GB 5009.227-2023 PDF EnglishUS$155.00 · In stock · Download in 9 seconds
GB 5009.227-2023: National food safety standard - Determination of peroxide value in foods Delivery: 9 seconds. True-PDF full-copy in English & invoice will be downloaded + auto-delivered via email. See step-by-step procedure Status: Valid GB 5009.227: Historical versions
Similar standardsGB 5009.227-2023: National food safety standard - Determination of peroxide value in foods---This is an excerpt. Full copy of true-PDF in English version (including equations, symbols, images, flow-chart, tables, and figures etc.), auto-downloaded/delivered in 9 seconds, can be purchased online: https://www.ChineseStandard.net/PDF.aspx/GB5009.227-2023GB NATIONAL STANDARD OF THE PEOPLE'S REPUBLIC OF CHINA National food safety standard - Determination of peroxide value in food Issued on. SEPTEMBER 6, 2023 Implemented on. MARCH 6, 2024 Issued by. National Health Commission of the People's Republic of China; State Administration for Market Regulation. Table of ContentsForeword... 3 1 Scope... 4 Method A - Indicator titration method... 4 2 Principle... 4 3 Reagents and materials... 4 4 Instruments and equipment... 6 5 Analysis steps... 6 6 Presentation of analysis results... 8 7 Precision... 10 Method B - Potentiometric titration... 10 8 Principle... 10 9 Reagents and materials... 10 10 Instruments and equipment... 11 11 Analysis steps... 11 12 Presentation of analysis results... 12 13 Precision... 12ForewordThis standard replaces GB 5009.227-2016 "National food safety standard - Determination of peroxide value in food". Compared with GB 5009.227-2016, the main changes in this standard are as follows. -- The scope of Method A "Indicator titration method" is modified; -- The sample preparation for non-dairy cream and powdered oil products is added. National food safety standard - Determination of peroxide value in food1 ScopeThis standard specifies the method for the determination of peroxide value in food. Method A is suitable for the determination of peroxide value in food. Method B is suitable for the determination of peroxide value in edible animal and vegetable oils, fats, and margarine. Method A - Indicator titration method2 PrincipleThe prepared oil and fat sample is dissolved in chloroform-glacial acetic acid solution, the peroxide reacts with potassium iodide to generate iodine, and the precipitated iodine is titrated with sodium thiosulfate standard titration solution. The amount of peroxide value is expressed as the mass fraction of peroxide equivalent to iodine or the number of millimoles of active oxygen in 1 kg of the sample.3 Reagents and materialsUnless otherwise stated, the reagents used in this method are of analytical grade, and the water is the third-grade water specified in GB/T 6682. 3.1 Reagents 3.1.1 Glacial acetic acid (CH3COOH). 3.1.2 Trichloromethane (CHCl3). 3.1.3 Potassium iodide (KI). 3.1.4 Petroleum ether. The boiling range is 30 ℃~60 ℃. Confirmation of petroleum ether. Take 100 mL of petroleum ether in a rotary evaporation bottle, and evaporate to dryness under reduced pressure by using a rotary evaporator in a water bath not higher than 40 °C. Wash the rotary evaporation bottle several times with 30 mL of chloroform-glacial acetic acid solution, and combine the washing liquid into a 250 mL iodine flask. Accurately add 1.00 mL of saturated potassium iodide solution, plug the bottle cap tightly, and shake gently for 0.5 min. Leave it in a dark place for 3 min, add 1.0 mL of starch indicator, and mix well. If no blue color appears, this petroleum ether can be used for the sample preparation; If a blue color appears after adding 1.0 mL of starch indicator and mixing, the reagent needs to be replaced. 3.1.5 Anhydrous sodium sulfate (Na2SO4). 3.1.6 Soluble starch. 3.1.7 Acetone (CH3COCH3). 3.1.8 Amylase (CAS number. 9000-92-4). The enzyme activity is ≥2000 U/g. 3.1.9 Papain (CAS number. 9001-73-4). The enzyme activity is ≥6000 U/mg. 3.1.10 Sodium thiosulfate (Na2S2O3 • 5H2O). 3.2 Reagent preparation 3.3 Preparation of standard solution 3.3.1 Sodium thiosulfate standard titration solution (0.1 mo1/L). It shall be prepared and calibrated in accordance with the requirements of GB/T 5009.1; or a standard titration solution with national certification and a Reference Material Certificate. 3.3.2 Sodium thiosulfate standard titration solution (0.01 mo1/L). It is prepared from diluting 0.1 mo1/L sodium thiosulfate standard titration solution with newly boiled and cooled water. Prepare the solution fresh just before use. 3.3.3 Sodium thiosulfate standard titration solution (0.002 mo1/L). It is prepared from diluting 0.01 mo1/L sodium thiosulfate standard titration solution with newly boiled and cooled water. Prepare the solution fresh just before use.4 Instruments and equipment4.1 Balance. The sensitivities are 0.01 g, 0.001 g, and 0.0001 g, respectively. 4.2 Electric constant-temperature drying oven. 4.3 Rotary evaporator. It is equipped with a brown rotary evaporation bottle. 4.4 Constant-temperature water bath oscillator. 4.5 High-speed refrigerated centrifuge. 4.6 Overhead stirrer. 4.7 Burette. The capacity is 10 mL, and the minimum scale is 0.05 mL. 4.8 Burette. The capacity is 25 mL or 50 mL, and the minimum scale is 0.1 mL.5 Analysis steps5.1 Sample preparation Strong light shall be avoided during the sample preparation process. After preparation, the oil and fat shall be stored in a sealed container and measured as soon as possible. 5.1.1 Animal and vegetable oils and fats For liquid samples, shake the closed container containing the sample, mix thoroughly, and then take a sample directly; for solid samples, select a representative sample and place it in a closed container, mix well, and then take a sample. If necessary, place the container containing the solid sample in a constant temperature water bath, and heat it until the sample begins to melt; let it completely melt at this temperature, shake and mix well, and take a sample for measurement immediately while the sample is in liquid state. 5.1.2 Oil products 5.1.2.1 Edible hydrogenated oil, shortening, cocoa butter substitute 5.1.2.2 Margarine Place the sample in a closed container, heat it in an electric constant-temperature drying oven at 60 °C to 70 °C until it melts, shake and mix, continue heating until the emulsification breaks down into layers, and filter the oil layer through the rapid qualitative filter paper into a beaker. The filtrate in the beaker is the sample to be tested, and the sample to be tested shall be clarified. Take a sample and measure it immediately while the sample to be tested is in a liquid state. 5.1.2.3 Non-dairy cream Take a representative sample in a beaker, add about 5 times the sample volume of petroleum ether, and stir for 2 minutes by using an overhead stirrer to mix evenly. While stirring, add anhydrous sodium sulfate of about 1.6 times the mass of the sample, continue stirring and mixing for 5 minutes, remove the beaker, and let the solution stand for 5 minutes to allow the petroleum ether to layer (if emulsification occurs, cover the top of the beaker with a layer of plastic wrap, and place the beaker in a water bath of not higher than 40 °C for 10 minutes to stratify the petroleum ether). Pour out the supernatant, add about 2 times the sample volume of petroleum ether to the beaker, and repeat the above stirring and standing operations; combine the petroleum ethers, filter, and transfer the filtrate into a brown rotary evaporation bottle; in a water bath of not higher than 40 ℃, use a rotary evaporator to evaporate the petroleum ether to dryness under reduced pressure. 5.2 Sample determination Sample determination shall be avoided under direct sunlight. Weigh 2 g~3 g of the prepared sample (accurate to 0.001 g), place it in a 250 mL iodine flask, add 30 mL of chloroform-glacial acetic acid solution, and shake the sample gently until it is completely dissolved. Accurately add 1.00 mL of saturated potassium iodide solution, plug the bottle cap tightly, shake gently for 0.5 min, and place in a dark place for 3 min. Take out and add 100 mL of water, shake well and immediately use sodium thiosulfate standard titration solution (when the estimated peroxide value is 0.15 g/100 g and below, use 0.002 mol/L standard titration solution; when the estimated peroxide value is greater than 0.15 g/100 g, use 0.01 mol/L standard titration solution) to titrate the precipitated iodine. When the solution turns to light yellow, add 1 mL of starch indicator, continue titrating, and shake vigorously until the blue color of the solution disappears, that is the end point.6 Presentation of analysis results6.1 When the peroxide value is expressed as the mass fraction of peroxide equivalent to iodine, it is calculated according to formula (1). 6.2 When the peroxide value is expressed in millimoles of active oxygen in 1 kg of the sample, it is calculated according to formula (2).7 PrecisionThe absolute difference between two independent determination results obtained under repeatability conditions shall not exceed 10% of the arithmetic mean.8 PrincipleThe prepared oil and fat sample is dissolved in isooctane-glacial acetic acid solution. The peroxide in the sample reacts with potassium iodide to generate iodine. After the reaction, the precipitated iodine is titrated with sodium thiosulfate standard titration solution, and the titration end point is determined with a potentiometric titrator. The amount of peroxide value is expressed as the mass fraction of peroxide equivalent to iodine or the number of millimoles of active oxygen in 1 kg of the sample.9 Reagents and materialsUnless otherwise stated, the reagents used in this method are of analytical grade, 9.1 Reagents 9.2 Reagent preparation 9.3 Preparation of standard solution The preparation is the same as 3.3.10 Instruments and equipment10.1 Balance. The sensitivities are 0.01 g, 0.001 g, and 0.0001 g, respectively. 10.2 Electric constant-temperature drying oven. 10.3 Potentiometric titrator. 10.4 Magnetic stirrer.11 Analysis steps11.1 Sample preparation The preparation is the same as 5.1.1 and 5.1.2.2. 11.2 Sample determination Weigh 5 g of the prepared sample (accurate to 0.001 g) and place it into the titration cup of the potentiometric titrator, add 50 mL of isooctane-glacial acetic acid solution, and shake gently to completely dissolve the sample. If the solubility of the sample is poor (such as stearin or animal fat), first add 20 mL of isooctane to the titration cup, shake gently to dissolve the sample, then add 30 mL of glacial acetic acid, and mix well. Accurately add 1.00 mL of saturated potassium iodide solution to the titration cup, start the magnetic stirrer, and react at a suitable stirring speed for 60 s±1 s. Immediately add 30 mL~100 mL water to the titration cup, insert the electrode and titration head, set the titration parameters, run the titration program, perform the titration, and observe the titration curve and potential changes. The added amount of sodium thiosulfate standard titration solution is generally controlled at 0.05 mL/drop~0.2 mL/drop. After reaching the titration end point, record the volume of standard solution consumed at the titration end point. After the titration of a sample is completed, the stirrer or stirring magnet, titration head, and electrode need to be immersed in isooctane to clean the oils and fats on the surface. A blank test is performed at the same time. Carry out titration and observe the titration curve and potential changes. The added amount of sodium thiosulfate standard titration solution is generally controlled at 0.005 mL/drop. After reaching the titration end point, record the volume V0 of the standard solution consumed at the titration end point. The volume V0 of the 0.01 mo1/L sodium thiosulfate standard titration solution consumed in the blank test shall not exceed 0.1 mL.12 Presentation of analysis resultsIt is the same as Chapter 6.13 PrecisionThe absolute difference between two independent determination results obtained under repeatability conditions shall not exceed 10% of the arithmetic mean. ......Source: Above contents are excerpted from the full-copy PDF -- translated/reviewed by: www.ChineseStandard.net / Wayne Zheng et al. |
