GB/T 12309-1990 English PDF (GBT12309-1990)

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GB/T 12309-1990: Industry corn starch
GB/T 12309-1990 (GB 12309-1990)
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
GB/T 12309-1990
Industry corn starch
工业玉米淀粉
ISSUED ON: APRIL 09, 1990
IMPLEMENTED ON: DECEMBER 01, 1990
Issued by: State Bureau of Technical Supervision
Table of Contents
1 Subject content and scope of application ... 3 
2 Normative references ... 3 
3 Technical requirements ... 3 
4 Test method ... 4 
5 Inspection rules ... 15 
6 Labeling, packaging, transportation, storage ... 15 
Appendix A SBN type starch spot counter (Supplement) ... 17 
Appendix B Trace nitrogen determination (Reference) ... 19 
Additional information ... 21 
Industry corn starch
1 Subject content and scope of application
This standard specifies the technical requirements, test methods, inspection rules,
product marking, packaging, transportation, storage of industrial corn starch.
This standard applies to industrial corn starch, which is made from corn as raw material,
through wet milling.
2 Normative references
GB 191 Packaging - Pictorial markings for handling of goods
GB 601 Chemical reagent - Preparations of standard volumetric solutions
GB 602 Chemical reagent - Preparations of standard volumetric solutions
GB 603 Chemical reagent - Preparations of reagent solutions for use in test methods
GB 604 Chemical reagent - General method for the determination of pH ranges
corresponding the colour transition of acid-base indicators
GB 7718 General standard for the labelling of foods
3 Technical requirements
3.1 Sensory requirements
See Table 1 for sensory requirements.
3.2 Physical and chemical requirements
The physical and chemical requirements are as shown in Table 2.
4.2 Sensory test
4.2.1 Appearance
Observe the color of the sample with the naked eye, under moderate light and shade.
Then observe the gloss of the sample, under strong sunlight.
4.2.2 Odor
Take 20 g of starch sample. Put it into a 100 mL ground-mouth bottle. Add 50 mL of
warm water at 50 °C. Cover it. Shake it for 30 s. Pour out the supernatant. Smell it.
4.3 Physical and chemical tests
4.3.1 Moisture (oven method)
4.3.1.1 Principle
Put the sample in an oven at 131 ± 2 °C. Measure the mass loss of the sample, after
drying.
4.3.1.2 Instruments
a. Electric drying oven: 131 ± 2 °C;
b. Aluminum box (or weighing bottle): Diameter 40 ~ 50 mm;
c. Desiccator: Use color-changing silica gel as desiccant.
4.3.1.3 Test procedure
Use an aluminum box (or weighing bottle), which has reached constant weight, to
weigh 4 ~ 5 g of the sample (accurate to 0.0001 g). Place it in an oven at 131 ± 2 °C.
Put the cover against the aluminum box (or weighing bottle). Take it out after drying
for 40 min. Quickly cover it. Put it in the desiccator. Cool it for 30 min to room
temperature. Weigh it (within 2 min).
4.3.1.4 Calculation
Where:
X1 - The moisture content of the sample, %;
m0 - The mass of the sample, g;
m1 - The mass of the sample and the aluminum box (or weighing bottle) before
drying, g;
m2 - The mass of the sample and the aluminum box (or weighing bottle) after drying,
g.
4.3.1.5 Allowable difference
The difference between two measurements of the same sample shall be less than 0.2%;
the result shall be kept to one decimal place.
4.3.2 Fineness
4.3.2.1 Principle
The sample is sieved by a sample sieve, to obtain the mass of the sample, which passes
through the sample sieve.
4.3.2.2 Instruments
100-mesh sieve.
4.3.2.3 Test procedure
Weigh 50 g of the sample (accurate to 0.01 g). Place it in a 100-mesh sieve. Cover it.
Use an oscillator or hand, to shake it vigorously. Pour it out carefully after sieving.
Weigh the residue on the sieve.
4.3.2.4 Calculation
Where:
X2 - The fineness of the sample, %;
m0 - The mass of the sample, g;
m1 - The mass of the residue on the sieve, g.
4.3.2.5 Allowable difference
The difference between the two measured values of the same sample shall be less than
0.2%; the result shall be kept to one decimal place.
4.3.3 Spots
4.3.3.1 Principle
according to GB 601;
b. The 1% phenolphthalein indicator solution: It is prepared according to GB 604.
4.3.4.4 Test procedure
Weigh 10 g of the sample (accurate to 0.01 g). Put it in a conical flask or a beaker. Add
100 mL of carbon dioxide-free distilled water, which has been boiled and cooled in
advance, as well as 5 ~ 8 drops of phenolphthalein indicator solution. Shake well. Use
0.1 mol/L sodium hydroxide standard solution for titration. When approaching the end
point, add 3 ~ 5 drops of phenolphthalein indicator solution. Continue titration, until
the solution is slightly pink, meanwhile the color does not fade for 30 seconds, which
is taken as the end point. At the same time, perform a blank test.
4.3.4.5 Calculation
Where:
X4 - The milliliters of 0.1 mol/L sodium hydroxide standard solution, which is
consumed to neutralize 100 g of dry starch, in mL;
V1 - The volume of 0.1 mol/L sodium hydroxide standard solution, which is
consumed during titration, in mL;
V0 - The volume of 0.1 mol/L sodium hydroxide standard solution, which is
consumed by the blank test, in mL;
C - The concentration of sodium hydroxide standard solution, in mol/L;
m - The mass of the sample, g;
X1 - The moisture content of the sample, % (m/m).
4.3.4.6 Allowable difference
The difference between two titration values of the same sample shall be less than 0.2
mL; the final calculation result shall be kept to one decimal place.
4.3.5 Ash content
4.3.5.1 Principle
Place the sample in a muffle furnace, at a temperature of 550 ± 25 °C for ashing, to
obtain the mass of the residue after ashing of the sample.
4.3.5.2 Instruments
a. Crucible: 50 mL;
b. Muffle furnace: 550 ± 25 °C.
4.3.5.3 Test procedure
Use a crucible with known constant weight, to weigh 2 ~ 3 g (accurate to 0.0001 g) of
the mixed sample. Carefully carbonize it on the electric furnace. Then put it into the
muffle furnace. Burn it at 550 ± 25 °C, until the residue has no black carbon particles
(about 2 h); the residue is white or off-white powder. Turn off the power. When the
temperature drops to 200 °C, take out the crucible. Place it in a desiccator. Cover it.
Cool it for 30 minutes. Weigh it. Burn it under the above conditions for 0.5 h. Cool
down. Weigh it, until it reaches constant weight (the difference between the two
weighing is less than 0.2 mg).
4.3.5.4 Calculation
Where:
X5 - The ash content of the sample, %;
m1 - The mass of the residue after burning, g;
m - The mass of the sample, g;
X1 - The moisture content of the sample, %.
4.3.5.5 Allowable difference
The difference between the two measured values of the same sample shall be less than
0.02%; the results shall be kept to two decimal places.
4.3.6 Protein
4.3.6.1 Principle
Under the action of the catalyst, decompose the sample by sulfuric acid. Then neutralize
the sample solution, to distill to release ammonia. Collect it by boric acid. Then titrate
it by a calibrated sulfuric acid solution, to obtain the consumption of sulfuric acid.
Convert it into nitrogen content.
4.3.6.2 Instruments
beads. Shake the flask gently, to make the sample completely wet. Then put the
Kjeldahl flask on the support, at an angle of 45 degrees. Cover a glass funnel to
the bottle mouth. Use an electric furnace, to start to heat it slowly. When the foam
disappears, heat ...