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GB 5009.9-2016 English PDF (GB5009.9-2016)

GB 5009.9-2016 English PDF (GB5009.9-2016)

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GB 5009.9-2016: Determination of starch in foods

This standard specifies the determination of starch in food. The method 1 and the method 2 of this standard apply to the determination of starch in food (except for meat products); the method 3 is applicable to the determination of starch in meat products, BUT it does not apply to the determination of starch in other additions which contains both the hydrolyzed and the reducing sugar.
GB 5009.9-2016
GB
NATIONAL STANDARD
OF THE PEOPLE REPUBLIC OF CHINA
National food safety standard -
Determination of starch in foods
ISSUED ON. DECEMBER 23, 2016
IMPLEMENTED ON. JUNE 23, 2017
Issued by. National Health and Family Planning Commission of the PRC;
State Food and Drug Administration
3. No action is required - Full-copy of this standard will be automatically & immediately delivered to your EMAIL address in 0~60 minutes.
Table of Contents
Foreword ... 3
1 Scope ... 4
2 Principles ... 4
3 Reagents and materials ... 4
4 Instruments and equipment ... 6
5 Analytical procedures ... 6
6 Expression of analytical results ... 9
7 Precision... 11
8 Principles ... 11
9 Reagents and materials ... 12
10 Instruments and equipment ... 13
11 Analytical procedures ... 13
12 Expression of analytical results ... 14
13 Precision ... 15
14 Principles ... 15
15 Reagents and materials... 15
16 Instruments and equipment ... 17
17 Analytical procedures ... 17
18 Expression of analytical results ... 19
19 Precision ... 21
Foreword
The standard replaces GB/T 5009.9-2008 ?€?Determination of starch in food?€?, GB/T 5514-2008 ?€?Inspection of grain and oils ?€? Determination of starch content in grain and oilseeds?€?, and GB/T 9695.14-2008 ?€?Meat products ?€?
Determination of starch content?€?.
As compared with GB/T 5009.9-2008, the main changes of this standard are as follows.
- ADD the determination operation of low content sample;
- ADD the determination of reagent blank;
- MODIFY the calculation formula in the method 1;
- ADD the method 3. Determination of starch content in meat products.
National food safety standard
Determination of starch in foods
1 Scope
This standard specifies the determination of starch in food.
The method 1 and the method 2 of this standard apply to the determination of starch in food (except for meat products); the method 3 is applicable to the determination of starch in meat products, BUT it does not apply to the
determination of starch in other additions which contains both the hydrolyzed and the reducing sugar.
Method 1. Enzymatic hydrolysis
2 Principles
After removing the fat and soluble sugar from the sample, the starch is hydrolyzed by amylase into small molecules, which is further hydrolyzed by hydrochloric acid into monosaccharides AND determined as reducing sugar, AND the result is converted into the starch content.
3 Reagents and materials
Unless otherwise stated, the reagents used in this method are of analytical pure AND water is the level 3 water as specified in GB/T 6682.
3.1 Reagents
3.1.1 Iodine (I2).
3.1.2 Potassium iodide (KI).
3.1.3 Taka-diastase amylase. enzyme activity ??? 1.6 U/mg.
3.1.4 Anhydrous ethanol (C2H5OH) or 95% ethanol.
3.1.5 Petroleum ether. boiling range of 60 ??C ~ 90 ??C.
3.1.6 Ether (C4H10O).
3.1.7 Toluene (C7H8).
3.1.8 Trichloromethane (CHCl3).
3.1.9 Hydrochloric acid (HCl).
3.1.10 Sodium hydroxide (NaOH).
3.1.11 Copper sulfate (CuSO4 ?€? 5H2O).
3.1.12 Potassium tartrate (C4H4O6KNa ?€? 4H2O).
3.1.13 Potassium ferrocyanide [K4Fe(CN)6 ?€? 3H2O].
3.1.14 Methylene blue (C16H18ClN3S ?€? 3H2O). indicator.
3.1.15 Methyl red (C15H15N3O2). indicator.
3.1.16 Glucose (C6H12O6).
3.2 Reagent preparation
3.2.1 Methyl red indicator solution (2 g/L). WEIGH 0.20 g of methyl red; USE a small amount of ethanol to dissolve it; ADD water to make its volume reach to 100 mL.
3.2.2 Hydrochloric acid solution (1 + 1). MEASURE 50 mL of hydrochloric acid; MIX it with 50 mL of water.
3.2.3 Sodium hydroxide solution (200 g/L). WEIGH 20 g of sodium hydroxide; ADD water to dissolve and make its volume reach to 100 mL.
3.2.4 Alkaline tartrate solution A. WEIGH 15 g of copper sulfate and 0.050 g of methylene blue; DISSOLVE it into water; MAKE its volume reach to 1000 mL. 3.2.5 Alkaline copper tartrate solution B. WEIGH 50 g of sodium potassium tartrate and 75 g of sodium hydroxide; DISSOLVE it in water; ADD 4 g of potassium ferrocyanide; after it is completely dissolved; USE water to make its volume reach to 1000 mL; STORE it in a glass bottle with rubber stopper. 3.2.6 Amylase solution (5 g/L). WEIGH 0.5 g of Taka-diastase amylase; ADD 100 mL of water to dissolve it; PREPARE it before use; AND it may also add several drops of toluene or chloroform to prevent mildew; PRESERVE it in refrigerator at 4 ??C.
Note. It may also use the aforementioned method to calibrate 4 mL ~ 20 mL of alkaline copper tartrate solution (50% of solution A and 50% of solution B) to adapt to the change of concentration of the reducing sugar in the sample. 5.2.2 Sample solution prediction
PIPETTE 5.00 mL of alkaline copper tartrate solution A and 5.00 mL of alkaline copper tartrate solution B; PLACE it in a 150 mL conical flask; ADD 10 mL of water; ADD two glass beads; HEAT to boil it within 2 min; MAINTAIN boiling; at the speed from fast to slow, USE the burette to add the sample solution; MAINTAIN the solution at boiling state; when the solution color becomes light, TITRATE it at the rate of one drop every two seconds, until the blue color of the solution disappears; RECORD the volume of the sample solution consumed. When the glucose concentration in the sample solution is to high, it shall make formal determination after appropriate dilution, so as to ensure that the volume of the sample solution consumed for each titration is controlled close to the volume of the glucose standard solution as consumed in calibrating the
alkaline copper tartrate solution, which is about 10 mL.
5.2.3 Determination of sample solution
PIPETTE 5.00 mL of alkaline copper tartrate solution A and 5.00 mL of alkaline copper tartrate solution B; PLACE it in a 150 mL conical flask; ADD 10 mL of water; ADD two glass beads; USE the burette to add the sample solution which is 1 mL less than the predicted volume into the conical flask; HEAT to boil it within 2 min; MAINTAIN the solution at boiling state; CONTINUE adding
glucose at the rate of one drop per two seconds, until the blue color of the solution just disappears; RECORD the total volume of the sample solution as consumed; and meanwhile MAKE three parallels; TAKE the average value;
MAKE calculation in accordance with the formula (1).
When the concentration is too low, then directly ADD 10.00 mL of sample solution; DO not add 10 mL of water; USE the glucose standard solution to make titration to the end; RECORD the glucose content (mg) in 10 mL of
sample solution which is equivalent to the difference of volume as consumed and the volume of the glucose standard solution as consumed during
calibration. MAKE calculation in accordance with the formula (2) and (3). 5.2.4 Determination of reagent blank
Meanwhile, MEASURE 20.00 mL of water and the amylase solution having an amount same as that used for sample solution treatment; USE the reverse dropping method to make reagent blank test. That is, USE the glucose
standard solution to titrate the reagent blank solution to the end. RECORD the glucose content (mg) in 10 mL of sample solution which is equivalent to the 100 - Constant volume of the sample to be measured (mL);
V0 - The volume of glucose standard solution consumed after the addition of the blank sample, in milliliters (mL);
Vs - The volume of the glucose standard solution consumed for calibrating 10 mL of alkaline copper tartrate solution (50% of solution A and 50% of solution B), in milligrams (mg).
6.4 The content of starch in the sample is calculated in accordance with the formula (6).
Where.
X - The content of starch in the sample, in gram per hundred grams (g/100 g);
0.9 - Conversion factor to convert the reducing sugar (in terms of glucose) into starch;
m - Sample mass, in grams (g).
When the result is < 1 g/100 g, the result is retained with two significant digits; AND when the result is ??? 1 g/100 g, the result is retained with three significant digits.
7 Precision
The absolute difference between the two independent determinations obtained under repeatability shall not exceed 10% of the arithmetic mean.
Metho...

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