GB/T 5009.6-2003 Determination of fat in foods

This standard specifies the method for determining the fat content in foods. This standard is applicable to the determination of crude fat content in meat products, bean products, cereals, nuts, fried fruits, Chinese and Western cakes, etc., but not applicable to milk and dairy products. GB/T 5009.6-2003 Determination of fat in foods GB/T5009.6-2003 standard download decompression password: www.bzxz.net

ICS 67.040
National Standard of the People's Republic of China
GB/T5009.6--2003
Replaces GB/T5009.6-1985
Determination of fat in foods
Determination of fat in foodsIssued on August 11, 2003
Ministry of Health of the People's Republic of China
Standardization Administration of the People's Republic of China
Implementation on January 1, 2004
GB/T5009.6--2003
This standard replaces GB/T5009.6--1985 "Determination of fat in foods". Compared with GB/T5009.6-1985, this standard has the following major revisions: the Chinese name of the standard has been revised and changed to "Determination of Fat in Foods"; the structure of the original standard has been revised in accordance with GB/T20001.4-2001 "Standard Preparation Rules Part 4: Chemical Analysis Methods".
This standard is proposed and managed by the Ministry of Health of the People's Republic of China. This standard was drafted by the Food Hygiene Supervision and Inspection Institute of the Ministry of Health. This standard was first issued in 1985 and this is the first revision. 44
1 Scope
Determination of Fat in Foods
This standard specifies the method for determining the fat content in foods. GB/T 5009.6-2003
This standard applies to the determination of crude fat content in meat products, bean products, cereals, nuts, fried fruits, Chinese and Western cakes, etc., but not to milk and dairy products.
Method 1
2 Principle
Soxhlet extraction method
The substance obtained by evaporating the solvent after the sample is extracted with anhydrous ether or petroleum ether is called crude fat. Because in addition to fat, it also contains pigments and volatile oils, waxes, resins and other substances. The fat measured by the extraction method is free fat. 3 Reagents
3.1 Anhydrous ether or petroleum ether.
3.2 Sea sand: Take sea sand or river sand washed with water to remove mud, first boil it with hydrochloric acid (1+1) for 0.5h, wash it with water until it is neutral, then boil it with sodium hydroxide solution (240g/L) for 0.5h, wash it with water until it is neutral, and dry it at 100℃±5℃ for use. 4 Instruments
Soxhlet extractor.
5 Analysis steps
5.1 Sample processingbzxZ.net
5.1.1 Solid sample: Grains or dry products are crushed with a pulverizer and passed through a 40-mesh sieve; meat is minced twice with a meat grinder; generally, it is crushed with a tissue crusher, and 2.00g to 5.00g is weighed (the sample after the water content is determined can be taken), and if necessary, it is mixed with sea sand, and all is transferred into the filter paper tube. 5.1.2 Liquid or semi-solid sample: 5.00g to 10.00g is weighed, placed in evaporator III, and about 20g of sea sand is added to evaporate to dryness in a boiling water bath, and then dried at 100℃±5℃, ground into powder, and all is transferred into the filter paper tube. Evaporator III and the glass rod with the sample are wiped clean with cotton wool soaked in ether, and the cotton wool is placed in the filter paper tube. 5.2 Extraction
Put the filter paper into the extraction cylinder of the fat extractor, connect it to the receiving bottle that has been dried to a constant volume, add anhydrous ether or petroleum ether from the upper end of the extractor condenser to two-thirds of the bottle's volume, heat it on a water bath, and make the ether or petroleum ether reflux and extract continuously (6 times/h~8 times/h), generally extract for 6 h~12 h. 5.3 Weighing
Remove the receiving bottle, recover the ether or petroleum ether, and evaporate it on a water bath when there is 1mL~2mL of ether left in the receiving bottle, then dry it at 100℃±5℃ for 2h, cool it in a dryer for 0.5h, and weigh it. Repeat the above operation until the constant volume is reached. 6 Calculation of results
X= m=mo × 100
Wherein:
The crude fat content in the sample, in grams per 100 grams (g/100g); (1)
GB/T5009.6—2003
The mass of the receiving bottle and the crude fat, in grams (g); -The mass of the receiving bottle, in grams (g); -The mass of the sample (if it is a sample after water content determination, it is calculated based on the mass before water content determination), in grams (g). m2—
The calculation result is expressed to one decimal place. 7 Precision
The absolute difference between two independent determination results obtained under repeatability conditions shall not exceed 10% of the arithmetic mean. Second method Acid hydrolysis method
8 Principle
The sample is hydrolyzed with acid and extracted with ether. The total fat content is obtained by removing the solvent. The total amount of free and bound fat is measured by the acid hydrolysis method.
9 Reagents
9.1 Hydrochloric acid.
9.2 Ethanol (95%).
9.3 Ether.
9.4 Petroleum ether (30℃～60℃ boiling range). 10 Apparatus
100mL graduated cylinder with stopper.
11 Analysis steps
11.1 Prepare the sample as follows. 11.1.1 Solid sample: Weigh about 2.00g of the sample prepared in 5.1.1 and place it in a 50mL large test tube, add 8mL of water, mix well, and then add 10mL of hydrochloric acid.
11.1.2 Liquid sample: Weigh 10.00g, place it in a 50mL large test tube, and add 10mL of hydrochloric acid. 11.2 Place the test tube in a 70℃～80℃ water bath, stir with a glass rod every 5min~～10min until the sample is completely digested, about 40 min~50 min.
11.3 Take out the test tube, add 10mL ethanol and mix. After cooling, transfer the mixture to a 100mL stoppered measuring cylinder, wash the test tube with 25mL ether in batches, and pour it into the measuring cylinder. After all the ether is poured into the measuring cylinder, add a stopper and shake for 1min, carefully open the stopper, release the gas, re-stopper, let it stand for 12min, carefully open the stopper, and rinse the stopper and the fat attached to the mouth of the cylinder with an equal amount of petroleum ether-ether mixture. Let it stand for 10min~20min, wait for the upper liquid to be clear, suck out the supernatant into a constant volume conical flask, add 5mL ether into the stoppered measuring cylinder, shake, let it stand, and still suck out the upper ether and put it into the original conical flask. Place the conical flask in a water bath to evaporate to dryness, place in an oven at 100℃±5℃ to dry for 2h, take out and cool in a desiccator for 0.5h, then weigh, repeat the above operation until constant weight is obtained. 12 Calculation
Same as Chapter 6.
13 Precision
Same as Chapter 7.
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