Some standard content:
ICS 67.040
National Standard of the People's Republic of China
GB/T5009.5—2003
GB/5009.5--1985
Determination of protein in foods
Promulgated on August 11, 2003
Ministry of Health of the People's Republic of China
Standardization Administration of the People's Republic of China
Implementation on January 1, 2004
GB/I5009.5—2203
This standard replaces GB/T30G9.5—14358 Determination of protein in foods. Compared with GB/TE0G9.51935, the main revisions of this standard are as follows: the Chinese name of the standard is modified, and the Chinese name of the standard is changed to "Food protein test method"; GB 21.41: Writing rules for standards, Part 4: Chemical valuation method, etc. are revised.
This standard was proposed and approved by the Ministry of Health of the People's Republic of China: The first draft of this standard was drafted by the Food Industry Inspection Institute of the Ministry of Health, and the second draft was drafted by the Health and Safety Station of Tangchuan City, Hebei Province.
This standard was first issued in 1956 and this is the third revision.
1 Scope
Determination of protein quality in food
This standard specifies the identification method of protein quality in food. This standard is applicable to the determination of egg yolk in dry food. This standard is not applicable to foods that require the addition of inorganic hydrogen, calcium, and ammonia. The inspection limit of this standard is ).n7<%/ mL linear cell national fire t~.0.0g/ml first method
2 Drying
GB/T5009.5-2033
Eggs are low in organic compounds. Feed with sulfuric acid and sulphuric acid, and heat with acid for 3 hours to digest, so that the protein is decomposed, and the decomposed hydrogen combines with sulfuric acid to form a sulphuric acid. The hydrogen is gradually separated. After absorption with sulphuric acid, it is titrated with standard hydrochloric acid or hydrochloric acid. The conversion coefficient is multiplied by the amount of acid to obtain the protein synthesis. 3 Reagents
Adjustment (CuSO-H:O)
3.2 Sulfate:
The density of sulfuric acid is 1.115/1,
3.4 Additive (29 g/1.).
3.5 Hydrogen bottle steel drop acid 4001)
3.G sulfuric acid standard titration sieve micro (1/2H.S),>C.U50)0mol/. point hydrochloric acid standard coke rate (HC.) = 0.056 0 mal/L-
3.7 Mixed indicator liquid: 1 core 7. Standard wear policy (1L) and 5 parts of phenol ethanol policy (18/T.> before use. -Echuan 3 parts of methyl ethyl ethanol (1/L) and [parts of methyl blue ethanol solution (%/L) before use. The instrument
determines the heat range of the stomach, as shown in Figure 1.
FA/T5009.5—2003
Water vapor generator [Huh refining report
small bucket and state death!
Reaction rate
Reaction to the outer layer:
-Prohibited quality tube receiving test case!
&—Transmission tube:
"One steam increase liquid receiving book.bzxZ.net
5 Analysis step
Around 1 Ammonia and hydrogen depletion device
Sample treatment: weigh ~2.0-.00 half-test sample or 5.
10.10m).~25.00mL of solution (about 30mg~-40mR of nitrogen). Add 3.2 sodium dodecanoate, 6g sulfuric acid and 20ml thioaldehyde to 100ml or 590ml of nitrogen determination plate. After decomposition, put a small bucket in the bottle, and place the bottle on an asbestos net with small holes at 4 corners. Heat carefully until all the contents are carbonized. After the decomposition stops completely, keep the bottle full and boil until the blue color disappears and it becomes transparent. Continue to heat for 3.5h-~! Remove the cooling effect, carefully return 20πL of water: after cooling, transfer to 139m. through the base, and wash the required sea and flow liquid with a small amount of sealing water, and then put it into the required capacity, and then put it into the water for use. At the same time, do the reagent test 5.2 determination: calibrate 1 full of nitrogen, fill the gas generator with water to two-thirds, add a few drops of red indicator liquid and a few liters of flow acid, and seal the water to acidity, raise the pressure regulator, add the water in the steam generation bottle, 5.3 collect the Dm.7. frequency acid shrink filter (g/1) and 1 drop ~ 2 according to the indicator, and let the cooling tube roll down, and absorb 10rl. The treatment was filled into the empty room by a small bucket, and washed with 1CJ. water. The small room is filled with people and the room is filled with people, and the sample is tightly plugged with a glass stopper. Put 10nl. True oxidation (4CC/1. Pour into a small cup, lift up. Limit the flow of the reaction mixture to a certain degree. Immediately tighten the plug and add water to the cup to prevent the negative gas. Or tighten the morning disaster, no curtain box. Fumigation for 5min, move the receiving bottle, the liquid level leaves the lower end of the condenser, and then decay for 1m, then use a volume to wash the outside of the lower end of the dangerous fragrance, and remove the receiving bottle. Use sulfuric acid to break the standard flow solution (0> full of natural color or blue case color as the observation point, and accurately absorb 0ml. Reagent digestion teaching connection. 3 replacement. 6 Result calculation
Formula in detail The protein content is calculated according to Formula 1, x = -x0. 014 xx icc
!X10/U
Wuhan City:
CB/T5009.5—2003
X——The protein content in the test sample, the unit is per ug or gram per year (/10ug or/1LIV, the volume of sulfuric acid or salt standard titration solution consumed by one sample, the unit price is mT.): The volume of sulfuric acid or salt standard titration solution consumed by the reagent is marked in liters (ml.)! Standard liquid concentration. Single symptom rate per liter (/L); 0.U14-1.UmL sulfuric acid e(1/2H,SC))=1,UU3mol./L) or salt according to te(JICI>-1.(0mal/LJ Standard net liquid concentration is the mass of the nitrogen in the unit of hyrogram (). The unit of weight of the sample is gram or <IF-nitrogen coefficient is calculated as food, 26, dairy products are 6.38; flour is 5.70; low rice, high Single is 6.24 raw 5.46: 5.3>1 rice and soybeans and their products 5.71; meat and meat products 5.2>: walk, millet, dried sesame 5.831, ask for 5,50 calculation results guarantee one significant digit,
7 precision
enterprise year width can be obtained under the standard two independent text results of the difference shall not exceed the technical average of 1. Second method
8 principle
food quality nitrogen content Organic compounds. Food is digested with a catalyst to decompose protein. The decomposed hydrogen combines with ethyl acetate to form ammonium hydroxide. Then, in a sodium acetate solution with a pH of 4.8, it reacts with acetyl lactone to form a yellow acetyl-2.5-dimethyl 1.4-monohydropyridine compound. The absorbance at a wavelength of 400 nm is measured and compared with the standard series. The result is the protein content. 1 Sulfuric acid test.
9.2 Potassium sulfate.
9.3 Pre-treatment.
9.4 Calcium oxide solution <300z/1 Weigh 100 g sodium oxide and dissolve in water, cool and dilute to 10cm/L. 9.5 p-Nitrophenol indicator (concentrated) (/1. Take 1.1 g nitrobenzene indicator and dissolve in 2 mL 95% ethanol: add water and dilute to 100ml
9.6 Acid dropwise (10l/L. Collect 5.1 mL glacial acetic acid and dilute to 100ml with water9.7 Sodium acetate (1mol/L): weigh 1 g sodium hydroxide (CHCl3HO). Dissolve in water and dilute to 100ml.
9. Sodium acetate-acetic acid buffer solution, measure c)mJ of sodium acetic acid (1ml/1) and mix with 1ml of acetic acid (1l/1), the concentration is 48.
9 1537% acetic acid and 101% acetic acid (water solution) are placed in the room for stabilization.
9.10 Oxygen and nitrogen standard solution (1.0g/1.) Accurately take 0.172% of 21% acetic acid, dissolve it in water and transfer it into 13ml of 10% acetic acid solution, add water to the scale, and the flow rate of this solution is more than 1.0mg/L (0% under ice).
9.11 Natural standard solution (1g/L): Accurately take 1ml nitrogen and hydrogen standard solution (1,0mg:mL in) volumetric bottle.Water type suburb to scale, wonton, this box of cold liters and equivalent to 10NH-N (1AT: lower refrigerator than 39
GR/T 5C03.5—2003
Bao! Month,
10 Fast instrument
10.1 Spectrophotometer,
0.2 Heat-resistant small bath steel <100=1.3r
10.3 10mL stoppered glass colorimetric tube,
11 Analysis steps
11.1 Sample digestion
Finishing Take a portion of the solid test sample (1g~.5 or semi-solid test sample 0.2A~1.0%) that has passed through a 10 sieve and transfer 1cc of the sample to a 25ml fixed atmosphere bottle, add 1g of flowing acid, 1mL of acid and 1mL of aldehyde, shake the bottle and add a safety funnel, place the funnel on a 4-point diagonal line with a mirror, carefully cut the grid to ensure that the contents are completely carbonized. Completely produce 1 stone, increase the fire, and keep the liquid flowing, the green body is bright, and can continue to heat C., cool under the table, carefully m) water, after cooling, transfer to 5 or 13ml volumetric medium, and use a small bottle with a small plate to select the volume of % and add water to the preparation room. Take the chain acid saw from the sample cabinet and treat it. Please do the air test according to the room.
11.2 Preparation of sample
Take 1ml~5ml of the test or reagent blank digestion solution in a 53mL~[CCmL volumetric bottle, add 1 drop of the base indicator (300/E.) and the color of the seedling, and transfer (1ml, L) until the solution is colorless, add water to the scale. Mix.
11.3 Drawing of standard curve
Collect 0.0.05.0.1.C.2,0.,n,0.,1.3ml. Oxygen and nitrogen standard (equivalent to NH,-VU,5.0,10.C,27.C,40.060.(.8C.0.0.000.0g) in 1CmL colorimetric solution, add 4mL sodium acetate-acetic acid standard solution (pF4) and 4m. colorimetric agent, add water to mix, place in 100℃ water bath, heat 15mm, cool to room temperature with water, then move into 1\ colorimetric stream, take zero tube as the reference, and at a wavelength of 40Cm Measure the absorbance, record the absorbance of each point and calculate the direct flashback equation.
11.4 Sample determination
Precisely absorb 0.5m--2.\mt. When the sample is about 100m>, the sample is suspended in the reagent room and the white float is reduced. The following is in accordance with 11. Add 4 sodium acetate-acetic acid solution (>1.x and. Is the color agent..\ and operate according to the law. Compare the sample absorbance with the standard curve or substitute the standard regression equation to obtain the integral, 12 Calculation results
Try to select the appropriate station according to formula (2) to perform the original, x=.
1 1n0 ×1 000
Cheng1 content, unit is gram per gram per hundred plate or gate 0: oxygen content in the sample determination, unit is gram ()! Reagent empty determination liquid, unit is microgram W
W sample digestion liquid volume, unit is milliliter (mI)) V: the volume of the digestion liquid of the sample preparation, unit is density (ml. The total volume of the sample is expressed as liter mI)
Transfer—specified test liquid is expressed as milliliter (1nl.): the sample pressure is expressed as gram or liter (6 or mF nitrogen conversion coefficient for protein
R/T 5009.5—20C3
The chlorine content of protein is generally 15%~17.6%, then multiply by 16 times 6.25 to get the protein content, and the product content is 6.33. The product content is 5.70 for corn products, 6.24 for peanuts, .46 for soybeans, 5.7 for meat and meat products, 5.23 for wheat, millet, and sesame, and the intermediate content is 5.0. The difference between the two active calcium determination results obtained under the complex soft software is not calculated by the arithmetic average.
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