GB 5009.229-2016 English PDF (GB5009.229-2016)

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GB 5009.229-2016: National food safety standard - Determination of Acid Value in Foods
GB 5009.229-2016
(Food safety national standard - Determination of acid value in foods)
National Standards of People's Republic of China
National Food Safety Standard
Determination of acid 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 "4.1", and also replaced
GB/T 5009.44-2003 "meat and meat products analysis of hygienic standard" in the "14.3", GB/T 5009.56-2003 "standard pastry Health
Analysis quasi "in" 4.1 "" 4.2 "" 4.3 ", GB/T 5009.77-2003" edible hydrogenated oils, margarine analysis of hygienic standard "
The "4.1", GB/T 15689-2008 "Determination of acidity oil plant oil", GB/T 14489.3-1993 "fat free oil in oil
Determination of fatty acid content "and GB/T 5530-2005" Animal and vegetable fats - Determination of acid value and acidity. "
This compared with the standard GB/T 5009.37-2003 of "4.1", the main changes are as follows.
--- Standard name was changed to "national food safety standards of food Determination of acid value";
--- Modify the scope of the standard;
--- Modify the phenolphthalein indicator titration method as the first method, that is cold solvent indicator titration;
--- Increased cold solvent for the second automatic potentiometric titration method;
--- Ethanol increases the thermal indicator titration method for the third;
--- Increasing the norm sample preparation food samples;
--- Increasing the specimen sample weight requirements;
--- Modify the precision requirements.
National Food Safety Standard
Determination of acid value
1 Scope
This standard specifies the method for the determination of three kinds of food acid value --- cold solvent indicator titration method (first method), automatic electric cold solvent
Titration (Method II) and hot ethanol indicator titration method (third method).
The first method is suitable for cold solvent at room temperature can be completely dissolved into the sample solution to clarify edible oils and fats, including the scope of edible plants
Oil (except chili oil), edible animal oil, hydrogenated edible oil, shortening, margarine, whipped cream, vegetable oil a total of seven categories.
The second method is suitable for cold solvent at room temperature can be completely dissolved into a clear solution of edible fats and oil samples extracted fat food
Samples, including the scope of edible vegetable oils (including chili oil), edible animal oil, hydrogenated edible oil, shortening, margarine, whipped cream,
Plant oil, fried snack foods, puffed food, baked fried food, nuts, pastries, bread, biscuits, fried noodles, nuts and seeds sauce,
Animal aquatic dried products, cured meat products, edible oil chili sauce added a total of 19 categories.
The third method is suitable for cold solvent at room temperature can not be completely dissolved into the sample solution to clarify edible oils and fats, including the scope of edible plants
Oil, edible animal oil, hydrogenated edible oil, shortening, margarine, whipped topping a total of six categories.
The first cold solvent indicator titration method
Principle 2
With an organic solvent to dissolve the oil sample into the sample solution, and then potassium hydroxide or sodium hydroxide standard titration solution and titrate the sample solution
Solution of free fatty acids to the corresponding color change indicator to determine the titration end point, final consumption by the end of the titration standard titration solution
The volume of oil calculated acid value of the sample.
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 isopropanol (C3H8O).
3.1.2 ether (C4H10O).
3.1.3 methyl tert-butyl ether (C5H12O).
3.1.4 95% ethanol (C2H6O).
3.1.5 phenolphthalein (C20H14O4), indicator, CAS. 77-09-8.
3.1.6 thyme phenolphthalein (C28H30O4), indicator, CAS. 125-20-2.
3.1.7 Basic Blue 6B (C37H31N3O4), indicator, CAS. 1324-80-7.
3.1.8 Anhydrous sodium sulfate (Na2SO4), at 105 ℃ ~ 110 ℃ drying conditions sufficient, then cooled and stored in sealed containers.
3.1.9 anhydrous ether (C4H10O).
3.1.10 petroleum ether, 30 ℃ ~ 60 ℃ boiling range.
3.2 reagent preparation
3.2.1 Potassium hydroxide or sodium hydroxide standard titration solution concentration of 0.1mol/L or 0.5mol/L, according to GB/T 601 standard to
Seeking preparation and calibration can be purchased commercially commercialized reagents.
3.2.2 ether - a mixture of isopropanol. isopropyl ether = 1 1,500mL diethyl ether and 500mL isopropanol mixed sufficiently miscible,
The time is now equipped with.
3.2.3 phenolphthalein indicator. Weigh 1g phenolphthalein added 100mL of 95% ethanol and stir until completely dissolved.
3.2.4 thyme phenolphthalein indicator. Weigh 2g thyme phenolphthalein added 100mL of 95% ethanol and stir until completely dissolved.
3.2.5 alkali blue 6B indicator. Weigh 2g of alkali blue 6B, 100mL of 95% ethanol was added and stirred until completely dissolved.
4 instruments and equipment
4.1 10mL microburette. minimum scale 0.05mL.
4.2 Balance. a sense of the amount of 0.001g.
4.3 constant temperature water bath.
4.4 Ovens.
4.5 Centrifuge. maximum speed of not less than 8000r/min.
4.6 rotary evaporator.
4.7 Soxhlet fat extraction apparatus.
4.8 plant oil mill or grinder.
Step 5 Analysis
5.1 Sample Preparation
Edible oils and fats 5.1.1 Preparation of the sample
If the edible oil directly at the sample is liquid at room temperature, and a clear liquid, then mix well after sampling, otherwise in accordance with the requirements of Appendix A feed
Line impurity and dehydration process; if the edible oils and fats are solid at room temperature samples, prepared in accordance with Appendix B; if the sample is emulsified processed food
Grease is prepared in accordance with Appendix C.
5.1.2 Preparation of plant oil sample
First with a grinder or a grinder to plant oil crushed into fine particles of uniform, high brittleness of plant oil (such as soybean, sunflower, cotton
Seed, rapeseed, etc.) should be crushed to a particle size of 0.8mm ~ 3mm even smaller fine particles, and lower brittleness plant oil (such as copra, palm
Palm kernel, etc.) should be ground to a particle size of not more than 6mm particles. Meanwhile, if significant fever, should be in accordance with Appendix D D.3 pulverized.
Plant oil charged fine particles get crushed Soxhlet fat extraction device, then add the appropriate amount of extraction solvent (3.1.9 or 3.1.10), plus
Hot and reflux extraction 4h. Finally, collect and combine all extracts in a flask and the water bath temperature not higher than 45 ℃ rotary evaporation
Within the instrument issued under 0.08MPa ~ 0.1MPa vacuum conditions, wherein the solvent rotary evaporated completely, the residual liquid oils taken as a sample inlet
Bank acid value determination.
If the residual turbid liquid oil, emulsifying, hierarchical or precipitation, impurity and dehydration should be treated in accordance with the requirements of Appendix A of.
5.2 Sample Weighing
Samples were prepared according to the color and the estimated acid value, in accordance with the provisions in Table 1 sample is measured.
Table 1 Sample said sample form
Estimated acid value
mg/g
The minimum sample sample weight
Concentration titrant
mol/L
The accuracy of the sample weighed
0 ~ 120 0.05 0.1
1 - 410 0.1 0.02
4 2.5 0.1 0.01 15 ~
15 ~ 75 ~ 3.0 0.1 or 0.5 0.5 0.001
> 0.2 to 1.0 0.5 0.001 75
Sample sample weight and the concentration of titrant titrant should be in an amount between 0.2mL ~ 10mL (after deducting the blank). If it is detected and found
Samples of the actual sample weight and acid value of the sample corresponding to the proper sample weight does not match the requirements shall be in accordance with Table 1, said the adjustment after re-testing the sample volume.
5.3 Determination of the sample
Take a clean 250mL Erlenmeyer flask, in accordance with the requirements of 5.2, said oil samples taken with the preparation of the balance, which is the unit mass m
G. Ether was added - a mixture of 50mL ~ 100mL of isopropanol and 3 drops to 4 drops of phenolphthalein indicator, sufficiently shaken to dissolve the sample. Then loaded
Standard titration solution (3.2.1) scale buret manually titrated sample solution when the sample solution is now beginning reddish, and no inner 15s
When can fade as the end point of the titration. Immediately stop the titration, in milliliters consumed in this titration standard titration solution of record, this value
To V.
For grease sample deep color, available thyme phenolphthalein indicator or alkaline blue 6B indicator substituted phenolphthalein indicator, titration, when
When the color changes to blue to red to blue by titration end thyme phenolphthalein titration end alkaline blue 6B indicator. Rice bran oil (rice
Determination of acid value can only use alkaline blue 6B indicator meter oil) cold solvent indicator method.
5.4 blank test
The other to take a clean 250mL Erlenmeyer flask, accurately and added to 5.3 when measured in the same sample volume, the same type of organic solvent
Mixture (3.2.2) and indicator (3.2.3,3.2.4 or 3.2.5) and shake to mix. Then use titration with a standard solution (3.2.1) scale drip
Tube set for manual titration, when beginning now reddish solution, and no obvious discoloration in the 15s, the end point of the titration. Titration immediately stop recording
Under milliliters consumed in this titration standard titration solution, this value is V0.
For the cold solvent indicator titration method can also be formulated to dissolve the sample solution (3.2.2) was added a few drops of indicator (or 3.2.3,3.2.4
3.2.5), then titrated with a standard solution (3.2.1) titration sample lysate corresponding to a color change in the 15s and no fade after stopping drops
Set, indicating that the sample was dissolved in acid and just be. Then such acid is dissolved in the oil sample and the sample was dissolved solution, using the same
The method continues with the titration of the sample solution to the appropriate color change and no appreciable fade within 15s after stop titration, titration record this consumption
Milliliters of standard titration solution, this value is V, so no further blank test, that V0 = 0.
6 expression analysis
The acid value (also known as acid number) in accordance with the requirements of the formula (1) is calculated as follows.
XAV =
(V-V0) × c × 56.1
(1)
Where.
XAV --- acid value, in milligrams per gram (mg/g);
Volume V --- measurement sample standard titration solution consumed in milliliters (mL);
Titration standard volume V0 --- corresponding blank determination consumed solution in milliliters (mL);
c molar concentration --- standard titration solution, expressed in moles per liter (mol/L);
56.1 --- molar mass of potassium hydroxide in grams per mole (g/mol);
Sample weight m --- oil sample in grams (g).
Acid value ≤1mg/g, calculation 2 decimal places; 1mg/g < acid value ≤100mg/g, the calculation result retained a decimal; acid
Price> 100mg/g, calculation reserved to the nearest whole number.
7 precision
When the acid value < 1mg/g, the two independent determination results obtained under repeated conditions shall not exceed the arithmetic mean of the absolute difference
15%; when the acid value ≥1mg/g, the two conditions under repeated independent determination results obtained shall not exceed the arithmetic mean absolute difference
Value of 12%.
The second method of cold solvent automatic potentiometric titration
Principle 8
Food samples extracted from the oil (pure oil sample directly sampled) as a sample with an organic solvent to dissolve the oil sample into a sample
Solution, and then potassium or sodium hydroxide standard titration solution, titration of free fatty acids in the sample solution, and titration process
The pH of the sample solution and draw the corresponding changes in the volume of real-time changes of pH- titration curve and its first derivative curve, in order to free fatty acids occur
The reaction caused by the "pH jump" is determined based on the titration end point, the volume of standard solution of final consumption of oil by titration endpoint computing
Fat acid value of the sample.
9 Reagents and materials
Unless otherwise indicated, the methods used were of analytical grade reagents and water for the three water GB/T 6682 regulations.
9.1 Reagents
Nitrogen (N2), a purity of> 99.99%.
9.2 Material
Speed qualitative filter paper.
10 instruments and equipment
10.1 automatic potentiometric titrator. pH electrode with automatic correction function, dynamic titration mode function; by computer control, real-time automatic drawing
And real-time volume record pH- titration curve and corresponding first derivative of the titration curve; titration accuracy should reach 0.01mL/drops, Telecommunications
No measurement accuracy of 0.1mV; titration Dosing tube with 20mL of; burette at the outlet of the head with non-proliferation.
10.2 non-aqueous acid-base titration special combination pH electrode. The Ag/AgCl internal reference electrode, a mobile sleeve diaphragm and electromagnetic screen
Shield function. An internal reference solution of 2mol/L ethanol solution of lithium chloride.
10.3 magnetic stirrer, magnetic stirrer with Teflon.
10.4 masher or food mill.
10.5 Organization-wide stainless steel masher with 1L ~ 2L all stainless steel cup mashed organization, at least speed up to 10000r/min.
10.6 porcelain mortar.
10.7 sieve hole. pore size of 2.5mm.
11 analysis steps
11.1 Sample Preparation
11.1.1 Preparation of edible oil samples
With 5.1.1.
11.1.2 Preparation of plant oil sample
With 5.1.2.
11.1.3 oily food sample preparation
11.1.3.1 sample separation and removal of different parts of the
For fillings and coatings containing foods (such as some types of bread, cakes, cookies, etc.), should be filling and coating and other food
The edible p...