This standard is modified to adopt ISO 3093:2004 "Determination of falling number for wheat, rye and flour, durum and semolina - Hagberg-Perten method" (English version). This standard replaces GB/T 10361-1989 "Determination of falling number for cereals". This standard specifies the method for determining the activity of α-amylase in cereals using the falling number method. This standard is applicable to cereals, especially to wheat, rye and flour, durum and semolina. This standard specifies the particle size of whole durum semolina and whole wheat flour. This standard is not applicable to the determination of low α-amylase activity. For relevant methods, please refer to ISO 7973. The main changes of this standard compared with GB/T 10361-1989 are as follows: --- Increase the scope of application of the method; --- Add the concept of liquefaction value; --- Specify the specific operation process of crushing samples; --- Add the correction formula for different altitudes and the conversion formula between falling number and liquefaction value; --- Modify the precision requirements; --- Add Appendix A (Formula for correction of falling number according to altitude) and Appendix B (Test results between laboratories). GB/T 10361-2008 Determination of falling number of wheat, rye and their flour, durum and their coarse meal Hagberg-Perten method GB/T10361-2008 standard download decompression password: www.bzxz.net
This standard is modified to adopt ISO 3093:2004 "Determination of falling number of wheat, rye and their flour, durum and their coarse meal Hagberg-Perten method" (English version). This standard replaces GB/T 10361-1989 "Determination of falling number in cereals". This standard specifies the method for determining the activity of α-amylase in cereals by the falling number method. This standard is applicable to cereals, especially wheat, rye and its flour, durum wheat and its semolina. This standard specifies the particle size of whole durum wheat semolina and whole wheat flour. This standard is not applicable to the determination of low α-amylase activity. For relevant methods, please refer to ISO 7973. The main changes of this standard compared with GB/T 10361-1989 are as follows: ———Increased the scope of application of the method; ———Increased the concept of liquefaction value; ———Specified the specific operation process of crushing samples; ———Added the correction formula for different altitudes and the conversion formula between falling number and liquefaction value; ———Modified the precision requirements; ———Added Appendix A (Formula for Correction of Falling Number According to Altitude) and Appendix B (Test Results between Laboratories).

The clauses in the following documents become the clauses of this standard through reference in this standard. For all dated referenced documents, all subsequent amendments (excluding errata) or revisions are not applicable to this standard. However, the parties to the agreement based on this standard are encouraged to study whether the latest versions of these documents can be used. For all undated referenced documents, the latest versions are applicable to this standard.
GB/T6005 Basic dimensions of mesh holes of wire mesh, perforated plate and electroformed sheet for test sieves (GB/T6005-1997, eqvISO565:1990)
GB/T21305 Conventional method for determination of moisture content of cereals and cereal products (GB/T21305-2007, ISO712:1998, IDT)
GB/T6003.1 Wire mesh test sieves (GB/T6003.1-1997, eqvISO3310-1:1990)
GB/T6682 Specifications and test methods for water for analytical laboratories (GB/T6682-2008, ISO3696:1987, MOD)

ICS 67.040
National Standard of the People's Republic of China
GB/T10361—2008
Replaces GB/T10361—1989
Wheat, rye and respeclive flours, durum wheat and durum wheat semolina--Determination of the falling number according to Hagberg-Perten(IS03093:2004,MOD)
Published on November 4, 2008
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
Implemented on January 1, 2009
GB/T 10361--2008
Determination of falling number
This standard modifies and adopts 1S03093:2004 "Wheat, rye and their flour, durum wheat and its semolina Haghcrg-Perten method" (English version). The main differences between this standard and ISO3093:2001 are as follows: The requirements for the basic size of the test sieve holes shall be in accordance with CB/T6005 (GB/T6005-1997, eqVISO565:1990). The requirements for metal wire mesh test sieves shall be in accordance with GB/T6003.1 (GB/T6003.1-1997eqISO3310-1:1990): - The specifications for water used in analytical laboratories shall be in accordance with GB/T6682 (GB/T6682-2008, ISO3696:1987, MOD). For ease of use, this standard has been edited as follows: the foreword of the international standard has been deleted, and "this international standard" has been changed to "this standard"; the decimal point "\" has been used instead of the decimal point "\" in the original text, and the relevant formulas have been numbered; the calculation formula of the liquefaction value in 9.4.2 of the original text, NL--6000/(IC-50), is incorrect, and "NL" has been changed to "LN\, and "IC" has been changed to "FN\. This standard replaces GB/T10361--1989 "Determination of Grain Falling Number". The main changes of this standard compared with GB/T10361--19389 are as follows: the scope of application of the method has been increased; the concept of liquefaction value has been added; t||Specifies the specific sample crushing operation process; -Adds correction formulas for different altitudes and conversion formulas between falling number and liquefaction value -Modifies precision requirements;
-Adds Appendix A (Formula for correcting falling number according to altitude) and Appendix B (Test results between laboratories). Appendix A of this standard is a normative appendix, and the appendix is ​​an informative appendix. This standard is proposed by the State Grain Industry.
This standard is under the jurisdiction of the National Technical Committee for Grain and Oil Standardization. Drafting units of this standard: National Grain Administration Scientific Research Institute, 1. Haijiading Grain and Oil Instrument Co., Ltd. Drafters of this standard: Tian Xiaohong, Xue Yalin, Zhuang Jian, Tan Hongzhuo, Tan Bin, Liu Ming. The previous versions of the standards replaced by this standard are: -GB/T 10361- 1989.
1 Scope
Determination of falling number of wheat, rye and its flour, durum wheat and its coarse powder Hagberg-Perten method GB/T 10361-—2008
This standard specifies the method for determining the activity of α-amylase in cereals using the falling number method. This standard is applicable to cereals, especially wheat, rye and its flour, durum wheat and its semolina. This standard specifies the particle size of whole durum wheat semolina and whole wheat flour
This standard is not applicable to the determination of low α-amylase activity. The relevant methods can refer to ISO7973. By converting the falling number to the liquefaction value (LN), the composition of the mixture of cereals, flour or semolina required to produce products with requirements for falling numbers can be calculated.
2 Normative references
The provisions in the following documents become the provisions of this standard through reference in this standard. For any dated referenced document, all subsequent amendments (excluding errata) or revisions are not applicable to this standard. However, parties to an agreement based on this standard are encouraged to Study whether the latest versions of these documents can be used. For any un-dated referenced documents, the latest versions shall apply to this standard. GB/T6005 Basic dimensions of sieve holes for metal wire mesh, perforated plate and electroformed plate for test sieves (GB/T6005-1997, ISO 565: 1990)
GB/T21305 Conventional method for determination of moisture in cereals and cereal products (GB/T21305-2007, ISO 712: 1998. ID)T) GB/T6003.1 Metal wire mesh test sieve (GB/T6003.1-1997, ISO 3310-1: 1990) GB/T6682 Specifications and test methods for water for analytical laboratories (GB/T6682-2008, ISO 3696: 1987, MOD) 3 Terms and definitions
The following terms and definitions apply to this standard. 3.1
Falling number
In a viscosity tube, a mixture of flour or semolina and water is heated to obtain a gelatinized product. The gelatinized product is liquefied under the action of α-amylase. A stirrer is passed through the gelatinized product. The time taken to pass a specific distance is the falling number in seconds. Note: The time is calculated from the time when the viscosity tube is immersed in the water. 3.2
Liquefactiounumber
The value converted from the falling number (FN) by simple calculation is used to estimate the composition of the mixture of grain flour or semolina required for the product with a falling number requirement during production.
Note: Unlike the falling number, the values ​​of the liquefaction number (LN) can be added. 4 Principle
Flour, semolina and wholemeal suspensions are rapidly gelatinized in a boiling water bath. Due to the different activities of α-amylase in the gelatinized materials, the starch in them is liquefied to different degrees. The different degrees of liquefaction require different times for the viscosity stirrer to fall a specific distance in the gelatinized materials. Therefore, the falling number indicates the difference in the corresponding amylase activity. A high falling number indicates low α-amylase activity, and vice versa.
5 Reagents
Water is distilled water or deionized water, which meets the requirements of GB/T6682 medium-grade water. 6 Instruments
Routine laboratory instruments, especially the following equipment: 6. "Falling number tester 1, including the following components 6.1. "Water bath device: composed of an integral heating single gas cooling system and a water level indicator 6.1.2 Electronic timer.
6.1.3 Viscosity stirrer: gold
in hard orange
6.1.4 Refined viscosity tube:
made of special corrugated glass
- inner diameter is 21.
- outer diameter is 23180
inner height is 20
6.1.5 Rubber stopper: match with
tube.
6.2 Automatic liquid adder
liquid calculation: capacity is
6.3 Analytical balance: sub
6.4 Experimental mill 2: hammer
e0.01g.
with a hole diameter of 0
mixed grain sample!
The laboratory mill should be equipped with
6.5 Inspection sieve aperture
7 Sampling
The sampling device in 1.2, especially
, should comply with
Sampling is not specified in this standard
Check the properties of experimental fat
wheat samples
, it is recommended to use ISO13690. The kernel weight requirements specified in
1.3 should be used. The samples received by the laboratory should be of quality and should not be damaged or changed during transportation or storage. The storage time and storage conditions of the samples in the laboratory have an important impact on the reduction value.
8 Sample preparation
8.1 Whole grain samples
8. 1,1 Impurity Removal
Take 300 representative samples from the experimental blank sample and remove impurities (such as sand, dust, husk or other grains) in the sample.
1) The falling number tester with a resolution stirrer produced by Pertcn is currently the most widely used instrument for measuring the falling number of grains. The instrument is patented. This information is provided only for the convenience of users of this standard and is not an ISO endorsement of the instrument. Any instrument that can obtain the same results as its method can be used.
2) The 310) and 120 mills produced by Ferten can be used. This information is provided only for the users of this standard and is not an ISO endorsement of the instrument. Any instrument that can obtain the same results as its method can be used. 2
Small samples of about 200 grams can provide less reproducible results and are generally used for routine inspections. If the sample size is less than 200 grams, the probability of erroneous results will increase. 8.1.2 Grinding samples
GB/T 10361—2008
Be careful when feeding the test mill to prevent overloading or overheating. An automatic sample feeding device can be used. After all the samples have entered the test mill, continue grinding for 30s to 405. If the bran particles remaining in the grinding chamber after grinding do not exceed 1% of the total mass, these brans can be discarded. All the pulverized samples must be fully mixed before use. Before testing, the pulverized samples (especially in the case of continuous pulverization) should be cooled at room temperature for 1h. 8.1.3 Whole wheat flour particle size
Warning: The particle size of whole wheat flour affects the falling value. The pulverized samples should meet the particle size distribution requirements in Table 1. Table 1 Requirements for particle distribution of total differential powder
Sieve size/μm
710(CQ10)
500(CQ14)
210.-200(CQ30)
The particle size distribution of the crushed sample (8.1.2) should be checked regularly. Undersize/%
95~100
The particle size distribution can be checked according to the following method. According to the provisions of Table 1, select a suitable sample sieve, and place the sample sieves from 1 to the bottom according to the principle of gradually decreasing sieve size, with the bottom layer as the sieve bottom. Weigh 50 representative samples and put them on the top sieve. Sieve horizontally, sieve at L, and the sieving time shall not be less than 5 minutes. If it is sieved electrically, the sieving time shall not be less than 10 minutes, and sieve until no sample passes through the sieve layer. Weigh the mass of the sample remaining on each sieve layer and calculate the percentage of the sample passing through each sieve layer. 8.2 Flour and Semolina Samples
The flour should be free of lumps. If there are lumps, use the test sieve (6.5) to remove the lumps and other impurities in the flour. For commercially available whole wheat flour or semolina, in order to prepare the test sample that meets the particle size distribution requirements in Table 1, use the laboratory mill (6.4) to grind the sample. All the ground samples should be mixed thoroughly before the sample is measured. 9 Operation steps
9.1 Moisture determination
The falling number method is based on a moisture content of 15% in wheat flour or other pulverized samples. Determine the moisture content of the test sample according to GI3/T21305. Alternatively, a rapid instrument method (near infrared reflectance method) calibrated according to GB/T21305 can be used.
9.2 Weighing
Measure two samples at the same time, or measure one sample immediately after measuring the other. To ensure that the samples for the falling number determination have the same substance, the sample amounts to be weighed for samples with different moisture contents are shown in the second column of Table 2.
If it is necessary to distinguish the falling number differences of samples with higher α-amylase activity (such as Ximai), the corresponding sample amounts can be weighed according to the third column of Table 2.
Weigh to an accuracy of 0.05 g
GB/T10361—2008
Moisture content/
Table 2 Relationship between sample weight and moisture content
Sample weight/g
Equivalent to 7g when moisture content
15%
Sample sample
9.3 Falling number determination
Equivalent to 9g when moisture content
15%
Moisture content/
Sample weight/g
Equivalent to 7g when moisture content
15%
Sample sample
Equivalent to 9g when moisture content
15%
Sample sample
9.3.1 Add water to the water bath (6.1.1) to the calibrated output line. Turn on the cooling system and ensure that cold water flows through the cooling cover. Turn on the power switch of the falling number tester and heat the water bath until the water boils: make sure that the water bath boils vigorously before and during the determination. 9.3.2 Transfer the weighed sample (9.2) into a dry, clean viscosity tube (6.1.4). Use an automatic liquid feeder (6.2) to add 25 mL ± 0.2 mL of water at a temperature of 22 °C + 2 °C (Chapter 5). 9.3.3 Immediately close the rubber stopper (6.1.5) and shake up and down 20 to 30 times to obtain a homogeneous suspension. Make sure that there is no dry flour or crushed material near the rubber stopper of the viscosity tube. If there is dry powder, move the rubber stopper slightly upward and shake again. 3) The automatic shaking device manufactured by Perten can easily make the suspension homogenous. This information is provided only for the convenience of users of this standard and does not constitute an endorsement of the instrument by IS().
GB/T10361—2008
9.3.4 Pull out the rubber stopper (6.1.5), scrape all the residues remaining at the bottom of the rubber stopper into the viscosity tube (6.1.4), use the viscosity stirrer (6.1.3) to scrape all the residues attached to the test tube wall into the suspension, and then put the viscosity stirrer into the viscosity tube. For the double test tube instrument, the operations of 9.3.2 to 9.3.4 should be completed within 30 seconds, and then the two viscosity tubes should be tested simultaneously. 9.3.5 Immediately put the viscosity tube (6.1.4) with the viscosity stirrer (6.1.3) into the boiling water bath through the hole on the cooling cover, and turn on the stirring head (single or double) according to the requirements of the instrument manual. The instrument will automatically operate and complete the test. When the viscosity stirrer reaches the bottom of the gel suspension, the measurement is complete. Record the time displayed on the electronic timer (6.1.2). This time is the falling number (FN). 9.3.6 Turn the stirring head or press the "stop" button to retract the stirring head and carefully remove the hot viscosity tube and stirrer from the boiling water bath. Thoroughly clean the viscosity tube and stirrer and dry them. Make sure that there is no residual material in the concave part of the rubber stopper, otherwise it will affect the drop of the viscosity stirrer. At the same time, make sure that the viscosity stirrer is dry when it is not used for the first time. 9.4 Calculation of results
9.4.1 Falling number (FN)
The falling number is most affected by the boiling point of water
, and the boiling point of water is related to the atmospheric pressure and sea level of the experimental air. Therefore, calibrating the boiling point of water
will lead to erroneous results.
The laboratory is located below 600°C above sea level.
The actual result does not require
the falling number of the powder sample.
If the laboratory temperature is below the mountain,
the calculation is performed to obtain the correct falling number result.
If the measurement shrinks
the summer and reproducibility
the measurement results. 9.4.2 Liquefaction value is within the range of 100% and 100% respectively. The falling number is 6000, and the falling number is 6000. The constant is 100% and the unit is seconds. The arithmetic mean of the results is used as the final linear relationship between the amount of starch required for complete gelatinization of the starch into a sample that is easily decomposed by the enzyme. The enzymatic activity of the starch is directly proportional to the mass within the normal range. The liquefaction values ​​of commercially available flours are compared with
10 Precision
10.1 Inter-laboratory testing
Appendix B summarizes the inter-laboratory testing results of the precision of this method. The values ​​obtained from these tests may not be applicable to other countries with the maximum range and other test objects.
10.2 Repeatability
In a laboratory, the absolute difference between two independent test results obtained by the same operator using the same equipment, following the same test method, and independently testing the same test object within a short period of time is greater than the repeatability limit () shown in Tables 3 and 4. The repeatability limit and reproducibility limit for wheat flour determination in Table 3 (from Table B.1 Inference) Falling number
60~199
200--229
230-259
260--289
290~319
320-~349
350--379
380--409
410--439
440--469
470~-499
Repeatability limit r
Reproducibility limit R
Repeatability limit and reproducibility limit for whole wheat flour determination Limit (derived from Table B.2) Falling number
60--79
80~109
110~-139
140--169
170-199
200~229
230-~259
260--289
290--319
320--349
350~379
Repeatability limit
If the results of two tests exceed the limit value, two more tests should be carried out. 10.3 Reproducibility
Reproducibility limit R
Unit: seconds
Unit: seconds
In different laboratories, different operators use different equipment, and the absolute difference between two independent test results of the same test object is greater than the reproducibility limit (R) shown in Table 3, which shall not exceed 5%. 11 Test report
The test report shall specify:
All relevant information required for the test sample: If the sampling method is known, indicate it;
The determination method involved in this standard, especially the quality of the test sample, which is not specifically described in this standard , or is considered optional, and all operational details that may have affected the test results;
The experimental results obtained, whether any correction has been made for the altitude; The measurement results, if a repeatability test has been performed, list the final results. 6
A.1 Whole wheat flour sample
Appendix A
(Normative Appendix)
Formula for correction of falling number according to altitude GB/T10361-—2008
The laboratory is located at an altitude of 600m (2000ft). At this time, the boiling point of the water bath is lower than 98℃. The falling number (Fn) can be corrected using formula (A.1):
Fn = iu
Where:
X = 1.0 × lgFit
According to the sea level straight gauge
in the given French
laboratory
calculated as feet
flour and coarse
experimental case one
Where:
X 10-4 ×A+ 2. 635 76 × 10- ×A+5. 75 30 × 10-5 × 1gF × AlgF
's landing
love
measured
degree, that is, sea
750m(25
0. 425 6 X
X -_ 8491
According to the falling value calculated from the sea level
, the measured
A-laboratory sea level
is calculated as feet.
, that is, the sea
, at this time, the water level
is expressed as feet. Then, the conversion factor 3.28 is used to convert meters to 98°. The falling value can be corrected by formula (A2)......(A.2)
- 0. 212 9 10 1× 1gFa XA°. Then, the conversion factor 3.28 is used to convert meters to the formula given by A.1 and Λ.2. The calculated falling value can also be supported by a conversion table. In the conversion table, there are actual altitudes and falling values. By looking up the table, the correct falling value can be obtained. GB/T 10361--2008
B.1 Wheat flour
Appendix B
(Informative Appendix)
Results of inter-laboratory determination
10 samples were tested by the International Association of Cereal Science and Technology in 11 laboratories (10 were retained after excluding erroneous results). The statistical results (according to the evaluation of reference [7]) are shown in Table 3.I. Table B, 1 Falling number data of wheat flourbzxZ.net
Average value
Repeatability standard deviation, 5.
Relative repeatability standard deviation/%
Repeatability limit, r(2.8,）
Reproducibility standard deviation, k
Relative reproducibility standard deviation/%
Reproducibility limit, R(2.8. yuan)
Relative repeatability standard deviation is less than or equal to 3.44%. The relative reproducibility standard deviation is less than or equal to 5.05%. 55
Reproducibility formula: 3—0.1023 yuan→2.103R'=0.689
Reproducibility formula: y-0.1069—13.547=0.8725
Figure B, 1 Repeatability and reproducibility curve of wheat flour Figure 7
Mean value s
Unit is second
B.2 Wheat
GB/T 10361—2008
The French Industry Analysis and Research Bureau tested 3 wheat samples in 11 laboratories (10 were retained after eliminating the wrong results), and the statistical results (according to the evaluation of ISO5725) are shown in Table B.2. Table B.2 Falling number data of wheat
Average value
Repeatability standard deviation, s;
Relative repeatability standard deviation/%
Repeatability limit, r<2.8 yuan,）
Reproducibility standard deviation: 52
Relative repeatability standard deviation/%
Reproducibility limit, R(2.8.）
Relative repeatability standard deviation is less than or equal to 1.6%. Relative reproducibility standard deviation is less than or equal to 9.5%. 105
X-axis: average value, unit is seconds (g).
Y-axis: repeatability limit, r, or reproducibility limit, R, unit is seconds (s). Reproducibility formula: 3=.2963±—2.8881R2 -0. 982 4
Repeatability formula: y=0,069 5+6,480 3-0.796 7
Figure B.2 Repeatability and reproducibility curve of wheat product
Unit is second
Average value/s
4) ISO5725:1986, Precision of the test method The determination of the repeatability and reproducibility of the test method within the laboratory is used to obtain accurate data.
GB/T 10361—2008
参考文献
[J] ISO 3310-2 Test sieves Technical requirements and testing Part 2:Test sieves of pcrforated metal plate.
[2] ISO 3310-3 Test sieves—-Technical requircmcnts and testing-Part 3: Test sieves pf elec-troformed sheets.
[37 IS0 5725-1 Accuracy(trueness and prccision)of measurement methods and rcsults- Partl:General principles and definitions.[4] ISO 5725-2 Accuracy(trucness and precision) of measureinent methods and results -Part2,Basic mcihad for the detcrtnination of rcpcatability and teproducibility of a standard mcasurencntmethod.
[5'] ISO 7973 Cereals and milled cereal products—Detertnination of the viscosity of flour—Metharlusinganamylograph.
L6] ISO 13690 Cercals,pulscs and milled products—Sampling of static batches.[7] ICC [07/1 Determination of the\Falling Number\according lo Hagberg-Pcrten as a measure of the degree of alpha-amylase activity in grain and flour.10
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