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GB/T 5009.39-2003 (GB/T5009.39-2003)

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GB/T 5009.39-2003: PDF in English (GBT 5009.39-2003)

GB/T 5009.39-2003
GB
ICS 67.040
C 53
NATIONAL STANDARD
OF THE PEOPLE’S REPUBLIC OF CHINA
Replacing GB/T 5009.39-1996
Method for analysis of hygienic standard of
soybean sauce
ISSUED ON. AUGUST 11, 2003
IMPLEMENTED ON. JANUARY 1, 2004
Issued by. Ministry of Health of the People’s Republic of China;
Standardization Administration Committee.
Table of Contents
Foreword ... 3
1 Scope ... 4
2 Reference standards ... 4
3 Sensory inspection ... 4
4 Physiochemical test ... 5
Foreword
This standard replaces GB/T 5009.39-1996 " Method for analysis of hygienic standard
of soybean sauce".
Compared with GB/T 5009.39-1996, the major changes of this standard are as follows.
- According to GB/T 20001.4-2001 "Rules for drafting standards - Part 4.
Methods for chemical analysis" of the original structure has been revised
standards;
- ADD Amino Nitrogen Colorimetric Method as the second method.
This standard was proposed and managed by Ministry of Health of the People's
Republic of China.
Drafting organizations of this standard. Beijing Municipal Health and Epidemic
Prevention Station, Handan City Health and Epidemic Prevention Station, and
Tangshan City Health and Epidemic Prevention Station.
This standard was first-time released in 1985, and the first-revision in 1996. This is the
second revision.
GB 17326-1998
Method for analysis of hygienic standard of
soybean sauce
1 Scope
This standard specifies the analysis method of health indicators of soybean sauce.
This standard applies to the analysis of health indicators of soybean sauce which is
brewed or prepared from the raw materials such as grain and its by-products soybean
meal and wheat bran.
The detection limit of the 2nd method - Amino Nitrogen Method in this standard, is 0.070
μg/mL, the linear range is 0-10 μg/mL.
2 Reference standards
The following documents contain provisions which, through reference in this Standard,
become provisions of this Standard. For dated references, their subsequent
amendments (excluding corrections) or revisions do not apply to this Standard.
However, the parties who enter into agreement based on this Standard are
encouraged to investigate whether the latest versions of these documents are
applicable. For undated reference documents, the latest versions apply to this
Standard.
GB/T 5009.2 Determination of relative density of foods
GB/T 5009.11 Determination of total arsenic and abio-arsenic in foods
GB/T 5009.12 Determination of lead in foods
GB/T 5009.22 Determination of aflatoxin B1 in foods
GB/T 5009.29 Determination of sorbic acid and benzioc acid in foods
3 Sensory inspection
3.1 Take 2 mL of sample in 25 mL with-stopper colorimetric tube. Add water to the
mark. Shake and observe the color and clarity. It shall be no-dirty, and no-sediment.
3.2 Take 30 mL of sample in 50 mL beaker. It shall be no-mold, no mildew and floating
film.
3.3 After stirring the sample in beaker with a glass rod, its taste shall be without smell
such as sour, bitter, or astringent.
GB 17326-1998
4.2.1.5 Result calculation
Amino nitrogen content of the sample shall be calculated according to equation (1).
In which.
X – the amino nitrogen content of the sample, in units of grams per hundred
milliliters (g/100 mL);
V1 – the volume of consumed sodium hydroxide standard titration solution after
formaldehyde is added into the test sample dilution, in units of milliliters (mL);
V2 – the volume of consumed sodium hydroxide standard titration solution after
formaldehyde is added into the reagent blank test, in units of milliliters (mL);
V3 - the taken amount of sample dilution, in units of milliliters (ml);
c - the concentration of sodium hydroxide standard titration solution , in units of
moles per liter (mol/L);
0.014 – the mass of nitrogen corresponding to 1.00 mL of sodium hydroxide
standard titration solution [c(NaOH) = 1.000 mol/L], in units of grams (g).
Calculation result shall retain 2 significant figures.
4.2.1.6 Precision
Under repeatability conditions, the absolute difference obtained from 2 independent
test results shall not exceed 10% of the arithmetic mean.
4.2.2 Second method - Colorimetry
4.2.2.1 Principle
In pH 4.8 sodium acetate-acetic acid buffer solution, the amino nitrogen is reacted with
acetyl acetone and formaldehyde to form a yellow 3,5-diacetyl-2,6-dimethyl-1,4-
dihydropyridine amino acid derivatives. Measure the absorbance at wavelength of 400
nm. Compare quantitatively with the standard series.
4.2.2.2 Reagents
4.2.2.2.1 Acetic acid solution (1 mol/L). Take 5.8 mL of glacial acetic acid. Add water
to dilute to 100 mL.
4.2.2.2.2 Sodium acetate solution (1 mol/L). Take 41 g of anhydrous sodium acetate
or 68 g of sodium acetate (CH3COONa • 3H2O). Add water to dissolve. And dilute to
500 mL.
GB 17326-1998
standard regression equation. Calculate the sample content.
4.2.2.5 Result calculation
Amino nitrogen content of the sample shall be calculated according to formula (2).
In which.
X – the amino nitrogen content of the sample, in units of grams per hundred
milliliters (g/100 mL);
c - the nitrogen mass in test sample solution, in units of micrograms (µg);
V1 - sample volume, in units of milliliters (mL);
V2 - volume of test sample solution, in units of milliliters (mL).
4.2.2.6 Precision
Under repeatability conditions, the absolute difference obtained from 2 independent
test results shall not exceed 10% of the arithmetic mean.
4.3 Salt (counted in NaCl)
4.3.1 Principle
Use silver nitrate standard solution to titrate sodium chloride in the sample. Generate
silver chloride to precipitate. After all silver chloride is precipitated, the extra titrated
silver nitrate and potassium chromate indicator generate silver chromate, until
the solution shows orange, that is the end. From the consumption of silver nitrate
standard titration solution, calculate the sodium chloride content.
4.3.2 Reagents
4.3.2.1 Silver nitrate standard titration solution [c(AgNO3) = 0.100 mol/L].
4.3.2.2 Potassium chromate solution (50 g/L). Weigh 5 g of potassium chromate. Use
a small amount of water to dissolve. Dilute to 100 mL.
4.3.3 Instruments
10 ml microburette.
4.3.4 Analysis steps
Draw 2.0 mL of sample dilution in a 150 mL-200 mL conical flask. Add 100 mL of water
and 1 mL of potassium chromate solution (50 g/L). Mix well. Use silver nitrate standard
GB 17326-1998
4.8 Benzoic acid, sorbic acid
Operate according to GB/T 5009.29.
4.9 Ammonium salt (semi-micro Kjeldahl method)
4.9.1 Principle
Sample is heated in an alkaline solution by distillation. Ammonia is evaporated. It is
absorbed by boric acid solution. Then use hydrochloric acid standard solution to titrate
and calculate the content.
4.9.2 Reagents
4.9.2.1 Magnesium oxide.
4.9.2.2 Boric acid solution (20 g/L).
4.9.2.3 Hydrochloric acid standard titration solution [c(HCl) = 0.100 mol/L].
4.9.2.4 Mixed indicator solution. 1 portion of methyl red-ethanol solution (2 g/L) and 5
portions of bromocresol green-ethanol solution (2 g/L). Mix well when using.
4.9.3 Analysis steps
Draw 2 mL of sample. Place in a 500 mL distillation flask. Add about 150 mL of water
and about 1 g of magnesium oxide. Connect the distillation device. The connection
bent tube at lower end of condensation tube is inserted below the liquid surface of
receiving bottle. In the receiving bottle, it contains 10 mL of boric acid solution (20 g/L)
and 2-3 drops of mixed indicator solution. Heat for distillation. Steam for about 30 min,
counted from the boiling. Rinse the bent tube with a little water. Use hydrochloric acid
standard solution (0.100 mol/L) to titrate to the end. Take the same amount of water,
magnesium oxide, and boric acid solution to conduct reagent blank test according the
same method.
4.9.4 Result calculation
Ammonium salt content of the sample (counted in ammonia) shall be calculated
according to formula (5).
In which.
X – the ammonium salt content (counted in ammonia), in units of grams per one
hundred milliliters (g/100 mL);
V1 - the volume of hydrochloric acid standard titration solution consumed in test
GB 17326-1998
sample dilution, in units of milliliters (mL);
V2 - the volume of hydrochloric acid standard titration solution consumed in reagent
blank, in units of milliliters (mL);
c - the actual concentration of hydrochloric acid standard titration solution, in units
of moles per liter (mol/L);
0.017 - the ammonium salt (counted in ammonia) mass corresponding to 1.00 ml
of hydrochloric acid standard solution [c(HCl)=1.000 mol/L], units in grams (g);
V3 - the sample volume, in units of milliliters (mL).
The result shall retain 2 significant figures.
4.9.5 Precision
Under repeatability conditions, the absolute difference obtained from 2 independent
test results shall not exceed 10% of the arithmetic mean.
......
 
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