL; the mass of soluble total solids and weighing bottle after constant weight, g; the mass of weighing bottle, g.
6.2.1.5 Allowable difference
The difference in the determination of parallel tests on the same sample shall not exceed 0.30g/100mL. 6.2.2 Determination of sodium chloride
6.2.2.1 Instrument
Microburette.
6.2.2.2 Reagents
GB18186-2000
0.1mol/L silver nitrate standard titration solution: Prepare and calibrate according to the method specified in GB/T601. Potassium chromate solution (50g/L): Weigh 5g potassium chromate, dissolve it in a small amount of water and make up to 100mL. 6.2.2.3 Analysis steps
Pipette 2.00mL of diluent (pick up 5.100mL sample, put it in a 200mL volumetric flask, add water to the mark, shake well) in a 250mL conical flask, add 100mL water and 1mL potassium chromate solution, mix well. Titrate with 0.1mol/L silver nitrate standard titration solution against a white tile background until an orange-red color appears. Perform a blank test at the same time. 6.2.2.4 Calculation
The content of sodium chloride in the sample is calculated according to formula (3): X, =
Where: XI-
(V-Vo)XciX0.0585
The content of sodium chloride in the sample, g/100mL; The volume of 0.1mol/L silver nitrate standard titration solution consumed in the titration of the sample diluent, mL; The volume of 0.1mol/L silver nitrate standard titration solution consumed in the blank test, mL; The concentration of the silver nitrate standard titration solution, mol/L; (3)
The mass of sodium chloride equivalent to 1.00mL silver nitrate standard titration solution [c(AgNOs)=1.000mol/L], g. 6.2.2.5 Allowable difference
The determination difference of parallel tests on the same sample shall not exceed 0.10g/100mL. 6.3 Total nitrogen
6.3.1 Instruments
a) Kjeldahl flask: 500mL;
b) Condenser;
c) Electric constant temperature dryer;
d) Nitrogen ball;
e) Analytical balance: sensitivity 0.1mg:
f) Acid burette: 25mL;
g) Pipette.
6.3.2 Reagents
a) Mixed indicator solution: 1 part of 0.2% methyl red ethanol solution mixed with 5 parts of 0.2% bromophenol green ethanol solution; b) Mixed reagent: 3 parts of copper sulfate mixed with 50 parts of potassium sulfate; c) Sulfuric acid: 95%~98%
d) 2% boric acid solution: weigh 2g of boric acid, add water to dissolve and make up to 100mL
f) 40% sodium hydroxide solution: weigh 40g of sodium hydroxide, dissolve in 60mL of water; g) 0.1mol/L hydrochloric acid standard titration solution: prepare and calibrate according to the method specified in GB/T601. 6.3.3 Analysis steps
Pull 2.00mL of the sample into a dry Kjeldahl flask, add 4g of copper sulfate-potassium sulfate mixed reagent and 10mL of sulfuric acid, and heat in a fume hood (put a small funnel on the mouth of the flask and tilt the flask at 45° on an electric stove). After all the contents are carbonized and the foam has completely stopped, keep the solution in the bottle slightly boiling. When all the carbon particles disappear and the digestion liquid is clear and light green, continue heating for 15 minutes, remove it, and cool it to room temperature. Slowly add 120mL of water, and immerse the catheter at the lower end of the condenser tube under the liquid surface of the conical flask containing 30mL of 2% boric acid solution and 2 to 3 drops of mixed indicator liquid. Slowly add 40mL of 40% sodium hydroxide solution and 2 zinc particles along the wall of the Kjeldahl flask, quickly connect the distillation device (the entire device should be tight and airtight), connect the condensed water, shake the Kjeldahl flask, and heat and distill until the distillate is about 120mL. Lower the position of the conical flask so that the lower end of the condenser tube leaves the liquid surface, distill for another 1 minute, and stop heating. Rinse the outside of the lower end of the condenser tube with a small amount of water and remove the conical flask. Titrate the collected solution with 0.1mol/L hydrochloric acid standard titration solution until it turns purple-red. Record the number of milliliters of 0.1 mol/L hydrochloric acid standard titration solution consumed. Perform a blank test at the same time. 6.3.4 Calculate the total nitrogen content in the sample according to formula (4): X, =
Where: X
6.3.5 Allowable differencebzxZ.net
(V2-V)Xc2X0.014
The total nitrogen content in the sample (in terms of nitrogen), g/100mL; The volume of 0.1 mol/L hydrochloric acid standard titration solution consumed in the titration sample, mL; The volume of 0.1 mol/L hydrochloric acid standard titration solution consumed in the blank test, mL; The concentration of the hydrochloric acid standard titration solution, mol/L; The mass of nitrogen equivalent to 1.00mL hydrochloric acid standard titration solution [c(HC1)=1.000mol/L], g. The determination difference of the same sample in parallel tests shall not exceed 0.03g/100mL. 6.4 Amino Acid Nitrogen
6.4.1 Instruments
a) Acidity meter: with magnetic stirrer;
b) Correct burette: 25mL;
c) Pipette.
6.4.2 Reagents
a) Formaldehyde solution: 37%~40%;
b) 0.05mol/L sodium hydroxide standard titration solution: prepared and calibrated according to the method specified in GB/T601. 6.4.3 Analysis steps
(4)
Pipette 5.0mL of sample and place it in a 100mL volumetric flask. Add water to the mark. Mix well and pipette 20.0mL. Place it in a 200mL beaker. Add 60mL of water. Turn on the magnetic stirrer and titrate with sodium hydroxide standard solution [c(NaOH)=0.05mol/L] until the pH meter indicates pH=8.2 [Record the number of milliliters of sodium hydroxide standard titration solution (0.05mol/L) consumed to calculate the total acid content]. Add 10.0mL of formaldehyde solution and mix well. Continue titrating with sodium hydroxide standard titration solution (0.05mol/L) until pH=9.2. Record the number of milliliters of sodium hydroxide standard titration solution (0.05mol/L) consumed. At the same time, take 80mL of water, first adjust the pH to 8.2 with sodium hydroxide solution (0.05mol/L), then add 10.0mL of formaldehyde solution, and titrate to pH=9.2 with sodium hydroxide standard titration solution (0.05mol/L), and perform a reagent blank test at the same time. 6.4.4 Calculation
The content of amino acid nitrogen in the sample is calculated according to formula (5): X4 =
Wherein: X4
(V4-V,)XcsX0.014
The content of amino acid nitrogen in the sample (in terms of nitrogen), g/100mL; The volume of 0.05mol/L sodium hydroxide standard titration solution consumed in the titration of the sample diluent, mL; The volume of 0.05mol/L sodium hydroxide standard titration solution consumed in the blank test, mL; The concentration of sodium hydroxide standard titration solution, mol/L; · (5)
The mass of nitrogen equivalent to 1.00mL sodium hydroxide standard titration solution [c(Na0H)=1.000mol/L], g. 6.4.5 Allowable difference
The determination difference of parallel tests on the same sample shall not exceed 0.03g/100mL. 6.5 Hygienic indicators and ammonium salts
Inspected according to GB4789.22 and GB/T5009.39. The 0.017 in the ammonium salt content calculation formula of GB/T5009.39 is changed to 0.014.
GB18186—2000
7 Inspection rules
7.1 Delivery inspection
Delivery inspection items include: sensory characteristics, soluble salt-free solids, total nitrogen, amino acid nitrogen, ammonium salts, microorganisms (total colony count, coliform group).
7.2 Type inspection
Type inspection items include: all items in the technical requirements. Type inspection is carried out every six months and should also be carried out when one of the following situations occurs: a) Change of main raw materials;
b) Change of key processes;
c) When the national quality supervision agency makes a request. 7.3 Batch
Products of the same variety produced on the same day are considered a batch. 7.4 Sampling
Randomly select 6 bottles (bags) from different parts of each batch of products, and conduct sensory characteristics, physical and chemical, and hygiene inspections respectively, and retain samples. 7.5 Judgment rules
7.5.1 If all the delivery inspection items or type inspection items meet this standard, they are judged as qualified products. 7.5.2 If one of the delivery inspection items or type inspection items does not meet this standard, double sampling can be carried out for re-inspection. If it still does not meet this standard after re-inspection, it is judged as unqualified.
8 Label
8.1 The content of the label should comply with the provisions of GB7718. The product name should indicate "brewed soy sauce", and the content of amino acid nitrogen, quality grade, and use for "meal and/or cooking" should also be indicated. 8.2 Implementation standard labeling method: high-salt dilute fermented soy sauce is labeled as "GB18186-2000 high-salt dilute"; low-salt solid fermented soy sauce is labeled as "GB18186-2000 low-salt solid". 9 Packaging
Packaging materials and containers should comply with the relevant national health standards. 10 Transportation
Products should be handled with care during transportation and protected from sun and rain. The means of transportation should be clean and hygienic, and should not be mixed with toxic or contaminated items.
11 Purchase and storage
11.1 Products should be stored in a special warehouse that is cool, dry and ventilated. 11.2 The shelf life of bottled products should not be less than 12 months; the shelf life of bagged products should not be less than 6 months. 582 The shelf life of bottled products should not be less than 12 months; the shelf life of bagged products should not be less than 6 months.2 The shelf life of bottled products should not be less than 12 months; the shelf life of bagged products should not be less than 6 months.Titrate with 1 mol/L silver nitrate standard titration solution until an orange-red color appears. Perform a blank test at the same time. 6.2.2.4 Calculate the sodium chloride content in the sample according to formula (3): X, =
Wherein: XI-
(V-Vo)XciX0.0585
The sodium chloride content in the sample, g/100mL; The volume of 0.1 mol/L silver nitrate standard titration solution consumed in the titration of the sample diluent, mL; The volume of 0.1 mol/L silver nitrate standard titration solution consumed in the blank test, mL; The concentration of the silver nitrate standard titration solution, mol/L; (3)
1.00mL silver nitrate standard titration solution [c(AgNOs)=1.000mol/L] is equivalent to the mass of sodium chloride, g. 6.2.2.5 Allowable difference
The determination difference of parallel tests on the same sample shall not exceed 0.10g/100mL. 6.3 Total nitrogen
6.3.1 Apparatus
a) Kjeldahl flask: 500mL;
b) Condenser;
c) Electric constant temperature dryer;
d) Nitrogen ball;
e) Analytical balance: sensitivity 0.1mg:
f) Acid burette: 25mL;
g) Pipette.
6.3.2 Reagents
a) Mixed indicator solution: 1 part of 0.2% methyl red ethanol solution mixed with 5 parts of 0.2% bromophenol green ethanol solution; b) Mixed reagent: 3 parts of copper sulfate mixed with 50 parts of potassium sulfate; c) Sulfuric acid: 95%~98%
d) 2% boric acid solution: weigh 2g of boric acid, add water to dissolve and make up to 100mL
f) 40% sodium hydroxide solution: weigh 40g of sodium hydroxide, dissolve in 60mL of water; g) 0.1mol/L hydrochloric acid standard titration solution: prepare and calibrate according to the method specified in GB/T601. 6.3.3 Analysis steps
Pull 2.00mL of the sample into a dry Kjeldahl flask, add 4g of copper sulfate-potassium sulfate mixed reagent and 10mL of sulfuric acid, and heat in a fume hood (put a small funnel on the mouth of the flask and tilt the flask at 45° on an electric stove). After all the contents are carbonized and the foam has completely stopped, keep the solution in the bottle slightly boiling. When all the carbon particles disappear and the digestion liquid is clear and light green, continue heating for 15 minutes, remove it, and cool it to room temperature. Slowly add 120mL of water, and immerse the catheter at the lower end of the condenser tube under the liquid surface of the conical flask containing 30mL of 2% boric acid solution and 2 to 3 drops of mixed indicator liquid. Slowly add 40mL of 40% sodium hydroxide solution and 2 zinc particles along the wall of the Kjeldahl flask, quickly connect the distillation device (the entire device should be tight and airtight), connect the condensed water, shake the Kjeldahl flask, and heat and distill until the distillate is about 120mL. Lower the position of the conical flask so that the lower end of the condenser tube leaves the liquid surface, distill for another 1 minute, and stop heating. Rinse the outside of the lower end of the condenser tube with a small amount of water and remove the conical flask. Titrate the collected solution with 0.1mol/L hydrochloric acid standard titration solution until it turns purple-red. Record the number of milliliters of 0.1 mol/L hydrochloric acid standard titration solution consumed. Perform a blank test at the same time. 6.3.4 Calculate the total nitrogen content in the sample according to formula (4): X, =
Where: X
6.3.5 Allowable difference
(V2-V)Xc2X0.014
The total nitrogen content in the sample (in terms of nitrogen), g/100mL; The volume of 0.1 mol/L hydrochloric acid standard titration solution consumed in the titration sample, mL; The volume of 0.1 mol/L hydrochloric acid standard titration solution consumed in the blank test, mL; The concentration of the hydrochloric acid standard titration solution, mol/L; The mass of nitrogen equivalent to 1.00mL hydrochloric acid standard titration solution [c(HC1)=1.000mol/L], g. The determination difference of the same sample in parallel tests shall not exceed 0.03g/100mL. 6.4 Amino Acid Nitrogen
6.4.1 Instruments
a) Acidity meter: with magnetic stirrer;
b) Correct burette: 25mL;
c) Pipette.
6.4.2 Reagents
a) Formaldehyde solution: 37%~40%;
b) 0.05mol/L sodium hydroxide standard titration solution: prepared and calibrated according to the method specified in GB/T601. 6.4.3 Analysis steps
(4)
Pipette 5.0mL of sample and place it in a 100mL volumetric flask. Add water to the mark. Mix well and pipette 20.0mL. Place it in a 200mL beaker. Add 60mL of water. Turn on the magnetic stirrer and titrate with sodium hydroxide standard solution [c(NaOH)=0.05mol/L] until the pH meter indicates pH=8.2 [Record the number of milliliters of sodium hydroxide standard titration solution (0.05mol/L) consumed to calculate the total acid content]. Add 10.0mL of formaldehyde solution and mix well. Continue titrating with sodium hydroxide standard titration solution (0.05mol/L) until pH=9.2. Record the number of milliliters of sodium hydroxide standard titration solution (0.05mol/L) consumed. At the same time, take 80mL of water, first adjust the pH to 8.2 with sodium hydroxide solution (0.05mol/L), then add 10.0mL of formaldehyde solution, and titrate to pH=9.2 with sodium hydroxide standard titration solution (0.05mol/L), and perform a reagent blank test at the same time. 6.4.4 Calculation
The content of amino acid nitrogen in the sample is calculated according to formula (5): X4 =
Wherein: X4
(V4-V,)XcsX0.014
The content of amino acid nitrogen in the sample (in terms of nitrogen), g/100mL; The volume of 0.05mol/L sodium hydroxide standard titration solution consumed in the titration of the sample diluent, mL; The volume of 0.05mol/L sodium hydroxide standard titration solution consumed in the blank test, mL; The concentration of sodium hydroxide standard titration solution, mol/L; · (5)
The mass of nitrogen equivalent to 1.00mL sodium hydroxide standard titration solution [c(Na0H)=1.000mol/L], g. 6.4.5 Allowable difference
The determination difference of parallel tests on the same sample shall not exceed 0.03g/100mL. 6.5 Hygienic indicators and ammonium salts
Inspected according to GB4789.22 and GB/T5009.39. The 0.017 in the ammonium salt content calculation formula of GB/T5009.39 is changed to 0.014.
GB18186—2000
7 Inspection rules
7.1 Delivery inspection
Delivery inspection items include: sensory characteristics, soluble salt-free solids, total nitrogen, amino acid nitrogen, ammonium salts, microorganisms (total colony count, coliform group).
7.2 Type inspection
Type inspection items include: all items in the technical requirements. Type inspection is carried out every six months and should also be carried out when one of the following situations occurs: a) Change of main raw materials;
b) Change of key processes;
c) When the national quality supervision agency makes a request. 7.3 Batch
Products of the same variety produced on the same day are considered a batch. 7.4 Sampling
Randomly select 6 bottles (bags) from different parts of each batch of products, and conduct sensory characteristics, physical and chemical, and hygiene inspections respectively, and retain samples. 7.5 Judgment rules
7.5.1 If all the delivery inspection items or type inspection items meet this standard, they are judged as qualified products. 7.5.2 If one of the delivery inspection items or type inspection items does not meet this standard, double sampling can be carried out for re-inspection. If it still does not meet this standard after re-inspection, it is judged as unqualified.
8 Label
8.1 The content of the label should comply with the provisions of GB7718. The product name should indicate "brewed soy sauce", and the content of amino acid nitrogen, quality grade, and use for "meal and/or cooking" should also be indicated. 8.2 Implementation standard labeling method: high-salt dilute fermented soy sauce is labeled as "GB18186-2000 high-salt dilute"; low-salt solid fermented soy sauce is labeled as "GB18186-2000 low-salt solid". 9 Packaging
Packaging materials and containers should comply with the relevant national health standards. 10 Transportation
Products should be handled with care during transportation and protected from sun and rain. The means of transportation should be clean and hygienic, and should not be mixed with toxic or contaminated items.
11 Purchase and storage
11.1 Products should be stored in a special warehouse that is cool, dry and ventilated. 11.2 The shelf life of bottled products should not be less than 12 months; the shelf life of bagged products should not be less than 6 months. 58Titrate with 1 mol/L silver nitrate standard titration solution until an orange-red color appears. Perform a blank test at the same time. 6.2.2.4 Calculate the sodium chloride content in the sample according to formula (3): X, =
Wherein: XI-
(V-Vo)XciX0.0585
The sodium chloride content in the sample, g/100mL; The volume of 0.1 mol/L silver nitrate standard titration solution consumed in the titration of the sample diluent, mL; The volume of 0.1 mol/L silver nitrate standard titration solution consumed in the blank test, mL; The concentration of the silver nitrate standard titration solution, mol/L; (3)
1.00mL silver nitrate standard titration solution [c(AgNOs)=1.000mol/L] is equivalent to the mass of sodium chloride, g. 6.2.2.5 Allowable difference
The determination difference of parallel tests on the same sample shall not exceed 0.10g/100mL. 6.3 Total nitrogen
6.3.1 Apparatus
a) Kjeldahl flask: 500mL;
b) Condenser;
c) Electric constant temperature dryer;
d) Nitrogen ball;
e) Analytical balance: sensitivity 0.1mg:
f) Acid burette: 25mL;
g) Pipette.
6.3.2 Reagents
a) Mixed indicator solution: 1 part of 0.2% methyl red ethanol solution mixed with 5 parts of 0.2% bromophenol green ethanol solution; b) Mixed reagent: 3 parts of copper sulfate mixed with 50 parts of potassium sulfate; c) Sulfuric acid: 95%~98%
d) 2% boric acid solution: weigh 2g of boric acid, add water to dissolve and make up to 100mL
f) 40% sodium hydroxide solution: weigh 40g of sodium hydroxide, dissolve in 60mL of water; g) 0.1mol/L hydrochloric acid standard titration solution: prepare and calibrate according to the method specified in GB/T601. 6.3.3 Analysis steps
Pull 2.00mL of the sample into a dry Kjeldahl flask, add 4g of copper sulfate-potassium sulfate mixed reagent and 10mL of sulfuric acid, and heat in a fume hood (put a small funnel on the mouth of the flask and tilt the flask at 45° on an electric stove). After all the contents are carbonized and the foam has completely stopped, keep the solution in the bottle slightly boiling. When all the carbon particles disappear and the digestion liquid is clear and light green, continue heating for 15 minutes, remove it, and cool it to room temperature. Slowly add 120mL of water, and immerse the catheter at the lower end of the condenser tube under the liquid surface of the conical flask containing 30mL of 2% boric acid solution and 2 to 3 drops of mixed indicator liquid. Slowly add 40mL of 40% sodium hydroxide solution and 2 zinc particles along the wall of the Kjeldahl flask, quickly connect the distillation device (the entire device should be tight and airtight), connect the condensed water, shake the Kjeldahl flask, and heat and distill until the distillate is about 120mL. Lower the position of the conical flask so that the lower end of the condenser tube leaves the liquid surface, distill for another 1 minute, and stop heating. Rinse the outside of the lower end of the condenser tube with a small amount of water and remove the conical flask. Titrate the collected solution with 0.1mol/L hydrochloric acid standard titration solution until it turns purple-red. Record the number of milliliters of 0.1 mol/L hydrochloric acid standard titration solution consumed. Perform a blank test at the same time. 6.3.4 Calculate the total nitrogen content in the sample according to formula (4): X, =
Where: X
6.3.5 Allowable difference
(V2-V)Xc2X0.014
The total nitrogen content in the sample (in terms of nitrogen), g/100mL; The volume of 0.1 mol/L hydrochloric acid standard titration solution consumed in the titration sample, mL; The volume of 0.1 mol/L hydrochloric acid standard titration solution consumed in the blank test, mL; The concentration of the hydrochloric acid standard titration solution, mol/L; The mass of nitrogen equivalent to 1.00mL hydrochloric acid standard titration solution [c(HC1)=1.000mol/L], g. The determination difference of the same sample in parallel tests shall not exceed 0.03g/100mL. 6.4 Amino Acid Nitrogen
6.4.1 Instruments
a) Acidity meter: with magnetic stirrer;
b) Correct burette: 25mL;
c) Pipette.
6.4.2 Reagents
a) Formaldehyde solution: 37%~40%;
b) 0.05mol/L sodium hydroxide standard titration solution: prepared and calibrated according to the method specified in GB/T601. 6.4.3 Analysis steps
(4)
Pipette 5.0mL of sample and place it in a 100mL volumetric flask. Add water to the mark. Mix well and pipette 20.0mL. Place it in a 200mL beaker. Add 60mL of water. Turn on the magnetic stirrer and titrate with sodium hydroxide standard solution [c(NaOH)=0.05mol/L] until the pH meter indicates pH=8.2 [Record the number of milliliters of sodium hydroxide standard titration solution (0.05mol/L) consumed to calculate the total acid content]. Add 10.0mL of formaldehyde solution and mix well. Continue titrating with sodium hydroxide standard titration solution (0.05mol/L) until pH=9.2. Record the number of milliliters of sodium hydroxide standard titration solution (0.05mol/L) consumed. At the same time, take 80mL of water, first adjust the pH to 8.2 with sodium hydroxide solution (0.05mol/L), then add 10.0mL of formaldehyde solution, and titrate to pH=9.2 with sodium hydroxide standard titration solution (0.05mol/L), and perform a reagent blank test at the same time. 6.4.4 Calculation
The content of amino acid nitrogen in the sample is calculated according to formula (5): X4 =
Wherein: X4
(V4-V,)XcsX0.014
The content of amino acid nitrogen in the sample (in terms of nitrogen), g/100mL; The volume of 0.05mol/L sodium hydroxide standard titration solution consumed in the titration of the sample diluent, mL; The volume of 0.05mol/L sodium hydroxide standard titration solution consumed in the blank test, mL; The concentration of sodium hydroxide standard titration solution, mol/L; · (5)
The mass of nitrogen equivalent to 1.00mL sodium hydroxide standard titration solution [c(Na0H)=1.000mol/L], g. 6.4.5 Allowable difference
The determination difference of parallel tests on the same sample shall not exceed 0.03g/100mL. 6.5 Hygienic indicators and ammonium salts
Inspected according to GB4789.22 and GB/T5009.39. The 0.017 in the ammonium salt content calculation formula of GB/T5009.39 is changed to 0.014.
GB18186—2000
7 Inspection rules
7.1 Delivery inspection
Delivery inspection items include: sensory characteristics, soluble salt-free solids, total nitrogen, amino acid nitrogen, ammonium salts, microorganisms (total colony count, coliform group).
7.2 Type inspection
Type inspection items include: all items in the technical requirements. Type inspection is carried out every six months and should also be carried out when one of the following situations occurs: a) Change of main raw materials;
b) Change of key processes;
c) When the national quality supervision agency makes a request. 7.3 Batch
Products of the same variety produced on the same day are considered a batch. 7.4 Sampling
Randomly select 6 bottles (bags) from different parts of each batch of products, and conduct sensory characteristics, physical and chemical, and hygiene inspections respectively, and retain samples. 7.5 Judgment rules
7.5.1 If all the delivery inspection items or type inspection items meet this standard, they are judged as qualified products. 7.5.2 If one of the delivery inspection items or type inspection items does not meet this standard, double sampling can be carried out for re-inspection. If it still does not meet this standard after re-inspection, it is judged as unqualified.
8 Label
8.1 The content of the label should comply with the provisions of GB7718. The product name should indicate "brewed soy sauce", and the content of amino acid nitrogen, quality grade, and use for "meal and/or cooking" should also be indicated. 8.2 Implementation standard labeling method: high-salt dilute fermented soy sauce is labeled as "GB18186-2000 high-salt dilute"; low-salt solid fermented soy sauce is labeled as "GB18186-2000 low-salt solid". 9 Packaging
Packaging materials and containers should comply with the relevant national health standards. 10 Transportation
Products should be handled with care during transportation and protected from sun and rain. The means of transportation should be clean and hygienic, and should not be mixed with toxic or contaminated items.
11 Purchase and storage
11.1 Products should be stored in a special warehouse that is cool, dry and ventilated. 11.2 The shelf life of bottled products should not be less than 12 months; the shelf life of bagged products should not be less than 6 months. 580585
Content of sodium chloride in the sample, g/100mL; Volume of 0.1 mol/L silver nitrate standard titration solution consumed in titrating the sample diluent, mL; Volume of 0.1 mol/L silver nitrate standard titration solution consumed in the blank test, mL; Concentration of silver nitrate standard titration solution, mol/L; (3)
The mass of sodium chloride equivalent to 1.00mL silver nitrate standard titration solution [c(AgNOs)=1.000mol/L], g. 6.2.2.5 Allowable difference
The difference in determination of parallel tests of the same sample shall not exceed 0.10g/100mL. 6.3 Total nitrogen
6.3.1 Instruments
a) Kjeldahl flask: 500mL;
b) Condenser;
c) Electric constant temperature dryer;
d) Nitrogen ball;
e) Analytical balance: sensitivity 0.1mg:
f) Acid burette: 25mL;
g) Pipette.
6.3.2 Reagents
a) Mixed indicator solution: 1 part of 0.2% methyl red ethanol solution mixed with 5 parts of 0.2% bromophenol green ethanol solution; b) Mixed reagent: 3 parts of copper sulfate mixed with 50 parts of potassium sulfate; c) Sulfuric acid: 95%~98%
d) 2% boric acid solution: weigh 2g of boric acid, add water to dissolve and make up to 100mL
f) 40% sodium hydroxide solution: weigh 40g of sodium hydroxide, dissolve in 60mL of water; g) 0.1mol/L hydrochloric acid standard titration solution: prepare and calibrate according to the method specified in GB/T601. 6.3.3 Analysis steps
Pull 2.00mL of the sample into a dry Kjeldahl flask, add 4g of copper sulfate-potassium sulfate mixed reagent and 10mL of sulfuric acid, and heat in a fume hood (put a small funnel on the mouth of the flask and tilt the flask at 45° on an electric stove). After all the contents are carbonized and the foam has completely stopped, keep the solution in the bottle slightly boiling. When all the carbon particles disappear and the digestion liquid is clear and light green, continue heating for 15 minutes, remove it, and cool it to room temperature. Slowly add 120mL of water, and immerse the catheter at the lower end of the condenser tube under the liquid surface of the conical flask containing 30mL of 2% boric acid solution and 2 to 3 drops of mixed indicator liquid. Slowly add 40mL of 40% sodium hydroxide solution and 2 zinc particles along the wall of the Kjeldahl flask, quickly connect the distillation device (the entire device should be tight and airtight), connect the condensed water, shake the Kjeldahl flask, and heat and distill until the distillate is about 120mL. Lower the position of the conical flask so that the lower end of the condenser tube leaves the liquid surface, distill for another 1 minute, and stop heating. Rinse the outside of the lower end of the condenser tube with a small amount of water and remove the conical flask. Titrate the collected solution with 0.1mol/L hydrochloric acid standard titration solution until it turns purple-red. Record the number of milliliters of 0.1 mol/L hydrochloric acid standard titration solution consumed. Perform a blank test at the same time. 6.3.4 Calculate the total nitrogen content in the sample according to formula (4): X, =
Where: X
6.3.5 Allowable difference
(V2-V)Xc2X0.014
The total nitrogen content in the sample (in terms of nitrogen), g/100mL; The volume of 0.1 mol/L hydrochloric acid standard titration solution consumed in the titration sample, mL; The volume of 0.1 mol/L hydrochloric acid standard titration solution consumed in the blank test, mL; The concentration of the hydrochloric acid standard titration solution, mol/L; The mass of nitrogen equivalent to 1.00mL hydrochloric acid standard titration solution [c(HC1)=1.000mol/L], g. The determination difference of the same sample in parallel tests shall not exceed 0.03g/100mL. 6.4 Amino Acid Nitrogen
6.4.1 Instruments
a) Acidity meter: with magnetic stirrer;
b) Correct burette: 25mL;
c) Pipette.
6.4.2 Reagents
a) Formaldehyde solution: 37%~40%;
b) 0.05mol/L sodium hydroxide standard titration solution: prepared and calibrated according to the method specified in GB/T601. 6.4.3 Analysis steps
(4)
Pipette 5.0mL of sample and place it in a 100mL volumetric flask. Add water to the mark. Mix well and pipette 20.0mL. Place it in a 200mL beaker. Add 60mL of water. Turn on the magnetic stirrer and titrate with sodium hydroxide standard solution [c(NaOH)=0.05mol/L] until the pH meter indicates pH=8.2 [Record the number of milliliters of sodium hydroxide standard titration solution (0.05mol/L) consumed to calculate the total acid content]. Add 10.0mL of formaldehyde solution and mix well. Continue titrating with sodium hydroxide standard titration solution (0.05mol/L) until pH=9.2. Record the number of milliliters of sodium hydroxide standard titration solution (0.05mol/L) consumed. At the same time, take 80mL of water, first adjust the pH to 8.2 with sodium hydroxide solution (0.05mol/L), then add 10.0mL of formaldehyde solution, and titrate to pH=9.2 with sodium hydroxide standard titration solution (0.05mol/L), and perform a reagent blank test at the same time. 6.4.4 Calculation
The content of amino acid nitrogen in the sample is calculated according to formula (5): X4 =
Wherein: X4
(V4-V,)XcsX0.014
The content of amino acid nitrogen in the sample (in terms of nitrogen), g/100mL; The volume of 0.05mol/L sodium hydroxide standard titration solution consumed in the titration of the sample diluent, mL; The volume of 0.05mol/L sodium hydroxide standard titration solution consumed in the blank test, mL; The concentration of sodium hydroxide standard titration solution, mol/L; · (5)
The mass of nitrogen equivalent to 1.00mL sodium hydroxide standard titration solution [c(Na0H)=1.000mol/L], g. 6.4.5 Allowable difference
The determination difference of parallel tests on the same sample shall not exceed 0.03g/100mL. 6.5 Hygienic indicators and ammonium salts
Inspected according to GB4789.22 and GB/T5009.39. The 0.017 in the ammonium salt content calculation formula of GB/T5009.39 is changed to 0.014.
GB18186—2000
7 Inspection rules
7.1 Delivery inspection
Delivery inspection items include: sensory characteristics, soluble salt-free solids, total nitrogen, amino acid nitrogen, ammonium salts, microorganisms (total colony count, coliform group).
7.2 Type inspection
Type inspection items include: all items in the technical requirements. Type inspection is carried out every six months and should also be carried out when one of the following situations occurs: a) Change of main raw materials;
b) Change of key processes;
c) When the national quality supervision agency makes a request. 7.3 Batch
Products of the same variety produced on the same day are considered a batch. 7.4 Sampling
Randomly select 6 bottles (bags) from different parts of each batch of products, and conduct sensory characteristics, physical and chemical, and hygiene inspections respectively, and retain samples. 7.5 Judgment rules
7.5.1 If all the delivery inspection items or type inspection items meet this standard, they are judged as qualified products. 7.5.2 If one of the delivery inspection items or type inspection items does not meet this standard, double sampling can be carried out for re-inspection. If it still does not meet this standard after re-inspection, it is judged as unqualified.
8 Label
8.1 The content of the label should comply with the provisions of GB7718. The product name should indicate "brewed soy sauce", and the content of amino acid nitrogen, quality grade, and use for "meal and/or cooking" should also be indicated. 8.2 Implementation standard labeling method: high-salt dilute fermented soy sauce is labeled as "GB18186-2000 high-salt dilute"; low-salt solid fermented soy sauce is labeled as "GB18186-2000 low-salt solid". 9 Packaging
Packaging materials and containers should comply with the relevant national health standards. 10 Transportation
Products should be handled with care during transportation and protected from sun and rain. The means of transportation should be clean and hygienic, and should not be mixed with toxic or contaminated items.
11 Purchase and storage
11.1 Products should be stored in a special warehouse that is cool, dry and ventilated. 11.2 The shelf life of bottled products should not be less than 12 months; the shelf life of bagged products should not be less than 6 months. 580585
Content of sodium chloride in the sample, g/100mL; Volume of 0.1 mol/L silver nitrate standard titration solution consumed in titrating the sample diluent, mL; Volume of 0.1 mol/L silver nitrate standard titration solution consumed in the blank test, mL; Concentration of silver nitrate standard titration solution, mol/L; (3)
The mass of sodium chloride equivalent to 1.00mL silver nitrate standard titration solution [c(AgNOs)=1.000mol/L], g. 6.2.2.5 Allowable difference
The difference in determination of parallel tests of the same sample shall not exceed 0.10g/100mL. 6.3 Total nitrogen
6.3.1 Instruments
a) Kjeldahl flask: 500mL;
b) Condenser;
c) Electric constant temperature dryer;
d) Nitrogen ball;
e) Analytical balance: sensitivity 0.1mg:
f) Acid burette: 25mL;
g) Pipette.
6.3.2 Reagents
a) Mixed indicator solution: 1 part of 0.2% methyl red ethanol solution mixed with 5 parts of 0.2% bromophenol green ethanol solution; b) Mixed reagent: 3 parts of copper sulfate mixed with 50 parts of potassium sulfate; c) Sulfuric acid: 95%~98%
d) 2% boric acid solution: weigh 2g of boric acid, add water to dissolve and make up to 100mL
f) 40% sodium hydroxide solution: weigh 40g of sodium hydroxide, dissolve in 60mL of water; g) 0.1mol/L hydrochloric acid standard titration solution: prepare and calibrate according to the method specified in GB/T601. 6.3.3 Analysis steps
Pull 2.00mL of the sample into a dry Kjeldahl flask, add 4g of copper sulfate-potassium sulfate mixed reagent and 10mL of sulfuric acid, and heat in a fume hood (put a small funnel on the mouth of the flask and tilt the flask at 45° on an electric stove). After all the contents are carbonized and the foam has completely stopped, keep the solution in the bottle slightly boiling. When all the carbon particles disappear and the digestion liquid is clear and light green, continue heating for 15 minutes, remove it, and cool it to room temperature. Slowly add 120mL of water, and immerse the catheter at the lower end of the condenser tube under the liquid surface of the conical flask containing 30mL of 2% boric acid solution and 2 to 3 drops of mixed indicator liquid. Slowly add 40mL of 40% sodium hydroxide solution and 2 zinc particles along the wall of the Kjeldahl flask, quickly connect the distillation device (the entire device should be tight and airtight), connect the condensed water, shake the Kjeldahl flask, and heat and distill until the distillate is about 120mL. Lower the position of the conical flask so that the lower end of the condenser tube leaves the liquid surface, distill for another 1 minute, and stop heating. Rinse the outside of the lower end of the condenser tube with a small amount of water and remove the conical flask. Titrate the collected solution with 0.1mol/L hydrochloric acid standard titration solution until it turns purple-red. Record the number of milliliters of 0.1 mol/L hydrochloric acid standard titration solution consumed. Perform a blank test at the same time. 6.3.4 Calculate the total nitrogen content in the sample according to formula (4): X, =
Where: X
6.3.5 Allowable difference
(V2-V)Xc2X0.014
The total nitrogen content in the sample (in terms of nitrogen), g/100mL; The volume of 0.1 mol/L hydrochloric acid standard titration solution consumed in the titration sample, mL; The volume of 0.1 mol/L hydrochloric acid standard titration solution consumed in the blank test, mL; The concentration of the hydrochloric acid standard titration solution, mol/L; The mass of nitrogen equivalent to 1.00mL hydrochloric acid standard titration solution [c(HC1)=1.000mol/L], g. The determination difference of the same sample in parallel tests shall not exceed 0.03g/100mL. 6.4 Amino Acid Nitrogen
6.4.1 Instruments
a) Acidity meter: with magnetic stirrer;
b) Correct burette: 25mL;
c) Pipette.
6.4.2 Reagents
a) Formaldehyde solution: 37%~40%;
b) 0.05mol/L sodium hydroxide standard titration solution: prepared and calibrated according to the method specified in GB/T601. 6.4.3 Analysis steps
(4)
Pipette 5.0mL of sample and place it in a 100mL volumetric flask. Add water to the mark. Mix well and pipette 20.0mL. Place it in a 200mL beaker. Add 60mL of water. Turn on the magnetic stirrer and titrate with sodium hydroxide standard solution [c(NaOH)=0.05mol/L] until the pH meter indicates pH=8.2 [Record the number of milliliters of sodium hydroxide standard titration solution (0.05mol/L) consumed to calculate the total acid content]. Add 10.0mL of formaldehyde solution and mix well. Continue titrating with sodium hydroxide standard titration solution (0.05mol/L) until pH=9.2. Record the number of milliliters of sodium hydroxide standard titration solution (0.05mol/L) consumed. At the same time, take 80mL of water, first adjust the pH to 8.2 with sodium hydroxide solution (0.05mol/L), then add 10.0mL of formaldehyde solution, and titrate to pH=9.2 with sodium hydroxide standard titration solution (0.05mol/L), and perform a reagent blank test at the same time. 6.4.4 Calculation
The content of amino acid nitrogen in the sample is calculated according to formula (5): X4 =
Wherein: X4
(V4-V,)XcsX0.014
The content of amino acid nitrogen in the sample (in terms of nitrogen), g/100mL; The volume of 0.05mol/L sodium hydroxide standard titration solution consumed in the titration of the sample diluent, mL; The volume of 0.05mol/L sodium hydroxide standard titration solution consumed in the blank test, mL; The concentration of sodium hydroxide standard titration solution, mol/L; · (5)
The mass of nitrogen equivalent to 1.00mL sodium hydroxide standard titration solution [c(Na0H)=1.000mol/L], g. 6.4.5 Allowable difference
The determination difference of parallel tests on the same sample shall not exceed 0.03g/100mL. 6.5 Hygienic indicators and ammonium salts
Inspected according to GB4789.22 and GB/T5009.39. The 0.017 in the ammonium salt content calculation formula of GB/T5009.39 is changed to 0.014.
GB18186—2000
7 Inspection rules
7.1 Delivery inspection
Delivery inspection items include: sensory characteristics, soluble salt-free solids, total nitrogen, amino acid nitrogen, ammonium salts, microorganisms (total colony count, coliform group).
7.2 Type inspection
Type inspection items include: all items in the technical requirements. Type inspection is carried out every six months and should also be carried out when one of the following situations occurs: a) Change of main raw materials;
b) Change of key processes;
c) When the national quality supervision agency makes a request. 7.3 Batch
Products of the same variety produced on the same day are considered a batch. 7.4 Sampling
Randomly select 6 bottles (bags) from different parts of each batch of products, and conduct sensory characteristics, physical and chemical, and hygiene inspections respectively, and retain samples. 7.5 Judgment rules
7.5.1 If all the delivery inspection items or type inspection items meet this standard, they are judged as qualified products. 7.5.2 If one of the delivery inspection items or type inspection items does not meet this standard, double sampling can be carried out for re-inspection. If it still does not meet this standard after re-inspection, it is judged as unqualified.
8 Label
8.1 The content of the label should comply with the provisions of GB7718. The product name should indicate "brewed soy sauce", and the content of amino acid nitrogen, quality grade, and use for "meal and/or cooking" should also be indicated. 8.2 Implementation standard labeling method: high-salt dilute fermented soy sauce is labeled as "GB18186-2000 high-salt dilute"; low-salt solid fermented soy sauce is labeled as "GB18186-2000 low-salt solid". 9 Packaging
Packaging materials and containers should comply with the relevant national health standards. 10 Transportation
Products should be handled with care during transportation and protected from sun and rain. The means of transportation should be clean and hygienic, and should not be mixed with toxic or contaminated items.
11 Purchase and storage
11.1 Products should be stored in a special warehouse that is cool, dry and ventilated. 11.2 The shelf life of bottled products should not be less than 12 months; the shelf life of bagged products should not be less than 6 months. 581 Apparatus
a) Kjeldahl flask: 500mL;
b) Condenser;
c) Electric constant temperature dryer;
d) Nitrogen ball;
e) Analytical balance: sensitivity 0.1mg:
f) Acid burette: 25mL;
g) Pipette.
6.3.2 Reagents
a) Mixed indicator solution: 1 part of 0.2% methyl red ethanol solution mixed with 5 parts of 0.2% bromophenol green ethanol solution; b) Mixed reagent: 3 parts of copper sulfate mixed with 50 parts of potassium sulfate; c) Sulfuric acid: 95%~98%
d) 2% boric acid solution: weigh 2g of boric acid, add water to dissolve and make up to 100mL
f) 40% sodium hydroxide solution: weigh 40g of sodium hydroxide, dissolve in 60mL of water; g) 0.1mol/L hydrochloric acid standard titration solution: prepare and calibrate according to the method specified in GB/T601. 6.3.3 Analysis steps
Pull 2.00mL of the sample into a dry Kjeldahl flask, add 4g of copper sulfate-potassium sulfate mixed reagent and 10mL of sulfuric acid, and heat in a fume hood (put a small funnel on the mouth of the flask and tilt the flask at 45° on an electric stove). After all the contents are carbonized and the foam has completely stopped, keep the solution in the bottle slightly boiling. When all the carbon particles disappear and the digestion liquid is clear and light green, continue heating for 15 minutes, remove it, and cool it to room temperature. Slowly add 120mL of water, and immerse the catheter at the lower end of the condenser tube under the liquid surface of the conical flask containing 30mL of 2% boric acid solution and 2 to 3 drops of mixed indicator liquid. Slowly add 40mL of 40% sodium hydroxide solution and 2 zinc particles along the wall of the Kjeldahl flask, quickly connect the distillation device (the entire device should be tight and airtight), connect the condensed water, shake the Kjeldahl flask, and heat and distill until the distillate is about 120mL. Lower the position of the conical flask so that the lower end of the condenser tube leaves the liquid surface, distill for another 1 minute, and stop heating. Rinse the outside of the lower end of the condenser tube with a small amount of water and remove the conical flask. Titrate the collected solution with 0.1mol/L hydrochloric acid standard titration solution until it turns purple-red. Record the number of milliliters of 0.1 mol/L hydrochloric acid standard titration solution consumed. Perform a blank test at the same time. 6.3.4 Calculate the total nitrogen content in the sample according to formula (4): X, =
Where: X
6.3.5 Allowable difference
(V2-V)Xc2X0.014
The total nitrogen content in the sample (in terms of nitrogen), g/100mL; The volume of 0.1 mol/L hydrochloric acid standard titration solution consumed in the titration sample, mL; The volume of 0.1 mol/L hydrochloric acid standard titration solution consumed in the blank test, mL; The concentration of the hydrochloric acid standard titration solution, mol/L; The mass of nitrogen equivalent to 1.00mL hydrochloric acid standard titration solution [c(HC1)=1.000mol/L], g. The determination difference of the same sample in parallel tests shall not exceed 0.03g/100mL. 6.4 Amino Acid Nitrogen
6.4.1 Instruments
a) Acidity meter: with magnetic stirrer;
b) Correct burette: 25mL;
c) Pipette.
6.4.2 Reagents
a) Formaldehyde solution: 37%~40%;
b) 0.05mol/L sodium hydroxide standard titration solution: prepared and calibrated according to the method specified in GB/T601. 6.4.3 Analysis steps
(4)
Pipette 5.0mL of sample and place it in a 100mL volumetric flask. Add water to the mark. Mix well and pipette 20.0mL. Place it in a 200mL beaker. Add 60mL of water. Turn on the magnetic stirrer and titrate with sodium hydroxide standard solution [c(NaOH)=0.05mol/L] until the pH meter indicates pH=8.2 [Record the number of milliliters of sodium hydroxide standard titration solution (0.05mol/L) consumed to calculate the total acid content]. Add 10.0mL of formaldehyde solution and mix well. Continue titrating with sodium hydroxide standard titration solution (0.05mol/L) until pH=9.2. Record the number of milliliters of sodium hydroxide standard titration solution (0.05mol/L) consumed. At the same time, take 80mL of water, first adjust the pH to 8.2 with sodium hydroxide solution (0.05mol/L), then add 10.0mL of formaldehyde solution, and titrate to pH=9.2 with sodium hydroxide standard titration solution (0.05mol/L), and perform a reagent blank test at the same time. 6.4.4 Calculation
The content of amino acid nitrogen in the sample is calculated according to formula (5): X4 =
Wherein: X4
(V4-V,)XcsX0.014
The content of amino acid nitrogen in the sample (in terms of nitrogen), g/100mL; The volume of 0.05mol/L sodium hydroxide standard titration solution consumed in the titration of the sample diluent, mL; The volume of 0.05mol/L sodium hydroxide standard titration solution consumed in the blank test, mL; The concentration of sodium hydroxide standard titration solution, mol/L; · (5)
The mass of nitrogen equivalent to 1.00mL sodium hydroxide standard titration solution [c(Na0H)=1.000mol/L], g. 6.4.5 Allowable difference
The determination difference of parallel tests on the same sample shall not exceed 0.03g/100mL. 6.5 Hygienic indicators and ammonium salts
Inspected according to GB4789.22 and GB/T5009.39. The 0.017 in the ammonium salt content calculation formula of GB/T5009.39 is changed to 0.014.
GB18186—2000
7 Inspection rules
7.1 Delivery inspection
Delivery inspection items include: sensory characteristics, soluble salt-free solids, total nitrogen, amino acid nitrogen, ammonium salts, microorganisms (total colony count, coliform group).
7.2 Type inspection
Type inspection items include: all items in the technical requirements. Type inspection is carried out every six months and should also be carried out when one of the following situations occurs: a) Change of main raw materials;
b) Change of key processes;
c) When the national quality supervision agency makes a request. 7.3 Batch
Products of the same variety produced on the same day are considered a batch. 7.4 Sampling
Randomly select 6 bottles (bags) from different parts of each batch of products, and conduct sensory characteristics, physical and chemical, and hygiene inspections respectively, and retain samples. 7.5 Judgment rules
7.5.1 If all the delivery inspection items or type inspection items meet this standard, they are judged as qualified products. 7.5.2 If one of the delivery inspection items or type inspection items does not meet this standard, double sampling can be carried out for re-inspection. If it still does not meet this standard after re-inspection, it is judged as unqualified.
8 Label
8.1 The content of the label should comply with the provisions of GB7718. The product name should indicate "brewed soy sauce", and the content of amino acid nitrogen, quality grade, and use for "meal and/or cooking" should also be indicated. 8.2 Implementation standard labeling method: high-salt dilute fermented soy sauce is labeled as "GB18186-2000 high-salt dilute"; low-salt solid fermented soy sauce is labeled as "GB18186-2000 low-salt solid". 9 Packaging
Packaging materials and containers should comply with the relevant national health standards. 10 Transportation
Products should be handled with care during transportation and protected from sun and rain. The means of transportation should be clean and hygienic, and should not be mixed with toxic or contaminated items.
11 Purchase and storage
11.1 Products should be stored in a special warehouse that is cool, dry and ventilated. 11.2 The shelf life of bottled products should not be less than 12 months; the shelf life of bagged products should not be less than 6 months. 581 Apparatus
a) Kjeldahl flask: 500mL;
b) Condenser;
c) Electric constant temperature dryer;
d) Nitrogen ball;
e) Analytical balance: sensitivity 0.1mg:
f) Acid burette: 25mL;
g) Pipette.
6.3.2 Reagents
a) Mixed indicator solution: 1 part of 0.2% methyl red ethanol solution mixed with 5 parts of 0.2% bromophenol green ethanol solution; b) Mixed reagent: 3 parts of copper sulfate mixed with 50 parts of potassium sulfate; c) Sulfuric acid: 95%~98%
d) 2% boric acid solution: weigh 2g of boric acid, add water to dissolve and make up to 100mL
f) 40% sodium hydroxide solution: weigh 40g of sodium hydroxide, dissolve in 60mL of water; g) 0.1mol/L hydrochloric acid standard titration solution: prepare and calibrate according to the method specified in GB/T601. 6.3.3 Analysis steps
Pull 2.00mL of the sample into a dry Kjeldahl flask, add 4g of copper sulfate-potassium sulfate mixed reagent and 10mL of sulfuric acid, and heat in a fume hood (put a small funnel on the mouth of the flask and tilt the flask at 45° on an electric stove). After all the contents are carbonized and the foam has completely stopped, keep the solution in the bottle slightly boiling. When all the carbon particles disappear and the digestion liquid is clear and light green, continue heating for 15 minutes, remove it, and cool it to room temperature. Slowly add 120mL of water, and immerse the catheter at the lower end of the condenser tube under the liquid surface of the conical flask containing 30mL of 2% boric acid solution and 2 to 3 drops of mixed indicator liquid. Slowly add 40mL of 40% sodium hydroxide solution and 2 zinc particles along the wall of the Kjeldahl flask, quickly connect the distillation device (the entire device should be tight and airtight), connect the condensed water, shake the Kjeldahl flask, and heat and distill until the distillate is about 120mL. Lower the position of the conical flask so that the lower end of the condenser tube leaves the liquid surface, distill for another 1 minute, and stop heating. Rinse the outside of the lower end of the condenser tube with a small amount of water and remove the conical flask. Titrate the collected solution with 0.1mol/L hydrochloric acid standard titration solution until it turns purple-red. Record the number of milliliters of 0.1 mol/L hydrochloric acid standard titration solution consumed. Perform a blank test at the same time. 6.3.4 Calculate the total nitrogen content in the sample according to formula (4): X, =
Where: X
6.3.5 Allowable difference
(V2-V)Xc2X0.014
The total nitrogen content in the sample (in terms of nitrogen), g/100mL; The volume of 0.1 mol/L hydrochloric acid standard titration solution consumed in the titration sample, mL; The volume of 0.1 mol/L hydrochloric acid standard titration solution consumed in the blank test, mL; The concentration of the hydrochloric acid standard titration solution, mol/L; The mass of nitrogen equivalent to 1.00mL hydrochloric acid standard titration solution [c(HC1)=1.000mol/L], g. The determination difference of the same sample in parallel tests shall not exceed 0.03g/100mL. 6.4 Amino Acid Nitrogen
6.4.1 Instruments
a) Acidity meter: with magnetic stirrer;
b) Correct burette: 25mL;
c) Pipette.
6.4.2 Reagents
a) Formaldehyde solution: 37%~40%;
b) 0.05mol/L sodium hydroxide standard titration solution: prepared and calibrated according to the method specified in GB/T601. 6.4.3 Analysis steps
(4)
Pipette 5.0mL of sample and place it in a 100mL volumetric flask. Add water to the mark. Mix well and pipette 20.0mL. Place it in a 200mL beaker. Add 60mL of water. Turn on the magnetic stirrer and titrate with sodium hydroxide standard solution [c(NaOH)=0.05mol/L] until the pH meter indicates pH=8.2 [Record the number of milliliters of sodium hydroxide standard titration solution (0.05mol/L) consumed to calculate the total acid content]. Add 10.0mL of formaldehyde solution and mix well. Continue titrating with sodium hydroxide standard titration solution (0.05mol/L) until pH=9.2. Record the number of milliliters of sodium hydroxide standard titration solution (0.05mol/L) consumed. At the same time, take 80mL of water, first adjust the pH to 8.2 with sodium hydroxide solution (0.05mol/L), then add 10.0mL of formaldehyde solution, and titrate to pH=9.2 with sodium hydroxide standard titration solution (0.05mol/L), and perform a reagent blank test at the same time. 6.4.4 Calculation
The content of amino acid nitrogen in the sample is calculated according to formula (5): X4 =
Wherein: X4
(V4-V,)XcsX0.014
The content of amino acid nitrogen in the sample (in terms of nitrogen), g/100mL; The volume of 0.05mol/L sodium hydroxide standard titration solution consumed in the titration of the sample diluent, mL; The volume of 0.05mol/L sodium hydroxide standard titration solution consumed in the blank test, mL; The concentration of sodium hydroxide standard titrat
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