This standard specifies the analytical method for the sanitary index of monosodium glutamate. This standard is applicable to the analysis of the sanitary index of sodium glutamate crystals purified by fermentation from grains. GB/T 5009.43-2003 Analytical method for sanitary standard of monosodium glutamate GB/T5009.43-2003 Standard download decompression password: www.bzxz.net

ICS67.040
National Standard of the People's Republic of China
GB/T5009.43--2003
Replaces GB/T5009.43--1996
Method for analysis of hygienic standard of monosodium glutamate
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/T5009.43--2003
This standard replaces GB/T5009.43--1996 "Method for analysis of hygienic standard of monosodium glutamate". Compared with GB/T5009.43-1996, the main modifications of this standard are as follows: The structure of the original standard has been modified in accordance with GB/T20001.4-2001 "Standard Writing Rules Part 4: Chemical Analysis Methods".
This standard is proposed and managed by the Ministry of Health of the People's Republic of China. This standard is drafted by Beijing Municipal Health and Epidemic Prevention Station and Zhejiang Provincial Food Hygiene Supervision and Inspection Institute. This standard was first issued in 1985 and revised for the first time in 1996. This is the second revision. 346
1 Scope
Analysis methods for sanitary standards of monosodium glutamate
This standard specifies the analysis methods for sanitary indicators of monosodium glutamate. This standard is applicable to the analysis of sanitary indicators of sodium glutamate crystals purified by fermentation with grain as raw materials. 2 Normative references
GB/T5009.432003
The clauses in the following documents become the clauses of this standard through reference in this standard. All the subsequent amendments (excluding errata) or revisions of dated references are not applicable to this standard. However, parties to an agreement based on this standard are encouraged to study whether the latest versions of these documents can be used. For undated references, the latest versions apply to this standard. GB/T5009.11 Determination of total and inorganic substances in food GB/T5009.12 Determination of lead in food
GB/T5009.14 Determination of zinc in food
GB/T5009.39—2003 Analytical methods for hygienic standards of soy sauce 3 Sensory inspection
Spread the monosodium glutamate sample on a piece of white paper and observe that its color should be white crystals without inclusions. Taste it and it should have no peculiar smell. 4
Physical and Chemical Test
4.1 Sodium Glutamate
4.1.1 Polarimeter Method
4.1.1.1 Principle
The molecular structure of sodium glutamate contains an asymmetric carbon atom, which has the ability to rotate the polarization vibration plane, that is, it has optical activity, the ability to rotate the polarization plane of the polarized light passing through it, expressed as an angle called optical rotation, which can be observed by a polarimeter. 4.1.1.2 Reagents
Hydrochloric acid solution (1+1).
4.1.1.3 Instruments
Polarimeter.
4.1.1.4 Analysis Steps
Weigh about 5.0g of the fully mixed sample, place it in a beaker, and add 20mL~30mL of water. Add 16mL of hydrochloric acid solution (1+1), dissolve it, transfer it to a 50mL volumetric flask, add water to the scale, and shake well. Place the solution in a 2dm polarimeter tube and observe the optical rotation. At the same time, measure the temperature of the solution in the polarimeter tube. If the temperature is lower or higher than 2°C, it needs to be corrected before calculation.
4.1.1.5 Result calculation
4.1.1.5.1 When the temperature is 20°C, calculate directly according to formula (1). Where:
X-x2x32×147.13x
dzo×50×187.13
the content of sodium glutamate in the sample (including 1 molecule of crystal water), in grams per 100 grams (g/100g); d2——the optical rotation observed at 20℃; (1)
GB/T5009.43—2003
32——the specific rotation of pure glutaric acid at 20℃;
the molecular weight of sodium glutamate containing 1 molecule of crystal water;
187.13—
147.13——the molecular weight of glutaric acid;
2——the length of the optical tube.
If the temperature is not 20℃, the measurement should be corrected. The correction value for glutaric acid is 0.060. 4.1.1.5.2 The specific rotation of pure glutaric acid at t℃ is calculated according to formula (2). [d,] = [32 + 0.06 (20-t)] × 147.13/187.13 = 25.16 + 0.047 (20t) 4.1.1.5.3 The content of sodium glutamate (including 1 molecule of crystal water) in the sample is calculated according to formula (3). d.×50×1000
X=5×2×[25.16+0.047(20-]
Wherein:
X, the content of sodium glutamate in the sample (including 1 molecule of crystal water), in grams per hundred grams (g/100g); d, the observed optical rotation at —t℃: — the temperature during measurement, in degrees Celsius (℃). The calculation result shall be rounded to three significant figures.
4.1.1.6 Precision
The absolute difference between two independent measurement results obtained under repeatability conditions shall not exceed 10% of the arithmetic mean. 4.1.2 Acidity meter method
4.1.2.1 Principle, reagents, instruments||t t||Same as 4.2.1.1~4.2.1.3 in GB/T5009.39-2003. 4.1.2.2 Analysis steps
...(3)
Weigh 0.50g of sample and put it in a 200mL beaker, add 60mL of water, start the magnetic stirrer, and titrate with sodium hydroxide standard solution (0.050mol/L) until the pH meter indicates pH 8.2L. Record the number of milliliters of sodium hydroxide standard titration solution (0.050mol/L) consumed, and the total acid content can be calculated.
Add 10.0mL of formaldehyde solution and mix well. Continue to titrate with sodium hydroxide standard solution (0.050mol/L) to pH 9.2, record The number of milliliters of sodium hydroxide standard solution (0.050 mol/L) consumed. At the same time, take 60 mL of water and first adjust it to pH 8.2 with sodium hydroxide standard solution (0.050 mol/L). Then add 10.0 mL of formaldehyde solution and titrate it to pH 9.2 with sodium hydroxide standard solution (0.050 mol/L) to perform a reagent blank test. 4.1.2.3 Result calculation
The content of sodium glutamate (including 1 molecule of crystalline water) in the sample is calculated according to formula (4). XV-V)×cX0.187×100
Wherein:
X is the content of sodium glutamate (including 1 molecule of crystalline water) in the sample, in grams per hundred grams (g/1 00g); m
-mass of sample, in grams (g); bzxz.net
-volume of sodium hydroxide standard solution consumed after formaldehyde is added to the sample diluent for determination, in milliliters (mL); Vi
volume of sodium hydroxide standard solution consumed after formaldehyde is added to the reagent blank test, in milliliters (mL); Vz
concentration of sodium hydroxide standard titration solution, in moles per liter (mol/L); 0.187-
(4)
mass of sodium glutamate containing one molecule of crystal water equivalent to 1.00mL of sodium hydroxide standard titration solution [c(NaOH)=1.000mol/L], in grams (g).
The calculated result shall be rounded to three significant figures.
4.1.2.4 Precision
The absolute difference between two independent determination results obtained under repeatability conditions shall not exceed 10% of the arithmetic mean. 348
Operate in accordance with GB/T5009.12.
Operate in accordance with GB/T5009.11.
Operate in accordance with GB/T5009.14.
GB/T5009.43—2003
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