GB 5009.2-2024 PDF EnglishUS$140.00 · In stock · Download in 9 seconds
GB 5009.2-2024: National food safety standard - Determination of relative density of food 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 5009.2: Historical versions
Similar standardsGB 5009.2-2024: National food safety standard - Determination of relative density of food---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/GB5009.2-2024GB NATIONAL STANDARD OF THE PEOPLE'S REPUBLIC OF CHINA National food safety standard - Determination of relative density of food Issued on. FEBRUARY 8, 2024 Implemented on. AUGUST 8, 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 - Density bottle method... 4 2 Principle... 4 3 Instruments and equipment... 4 4 Analysis steps... 4 5 Expression of analysis results... 5 6 Precision... 5 Method B - Balance method... 5 7 Principle... 5 8 Instruments and equipment... 6 9 Analysis steps... 6 10 Expression of analysis results... 6 11 Precision... 7 Method C - Hydrometer method... 7 12 Principle... 7 13 Instruments and equipment... 7 14 Analysis steps... 7 15 Expression of analysis results... 7 16 Precision... 8 Method D - Oscillating u-tube digital densimeter method... 8 17 Principle... 8 18 Instruments and equipment... 8 19 Analysis steps... 9 20 Presentation of analysis results... 9 21 Precision... 9 Appendix A Density bottle diagram... 10 Appendix B Schematic diagram of Westphal relative density balance... 11ForewordThis standard replaces GB 5009.2-2016 National food safety standard - Determination of relative density of food. Compared with GB 5009.2-2016, the main changes in this standard are as follows. -- A calculation formula is added in Method C; -- Method D, oscillating U-tube digital densimeter method, is added. National food safety standard - Determination of relative density of food1 ScopeThis standard specifies the method for the determination of the relative density of liquid foods. This standard is applicable to the determination of the relative density of liquid foods. Method A - Density bottle method2 PrincipleThe masses of water and the sample filled in the same density bottle at 20 °C are measured, respectively. The volume of the density bottle, which is the sample volume, can be determined from the mass of the water. The density of the sample can be calculated based on the mass and volume of the sample. The ratio of sample density to water density is the relative density of the sample.3 Instruments and equipment3.1 Density bottle. Precision density bottle, see Figure A.1 in Appendix A. 3.2 Constant temperature water bath. The accuracy is ±1 °C.4 Analysis stepsTake a clean, dry, constant weight, and accurately weighed density bottle. After filling it with the sample, place it in a water bath and soak it for 0.5 hours until the temperature of the sample inside reaches (20±1) °C;5 Expression of analysis resultsThe relative density of the sample is calculated according to formula (1).6 PrecisionThe absolute difference between two independent determination results obtained under repeatability conditions shall not exceed 5% of the arithmetic mean.7 PrincipleAt 20°C, the buoyancy of the glass hammer in water and in the sample are measured, respectively.8 Instruments and equipment8.1 Westphal relative density balance. The sensitivity is 0.1 mg; see Figure B.1 in Appendix B.9 Analysis stepsWhen measuring, place the stand on a flat table, place the beam on the knife edge, hang a weight on the hook, adjust the lifting knob to the appropriate height, and rotate the zero-setting knob to make the two pointers match. Then remove the weight, hang up the glass hammer, add water to the 4/5 position in the glass cylinder, and put it into a constant temperature water bath; make the water temperature in the glass cylinder balance and stabilize at (20±1) ℃, let the glass hammer sink to the glass cylinder, try placing four kinds of riders until the two pointers on the beam coincide, and the reading at this time is P1;10 Expression of analysis resultsThe relative density of the sample is calculated according to formula (2).11 PrecisionThe absolute difference between two independent determination results obtained under repeatability conditions shall not exceed 5% of the arithmetic mean.12 PrincipleArchimedes' principle is used; the liquid sample to be tested is poured into a higher container, and then the hydrometer is placed into the liquid sample after the temperature stabilizes at 20 °C.13 Instruments and equipment13.1 Hydrometer. There is a scale label in the upper thin tube to indicate the density reading. 13.2 Constant temperature water bath. The accuracy is ±1 °C.14 Analysis stepsWash and dry the hydrometer, and slowly place it into a suitable measuring cylinder containing an appropriate amount of liquid sample to be tested, and the cylinder has been at (20±1) °C in a constant temperature water bath. Do not let the hydrometer touch the wall and bottom of the container.15 Expression of analysis resultsThe relative density of the sample is calculated according to formula (3).16 PrecisionThe absolute difference between two independent measurement results obtained under repeatability conditions shall not exceed 5% of the arithmetic mean.17 PrincipleElectromagnetic induces the oscillation of the glass U-tube, the magnitude of the oscillation frequency squared is linearly related to the density of the sample in the measuring cell, and the density of the sample is thus determined.18 Instruments and equipment18.1 Oscillating U-tube digital densimeter. with automatic viscosity correction and temperature and thermal balance functions.19 Analysis steps19.1 Calibration of the instrument Before testing, calibrate the instrument according to the instructions of the instrument.20 Presentation of analysis resultsThe result is expressed to the third decimal place.21 PrecisionThe absolute difference between two independent measurement results obtained under repeatability conditions shall not exceed 5% of the arithmetic mean. ......Source: Above contents are excerpted from the full-copy PDF -- translated/reviewed by: www.ChineseStandard.net / Wayne Zheng et al. 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