Search Result of Chinese Standard: 'GB 5009.227-2016'
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Method for analysis of hygienic standard of edible oils
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GB 5009.227-2016
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GB 5009.227-2016 | Chinese | 15 |
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Detail Information of GB 5009.227-2016; GB5009.227-2016 Description (Translated English): Method for analysis of hygienic standard of edible oils Sector / Industry: National Standard Classification of Chinese Standard: X09 Word Count Estimation: 8,859 Date of Issue: 2016-08-31 Date of Implementation: 2017-03-01 Older Standard (superseded by this standard): SN/T 0801.3-2011; GB/T 5538-2005; GB/T 5009.37-2003 Regulation (derived from): Announcement of the State Administration of Public Health and Family Planning 2016 No.11
GB 5009.227-2016
(Food safety national standard - Determination of peroxide value in foods)
National Standards of People's Republic of China
National Food Safety Standard
Determination of peroxide value
Issued on: 2016-08-31
2017-03-01 implementation
People's Republic of China
National Health and Family Planning Commission released
Foreword
This standard replaces GB/T 5009.37-2003 "analysis of hygienic standard of edible vegetable oil" in the "4.2 peroxide value"
GB/T 5538-2005 "Determination of peroxide value over animal fats", SN/T 0801.3-2011 "export animal fat peroxide value check
Test methods. "
This standard and GB/T 5009.37-2003 as compared to "4.2 peroxide value", the main changes are as follows:
--- Standard name was changed to "national food safety standards in food Peroxide Value Determination";
--- Modify the concentration of the first law of sodium thiosulfate standard titration solution;
--- Remove the second method, "method", increasing the potentiometric titration method as the second;
--- Increasing the scope of application of the method;
--- Added "sample preparation" section.
National Food Safety Standard
Determination of peroxide value
1 Scope
This standard specifies two methods for determining the foods peroxide value: titration and potentiometric titration.
This standard is the first law applies to edible animal fats, edible oils and fats products, wheat flour, grains, nuts and other plant foods as raw material
Fried food, puffed, baked, modulation, frying and other processing process and made, as well as animal foods as raw material frozen, dried, salted, etc.
Processing and food made; second method is applicable to animal and plant oils and margarine, the measurement range is 0g/100g ~ 0.38g/100g.
This standard does not apply to the determination at the end of fat-sik and other embedded class oil products.
First titration method
Principle 2
Oil samples prepared in chloroform and dissolved in glacial acetic acid, wherein the reaction of peroxide and potassium iodide, sodium thiosulfate
Precipitation titration standard solution of iodine. Peroxide equivalent of iodine or 1kg mass fraction of active oxygen in the sample indicates the number of millimoles peroxide
Quantized values.
3 Reagents and materials
Unless otherwise indicated, the methods used were of analytical grade reagents and water for the three water GB/T 6682 regulations.
3.1 Reagents
3.1.1 glacial acetic acid (CH3COOH).
3.1.2 chloroform (CHCl3).
3.1.3 potassium iodide (KI).
3.1.4 sodium thiosulfate (Na2S2O3 · 5H2O).
3.1.5 petroleum ether: boiling range 30 ℃ ~ 60 ℃.
3.1.6 anhydrous sodium sulfate (Na2SO4).
3.1.7 soluble starch.
3.1.8 Potassium dichromate (K2Cr2O7): work reference reagents.
3.2 reagent preparation
3.2.1 chloroform - acetic acid mixture (volume ratio 40 60): Measure 40mL of chloroform, add 60mL glacial acetic acid, and mix.
3.2.2 saturated potassium iodide solution: Weigh 20g of potassium iodide was added 10mL freshly boiled cooled water, shake well and stored in a brown bottle and stored in a
Dark place back. To ensure a saturated solution of potassium iodide in the presence of crystallization. Check before use: in 30mL chloroform - acetic acid mixture
Saturated solution of potassium iodide was added 1.00mL and 2 drops of 1% starch indicator, if there is blue, and the need to use more than one drop of 0.01mo1/L
Sodium thiosulfate solution can be eliminated, this can not be used potassium iodide solution should be reconstituted.
3.2.3 1% starch indicator: Weigh 0.5g soluble starch, add a little water into a paste. Stirring, pour 50mL boiling water, cook
After boiling, stir, let cool reserve. Pro preparation before use.
3.2.4 Processing of petroleum ether: petroleum ether to take 100mL distillation flask, below 40 ℃ water bath, using a rotary evaporator under reduced pressure to dryness.
With 30mL chloroform - acetic acid mixture was washed several times retort, combined washing liquid in 250mL iodine bottle. Join accurately
After 1.00mL saturated solution of potassium iodide, stoppered bottle and gently shaking 0.5min, placed in the dark 3min, add 1.0mL starch indicator
Mix, without blue appears this petroleum ether for sample preparation; such as after adding 1.0mL mix blue starch indicator appears, replace
Reagents.
3.3 Standard Solution
3.3.1 0.1mo1/L sodium thiosulfate standard solution: Weigh 26g sodium thiosulfate (Na2S2O3 · 5H2O), plus 0.2g of anhydrous carbonate
Sodium, dissolved in 1000mL of water, slowly boiled 10min, cooled. After filtration for two weeks, calibration.
3.3.2 0.01mo1/L sodium thiosulfate standard solution: from 3.3.1 to freshly boiled cooled water diluting. Pro preparation before use.
3.3.3 0.002mo1/L sodium thiosulfate standard solution: from 3.3.1 to freshly boiled cooled water diluting. Pro preparation before use.
4 instruments and equipment
4.1 iodine bottle: 250mL.
4.2 Buret: 10mL, minimum scale 0.05mL.
4.3 Buret: 25mL or 50mL, minimum scale 0.1mL.
4.4 Balance: a sense of the amount of 1mg, 0.01mg.
4.5 electric oven.
4.6 rotary evaporator.
Note: All vessels used in this process must not contain reducing or oxidizing substances. Frosted glass surface can not be oiled.
Step 5 Analysis
5.1 Sample Preparation
Sample preparation should avoid bright light and to avoid as far as possible into the air.
5.1.1 oil plants and animals
For liquid samples, shaking the closed container containing the sample directly after sampling sufficiently uniform; for solid samples, select the sample set has representative
After mixing the sample in a closed container.
5.1.2 Oil Products
5.1.2.1 edible hydrogenated oil, shortening, cocoa butter substitutes
For liquid samples, shaking the closed container containing the sample, mix well and direct sampling; for solid samples, select the sample set has representative
After mixing the sample in a closed container. If necessary, a closed container filled with solid sample placed in a thermostatic oven was slowly warmed to just
Can melt, shaking mixing, the sample was measured immediately take advantage of the sample is liquid.
5.1.2.2 margarine
The sample is placed in a sealed container in the oven temperature 60 ℃ ~ 70 ℃ was heated to melt, shaking after mixing and heating was continued to break
Milk layers were separated and the oil layer by rapid qualitative filter paper into a beaker of samples to be tested in the filtrate. Preparation of samples to be tested should be clarified.
While the test sample is a liquid sample was measured immediately.
5.1.3 wheat flour, grains, nuts and other plant foods as raw, fried, puffed, baked, modulation, frying and other processing of foods made
All samples taken from the taking of representative samples of the edible parts, ground in a glass mortar, the crushed sample was placed in jar
Added 2 to 3 times the sample volume of petroleum ether (3.2.4), shake and let stand after mixing the above extraction 12h, by containing anhydrous sodium sulfate
Funnel, the filtrate, below 40 ℃ water bath, using a rotary evaporator under reduced pressure to dryness petroleum ether, the residue sample is to be tested.
5.1.4 In animal foods as raw material frozen, dried, salted processing technology made food
Remove all the samples taken from a representative sample of the edible portion, after it is crushed and mixed thoroughly into the jar, add 2 ~
3 times the sample volume of petroleum ether (3.2.4), shake thoroughly mixed extraction 12h after standing over by the funnel containing anhydrous sodium sulfate was filtered,
The filtrate, below 40 ℃ water bath, using a rotary evaporator under reduced pressure to dryness petroleum ether, the residue sample is to be tested.
5.2 Determination of the sample
Avoid direct sunlight measured sample. Weigh the sample prepared in "5.1.1 ~ 5.1.4" 2g ~ 3g (accurate to 0.001g),
Placed in 250mL iodometric flask, 30mL chloroform - acetic acid mixture, gently shaking the sample is completely dissolved. Join accurately
1.00mL saturated solution of potassium iodide, stoppered bottle and gently shaking 0.5min, placed in the dark 3min. Remove add 100mL water, shake
Immediately after the sodium thiosulphate standard solution (peroxide value estimates at below 0.15g/100g and with 0.002mol/L standard solution;
When the value is greater than the estimated value peroxide 0.15g/100g, with 0.01mol/L standard solution) precipitated iodine titration, titration to pale yellow, add 1
mL of starch indicator and continue the titration to the solution and strongly shaken disappearance of the blue as the end point. At the same time a blank test. Consumed blank test
0.01mo1/L sodium thiosulfate solution should not exceed the volume V0 0.1mL.
6 expression analysis
6.1 peroxide equivalent iodine content represents peroxide value, according to equation (1):
X1 =
(V-V0) × c × 0.1269
m × 100
(1)
Where:
X1 --- peroxide value in grams per hundred grams (g/100g);
Sodium thiosulfate standard solution volume V --- sample consumed in milliliters (mL);
V0 --- blank test sodium thiosulfate standard solution volume consumed in milliliters (mL);
c --- sodium thiosulfate standard solution concentration, in units of moles per liter (mol/L);
.1269 --- And 1.00mL sodium thiosulfate standard titration solution [c (Na2S2O3) = 1.000mol L /] equivalent to the mass of iodine;
m --- sample mass, in grams (g);
100 --- conversion factor.
The arithmetic mean of the results obtained with the two under the same condition of independent measurement results represent the results to two significant figures.
6.2 expressed as millimoles active oxygen 1kg sample peroxide value, according to equation (2):
X2 =
(V-V0) × c
2 × m ×
1000 (2)
Where:
X2 --- peroxide value, in millimoles per kilogram (mmol/kg);
Sodium thiosulfate standard solution volume V --- sample consumed in milliliters (mL);
V0 --- blank test sodium thiosulfate standard solution volume consumed in milliliters (mL);
c --- sodium thiosulfate standard solution concentration, in units of moles per liter (mol/L);
m --- sample mass, in grams (g);
1000 --- conversion factor.
The arithmetic mean of the results obtained with the two under the same condition of independent measurement results represent the results to two significant figures.
7 precision
Two independent determination results under the absolute difference in repeatability condition must not exceed 10% of the arithmetic mean.
The second method potentiometric titration
Principle 8
Oil sample preparation was dissolved in iso-octane and glacial acetic acid in the sample peroxide reacts with potassium iodide iodine, after reaction with thiosulfate
Precipitation titration standard solution of sodium iodide, potentiometric titrator determine the endpoint. Peroxide equivalent iodine content or 1kg sample
Millimoles of active oxygen in the product expressed amount of peroxide value.
9 Reagents and materials
Unless otherwise indicated, the methods used were of analytical grade reagents. Water for the three water GB/T 6682 regulations.
9.1 Reagents
9.1.1 glacial acetic acid (CH3COOH).
9.1.2 iso-octane (C8H18).
9.1.3 Potassium iodide (KI).
9.1.4 sodium thiosulfate (Na2S2O3 · 5H2O).
9.1.5 Potassium dichromate (K2Cr2O7): work reference reagents.
9.2 reagent preparation
9.2.1 isooctane - glacial acetic acid mixture (4060): isooctane amount of 40mL, plus 60mL glacial acetic acid, and mix.
9.2.2 saturated potassium iodide solution: Weigh 20g of potassium iodide was added 10mL freshly boiled cooled water, shake well and stored in a brown bottle and stored in a
Dark place back. To ensure a saturated solution of potassium iodide in the presence of crystallization. Check before use: in 30mL isooctane - a mixture of glacial acetic acid
(9.2.1) was added 0.5mL saturated solution of potassium iodide and 2 drops of 1% starch indicator, if there is blue, and required 0.01mo1/L thiosulfate
Sodium sulfate solution to eliminate more than one drop of this solution should be reconstituted.
9.3 Standard Solution
9.3.1 0.1mo1/L sodium thiosulfate standard solution: Weigh 26g sodium thiosulfate (Na2S2O3 · 5H2O), plus 0.2g of anhydrous carbonate
Sodium, dissolved in 1000mL of water, slowly boiled 10min, cooled. After filtration for two weeks, calibration.
9.3.2 0.01mo1/L sodium thiosulfate standard solution: from 9.3.1 to freshly boiled cooled water diluting. Pro preparation before use.
10 instruments and equipment
10.1 Analytical Balance: a sense of the amount of 1mg, 0.01mg.
10.2 electric oven.
10.3 potentiometric titrator: accuracy of ± 2mV; can show the potential value of the titration process in real time - volume titration curves; compound with platinum ring
Oxide electrodes or other similar indication function reduction electrode and 10mL, 20mL burette with the titration head of non-proliferation.
10.4 magnetic stirrer.
Note: All containers used must not contain reducing or oxidizing substances. Frosted glass surface can not be oiled.
11 analysis steps
11.1 Sample Preparation
Sample preparation with "5.1.1 ~ 5.1.2."
Note: The sample preparation should be avoided in direct sunlight.
11.2 Determination of the sample
Weigh oil samples 5g "5.1.1 ~ 5.1.2" prepared (accurate to 0.001g) in titrator titration cup, add 50mL
Isooctane - glacial acetic acid mixture, gently shaking the sample is completely dissolved. If the sample is less soluble (such as stearic or animal fat), may first
Isooctane was added 20mL titration cup, gently shaking to dissolve the sample, plus 30mL glacial acetic acid and mix.
Was added to the titration cell accurately 0.5mL saturated potassium iodide solution, starting with a magnetic stirrer, and the reaction was stirred at an appropriate speed 60s ±
1s. Now added to the titration cell 30mL ~ 100mL of water, insert the electrode and the titration head, titration set parameters, run the titration procedure, mining
Titration titration with dynamic mode and observe the titration curve and potential changes, sodium thiosulfate standard solution Dosing volume control in general
0.05mL/drop ~ 0.2mL/drops. After reaching the end of the titration, the titration end point recording standard solution volume consumed V. A sample of each completed
After titration, shall stirrer or magnetic stir, titration heads and electrode immersed in isooctane clean grease from the surface.
At the same time a blank test. Using the same amount of titration titration mode and observe the titration curve and potential changes, sodium thiosulfate standard solution
Liquid dosing is generally controlled 0.005mL/drops. After reaching the end of the titration, the recording volume V0 standard solution titration end consumption. Blank test
Inspection consumed 0.01mo1/L sodium thiosulfate solution volume V0 not exceed 0.1mL.
Note 1: To ensure that the sample mix without bubbles affect electrode response. According to the guidance of the manufacturer's instructions and choose a suitable stirring speed.
Note 2: The instrument can be adjusted according to the amount of water, the amount of water will affect the initial potential, but does not affect the measurement results. It is located on the lower titration phase, a greater amount of
Water is conducive to phase inversion, the greater the amount of water, the greater the potential difference between the titration start and end point of the titration, the inflection point on the titration curve more pronounced.
Note 3: Avoid direct sunlight measured sample.
12 analysis results presentation
When peroxide is equivalent to 12.1 with iodine content r......
Related standard: GB 5009.241-2017
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