Some standard content:
1CS 67.040
National Standard of the People's Republic of China
GB/T 14488.1—2008
Replaces CB/T 14488.11993
Vegetable oils
Determination of oil content
Oilseeds--Determination of oil content(IS0 659;1998,MOD)
Issued on 2008-11-04
General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China Administration of Standardization of the People's Republic of China
Implementation on 2009-01-01
GB/T 14488.1-2008
This standard modifies and adopts IS0659:1998 & Determination of oil content of vegetable oils (reference method)" (English version). The main differences between this standard and ISO659:1998 are as follows: - The method for determining the impurity content of oil shall be in accordance with GB/T14488.2 (GB/T14488.2-1993, ISO658:1980); The method for determining the moisture and volatile matter content of oil shall be in accordance with GB/T14489.1 (GB/T14489.1-1993, cQvISO665:1977).
For ease of use, this standard has made the following editorial changes: the term "this international standard" has been changed to "this standard"; the decimal point "" has been used instead of the comma "" as a decimal point; the foreword of the international standard has been deleted:
Add serial numbers to the calculation formulas.
This standard replaces GB/T14488.1-1993 "Determination of oil content in oilseeds". The main changes of this standard compared with GB/T14488.1-1993 are as follows: - The sample weight has been modified;
The number of grinding times has been modified;
The drying time has been modified. Modified;
The extraction time was modified.
Appendix A of this standard is an informative appendix.
This standard is proposed by the State Administration of Grain.
This standard is under the jurisdiction of the National Technical Committee for Grain and Oil Standardization. The drafting unit of this standard: Hubei National Grain Quality Monitoring Center. The main drafters of this standard are Liu Li, Liu Zihao, Wang Tuo, Yu Dunnian, Xiong Ning, Zheng Zhiming, and Min Guochun. 1
1 Scope
Determination of oil content in vegetable oils
This standard specifies the method and principle for determining the oil content in vegetable oils. GB/T 14488.1—2008
This method is applicable to the determination of the oil content of rapeseed, soybean and sunflower seeds used as industrial raw materials. However, this method does not exclude the use of this method to determine the oil content of other vegetable oil seeds.
Note: If necessary, the following items can be measured separately: 1. The oil content of the net sample and the oil content of impurities (see 9.3); 2. When measuring the oil content of peanuts, the oil content of the peanut kernel, the oil content of the whole peanut crushed material, the oil content of non-oil-containing impurities and the oil content of oil-containing impurities can be measured separately.
2 Normative referenced documents
The clauses in the following documents become the clauses of this standard through reference in this standard. For all referenced documents with dates, all subsequent amendments (excluding errata) or revisions All versions of the above documents are not applicable to this standard. However, parties to an agreement based on this standard are encouraged to investigate whether the latest versions of these documents can be used. For any undated referenced document, the latest version shall apply to this standard. G13/T14488.2 Determination of impurities in oilseeds (GB/T14488.2--1993, neqISO658:1980) GB/T14489.1 Determination of moisture and volatile matter content in oilseeds (GB/T14489.1---1993, eqvISO665:1977) ISO664 Sample separation method for laboratory tests on oilseeds 3 Terms and definitions
The following terms and definitions apply to this standard. 3.1
Oil content (n-hexane extract) oil Content (hexane extract): Under the conditions specified in this standard, the oil is extracted with n-hexane or petroleum ether as solvent, and the mass fraction of the obtained extract in the original sample or the net sample.
Note: It can be used to indicate the content of the substance if necessary. 4 Principle
Use n-hexane or petroleum aldehyde as solvent, use appropriate extraction equipment to extract the n-hexane or petroleum aldehyde solubles in the vegetable oil, remove the solvent, and weigh the mass of the extract. 5 Reagents
n-hexane or petroleum ether: a hydrocarbon composed of 6 carbon atoms, with a boiling range of 40℃～60℃ or 50℃～70℃, and the substance with a boiling range below 40℃ is less than 5%. The distillation residue of each 100mL solvent shall not exceed 2mg 6 Instruments and equipment
General laboratory instruments and equipment and the following instruments and equipment. 6.1 Analytical balance: sensitivity 0.001g.
6,2 Grinding machine: easy to clean, suitable for grinding oil, and can grind oil into uniform particles. No heat is generated during the grinding process, and the moisture content or oil content does not change significantly after grinding. Note: The ChristyNorris BI Laboratory Mill, the Uilira Centrifugal Mill (UCM) type laboratory mill is applicable. The specifications of the bar screen of the ChristyNorris 8 Laboratory Mill can be selected according to the type of sample (such as 0.8mm sieve plate, 3lun.6mm long bar screen, see 8.3.2, 8.3.3 and 8.3.4) Ultra Centrifugai Mill (LCM) uses a 1mm sieve when crushing steamed flower seeds. Different sieves can be selected according to the type of sample. 6.3 Crusher: It can crush oil into fine powder with a particle size of less than 160μm, but does not include the shell. The particle size of the shell part after crushing can reach 40μm.
Note Dengoumau type laboratory mill has a capacity of 150ml., and contains steel balls with diameters of 1cm, 2cm, and 3cm (weight about 7g, 30g, and 130g). It is suitable for crushing samples.
The following laboratory mills are also suitable: Retsch, \[E Retsch, Plarelary Ball Mill, S1 and S2 Centrifugal Ball Mills, Batam Mikru Hammer Mill, IKA Mill, Fritch Pulverisette 5 Planetary Ball Mill and Yanqi. 6.4 Filter paper and absorbent cotton: no hexane or oil ether soluble matter 6.5 Extractor: reflux extractor, direct drop extractor and other extractors. The extraction bottle capacity of the reflux extractor and the direct drop extractor is 200mL~250mL. In order to ensure the consistency of the oil content measured by different extractors, it is necessary to determine whether the selected extraction equipment meets the requirements by measuring samples with known oil content. Note: The Butt, Sinallcy or Bol1.on-Williams direct drop extractor is suitable for 6.6 Zeolite: Light small stones or other zeolites: Dry in an oven at (130±2)℃ before use and place in a desiccator for standby use. 6.7 Device for volatilizing organic solvents in filter paper tubes (such as a hair dryer that can generate hot air). 6.8 Electric heating device: sand bath pot, water bath pot, heating jacket and electric heating plate, etc. 6.9 Electric oven: temperature control requirement (103±2)℃, it has normal pressure T-drying and vacuum T-drying functions. 6.10 Dryer (equipped with effective desiccant, such as color-changing silica gel or phosphorus pentoxide). 6.11 Electric oven: temperature control requirement (130 + 2) ℃, used for drying cotton seeds, see 8.3.5. 6.12 Flat metal pan: diameter 100mm, height about 40mm. 7 Sampling
The sample taken should be representative and not damaged or deteriorated during transportation and storage. This standard does not specify the sample support method, and ISO542 is recommended. 8 Sample preparation
8.1 Sampling
Prepare the sample according to ISO 664: If the large non-oil impurities have been removed before sampling, calculate the oil content according to formula (3). Decide whether to remove impurities according to the inspection requirements
8.2 Pre-drying
Before extracting the oil from the sample, the moisture content of the sample should be less than 10%. Note: If this point is not paid attention to, it may lead to inaccurate measurement results. Use the rapid screening method to test the moisture content of the sample (8.1). If the moisture content of the sample is greater than 10%, the sample (8.1) needs to be placed in a pan and dried in an oven at a temperature not higher than 80°C to reduce the moisture content to less than 10%. The dried sample is placed in a wide-mouth bottle and sealed for later use. When testing the oil content of the sample, it is necessary to follow GB/T14489.1 Determine the moisture content of the original sample and the dried sample respectively. The oil content is calculated according to formula (6) 1) Chrisly Nurris 8-type laboratory mill and Ultra Centrifugal Mill (UICM) are suitable, but the International Organization for Standardization (ISO) does not specify these laboratory mills as special equipment.
2) The above list is only suitable for laboratory mills. But the International Organization for Standardization (ISO) does not specify these experiments as special equipment. 3) The Butt, Smalley or Bolton Williams direct drop extractor is suitable. But the International Organization for Standardization (ISO) does not specify these direct drop extractors as special equipment.
8.3 Test specimens
8.3.1 General
The sample should be extracted within 30 minutes after grinding, especially for samples with high free fatty acids. GB/T14488.1--2008
The laboratory mill should be carefully cleaned before and after grinding the sample, and the sample remaining on the mill should be mixed with the crushed sample. Note: The seeds or kernels mentioned below refer to the complete seeds or kernels and their broken particles. 8.3.2 Palm kernel
When determining the oil content, 600 samples should be prepared. After removing the outer shell as an impurity and other impurities, the palm kernel should be crushed to a fineness of no more than 611m before testing. If the oil content of the raw sample needs to be measured, the palm kernel and impurities should be ground separately because the outer shell is difficult to grind to avoid uneven sample grinding. Then the oil content of the palm kernel and impurities should be determined separately. The oil content is calculated according to formula (2). The determination of impurities shall be carried out in accordance with GB/T14488.2.
: Palm kernels can be crushed using a ChristyNorris8LaboratoryMil\ (6.2) equipped with a 6mm bar screen. Shells and soil impurities can be crushed for 10 minutes using a crusher equipped with 3cm diameter steel balls as listed in 6.3. 8.3.3 Coconut
The entire sample can be crushed using a ChristyNorris8LaboratoryMill (6.2) equipped with a 6mm bar screen. The sample should be frozen before grinding. The sample should avoid absorbing moisture during and after the crushing process. The crushing fineness is about 2mm and should not exceed 5mm. The sample should be measured quickly after mixing.
8. 3.4 Large and medium-grained oilseeds (grass seeds, butter fruit, sunflower seeds, peanuts, soybeans, etc.) should be quickly ground into uniform fine particles using a grinding mill (6.2). The particle size of soybean and sunflower seed is less than 1 mm, that of walnut is less than 3 mm, and that of other large and medium-sized oil seeds is less than 6 mm. Discard about one twentieth of the sample that is first crushed, collect the remaining part and mix it quickly for determination.
Soybean can be crushed with Christy Norris Laboratory Mill equipped with 0.8 mm sieve plate or Ultra Centrifugal Mill equipped with 1 mm sieve.
Sunflower seed can be crushed with Ultra Centrifugal Mill (UCM) equipped with 1 mm sieve. Peanut can be crushed with Christy Norris Laboratory Mill equipped with 3 mm bar sieve. When the oil content of the sample exceeds 45%, the sample should be avoided as much as possible to form a paste. When crushing other oil seeds, a 6-mm bar sieve can be used. Note: To facilitate the crushing of samples with high oil content, they can be frozen at -10 'C ~ -20 ℃ before crushing. The sample after cold refining should avoid absorbing moisture during and after the pulverization process. 8.3.5 Cottonseed
Weigh 15 samples in a metal pan (6.12) with an accuracy of 0.001. Place in an oven (6.11) heated to 130 °C for 2 h and cool in air for 30 min. Then grind them all with a grinder (6.2) and transfer them to a filter paper tube (6.4) lined with absorbent cotton for testing.
8.3.6 Small-grained oilseed (flaxseed, rapeseed, etc.) Select a representative sample of about 100 g for pulverization, ensuring that each grain is pulverized. Collect the sample remaining on the grinder and mix it with other pulverized samples. The pulverized sample should be mixed evenly as a whole, and the moisture of the sample should be prevented from evaporating and dissipating during the whole process. If the time and speed of the pulverizer for pulverizing the sample are adjustable, the pulverization time and speed should be set according to the characteristics of the pulverizer and the sample before the measurement. Crushing should not cause the kernel and shell to separate, the sample should not produce oil and at least 95% (mass fraction) should be able to pass through a 1 mm sieve. If the oil content of the clean sample needs to be determined, remove impurities according to GB/T14488.2 and prepare at least 30 g of clean sample (including broken kernels). Because for samples with particularly small grains such as sesame, it is difficult to prepare a 100 g clean sample. 9 Operation steps
Note: If the repeatability (11.2) test is carried out, perform parallel determinations according to 9.1 and 9.2. 4) See footnote 1).
GB/T14488.1—2008
9.1 Determination
9.1.1 Weigh 10 g ± 0.58 of the crushed sample (8.3) to the nearest 0.001. For the determination of oil content in impurities, see 9.3. 9.1.2 Carefully transfer the sample to a filter paper tube (6.4) and wipe the weighing tray and the sample transfer device with a piece of boned cotton (6.1) dipped in a small amount of solvent (Chapter 5) until there is no trace of sample and oil. Finally, transfer the absorbent cotton to the filter paper tube, seal it with absorbent cotton, and press it against the sample.
9.2 Extraction
9.2.1 Prepare the extraction bottle
Place the extraction bottle (6.5) containing zeolite (6.6) in an oven to dry until constant mass, cool it in a desiccator, and weigh the mass. Accurate to 0.001 g.
9.2.2 Extraction
Allow ±10 seconds for the time specified in the three extraction steps (see 9.2.2.1, 9.2.2.2 and 9.2.2.3) min. If there is no special instruction, there is no need to extend the extraction time.
9.2.2.1 Step 1
Add an appropriate amount of solvent (5.1) to the extraction bottle (6.5). Connect the extraction tube with the filter paper tube (6.4) to the extraction bottle. Install the condenser, turn on the cooling water, and place the extraction flask on the electric heater (6.8) to heat it. Control the temperature so that the solvent reflux rate is at least 3 drops per second. Boiling is moderate, without explosive boiling.
After 4 hours of extraction, remove the filter paper tube from the cooled extraction tube and use the solvent volatilization device (6.7) to shake off most of the bath agent. 9. 2. 2.2 Step 2
Take out the sample from the filter paper tube and grind it for the second time (6.3). After grinding for 7 minutes, transfer the sample to the filter paper tube and scrub the grinder with absorbent cotton dipped in a little solvent until there is no sample and oil stains. Finally, transfer the absorbent cotton to the filter paper tube and seal the top with absorbent cotton to press the sample. Put the filter paper tube into the extraction device and continue to use the extraction flask used in the first step for another 2 hours. After the extraction is completed, remove the filter paper tube, drain most of the residual solvent and cool it, and then grind the sample for the second time. 9. 2. 2.3 The third step
Transfer the crushed sample into the filter paper tube, and perform the same operation as in 9.2.2.2 and clean the crusher. Use the same extraction bottle and perform the same extraction operation as in 9.2.2.1 for another 2 hours.
9.2.3 Evaporation of solvent and weighing
Take out the filter paper tube, and place the extraction bottle on an electric heater to evaporate and recover most of the solvent. Air or inert gas (such as nitrogen, carbon dioxide) can be introduced into the extraction bottle to assist the evaporation of the solvent. Then place it in an oven (6.9) at (103±2)℃ and dry it under normal pressure for 30min~60min, or place it in an oven at 80℃ and dry it under vacuum for 30min~60min. After taking it out, place it in a dryer (6.10) to cool for 1 hour, weigh it to an accuracy of 0.001 g, and dry it for another 20min~30min under the same conditions. min, weigh after cooling, the difference between the two weighing results should not exceed 5mg. If exceeded, re-dry, cool and weigh again until the difference between the two weighing results is within 5mg. Record the final mass of the extraction bottle. The increased mass of the extraction bottle is the oil content of the measured sample. If the mass of the extraction bottle increases by more than 5mg after drying, it means that the oil has been oxidized during the drying process, and measures should be taken during the analysis process to prevent the oil from being oxidized:
. The extracts of oils containing more volatile acids (such as coconut oil, palm kernel, etc.) must be dried at normal pressure below 80℃; volatile or semi-drying oils must be dried by reduced pressure drying; oils without volatile acids should be dried under vacuum conditions in an oven at 80℃. 9.2.4 Determination of impurities in extraction
If the extracted oil contains impurities, add an appropriate amount of solvent to the extraction bottle to dissolve the oil, and then filter it with a filter paper that has been dried in an oven at (103±2)℃ to constant quality, cooled and weighed, and then repeatedly wash the filter paper with petroleum ether to completely remove the residual oil on the filter paper. Place the filter paper in an oven at (103±2)℃ and dry it to constant quality, take it out and place it in a desiccator to cool and weigh it. The increased mass of the filter paper is the mass of the impurity. The mass of the total extract minus the mass of the impurity is the mass of the oil. 4
9.3 Determination of oil content in impurities
GB/T 14488.1-2008
The method for determining the oil content in impurities is the same as that for the sample. Extract 5g~10g of the impurities weighed for 4h. 10 Calculation of results
10.1 Calculation method
If the test result meets the tolerance requirement in repeatability (11.2), take the arithmetic mean of the two tests as the test result, and keep one decimal place. Otherwise, take two more samples for further testing. If the difference between the test results still exceeds the tolerance range, and the range of the four results does not exceed 1.5%, take the average of the four test results as the test result. 10.1.1 Oil content (w.) is expressed as the mass fraction of the test sample. Calculate according to formula (1): we-
Where:
Oil content (in mass fraction), %;
Mass of the test sample, in grams (g); m
Mass of the dried extract, in grams (g) (9.2.3). 10.1.2 Palm kernel oil content (), calculated according to formula (2): Determine the oil content of the kernel and impurities separately and calculate according to formula (1). =
Wherein:
Oil content of brown plum kernel (by mass fraction), %;
Oil content of pure kernel (by mass fraction), %; Oil content in impurities (by mass fraction), %Mass fraction of impurities in the total sample, %.
-(2)
10.1.3If large non-oil impurities have been removed before testing (see 8.1), the oil content of the original sample should be calculated according to formula (3) based on the result calculated according to formula (2):
·(3)
Oil content of the sample after removing large non-oil impurities (by mass fraction), % (the calculation formula is determined according to different oils),
Mass fraction of large non-oil impurities, %. 10.1.4 The oil content of peanuts (w,) shall be calculated according to formula (4): Wo = w
Wherein:
Peanut oil content (by mass fraction), %; P --- Mass fraction of fine impurities, %;
Mass fraction of oil-containing impurities, %;
.... -- Mass fraction of non-oil-containing impurities, %
l --- Pure kernel oil content (by mass fraction), %; Oil content in impurities (by mass fraction), %. If the oil content of the original sample is tested, it shall be calculated according to formula (1). (:—w)
10.1.5 The oil content is expressed as the mass fraction of the dry matter of the sample and is calculated according to formula (5): (4)
GB/T 14488.1—2008
Wu Zhong:
Oil content of the sample, %;
100 -0
U-·.·The moisture and volatile matter content of the sample determined in accordance with G3/114489.1, %.10.1.6 The oil content at a specific moisture content (zu) is calculated according to formula (6): 1100-U'
w =w×(100-)
·The oil content of the sample when the moisture content is U, %; The oil content of the sample when the moisture content is U\, %. (5)
Sometimes it is necessary to convert the oil content at one moisture content into the oil content at another moisture content. For example, the oil content of the pre-dried sample is calculated according to formula (6). 11 Precision
11.1 Joint laboratory test
Appendix A summarizes the joint laboratory test data on the precision of this method. For other concentration ranges and test objects, these test data may not be applicable. 11.2 Repeatability
In a short period of time, in a laboratory, by the same operator using the same instrument, using the same method, testing the same sample, the absolute difference between the two test results should not be greater than: rapeseed 0.4%, soybean 0.4%, sunflower seed 0.5%. The premise is that it is no more than 5%.
11.3 Reproducibility
In different laboratories, by different operators, using different instruments, using the same test method, testing the same sample, and measuring two independent results. The absolute difference between the two test results should not be greater than their average value: rapeseed 1.6%, soybean 1.1%, sunflower seed 1.6%. The premise is that the amount is no more than 5% greater than this. 12 Experimental report
The experimental report shall state:
All information required for complete identification of the sample; sampling method of the sample;
-Test method adopted:
Solvent used;
All operating details that are not specified in this standard or considered optional, as well as other events that may have affected the test results; The test results shall clearly indicate whether they are calculated on a decimal basis or at a specific moisture content. Whether the sample is free of impurities or external fillings before testing;
If repeatability is tested, list the results.
Appendix A
(Informative Appendix)
Joint laboratory test results
GB/T14488.1--2008
The test was conducted in a series of joint laboratories at an international level using the force method of direct drop extraction. Statistical results (calculated according to ISO5725) are shown in Tables A.1 to A.3. A.1 Rapeseed
Testing time: 1992.
Number of participating laboratories: 42
Number of repetitions: 2 times.
Participating countries: 13.
Table A.1 Rapeseed Joint Laboratory Test Results ItemwwW.bzxz.Net
Number of laboratories after excluding abnormal results Average value/%
Quality standard deviation S./%
Repeatability coefficient of variation/%
Repeatability limit r, 2. 83×S./%
Reproducibility standard deviation Sx/%
Reproducibility coefficient of variation/%
Reproducibility limit R, 2. 83×SR/%
A.2 Soybean
Testing time: 1990.
Participating laboratories: 33.
Number of repetitions: 2 times.
Participating countries: 12.
Laboratory average value after excluding abnormal results/%
Repeatability standard deviation S,/ %
Repeatability coefficient of variation/%
Repeatability limit, 2. 83× S / %
Reproducibility standard deviation S%/%
Reproducibility coefficient of variation/ %
Reproducibility limit R, 2.83×S/%
Test 1
Table A, 2 Test results of soybean joint laboratory Test 1
Test 2
Test 2
GB/T14488.1—2008
A.3 Vinegar seeds
Test time: 1994.
Participating test laboratories: 22.
Number of repeats: 2 times.
Participating countries: 9.
Number of laboratories after excluding abnormal results Average value of the number of laboratories/%
Reproducibility standard deviation S./%
Reproducibility coefficient of variation/%
Reproducibility limit r, 2. 83× S./%
Reproducibility standard deviation S/%
Reproducibility coefficient of variation/%
Reproducibility limit R, 2.83×S/%
3Test results of Fanhuazi Joint Laboratory
Test 1
Test 2
References
GB/T14488.1—2008
[17Is0542:1990Oilsceds—Sampling[2] ISO 5725:1986 Determination of repcatability and reproducibility for a standard 1est method by inter-laboratorytests.E
GB/T 14488.1-2008
People's Republic of China
National standard promotion
Determination of oil content in vegetable oilseeds
GB/T 14488.1—2008
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