Powered by Google www.ChineseStandard.net Database: 189760 (25 May 2024)

GB/T 12309-1990 PDF in English


GB/T 12309-1990 (GB/T12309-1990, GBT 12309-1990, GBT12309-1990)
Standard IDContents [version]USDSTEP2[PDF] delivered inName of Chinese StandardStatus
GB/T 12309-1990English360 Add to Cart 0-9 seconds. Auto-delivery. Industry corn starch


Standards related to: GB/T 12309-1990

GB/T 12309-1990: PDF in English (GBT 12309-1990)

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 it strongly until it boils. When there are no carbonized substances
attached to the bottle wall AND the liquid in the bottle is clear and light green,
continue heating for 30 minutes, to make it completely decompose (the above
operations shall be carried out in a fume hood).
b. Distillation: After the decomposition liquid is cooled, use distilled water to rinse
the glass funnel and the neck of the flask. Dilute it to 200 mL. Move the Kjeldahl
flask to the distillation stand. Connect a 500 mL conical flask under the condenser
tube, as a receiver. Pre-inject 50.0 mL of 2% boric acid solution and 10 drops of
mixed indicator solution. Insert the lower opening of the condenser tube into the
liquid in the conical flask. Then slowly add 70 ~ 100 mL of 40% sodium
hydroxide solution, along the neck wall of the Kjeldahl flask. Turn on the cooling
water. Immediately connect the distillation device. Shake the Kjeldahl flask
gently, to mix the solution evenly. Heat and distill it. Stop heating when the
distillate is 3/5 of the original volume. Make the lower end of the condenser tube
leave the conical flask. Use a small amount of water to rinse the condenser tube.
Combine the rinsing solution into the conical flask.
c. Titration: Use 0.05 mol/L sulfuric acid standard solution, to titrate the liquid in the
conical flask, to make the solution change from blue-green to gray-purple, which
is taken as the end point.
At the same time, perform a blank test.
4.3.6.5 Calculation
Where:
X6 - The protein content in the sample, %;
V1 - The volume of 0.05 mol/L sulfuric acid standard solution, which is consumed
to titrate the sample, mL;
V0 - The volume of 0.05 mol/L sulfuric acid standard solution, which is consumed
during the blank test, mL;
C - The concentration of sulfuric acid standard solution, mol/L;
m - The sample mass, g;
X1 - The moisture content of the sample, %;
6.25 - The factor for converting nitrogen to protein;
0.028 - The mass of nitrogen, which is equivalent to 1 mL of 1 mol/L sulfuric acid
standard solution, g.
4.3.6.6 Allowable difference
The difference in volume of sulfuric acid solution, which is consumed for two titrations
of the same sample, shall be less than 0.1 mL; the final result shall be kept to two
decimal places.
Note: If the trace nitrogen determination method is used, please refer to Appendix B (reference).
4.3.7 Fat
4.3.7.1 Principle
The fat in the sample is extracted by ether. Dry it, to obtain the percentage of the total
fat residue in the sample to the original sample mass.
4.3.7.2 Instruments
a. Soxhlet extractor;
b. Electric water bath;
c. Oven.
4.3.7.3 Reagents and materials
a. Anhydrous ether;
b. Filter paper tube and degreasing filter paper.
4.3.7.4 Test procedure
Accurately weigh 5 g of the absolute dry sample (accurate to 0.0001 g). Use the dried
degreased filter paper to wrap the sample. Place it in a filter paper tube. Place it into the
extraction tube of the Soxhlet extractor. Connect the extraction tube to a dried extraction
bottle of known mass. Pour ether into the extraction tube to above the height of the
siphon tube, to siphon the ether down. After two times, pour ether to 2/3 of the height
of the siphon tube. Install a condenser tube. Perform reflux extraction on a water bath
of distilled water, at 65 °C for 4 hours. Take out the filter paper tube. Recover ether,
until the residual liquid in the extraction bottle is 1 ~ 2 mL. Take off the extraction bottle.
Drive off the residual ether on a water bath. Clean the outside of the bottle. Place it in
an oven at 105 °C. Dry it to constant weight (the difference between the two weighing
shall not exceed 0.2 mg, taking the smaller weighing result).
4.3.8.5 Allowable difference
The difference between two titration values of the same sample shall be less than 0.02
mL; the final result shall be rounded to three decimal places.
4.3.9 Iron salts
4.3.9.1 Instruments
a. Conical flask: 200 mL;
b. Nessler colorimetric tube: 50 mL;
c. Quantitative filter paper.
4.3.9.2 Reagents
a. 30% ammonium thiocyanate solution;
b. Hydrochloric acid;
c. Ammonium persulfate;
d. Butanol;
e. Sulfuric acid;
f. Iron standard solution (1 mL = 10 µg): Prepare iron standard solution, according
to GB 602, 1 mL = 0.1 mg. When using, accurately dilute 10 folds.
4.3.9.3 Test procedure
Weigh 0.5 g of the sample (accurate to 0.0001 g). Place it in a 200 mL conical flask.
Add 15 mL of water and 2 mL of concentrated hydrochloric acid. Shake for 5 min. Filter
in a Nessler colorimetric tube. Use a small amount of water to wash the residue.
Combine the rinsing solution. Add 50 mg of ammonium persulfate. Use water to dilute
it to about 35 mL. Add 3 mL of ammonium thiocyanate solution. Add water to dilute to
the mark. Shake well.
Accurately draw 1.00 mL of iron standard solution (1 mL = 10 µg Fe) into another
Nessler colorimetric tube. Use the same method to make a control solution. Then
perform visual color comparison with the sample.
If the color tone of the specimen tube and the control tube are inconsistent, they can be
moved to the separating funnel, respectively. Add 20 mL of n-butanol. Shake and
extract and let it stand still. After stratification, move the n-butanol liquid layer into a
50 mL Nessler colorimetric tube. Then use n-butanol to dilute it to 25 mL. Carry out
color comparison.
4.3.9.4 Result Judgment
If the color of the specimen tube is lighter than that of the control tube, the iron salt
content is less than 0.002%. If the color of the specimen tube is darker than the control
tube, the iron salt content is greater than 0.002%; it is judged as unqualified.
Note: The instruments used in this test must be boiled with dilute nitric acid and rinsed with
deionized water.
5 Inspection rules
5.1 The starch, which is produced in the same production period, packaged and shipped
out, with the same batch number and the same quality certificate, forms the same batch
of products.
5.2 The manufacturer must carry out inspection batch by batch, according to the
provisions of this standard. It shall be accompanied by the product quality certificate,
which is issued by the quality inspection department, before leaving the factory.
5.3 When receiving the goods, the recipient has the right to take samples from the
product and conduct inspections, according to the provisions of this standard. If one of
the indicators does not meet the standard requirements, it shall take double quantity of
samples from the same batch of samples for re-inspection. The re-inspection results
shall prevail. If it still does not meet the standard requirements, the receiver can make
a request to the supplier, within 30 days after receiving the goods, OR as negotiated
between the supplier and the purchaser. In case of any dispute, the higher-level legal
quality inspection department can be requested to arbitrate. When the product conforms
to the standard, the sample and inspection costs shall be borne by the receiver; otherwise,
the supplier shall be responsible.
6 Labeling, packaging, transportation, storage
6.1 Product signs and labels
The label mark of the product shall be implemented, according to GB 7718. It shall
clearly mark the code of the standard grade of the starch product. The text content and
illustrations on the outer packaging shall comply with the standard GB 191.
6.2 Packaging
6.2.1 The packaging of the product must be of strong quality, with clear and tidy labels;
the mouth of the bag shall be sealed, to ensure no leakage during loading, unloading,
transportation and storage. Product packaging bags used in the food industry must also
meet food hygiene requirements.
......
 
Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.