CN102879538A - Method for measuring protein content in milk powder - Google Patents
Method for measuring protein content in milk powder Download PDFInfo
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- CN102879538A CN102879538A CN2012103049415A CN201210304941A CN102879538A CN 102879538 A CN102879538 A CN 102879538A CN 2012103049415 A CN2012103049415 A CN 2012103049415A CN 201210304941 A CN201210304941 A CN 201210304941A CN 102879538 A CN102879538 A CN 102879538A
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Abstract
The invention discloses a method for measuring the protein content in milk powder. The nitrogen element content in a sample can be measured by using an organic element analysis theory and an organic element analysis instrument through optimizing parameters such as the using amount of the sample, the oxygen feeding time and combustion temperature, so that the protein content in the milk powder such as powdered milk, protein powder and nutrient powder can be measured. The method has the advantages of small sample demand, small reagent using amount, simplicity in operation, high measurement efficiency, high measurement precision and the like and is suitable for measuring the protein content in various types of milky products.
Description
Technical field
The present invention relates to the food nutrition material sphere, particularly a kind of method of measuring protein content in the milk powder.
Background technology
Protein (protein) is the important component that consists of the biological cell tissue, is the substance basis of life.Protein and Nutrition and Metabolism, eucaryotic cell structure, enzyme, hormone, virus, immunity, substance operation, heredity etc. are closely related, and human body must absorb enough protein to keep the normal operation of every physiological function from food.Therefore, protein content is one of most important nutritive index of the food such as milk powder.Because protein is very complicated organic compound, there is no at present Direct Determination, it detects the Kjeldahls methods that adopt more, and its ultimate principle is: under catalyst action, destroy organism with sulfuric acid, make nitrogenous thing change into ammonium sulfate.Adding highly basic distills ammonia is overflowed, and after absorbing with boric acid, uses acidometric titration again, measures nitrogen content, and the result be multiply by reduction coefficient, calculates crude protein content.In addition, also there are human ultraviolet spectrophotometry, Coomassie brilliant blue method, biuret method, Folin-phenol method, isoelectric point precipitation etc. to carry out the mensuration of protein content in the milk powder.In these assay methods, with regard to the accuracy and precision and level of application of method, international classical assay method-Kjeldahls method is first-selected, and this method also is one of the classical method of testing that must grasp of relevant speciality personnel.But the Kjeldahls method detecting step is loaded down with trivial details, catalysis time is long, larger to the catalyst consumption amount.Although existing semi-automatic or full-automatic Kjeldahl determination device emerges at present, because this automation equipment price comparison of kjeldahl apparatus is expensive, popularization is wideless.
Organic elemental analysis is to identify the analytical approach that has element and its assay in the organism, and be mainly used in analyzing and researching C, H, N element form.Identical with Kjeldahls method, elemental microanalysis method can directly be measured the percentage composition of N element in the sample, therefore can be used for the mensuration of protein content in the milk powder.
Summary of the invention
Goal of the invention: for solving above-mentioned technical matters of the prior art, provide a kind of method of measuring protein content in the milk powder.
The technical scheme that adopts: a kind of method of measuring protein content in the milk powder is provided, it is characterized in that, use organic element analysis principle and instrument, by optimizing milk powder sample use amount, the logical oxygen time, the temperature of combustion parameters is measured nitrogen element content in the milk powder sample, multiply by reduction coefficient, can obtain protein content in the corresponding milk powder sample;
A kind of method of measuring protein content in the milk powder specifically may further comprise the steps:
Step 100: the mode determination of setting organic element analyzer: CHN pattern or CHNS pattern;
Step 200: open the organic element analyzer switch, to its test of hunting leak, in the situation without gas leakage, the organic element analyzer device is carried out running parameter set;
Step 210: for the CHN pattern, oxidation furnace temperature: 950
oC, reduction furnace temperature: 500
oC; For the CHNS pattern, oxidation furnace temperature: 1150
oC, reduction furnace temperature: 850
oC;
Step 220: the thermal conductivity detector (TCD) temperature of above two kinds of patterns is made as: 52
oC; Carrier gas (He) pressure: 125 kPa; Carrier gas flux 200 ml/min; Oxygen pressure: 250 kPa, logical oxygen time: 90s～180s;
Step 300: carry out blank assay, number of times is as the criterion less than 1000 less than 100, H peak area with CN S peak area;
Step 400: for the CHN pattern, do three conditionings test with the reference material antifebrin; For the CHNS pattern, do three conditionings test with the reference material aminobenzenesulfonic acid;
Step 500: for the CHN pattern, record a day correction factor with the reference material antifebrin, triplicate is averaged; For the CHNS pattern, record a day correction factor with the reference material aminobenzenesulfonic acid, triplicate is averaged;
Step 600: take by weighing the milk powder sample: accurately take by weighing an amount of milk powder sample of 1.5～200 mg with micro-electronic balance, and wrap in the automatic sampler that compacting sends into organic element analyzer in batches with Xi Zhou;
Step 700: thermal conductivity detector (TCD) detects, and organic element analyzer automatic analysis, calculating obtain nitrogen element content percentage;
Step 800: repeating step 600 and step 700 twice, two the nitrogen element content percentages of getting back;
Step 900: get the mean value of the milk powder sample nitrogen element content percentage that step 700 and step 800 record for three times, multiply by reduction coefficient 6.25, calculate the crude protein content of milk powder sample.
Tested milk powder sample is measured the absolute deviation of resulting three secondary data for three times all less than 2/1000ths; Per 25 left and right sides data three reference materials day correction factor of resurveying of reforming.
Wherein, described milk powder sample comprises: milk powder, and albumen powder, all kinds of solid milk powder of nutrient powder, described nutrient powder is: ground rice, walnut powder, oatmeal, soymilk powder, lotus root starch.
Beneficial effect: the present invention has that the sample demand is few, reagent dosage is few, simple to operate, determination efficiency is high, measure the degree of accuracy advantages of higher, is applicable to the mensuration of protein content in all kinds of dairy products.
Description of drawings
Fig. 1 is the CHN ultimate analysis measurement peak that the milk powder sample carries out ultimate analysis among the embodiment 1.
Fig. 2 is the CHN ultimate analysis measurement peak that the milk powder sample carries out ultimate analysis among the embodiment 7.
Embodiment
A kind of method of measuring protein content in the milk powder of the present invention, it is characterized in that, use organic element analysis principle and instrument, by optimizing milk powder sample use amount, the logical oxygen time, the temperature of combustion parameters is measured nitrogen element content in the milk powder sample, multiply by reduction coefficient, can obtain protein content in the corresponding milk powder sample;
A kind of method of measuring protein content in the milk powder specifically may further comprise the steps:
Step 100: the mode determination of setting organic element analyzer: CHN pattern or CHNS pattern;
Step 200: open the organic element analyzer switch, to its test of hunting leak, in the situation without gas leakage, the organic element analyzer device is carried out running parameter set;
Step 210: for the CHN pattern, oxidation furnace temperature: 950
oC, reduction furnace temperature: 500
oC; For the CHNS pattern, oxidation furnace temperature: 1150
oC, reduction furnace temperature: 850
oC;
Step 220: the thermal conductivity detector (TCD) temperature of above two kinds of patterns is made as: 52
oC; Carrier gas (He) pressure: 125 kPa; Carrier gas flux 200 ml/min; Oxygen pressure: 250 kPa, logical oxygen time: 90s～180s;
Step 300: carry out blank assay, number of times is as the criterion less than 1000 less than 100, H peak area with CN S peak area;
Step 400: for the CHN pattern, do three conditionings test with the reference material antifebrin; For the CHNS pattern, do three conditionings test with the reference material aminobenzenesulfonic acid;
Step 500: for the CHN pattern, record a day correction factor with the reference material antifebrin, triplicate is averaged; For the CHNS pattern, record a day correction factor with the reference material aminobenzenesulfonic acid, triplicate is averaged;
Step 600: take by weighing the milk powder sample: accurately take by weighing an amount of milk powder sample of 1.5～200 mg with micro-electronic balance, and wrap in the automatic sampler that compacting sends into organic element analyzer in batches with Xi Zhou;
Step 700: thermal conductivity detector (TCD) detects, and organic element analyzer automatic analysis, calculating obtain nitrogen element content percentage;
Step 800: repeating step 600 and step 700 twice, two the nitrogen element content percentages of getting back;
Step 900: get the mean value of the milk powder sample nitrogen element content percentage that step 700 and step 800 record for three times, multiply by reduction coefficient 6.25, calculate the crude protein content of milk powder sample.
Tested milk powder sample is measured the absolute deviation of resulting three secondary data for three times all less than 2/1000ths; Per 25 left and right sides data three reference materials day correction factor of resurveying of reforming.
Wherein, described milk powder sample comprises: milk powder, and albumen powder, all kinds of solid milk powder of nutrient powder, described nutrient powder is: ground rice, walnut powder, oatmeal, soymilk powder, lotus root starch.
The present invention is described in detail below in conjunction with drawings and Examples.
Embodiment 1
Take by weighing 2.000 mg powdered milk samples in the tin boat, wrap the automatic sampler that compacting places organic element analyzer; The operating parameter of ultimate analysis is: the CHN pattern, temperature of combustion is made as 950
oC, logical O
2Time is 90 s; Carrying out determination of elemental analysis N content is 2.731%.Repeat to comprise the above operation twice of weighing, determination of elemental analysis N content is respectively 2.724%, 2.698%; Get mean value 2.718% three times, multiply by reduction coefficient 6.25, the crude protein content that obtains in the powdered milk sample is 16.99%, with reference to Fig. 1.
Embodiment 2
Get 10.000 mg powdered milk samples in the tin boat, wrap the automatic sampler that compacting places organic element analyzer; The operating parameter of ultimate analysis is: the CHNS pattern, temperature of combustion is made as 1150
oC, logical O
2Time is 120 s; Carrying out determination of elemental analysis N content is 3.018%.Repeat to comprise the above operation twice of weighing, determination of elemental analysis N content is respectively 3.032%, 2.984%, gets mean value 3.011% three times, multiply by reduction coefficient 6.25, and the crude protein content that obtains in the powdered milk sample is 18.82%.
Embodiment 3
Get 50.000 mg ourishing rice flour samples in the tin boat, wrap the automatic sampler that compacting places organic element analyzer; The operating parameter of ultimate analysis is: the CHNS pattern, temperature of combustion is made as 1150
oC, logical O
2Time is 150 s; Carrying out determination of elemental analysis N content is 1.056%.Repeat to comprise the above operation twice of weighing, determination of elemental analysis N content is respectively 1.053%, 1.036%, gets mean value 1.048% three times, multiply by reduction coefficient 6.25, and the crude protein content that obtains in the ourishing rice flour sample is 6.55%.
Embodiment 4
Get 200.000 mg nutrition walnut powder samples in the tin boat, wrap the automatic sampler that compacting places organic element analyzer; The operating parameter of ultimate analysis is: the CHN pattern, temperature of combustion is made as 950
oC, logical O
2Time is 180 s; Carrying out determination of elemental analysis N content is 1.004%.Repeat to comprise the above operation twice of weighing, determination of elemental analysis N content is respectively 1.028%, 1.018%, gets mean value 1.017% three times, multiply by reduction coefficient 6.25, and the crude protein content that obtains in the walnut powder sample is 6.36%.
Embodiment 5
Get 100.000 mg nutrition oatmeal samples in the tin boat, wrap the automatic sampler that compacting places organic element analyzer; The operating parameter of ultimate analysis is: the CHNS pattern, temperature of combustion is made as 1150
oC, logical O
2Time is 150 s; Carrying out determination of elemental analysis N content is 2.015%.Repeat to comprise the above operation twice of weighing, determination of elemental analysis N content is respectively 1.945%, 1.933%, gets mean value 1.964% three times, multiply by reduction coefficient 6.25, and the crude protein content that obtains in the nutrition oatmeal sample is 12.28%.
Embodiment 6
Get 1.500 mg soymilk powder in the tin boat, wrap the automatic sampler that compacting places organic element analyzer; The operating parameter of ultimate analysis is: the CHN pattern, temperature of combustion is made as 950
oC, logical O
2Time is 90 s; Carrying out determination of elemental analysis N content is 2.626%.Repeat to comprise the above operation twice of weighing, determination of elemental analysis N content is respectively 2.577%, 2.590%, gets mean value 2.598% three times, multiply by reduction coefficient 6.25, and the crude protein content that obtains in the albumen powder sample is 16.24%.
Embodiment 7
Get 2.000 mg protein powders in the tin boat, wrap the automatic sampler that compacting places organic element analyzer; The operating parameter of ultimate analysis is: the CHN pattern, temperature of combustion is made as 950
oC, logical O
2Time is 90 s; Carrying out determination of elemental analysis N content is 12.45%.Repeat to comprise the above operation twice of weighing, determination of elemental analysis N content is respectively 12.64%, 12.58%, gets mean value 12.56% three times, multiply by reduction coefficient 6.25, and the crude protein content that obtains in the albumen powder sample is 78.50%, with reference to Fig. 2.
Above content is the further description of the present invention being done in conjunction with optimal technical scheme, can not assert that the implementation of invention only limits to these explanations.Concerning the general technical staff of the technical field of the invention, under the prerequisite that does not break away from design of the present invention, can also make simple deduction and replacement, all should be considered as protection scope of the present invention.
Claims (2)
1. method of measuring protein content in the milk powder, it is characterized in that, use organic element analysis principle and instrument, by optimizing milk powder sample use amount, the logical oxygen time, the temperature of combustion parameters is measured nitrogen element content in the milk powder sample, multiply by reduction coefficient, can obtain protein content in the corresponding milk powder sample;
A kind of method of measuring protein content in the milk powder specifically may further comprise the steps:
Step 100: the mode determination of setting organic element analyzer: CHN pattern or CHNS pattern;
Step 200: open the organic element analyzer switch, to its test of hunting leak, in the situation without gas leakage, the organic element analyzer device is carried out running parameter set;
Step 210: for the CHN pattern, oxidation furnace temperature: 950
oC, reduction furnace temperature: 500
oC; For the CHNS pattern, oxidation furnace temperature: 1150
oC, reduction furnace temperature: 850
oC;
Step 220: the thermal conductivity detector (TCD) temperature of above two kinds of patterns is made as: 52
oC; Nebulizer gas pressure: 125 kPa; Carrier gas flux 200 ml/min; Oxygen pressure: 250 kPa, logical oxygen time: 90s～180s;
Step 300: carry out blank assay, number of times is as the criterion less than 1000 less than 100, H peak area with CN S peak area;
Step 400: for the CHN pattern, do three conditionings test with the reference material antifebrin; For the CHNS pattern, do three conditionings test with the reference material aminobenzenesulfonic acid;
Step 500: for the CHN pattern, record a day correction factor with the reference material antifebrin, triplicate is averaged; For the CHNS pattern, record a day correction factor with the reference material aminobenzenesulfonic acid, triplicate is averaged;
Step 600: take by weighing the milk powder sample: accurately take by weighing an amount of milk powder sample of 1.5～200 mg with micro-electronic balance, and wrap in the automatic sampler that compacting sends into organic element analyzer in batches with Xi Zhou;
Step 700: thermal conductivity detector (TCD) detects, and organic element analyzer automatic analysis, calculating obtain nitrogen element content percentage;
Step 800: repeating step 600 and step 700 twice, two the nitrogen element content percentages of getting back;
Step 900: get the mean value of the milk powder sample nitrogen element content percentage that step 700 and step 800 record for three times, multiply by reduction coefficient 6.25, calculate the crude protein content of milk powder sample.
2. described a kind of method of measuring protein content in the milk powder according to claim 1, it is characterized in that described milk powder sample comprises: milk powder, albumen powder, all kinds of solid milk powder of nutrient powder, described nutrient powder is: ground rice, walnut powder, oatmeal, soymilk powder, lotus root starch.
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|---|---|---|---|
| CN2012103049415A CN102879538A (en) | 2012-08-26 | 2012-08-26 | Method for measuring protein content in milk powder |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103487461A (en) * | 2013-09-22 | 2014-01-01 | 西安航天化学动力厂 | Quick analysis method for content of bound acrylonitrile in chemigum |
| CN107677796A (en) * | 2017-08-22 | 2018-02-09 | 上海市质量监督检验技术研究院 | The quantitative detecting method of graphene in textile |
| CN111351894A (en) * | 2020-04-24 | 2020-06-30 | 内蒙古利诚实业有限公司 | Milk powder adulteration detection device and method |
| CN116399996A (en) * | 2023-06-02 | 2023-07-07 | 海能未来技术集团股份有限公司 | Organic element analysis method and device based on thermal conductivity detection and electronic equipment |
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| US4497898A (en) * | 1982-08-25 | 1985-02-05 | The United States Of America As Represented By The Secretary Of Agriculture | Spectrophotometric method for simultaneously analyzing protein and fat contents in milk |
| CN101034065A (en) * | 2006-03-07 | 2007-09-12 | 桑华春 | Reagent kit for quickly testing protein content of milk powder and method for making same |
| CN101059447A (en) * | 2007-05-25 | 2007-10-24 | 中国农业大学 | Method for analyzing protein nitrogen content of milk powder |
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| US4497898A (en) * | 1982-08-25 | 1985-02-05 | The United States Of America As Represented By The Secretary Of Agriculture | Spectrophotometric method for simultaneously analyzing protein and fat contents in milk |
| CN101034065A (en) * | 2006-03-07 | 2007-09-12 | 桑华春 | Reagent kit for quickly testing protein content of milk powder and method for making same |
| CN101059447A (en) * | 2007-05-25 | 2007-10-24 | 中国农业大学 | Method for analyzing protein nitrogen content of milk powder |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103487461A (en) * | 2013-09-22 | 2014-01-01 | 西安航天化学动力厂 | Quick analysis method for content of bound acrylonitrile in chemigum |
| CN107677796A (en) * | 2017-08-22 | 2018-02-09 | 上海市质量监督检验技术研究院 | The quantitative detecting method of graphene in textile |
| CN111351894A (en) * | 2020-04-24 | 2020-06-30 | 内蒙古利诚实业有限公司 | Milk powder adulteration detection device and method |
| CN116399996A (en) * | 2023-06-02 | 2023-07-07 | 海能未来技术集团股份有限公司 | Organic element analysis method and device based on thermal conductivity detection and electronic equipment |
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Application publication date: 20130116 |