This standard specifies the sampling and testing methods for compressed hops and hop pellets. This standard applies to the sampling and testing of compressed hops and hop pellets. QB/T 3770.2-1999 Sampling and testing methods for compressed hops and hop pellets QB/T3770.2-1999 Standard download decompression password: www.bzxz.net

GB10347.2-89
National Standard of the People's Republic of China
Sampling and examination methods of compressed hops and hoppellets QB/T3770.2-1999
Subject content and scope of application
This standard specifies the sampling and test methods of compressed hops and hoppellets. This standard applies to the sampling and testing of compressed hops and hoppellets. 2 Reference standards
GB10347.1
Compressed hops and hoppellets
3 Sampling
3.1 Number of pieces to be drawn
The number of pieces to be drawn is calculated according to the following formula:
Where: X is the number of pieces to be drawn;
N is the total number of pieces in the whole batch.
3.2 Sampling tools
3.2.1 Container with tight cover, clean metal cylinder or airtight plastic bag. 3.2.2 Knife Made of stainless steel with guard.
3.3 Sampling method
3.3.1 Randomly select a number of pieces from the upper and lower inner and outer parts of the stack of the same batch of products. The total sampling amount of each batch shall not be less than 600g. When the number of pieces is small, the sampling amount of each piece can be appropriately increased. 3.3.2 Compressed hop sampling method.
Before sampling, check the inspection form to verify the product batch, quantity, packaging, etc., then select two points on any side of the compressed hop package with a distance of not less than 250mm, use the 3.2.2 knife to make an incision, open the packaging material, take a sample of not less than 30g from 50~100mm below the incision, and quickly put it into the prepared 3.2.1 container. When sampling, pay attention to the appearance, aroma, harmful inclusions, and differences between the product and the general public, and keep records.
3.3.3 Sampling method of pellet hops
Before sampling, check the inspection form to check the product batch, quantity, packaging, etc., then unpack the packaging box (barrel), take one bag or one package from each box (barrel), use a small shovel to shovel 25~50g of sample at will, and quickly put it into the prepared 3.2.1 container. When sampling, pay attention to the appearance, aroma, and uniformity of the product at any time, and keep records. 3.4 Sample distribution and processing
3.4.1 Compressed hops
In the laboratory, all the compressed hops collected are evenly divided into two parts, each about 300g, one part is sealed in a sampling container for future reference, and the other part is used as a sample. The sample is evenly divided into two parts, each about 150g, one part is used for color, aroma, brown flower pieces, and inclusions testing; the other part of 6~8g is used for moisture testing, and 15g is crushed for α-acid testing.
3.4.2 Granulated hops
In the laboratory, all the granulated hops collected are evenly divided into two parts, each about 300g, one part is sealed in a sampling container for future reference, and the other part is used as a sample. The sample is then divided into two equal parts, each about 150g for color, aroma, uniformity, hardness, and disintegration time tests; the other part is evenly taken 30g, crushed for moisture and α-acid tests.
4 Test method
4.1 Color and aroma
Take the test sample of 3.4.1 or 3.4.2, and judge the color and aroma in a place with sufficient light (avoid direct sunlight) and no bad odor, and refer to the record description in 3.3.2 or 3.3.3 of this standard according to the technical requirements of 4.1 or 4.2 of GB10347.1 and the record description in 3.3.2 or 3.3.3 of this standard to determine the results. 4.2 Flower body integrity
Take the compressed hop test sample of 3.4.2 for observation, and judge the results according to the technical requirements of 4.1 of GB10347.1 and the record description in 3.3.2 of this standard. 4.3 Evenness
Take 20g of the hop pellet test sample of 3.4.2, observe whether the pellets are evenly sized, collect the loose pellets and crushed powder that are less than half of the pellet diameter, weigh them on a balance with a sensitivity of 0.1g, and express them as a percentage of their weight, taking one decimal place.
4.4 Brown flower flakes
Weigh 20g of the compressed hop pellet test sample of 3.4.1, wipe out the brown flower flakes, weigh them on a balance with a sensitivity of 0.1g, and express them as a percentage of their weight, taking one decimal place. 4.5 Inclusions
Weigh 20g of the compressed hop pellet test sample of 3.4.1, wipe out the flower stalks, leaves, etc., weigh them on a balance with a sensitivity of 0.1g, and express them as a percentage of their weight, taking one decimal place. 4.6 Hardness
4.6.1 Instrument
Spinning spring type hop pellet hardness tester. 4.6.2 Determination
Retract the push spring screw of the hardness tester to the position where the indicator plate is 0kg, place the granular hop sample upright on the sample stand, and gently turn the top screw until the sample contacts the upper conical head and is no longer subjected to force. At this time, the sample should be horizontal to the instrument and should not be skewed. Slowly push the push spring screw in a clockwise direction until the sample is crushed, and record the kilograms indicated on the hardness tester. 4.7 Disintegration time
Pour about 200mL of tap water into a 400mL beaker, heat it on an electric stove, and put 2 to 3 granular hop samples of 3.4.2 into the boiling state. Immediately press the stopwatch to start the timing when the granular hops are observed to have expanded and become loose in the boiling water, stop the stopwatch, and record the time (s). 4.8 Packaging density
4.8.1 Measurement and weighing
Measure the length, width and height of the compressed hops package extracted in 3.3.1 (m), then weigh (kg), and convert it into kilograms of compressed hops per cubic meter volume according to formula (2), and express it as the average result. 4.8.2 Calculation
X,=LxBxH
Where: X packaging density, kg/m;
m mass of each package of compressed hops, kg;
L length of each package of compressed hops, m; B width of each package of compressed hops, m;
Approved by the Ministry of Industry of the People's Republic of China on February 22, 1989 (2)
Implementation on September 1, 1989
GB10347.2-89
height of each package of compressed hops, m.
4.9 Moisture
4.9.1 Apparatus
a. Analytical balance: sensitivity 0.001g;
b. Electric oven: 250±1℃;
c. Flat-bottom oven: with lid, D=55~70mm (aluminum oven is preferred); d. Desiccator: glass desiccator, with color-changing silica gel as desiccant. 4.9.2 Test
Weigh 3g of the sample of 3.4.1 or 4g of the crushed sample of 3.4.2, accurate to 0.001g, and place them in flat-bottom ovens that have been dried to constant weight, and put them in an electric oven with a constant temperature of 103~104℃ for 1h, cover them, take them out, put them in a desiccator, cool them to room temperature, and weigh them with lids. 4.9.3 Calculate
X,=m -m2
-water content, %;
Where: X2
Mass of blood and sample before drying, g;
Mass of blood and sample after drying, g;
Mass of flat-bottomed blood, g.
Note: The error of the results of two parallel tests shall not exceed 0.5%, otherwise the test shall be repeated and the report shall be expressed as the average of the parallel test results with one decimal place. 4.10 α-acid
4.10.1 Ultraviolet spectrophotometry (arbitration method) 4.10.1.1 Instruments
a. Ultraviolet spectrophotometer: wavelength 200~800nm; b. Balance: sensitivity 0.0001g;
c. Pulverizer: 5000r/min.
4.10.1.2 Reagents
a. Toluene: analytical grade;
b. Methanol: analytical grade;
c. Sodium hydroxide: analytical grade.
4.10.1.3 Preparation of reagents.
a. Saturated sodium hydroxide solution: Prepare sodium hydroxide into a saturated solution, inject it into a plastic bottle, seal it and leave it until the solution is clear:
b. 6.0 mol/L sodium hydroxide solution: Take 31.2 mL of the saturated sodium hydroxide solution in 4.10.1.3a and inject it into 100 mL of distilled water without carbon dioxide; c. Methanol solution: Add 0.2 mL of 6.0 mol/L sodium hydroxide solution to every 100 mL of methanol. This solution should be prepared on the day of use.
4.10.1.4 Test
4.10.1.4.1 Extraction
Weigh 5 g of two portions of the pulverized sample of 3.4.1 or 3.4.2 and weigh them to the nearest 0.001g, respectively, into a 250mL clean conical flask with a ground stopper, and pipette into 100mL toluene. After adding the stopper and weighing, shake it gently by hand (or on an oscillator) for 30 minutes. If the weight loss exceeds 0.3g after shaking for 30 minutes, the test should be repeated. Tilt the conical flask and let it stand to clarify for use. Approved by the Ministry of Industry of the People's Republic of China on February 22, 1989, and implemented on September 1, 1989
GB10347.2-89
4.10.1.4.2 Determination
Dilute A solution: Take 5.0mL of the extract and dilute it to 100mL with methanol. Dilute B solution: Take 3.0mL of dilute A solution and dilute it to 50mL with methanol. Reference solution: Take 5.0mL of toluene and dilute it to 100mL with methanol, and take 3.0mL and dilute it to 50mL with methanol.
According to the instrument manual, adjust the UV spectrophotometer to normal working state, use 10mm quartz blood to calibrate the instrument absorbance to zero with reference solution, and then measure the absorbance of diluted B solution at wavelengths of 275, 325, and 355nm respectively. When measuring, the reading should be taken quickly. 4.10.1.4.3 Calculation
X4=0.667 x
Where: X3
DA×DB
50×E×V
100×50
500x5x3
×A355)+(73.79 X
Dilution factor;
α-acid content, %;
α-acid in dry form, %;
Volume of diluent A, mL;
Volume of diluent B, mL;
Conversion factor:
E——Volume of the extracted solution, mL
VWhen preparing solution B, the volume of diluted solution A is drawn, mL. Note: ①Report the result to one decimal place.
②The difference between two parallel tests should not exceed 0.2%, otherwise, repeat the test. 4.10.2 Conductometric titration
4.10.2.1 Instruments
a. Conductivity meter: DDS11A type;
b. Magnetic stirrer: adjustable speed;
c. .Micro burette: 5mL;
d. Balance: sensitivity 0.0001g. wwW.bzxz.Net
4.10.2.2 Reagents
a. Toluene: analytical grade;
b. Methanol: analytical grade;
c. Dimethyl sulfoxide: analytical grade
d. Glacial acetic acid: analytical grade
e. Lead acetate: analytical grade.
4.10.2.3 Preparation of reagents
a. 2% lead acetate solution, weigh lead acetate (PbC2H302)2·3H2010g, weigh to 0.0002g, put it in a small beaker, add a small amount of methanol and 2~3 drops of glacial acetic acid to dissolve it, dilute and wash with methanol, transfer to a 500mL volumetric flask, dilute to the mark with methanol, shake well and set aside. b. Electrode soaking: add one part of methanol to one part of glacial acetic acid. 4.10.2.4 Test
Approved by the Ministry of Industry of the People's Republic of China on February 22, 1989, and implemented on September 1, 1989
GB10347.2-89
4.10.2.4.1 Extraction
Same as 4.10.1.4.1.
4.10.2.4.2 Determination
a. Install and adjust the conductivity meter according to the instructions to put it into working state. This determination uses a platinum black electrode (DJS-1) with the range set to ×10. b. Pipette 10mL of the extracted clear solution into a 50mL or 100mL clean beaker, add 40mL of methanol (add 10mL of dimethyl sulfoxide when measuring old hops), put in a glass iron core rotor, place the beaker on the magnetic stirrer platform, insert the platinum black electrode below the liquid surface, turn on the magnetic stirrer, drip 0.1mL or 0.2mL of 2% lead acetate solution from the burette, and record the conductivity reading. Record a reading every time 0.1mL or 0.2mL is dripped. When the conductivity rises sharply, drip 6 to 7 more times and record the conductivity each time. The entire titration operation is required to be completed within 5 minutes. After the titration is completed, soak the electrode in the solution of 4.10.2.3 (b) for a few minutes, and then rinse with methanol for the next titration. 4.10.2.4.3 Plot
On rectangular millimeter coordinate paper, use the milliliters of 2% lead acetate solution as the horizontal axis and the conductivity as the vertical axis. Plot points on the graph to represent the milliliters of 2% lead acetate solution consumed in each titration and its corresponding conductivity and its corresponding conductivity reading. Connect the points to obtain an initial approximately horizontal straight line and a straight line with a sharp increase in conductivity. Extend the two straight lines and draw a perpendicular line to the horizontal axis at the intersection of the two straight lines. This is the number of milliliters of 2% lead acetate solution consumed at the titration endpoint, which is read on the horizontal axis. 4.10.2.4.4 Drawing example
2% lead acetate solution
Conductivity
Approved by the Ministry of Industry of the People’s Republic of China on February 22, 19892% lead acetate solution
Conductivity
Implementation on September 1, 1989
GB10347.2-89
4.10.2.4.5 Calculation
Where: X.
2962Calcium acid filter standard
C×V×358×100
-x100:
+×5×10×2
-α-acid content, %;
-α-acid in dry form, %;
CxV×188.75
Concentration of lead acetate solution, %;
The volume of lead acetate solution consumed at the end of titration, mL;-the molar mass of α-acid, g/mol;
-the molar mass of lead acetate, g/mol;
-the mass of the sample, g;
The volume of the extracted solution absorbed, mL.
Note: ①The error of two parallel tests should not exceed 0.2%. Approved by the Ministry of Industry of the People's Republic of China on February 22, 1989 Ha.92mL
Implemented on September 1, 1989
GB10347.2-89
②Calculation results are rounded to one decimal place.
4. 11β-acid (ultraviolet spectrophotometry) 4.11.1 The preparation, extraction and determination of instruments and reagents are exactly the same as those in 4.10.1. Only the measured values ​​are taken for calculation.
4.11.2 Calculation
Xs-0.667 ×[+(55.57 ×
Where: X: β-acid content, %;
X—β-acid in dry form, %.
Note: Report the result to one decimal place.
Additional remarks:
..... (9)
This standard is proposed by the Ministry of Light Industry of the People's Republic of China and the State Import and Export Commodity Inspection Bureau. This standard is under the jurisdiction of the Food Fermentation Industry Science Research Institute of the Ministry of Light Industry, the Standard Division of the State Import and Export Commodity Inspection Bureau, and the Science and Technology Division of the Agricultural Reclamation Bureau of the Ministry of Agriculture, Animal Husbandry and Fisheries. This standard was drafted by the Standard Division of the State Import and Export Commodity Inspection Bureau, the Food Fermentation Industry Science Research Institute of the Ministry of Light Industry, the Horticulture Department of Beijing Agricultural University, and the Xinjiang Import and Export Commodity Inspection Bureau. The main drafters of this standard are Li Zengyou, Du Zhong, Pan Jishu, and Wang Zhonggui. Approved by the Ministry of Industry of the People's Republic of China on February 22, 1989 and implemented on September 1, 198979 X
Dilution factor;
α-acid content, %;
α-acid in dry form, %;
Volume of diluent A, mL;
Volume of diluent B, mL;
Conversion factor:
E——Volume of extract, mL
VVolume of diluent A, mL when preparing B solution. Note: ①Report the result with one decimal place.
②The difference between two parallel tests should not exceed 0.2%, otherwise, repeat the test. 4.10.2 Conductometric titration method
4.10.2.1 Apparatus
a. Conductivity meter: DDS11A;
b. Magnetic stirrer: adjustable speed;
c. Microburette: 5mL;
d. Balance: sensitivity 0.0001g.
4.10.2.2 Reagents
a. Toluene: analytical grade;
b. Methanol: analytical grade;
c. Dimethyl sulfoxide: analytical grade
d. Glacial acetic acid: analytical grade
e. Lead acetate: analytical grade.
4.10.2.3 Preparation of reagents
a. 2% lead acetate solution, weigh 10g of lead acetate (PbC2H302)2·3H20, weigh to 0.0002g, put it in a small beaker, add a small amount of methanol and 2~3 drops of glacial acetic acid to dissolve it, dilute and wash it with methanol, transfer it to a 500mL volumetric flask, dilute to the mark with methanol, shake well and set aside. b. Electrode soaking: mix one part of methanol and one part of glacial acetic acid. 4.10.2.4 Test
Approved by the Ministry of Industry of the People's Republic of China on February 22, 1989 and implemented on September 1, 1989
GB10347.2-89
4.10.2.4.1 Extraction
Same as 4.10.1.4.1.
4.10.2.4.2 Determination
a. Install and adjust the conductivity meter according to the instructions to put it into working state. This measurement uses a platinum black electrode (DJS-1) and the range is set to ×10. b. Pipette 10mL of the extracted clear solution into a 50mL or 100mL clean beaker, add 40mL of methanol (add 10mL of dimethyl sulfoxide when measuring old hops), put in a glass iron core rotor, place the beaker on the magnetic stirrer platform, insert the platinum black electrode below the liquid surface, turn on the magnetic stirrer, drip 0.1mL or 0.2mL of 2% lead acetate solution from the burette, and record the conductivity reading. Record a reading every time 0.1mL or 0.2mL is dripped. When the conductivity rises sharply, drip 6 to 7 more times and record the conductivity each time. The entire titration operation is required to be completed within 5 minutes. After the titration is completed, soak the electrode in the solution of 4.10.2.3 (b) for a few minutes, and then rinse with methanol for the next titration. 4.10.2.4.3 Plot
On rectangular millimeter coordinate paper, use the milliliters of 2% lead acetate solution as the horizontal axis and the conductivity as the vertical axis. Plot points on the graph to represent the milliliters of 2% lead acetate solution consumed in each titration and its corresponding conductivity and its corresponding conductivity reading. Connect the points to obtain an initial approximately horizontal straight line and a straight line with a sharp increase in conductivity. Extend the two straight lines and draw a perpendicular line to the horizontal axis at the intersection of the two straight lines. This is the number of milliliters of 2% lead acetate solution consumed at the titration endpoint, which is read on the horizontal axis. 4.10.2.4.4 Drawing example
2% lead acetate solution
Conductivity
Approved by the Ministry of Industry of the People’s Republic of China on February 22, 19892% lead acetate solution
Conductivity
Implementation on September 1, 1989
GB10347.2-89
4.10.2.4.5 Calculation
Where: X.
2962Calcium acid filter standard
C×V×358×100
-x100:
+×5×10×2
-α-acid content, %;
-α-acid in dry form, %;
CxV×188.75
Concentration of lead acetate solution, %;
The volume of lead acetate solution consumed at the end of titration, mL;-the molar mass of α-acid, g/mol;
-the molar mass of lead acetate, g/mol;
-the mass of the sample, g;
The volume of the extracted solution absorbed, mL.
Note: ①The error of two parallel tests should not exceed 0.2%. Approved by the Ministry of Industry of the People's Republic of China on February 22, 1989 Ha.92mL
Implemented on September 1, 1989
GB10347.2-89
②Calculation results are rounded to one decimal place.
4. 11β-acid (ultraviolet spectrophotometry) 4.11.1 The preparation, extraction and determination of instruments and reagents are exactly the same as those in 4.10.1. Only the measured values ​​are taken for calculation.
4.11.2 Calculation
Xs-0.667 ×[+(55.57 ×
Where: X: β-acid content, %;
X—β-acid in dry form, %.
Note: Report the result to one decimal place.
Additional remarks:
..... (9)
This standard is proposed by the Ministry of Light Industry of the People's Republic of China and the State Import and Export Commodity Inspection Bureau. This standard is under the jurisdiction of the Food Fermentation Industry Science Research Institute of the Ministry of Light Industry, the Standard Division of the State Import and Export Commodity Inspection Bureau, and the Science and Technology Division of the Agricultural Reclamation Bureau of the Ministry of Agriculture, Animal Husbandry and Fisheries. This standard was drafted by the Standard Division of the State Import and Export Commodity Inspection Bureau, the Food Fermentation Industry Science Research Institute of the Ministry of Light Industry, the Horticulture Department of Beijing Agricultural University, and the Xinjiang Import and Export Commodity Inspection Bureau. The main drafters of this standard are Li Zengyou, Du Zhong, Pan Jishu, and Wang Zhonggui. Approved by the Ministry of Industry of the People's Republic of China on February 22, 1989 and implemented on September 1, 198979 X
Dilution factor;
α-acid content, %;
α-acid in dry form, %;
Volume of diluent A, mL;
Volume of diluent B, mL;
Conversion factor:
E——Volume of extract, mL
VVolume of diluent A, mL when preparing B solution. Note: ①Report the result with one decimal place.
②The difference between two parallel tests should not exceed 0.2%, otherwise, repeat the test. 4.10.2 Conductometric titration method
4.10.2.1 Apparatus
a. Conductivity meter: DDS11A;
b. Magnetic stirrer: adjustable speed;
c. Microburette: 5mL;
d. Balance: sensitivity 0.0001g.
4.10.2.2 Reagents
a. Toluene: analytical grade;
b. Methanol: analytical grade;
c. Dimethyl sulfoxide: analytical grade
d. Glacial acetic acid: analytical grade
e. Lead acetate: analytical grade.
4.10.2.3 Preparation of reagents
a. 2% lead acetate solution, weigh 10g of lead acetate (PbC2H302)2·3H20, weigh to 0.0002g, put it in a small beaker, add a small amount of methanol and 2~3 drops of glacial acetic acid to dissolve it, dilute and wash it with methanol, transfer it to a 500mL volumetric flask, dilute to the mark with methanol, shake well and set aside. b. Electrode soaking: mix one part of methanol and one part of glacial acetic acid. 4.10.2.4 Test
Approved by the Ministry of Industry of the People's Republic of China on February 22, 1989 and implemented on September 1, 1989
GB10347.2-89
4.10.2.4.1 Extraction
Same as 4.10.1.4.1.
4.10.2.4.2 Determination
a. Install and adjust the conductivity meter according to the instructions to put it into working state. This measurement uses a platinum black electrode (DJS-1) and the range is set to ×10. b. Pipette 10mL of the extracted clear solution into a 50mL or 100mL clean beaker, add 40mL of methanol (add 10mL of dimethyl sulfoxide when measuring old hops), put in a glass iron core rotor, place the beaker on the magnetic stirrer platform, insert the platinum black electrode below the liquid surface, turn on the magnetic stirrer, drip 0.1mL or 0.2mL of 2% lead acetate solution from the burette, and record the conductivity reading. Record a reading every time 0.1mL or 0.2mL is dripped. When the conductivity rises sharply, drip 6 to 7 more times and record the conductivity each time. The entire titration operation is required to be completed within 5 minutes. After the titration is completed, soak the electrode in the solution of 4.10.2.3 (b) for a few minutes, and then rinse with methanol for the next titration. 4.10.2.4.3 Plot
On rectangular millimeter coordinate paper, use the milliliters of 2% lead acetate solution as the horizontal axis and the conductivity as the vertical axis. Plot points on the graph to represent the milliliters of 2% lead acetate solution consumed in each titration and its corresponding conductivity and its corresponding conductivity reading. Connect the points to obtain an initial approximately horizontal straight line and a straight line with a sharp increase in conductivity. Extend the two straight lines and draw a perpendicular line to the horizontal axis at the intersection of the two straight lines. This is the number of milliliters of 2% lead acetate solution consumed at the titration endpoint, which is read on the horizontal axis. 4.10.2.4.4 Drawing example
2% lead acetate solution
Conductivity
Approved by the Ministry of Industry of the People’s Republic of China on February 22, 19892% lead acetate solution
Conductivity
Implementation on September 1, 1989
GB10347.2-89
4.10.2.4.5 Calculation
Where: X.
2962Calcium acid filter standard
C×V×358×100
-x100:
+×5×10×2
-α-acid content, %;
-α-acid in dry form, %;
CxV×188.75
Concentration of lead acetate solution, %;
The volume of lead acetate solution consumed at the end of titration, mL;-the molar mass of α-acid, g/mol;
-the molar mass of lead acetate, g/mol;
-the mass of the sample, g;
The volume of the extracted solution absorbed, mL.
Note: ①The error of two parallel tests should not exceed 0.2%. Approved by the Ministry of Industry of the People's Republic of China on February 22, 1989 Ha.92mL
Implemented on September 1, 1989
GB10347.2-89
②Calculation results are rounded to one decimal place.
4. 11β-acid (ultraviolet spectrophotometry) 4.11.1 The preparation, extraction and determination of instruments and reagents are exactly the same as those in 4.10.1. Only the measured values ​​are taken for calculation.
4.11.2 Calculation
Xs-0.667 ×[+(55.57 ×
Where: X: β-acid content, %;
X—β-acid in dry form, %.
Note: Report the result to one decimal place.
Additional remarks:
..... (9)
This standard is proposed by the Ministry of Light Industry of the People's Republic of China and the State Import and Export Commodity Inspection Bureau. This standard is under the jurisdiction of the Food Fermentation Industry Science Research Institute of the Ministry of Light Industry, the Standard Division of the State Import and Export Commodity Inspection Bureau, and the Science and Technology Division of the Agricultural Reclamation Bureau of the Ministry of Agriculture, Animal Husbandry and Fisheries. This standard was drafted by the Standard Division of the State Import and Export Commodity Inspection Bureau, the Food Fermentation Industry Science Research Institute of the Ministry of Light Industry, the Horticulture Department of Beijing Agricultural University, and the Xinjiang Import and Export Commodity Inspection Bureau. The main drafters of this standard are Li Zengyou, Du Zhong, Pan Jishu, and Wang Zhonggui. Approved by the Ministry of Industry of the People's Republic of China on February 22, 1989 and implemented on September 1, 19893 Draw a graph
On a rectangular millimeter coordinate paper, use the milliliters of 2% lead acetate solution as the horizontal axis and the conductivity as the vertical axis. Plot points on the graph for the milliliters of 2% lead acetate solution consumed in each titration and its corresponding conductivity and its corresponding conductivity reading. Connect the points to obtain an initial approximately horizontal straight line and a straight line with a sharp increase in conductivity. Extend the two straight lines and draw a perpendicular line to the horizontal axis at the intersection of the two straight lines. That is, read the milliliters of 2% lead acetate solution consumed at the titration endpoint on the horizontal axis. 4.10.2.4.4 Drawing example
2% lead acetate solution
Conductivity
Approved by the Ministry of Industry of the People’s Republic of China on February 22, 19892% lead acetate solution
Conductivity
Implementation on September 1, 1989
GB10347.2-89
4.10.2.4.5 Calculation
Where: X.
2962Calcium acid filter standard
C×V×358×100
-x100:
+×5×10×2
-α-acid content, %;
-α-acid in dry form, %;
CxV×188.75
Concentration of lead acetate solution, %;
The volume of lead acetate solution consumed at the end of titration, mL;-the molar mass of α-acid, g/mol;
-the molar mass of lead acetate, g/mol;
-the mass of the sample, g;
The volume of the extracted solution absorbed, mL.
Note: ①The error of two parallel tests should not exceed 0.2%. Approved by the Ministry of Industry of the People's Republic of China on February 22, 1989 Ha.92mL
Implemented on September 1, 1989
GB10347.2-89
②Calculation results are rounded to one decimal place.
4. 11β-acid (ultraviolet spectrophotometry) 4.11.1 The preparation, extraction and determination of instruments and reagents are exactly the same as those in 4.10.1. Only the measured values ​​are taken for calculation.
4.11.2 Calculation
Xs-0.667 ×[+(55.57 ×
Where: X: β-acid content, %;
X—β-acid in dry form, %.
Note: Report the result to one decimal place.
Additional remarks:
..... (9)
This standard is proposed by the Ministry of Light Industry of the People's Republic of China and the State Import and Export Commodity Inspection Bureau. This standard is under the jurisdiction of the Food Fermentation Industry Science Research Institute of the Ministry of Light Industry, the Standard Division of the State Import and Export Commodity Inspection Bureau, and the Science and Technology Division of the Agricultural Reclamation Bureau of the Ministry of Agriculture, Animal Husbandry and Fisheries. This standard was drafted by the Standard Division of the State Import and Export Commodity Inspection Bureau, the Food Fermentation Industry Science Research Institute of the Ministry of Light Industry, the Horticulture Department of Beijing Agricultural University, and the Xinjiang Import and Export Commodity Inspection Bureau. The main drafters of this standard are Li Zengyou, Du Zhong, Pan Jishu, and Wang Zhonggui. Approved by the Ministry of Industry of the People's Republic of China on February 22, 1989 and implemented on September 1, 19893 Draw a graph
On a rectangular millimeter coordinate paper, use the milliliters of 2% lead acetate solution as the horizontal axis and the conductivity as the vertical axis. Plot points on the graph for the milliliters of 2% lead acetate solution consumed in each titration and its corresponding conductivity and its corresponding conductivity reading. Connect the points to obtain an initial approximately horizontal straight line and a straight line with a sharp increase in conductivity. Extend the two straight lines and draw a perpendicular line to the horizontal axis at the intersection of the two straight lines. That is, read the milliliters of 2% lead acetate solution consumed at the titration endpoint on the horizontal axis. 4.10.2.4.4 Drawing example
2% lead acetate solution
Conductivity
Approved by the Ministry of Industry of the People’s Republic of China on February 22, 19892% lead acetate solution
Conductivity
Implementation on September 1, 1989
GB10347.2-89
4.10.2.4.5 Calculation
Where: X.
2962Calcium acid filter standard
C×V×358×100
-x100:
+×5×10×2
-α-acid content, %;
-α-acid in dry form, %;
CxV×188.75
Concentration of lead acetate solution, %;
The volume of lead acetate solution consumed at the end of titration, mL;-the molar mass of α-acid, g/mol;
-the molar mass of lead acetate, g/mol;
-the mass of the sample, g;
The volume of the extracted solution absorbed, mL.
Note: ①The error of two parallel tests should not exceed 0.2%. Approved by the Ministry of Industry of the People's Republic of China on February 22, 1989 Ha.92mL
Implemented on September 1, 1989
GB10347.2-89
②Calculation results are rounded to one decimal place.
4. 11β-acid (ultraviolet spectrophotometry) 4.11.1 The preparation, extraction and determination of instruments and reagents are exactly the same as those in 4.10.1. Only the measured values ​​are taken for calculation.
4.11.2 Calculation
Xs-0.667 ×[+(55.57 ×
Where: X: β-acid content, %;
X—β-acid in dry form, %.
Note: Report the result to one decimal place.
Additional remarks:
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This standard is proposed by the Ministry of Light Industry of the People's Republic of China and the State Import and Export Commodity Inspection Bureau. This standard is under the jurisdiction of the Food Fermentation Industry Science Research Institute of the Ministry of Light Industry, the Standard Division of the State Import and Export Commodity Inspection Bureau, and the Science and Technology Division of the Agricultural Reclamation Bureau of the Ministry of Agriculture, Animal Husbandry and Fisheries. This standard was drafted by the Standard Division of the State Import and Export Commodity Inspection Bureau, the Food Fermentation Industry Science Research Institute of the Ministry of Light Industry, the Horticulture Department of Beijing Agricultural University, and the Xinjiang Import and Export Commodity Inspection Bureau. The main drafters of this standard are Li Zengyou, Du Zhong, Pan Jishu, and Wang Zhonggui. Approved by the Ministry of Industry of the People's Republic of China on February 22, 1989 and implemented on September 1, 1989
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