CN104165886A - Method for determining grain protein - Google Patents
Method for determining grain protein Download PDFInfo
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- CN104165886A CN104165886A CN201410376482.0A CN201410376482A CN104165886A CN 104165886 A CN104165886 A CN 104165886A CN 201410376482 A CN201410376482 A CN 201410376482A CN 104165886 A CN104165886 A CN 104165886A
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Abstract
The invention discloses a method for determining grain protein. The method comprises the following specific steps: putting a certain quantity of grain samples into a 50ml digestive tube; performing digestion on the samples in the presence of concentrated H2SO4-H2O2 in a digestion furnace until a solution is clear bright; transferring digestion liquor into a 100ml volumetric flask, filtering, and determining filter liquor with a Nessler method. The method has the advantages of high measurement precision and easiness and convenience in operation and can be suitable for detecting the protein content of various grains.
Description
Technical field
The present invention relates to a kind of assay method of corn protein.
Background technology
Protein is an important indicator that determines cereal edible quality, and conventional national standard method adopts dense H at present
2sO
4-catalyzer disappears and boils, Kjeldahl nitrogen determination.But the method has the following disadvantages: dense H
2sO
4-catalyzer disappear boil with these two processes of kjeldahl determination consuming time time-consuming all longer, complex operation, disappearing, it is many to boil catalyst amount.In production and scientific research, for completing the mensuration of gross sample, need to adopt quick, easy analytical approach.At present, in bibliographical information, there is the rapid assay methods of many corn proteins, for example biuret colourimetry, dye binding method, ninhydrin method.
Summary of the invention
The object of the invention is to overcome the deficiency in current national standard method, then for the mensuration of corn protein provide a kind of relatively accurately, fast, the method for easy operating.The present invention adopts dense H
2sO
4-H
2o
2disappear and boil, use dense H
2sO
4and H
2o
2carbohydrates in cereal is converted into carbon dioxide and water, the nitrogen in protein is converted into ammonium nitrogen, the ammonium nitrogen boiling in liquid that disappears is measured with Na's colorimetry.Compare with national standard method, this method has the following advantages: in (1) national standard method, adopt dense H
2sO
4-catalyzer disappears and boils, and catalyst amount is more, and this method is without with catalyzer, thereby has reduced analysis cost, and Digestion time can shorten 1/3 simultaneously.(2) in the mensuration of gross sample, in national standard method, Kjeldahl's method is consuming time longer, and water consumption is more, and Na's colorimetry has not only been saved the time, has also saved cost.
Technical scheme of the present invention is:
An assay method for corn protein content, is characterized in that, comprises the following steps:
(1) the paddy rice sample that takes 0.1000-0.3000g is placed in 50ml digest tube, adds the dense H of 5ml
2sO
4, be placed in far infrared and disappear and boil stove, in 80-100 ℃ of heating, treat dense H
2sO
4decompose and emit white cigarette rising temperature, until solution transfers brownish black to;
(2) take off cooling 1-5 minute, drip 300g/L H
2o
25-10 drips, and shakes up, and disappears to boil on stove heat 5-10min in far infrared, takes off cooling 1-5 minute, drips 300g/L H
2o
25-10 drips and shakes up, and disappears to boil on stove, heat 5-10min in far infrared, so repeatedly until disappear and boil liquid and be after colourless or limpid look, then heats 5-10min, disappears that it is complete to boil, and will disappear to boil liquid and be transferred in 100ml volumetric flask, after constant volume, filters;
(3) preparation typical curve: draw respectively 10ug/ml nitrogen (NH
4 +-N) standard solution 0.0,0.5,1.0,2.0,4.0,6.0,8.0,10ml, in 50ml color comparison tube, add the 500g/L potassium sodium tartrate solution of 1ml, add 1ml nessler reagent after shaking up again, and shake up; Place 10min, in wavelength 420nm place colorimetric; Take absorbance for being horizontal ordinate, and corresponding nitrogen content (ug) is ordinate, drawing standard curve;
(4) accurately draw 1ml filtrate in 50ml color comparison tube, add suitable quantity of water, with NaOH solution, be adjusted to neutrality, add 1ml 500g/L potassium sodium tartrate solution, then add 1ml nessler reagent, after constant volume, shake up, after 10min in 420nm colorimetric; The computing formula of corn protein is:
In formula:
ρ-check in from the typical curve content (ug) of nitrite ion N;
Ts-minute get multiple, disappears and boils liquid constant volume (ml)/absorption and disappear and boil liquid long-pending (ml);
K-nitrogen is converted into the coefficient of protein, and paddy rice coefficient is 5.95, and corn coefficient is 6.25, and oat coefficient is 5.83;
M-sample quality (g).
The present invention adopts dense H
2sO
4-H
2o
2disappear and boil, H
2o
2add mode for taking off after cooling 1-5 minute, dropwise add 300g/L H
2o
210, shake up, then heat 10min, take off after cooling 1-5 minute, then add H
2o
25-10 drips, and 2-3 time so repeatedly, until disappear, boils liquid and is colourless or limpid look.
Drip H
2o
2at the bottom of should directly splashing into bottle, prevent that it from decomposing, and loses oxidation effectiveness.
This method to the mensuration of corn protein relatively accurately and easy operating, not only economy but also save time.
Embodiment
Invention is further described in conjunction with the embodiments.
Embodiment 1: a kind of assay method of corn protein
Take 0.1152g paddy rice sample and be placed in 50ml digest tube, add the dense H of 5ml
2sO
4, be placed in far infrared and disappear and boil on stove, in 80-100 ℃ of heating, treat dense H
2sO
4decompose and emit white cigarette rising temperature, until solution transfers brownish black to, digest tube is boiled to stove from disappearing and take off, cooling 1 minute, dropwise add 300g/LH
2o
210, shake up, in disappearing, boil on stove and heat again 10min, take off cooling 1 minute, after add again 300g/LH
2o
210,2-3 time so repeatedly, until disappear, boil liquid and be after colourless or limpid look, then heat 10min, to eliminate superfluous H
2o
2, disappearing, it is complete to boil; To disappear and boil liquid and be transferred in 100ml volumetric flask, after constant volume, filter; Accurately draw 1ml filtrate in 50ml color comparison tube, add suitable quantity of water, with NaOH solution, be adjusted to neutrality, add 1ml 500g/L potassium sodium tartrate solution, add again 1ml nessler reagent, after constant volume, shake up, place after 10min, under wavelength 420nm, use 1cm cuvette, with water, make reference, measure absorbance; Preparation typical curve: draw respectively 0.0,0.5,1.0,2.0,4.0,6.0,8.0,10ml10ug/ml nitrogen standard solution in 50ml color comparison tube, add 1ml potassium sodium tartrate solution, after shaking up, add again 1ml nessler reagent, shake up; Place 10min, at wavelength 420nm place, measure absorbance; Take absorbance as horizontal ordinate, and take its corresponding nitrogen content (ug) is ordinate, drawing standard curve.The content that checks in N from typical curve is 17.2ug, and minute getting multiple is 100, utilizes the computing formula of corn protein, and the content that calculates protein in paddy rice is 8.88%.
Embodiment 2: a kind of assay method of corn protein
Take 0.1232g corn sample and be placed in 50mlization pipe, add the dense H of 5ml
2sO
4, be placed in far infrared and disappear and boil on stove, in 80-100 ℃ of heating, treat dense H
2sO
4decompose and emit white cigarette rising temperature, until solution transfers brownish black to, digest tube is boiled to stove from disappearing and take off, cooling 5 minutes, dropwise add 300g/L H
2o
210, shake up, in disappearing, boil on stove and heat again 10min, take off after cooling 5 minutes and add again 300g/L H
2o
25,2-3 time so repeatedly, until disappear, boil liquid and be after colourless or limpid look, then heat 5min, to eliminate superfluous H
2o
2, disappearing, it is complete to boil; To disappear and boil liquid and be transferred in 100ml volumetric flask, after constant volume, filter; Accurately draw 1ml filtrate in 50ml color comparison tube, add suitable quantity of water, with NaOH solution, be adjusted to neutrality, add 1ml 500g/L potassium sodium tartrate solution, add again 1ml nessler reagent, after constant volume, shake up, place after 10min, under wavelength 420nm, use 1cm cuvette, with water, make reference, measure absorbance; Do blank test simultaneously; Preparation typical curve: draw respectively 0.0,0.5,1.0,2.0,4.0,6.0,8.0,10ml 10ug/ml ammonia nitrogen standard solution in 50ml color comparison tube, add 1ml potassium sodium tartrate solution, after shaking up, add again 1ml nessler reagent, shake up.Place 10min, at wavelength 420nm place, measure absorbance; Take absorbance as ordinate, and take its corresponding nitrogen content (ug) is horizontal ordinate, drawing standard curve; The content that checks in N from typical curve is 16.04ug, and minute getting multiple is 100, utilizes the computing formula of corn protein, and the content that calculates protein in paddy rice is 8.14%.
In addition, the accuracy for checking the method result, compares with national standard method, the results are shown in Table 1.
The measurement result of table 1 corn protein (%)
As seen from Table 1, measurement result of the present invention and national standard method measured result difference are little, and the error between parallel is also all within error allowed band.
Claims (3)
1. an assay method for corn protein content, is characterized in that, comprises the following steps:
(1) the paddy rice sample that takes 0.1000-0.3000g is placed in 50ml digest tube, adds the dense H of 5ml
2sO
4, be placed in far infrared and disappear and boil stove, in 80-100 ℃ of heating, treat dense H
2sO
4decompose and emit white cigarette rising temperature, until solution transfers brownish black to;
(2) take off cooling 1-5 minute, drip 300g/L H
2o
25-10 drips, and shakes up, and disappears to boil and on stove, heats 5-10min, then take off cooling 1-5 minute in far infrared, drips 300g/L H
2o
25-10 drips and shakes up, and disappears to boil on stove, heat 5-10min in far infrared, so repeatedly until disappear and boil liquid and be after colourless or limpid look, then heats 5-10min, disappears that it is complete to boil, and will disappear to boil liquid and be transferred in 100ml volumetric flask, after constant volume, filters;
(3) preparation typical curve: draw respectively 10ug/ml nitrogen (NH
4 +-N) standard solution 0.0,0.5,1.0,2.0,4.0,6.0,8.0,10ml, in 50ml color comparison tube, add the 500g/L potassium sodium tartrate solution of 1ml, add 1ml nessler reagent after shaking up again, and shake up; Place 10min, in wavelength 420nm place colorimetric; Take absorbance for being horizontal ordinate, and corresponding nitrogen content (ug) is ordinate, drawing standard curve;
(4) accurately draw 1ml filtrate in 50ml color comparison tube, add suitable quantity of water, with NaOH solution, be adjusted to neutrality, add 1ml 500g/L potassium sodium tartrate solution, then add 1ml nessler reagent, after constant volume, shake up, after 10min in 420nm colorimetric; The computing formula of corn protein is:
In formula:
ρ-check in from the typical curve content (ug) of nitrite ion N;
Ts-minute get multiple, disappears and boils liquid constant volume (ml)/absorption and disappear and boil liquid long-pending (ml);
K-nitrogen is converted into the coefficient of protein, and paddy rice coefficient is 5.95, and corn coefficient is 6.25, and oat coefficient is 5.83;
M-sample quality (g).
2. a kind of assay method of corn protein according to claim 1, it is characterized in that: adopt dense H2SO4-H2O2 to disappear and boil, H2O2 adds mode for taking off after cooling 1-5 minute, dropwise add 300g/L H2O210 to drip, shake up, then heat 10min, take off after cooling 1-5 minute, add again H2O25-10 and drip, 2-3 time so repeatedly, until disappear, boil liquid and be colourless or limpid look.
3. a kind of assay method of corn protein according to claim 1, is characterized in that: at the bottom of dripping H2O2 and should directly splashing into bottle.
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|---|---|---|---|
| CN201410376482.0A CN104165886A (en) | 2014-08-01 | 2014-08-01 | Method for determining grain protein |
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|---|---|---|---|
| CN201410376482.0A CN104165886A (en) | 2014-08-01 | 2014-08-01 | Method for determining grain protein |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106908408A (en) * | 2017-03-01 | 2017-06-30 | 四川农业大学 | A kind of assay method of Itanlian rye crude protein content |
| CN107941801A (en) * | 2017-12-29 | 2018-04-20 | 青岛袁策生物科技有限公司 | A kind of method of high frequency zone salt alkaline tolerance rice |
| CN111089861A (en) * | 2020-01-20 | 2020-05-01 | 甘肃省农业科学院经济作物与啤酒原料研究所（甘肃省农业科学院中药材研究所） | Method for determining nitrogen, phosphorus and potassium contents of barley plants |
| CN111398193A (en) * | 2020-04-02 | 2020-07-10 | 重庆瑞钛科技有限公司 | Method for rapidly detecting protein content in grain for wine brewing |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN2862011Y (en) * | 2006-01-23 | 2007-01-24 | 张志有 | Slaking furnace |
| US20140024120A1 (en) * | 2007-08-29 | 2014-01-23 | Cem Corp. | Automated protein analyzer |
| CN203605717U (en) * | 2013-11-15 | 2014-05-21 | 廊坊师范学院 | Digestion furnace special for food chemistry |
-
2014
- 2014-08-01 CN CN201410376482.0A patent/CN104165886A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN2862011Y (en) * | 2006-01-23 | 2007-01-24 | 张志有 | Slaking furnace |
| US20140024120A1 (en) * | 2007-08-29 | 2014-01-23 | Cem Corp. | Automated protein analyzer |
| CN203605717U (en) * | 2013-11-15 | 2014-05-21 | 廊坊师范学院 | Digestion furnace special for food chemistry |
Non-Patent Citations (2)
| Title |
|---|
| 徐卸佐，鋃正: "H2SO4-H2O2消化纳氏比色测定蛋白质", 《浙江预防医学》 * |
| 鲍士旦: "《农蓄水产品品质化学分析》", 31 July 1996, 中国农业出版社 * |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106908408A (en) * | 2017-03-01 | 2017-06-30 | 四川农业大学 | A kind of assay method of Itanlian rye crude protein content |
| CN107941801A (en) * | 2017-12-29 | 2018-04-20 | 青岛袁策生物科技有限公司 | A kind of method of high frequency zone salt alkaline tolerance rice |
| CN111089861A (en) * | 2020-01-20 | 2020-05-01 | 甘肃省农业科学院经济作物与啤酒原料研究所（甘肃省农业科学院中药材研究所） | Method for determining nitrogen, phosphorus and potassium contents of barley plants |
| CN111398193A (en) * | 2020-04-02 | 2020-07-10 | 重庆瑞钛科技有限公司 | Method for rapidly detecting protein content in grain for wine brewing |
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Application publication date: 20141126 |