GB/T 5009.181-2003 Determination of malondialdehyde in lard

This standard specifies the determination method of malondialdehyde in lard. This standard is applicable to the determination of malondialdehyde in lard. GB/T 5009.181-2003 Determination of malondialdehyde in lard GB/T5009.181-2003 Standard download decompression password: www.bzxz.net

ICS67.040
National Standard of the People's Republic of China
GB/T5009.181—2003
Partially replaces GB10146--1988
Determination of propyldialdehyde in lard
Determination of propyldialdehyde in lardPublished on August 11, 2003
Implemented on January 1, 2004
Ministry of Health of the People's Republic of China
Standardization Administration of the People's Republic of China
GB/T5009.181—2003
This standard replaces the test method of 5.1 malondialdehyde in GB10146-1988 "Hygienic Standard for Lard". This standard is proposed and managed by the Ministry of Health of the People's Republic of China. This standard is drafted by Shanghai Food Hygiene Supervision and Inspection Institute and Guangzhou Health and Epidemic Prevention Station. The main drafter of this standard: Zhou Lianbin.
1 Scope
Determination of MDA in Lard
This standard specifies the determination method of MDA in lard. This standard is applicable to the determination of MDA in lard. 2 Principle
GB/T5009.181—2003
Lard is subjected to the effects of light, heat, and oxygen in the air, causing rancidity reactions and decomposition of compounds such as aldehydes and acids. MDA is one of the decomposition products, which can react with thiobarbituric acid (TBA) to generate pink compounds with an absorption peak at a wavelength of 538nm. This property can be used to measure the MDA content, thereby deriving the degree of rancidity of lard. 3 Reagents
3.1 Thiobarbituric acid (TBA) aqueous solution: Accurately weigh 0.288g of thiobarbituric acid (TBA) and dissolve it in water, and dilute it to 100mL (if TBA is not easily soluble, it can be heated until it is completely dissolved and clarified, and then diluted to 100mL), equivalent to 0.02mol/L. 3.2 Triacetic acid mixed solution: Accurately weigh 7.5g of trichloroacetic acid and 0.1g of EDTA (disodium ethylenediaminetetraacetate) and dissolve it in water, and dilute it to 100mL
3.3 Malondialdehyde standard stock solution: Accurately weigh 0.315g of 1,1,3,3-tetraethoxypropane (E.Mesck97%), dissolve it and dilute it to 1000mL (equivalent to 100μg of malondialdehyde per milliliter), and store it in a refrigerator. 3.4 MDA standard solution: Accurately pipette 10 mL of the above stock solution and dilute it to 100 mL (equivalent to 10 ug of MDA per mL) and place it in the refrigerator for later use.
3.5 Trinitroform.
4 Instruments
4.1 Constant temperature water bath.
4.2 Centrifuge 2000z/min.
4.3 72-type spectrophotometer.
4.4 100 mL Erlenmeyer flask with cover.
4.5 25 mL Nessler colorimetric tube.
4.6 100 mm x 13 mm test tube.
4.7 Qualitative filter paper. wwW.bzxz.Net
5 Analysis steps
5.1 Sample treatment
Accurately weigh 10 g of lard liquid evenly melted in a 70℃ water bath, place it in a 100mL Erlenmeyer flask with a lid, add 50mL of trifluoroacetic acid mixed solution, shake for 0.5h (keep the lard in a molten state, if it freezes, slightly heat it in a 70℃ water bath to melt it and continue shaking), filter with double-layer filter paper to remove grease and filter residue, and repeat the filtration with double-layer filter paper once. 5.2 Determination
Accurately transfer 5 mL of the above filtrate into a 25 mL Nessler colorimetric tube, add 5 mL of TBA solution, mix well, add a stopper, place in a 90°C water bath for 40 min, take out, cool for 1 h, transfer to a small test tube, centrifuge for 5 min, pour the supernatant into a 25 mL Nessler colorimetric tube, add 5 mL of trinitroform, shake well, let stand, separate layers, aspirate the supernatant and compare colors at a wavelength of 538 nm (simultaneously perform a blank test). 469
GB/T5009.181—2003
5.3 Preparation of standard curve
Use the standard solutions containing 1 μg, 2 pg, 3 pg, 4 μg, and 5 ug of MDA to perform the above steps, and make a standard curve based on the relationship between concentration and absorbance.
6 Result calculation
Malondialdehyde content (mg%) =
A—corresponding concentration of lard.
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