This standard applies to the inspection of industrial casein. QB/T 3781-1999 Inspection method for industrial casein QB/T3781-1999 Standard download decompression password: www.bzxz.net

Classification number, X16
Light Industry Standard of the People's Republic of China
QB/T3781-1999
Industrial Casein Test Method
Published on April 21, 1999
Published by the State Bureau of Light Industry
Implemented on April 21, 1999
Q8/T3781--1999
This standard is the original national standard GB5425-1985 industrial casein test method, which was converted to QR/T3781-1999 after being published by the State Administration of Industry and Commerce in Document No. 1999112. The content remains unchanged. It is under the jurisdiction of the National Technical Committee for Standardization of Milk Products. The eighth standard was drafted by the Fujian Dairy Industry Research Institute. Drafters of the standard: Zhang Chushu, Zhang Baoduo, Li Yuxian, Norman Fanhua. TKAONYKA
Light Industry Standard of the People's Republic of China
Industrial Casein Test Method
This standard applies to the test of industrial cheese. 1. Standard of the product
QB/T 3781—1999
Samples for chemical test shall be processed as follows: 1. After the industrial cheese sample is finely sieved, 30-50g shall be taken and ground into powder in a mortar. The sieved casein shall be passed through a 0.5 μm pore size glass and placed in a glass with a ground stopper for testing. Test Method
7. Physical Test
2.1.1 Determination of color and texture
2.1.1. InstrumentWww.bzxZ.net
Single 5ml volumetric cylinder or a graduated test tube.
b. White shiny paper.
2.1.1.2 Formula
Use a 5ml measuring tube to take 1-2ml of cheese sample, count on the paper, use a needle to remove the yellow or dark brown and other abnormal color particles, place them in a graduated test tube, calculate the number of liters, and calculate the percentage of abnormal color particles by formula (!).
Abnormal color (%)
Where; V——sampling volume, ml.
——Select unqualified casein light content, ml. X100
2.1.2 Determination of particle size
Use a 10-20ml enzyme from the carefully mixed sample and perform an enzyme test with a pulse calibrator. 2.2 Chemical Test
2.2.1 Determination of Moisture
2.2.1.1 Instrument: Place the weighing blood with glass (aluminum blood glass) in an oven at 102~106℃, dry for 30 minutes, cool in a desiccator, weigh, weigh to constant weight, and the difference between two weighings should not exceed 2m. 2.2.1.2 Method
Take 2~~2.5g sample (accurate to 0.2mg) from a weighing device with known constant weight, cover it in an oven at 102~105℃ and dry for 2h, stir it for 20min to accelerate the operation, take it out and cool it in a desiccator for 30min, weigh it. Dry it for another 1h, take it out and cool it, weigh it again, and the difference between two weighings should not exceed 2m. Calculated by formula (2), moisture () =
empty blood, glass sample and sample,
where:
empty group ground glass drop and dry sample acid plate, g! State Light Industry Bureau 1999-04~21 approved
1999-04-21 implementation
empty and glass wool again, name.
2.2,2 Determination of fat
QB/T 3781-1999
1.2.2.1 Apparatus: GB5413--85 Milk Standard Test Recipe 2.4, 2.1.1. 2.2.2.2 Reagents
self-made, researched and tested, specific gravity 1.84,
b. Isopropyl alcohol: specific gravity 0.8190-0.8115
In the milk fat meter, the specific gravity is 1,82% magnetic acid 10m, and then carefully inject 8-8.ml distilled water along the wall. Weigh the prepared casein (accurate to 0.5 g), add 10% amyl alcohol to the milk fat, plug it with a dry rubber stopper, be careful to mix the casein with the acid, but do not turn the casein meter upside down to avoid the casein particles from falling off the scale. Push the casein upward into a water pan until the cheese is completely dissolved. Centrifuge it in a centrifuge at the specified centrifugal factor for 5 minutes, then heat it in water and take it out. Hold the fat in the milk fat meter down and place it on the same plane as the eye, and observe the movable stopper. Make the lower end of the surface coincide with the scale mark, and read the percentage of fat content. Set the reading to 3.67. 2.2.4 Determination of acidity
2.2.3.1 Instrument
, 250ml conical flask.
b.0tn.
c. 25ml titration.
2.2.2 Reagents
. 0.1N sodium hydroxide solution
b. 2% acyl alcohol solution.
2.2.a.8 Method
Weigh 5% of the prepared sample (accurate to 10) in a sample bottle, add 50ml of water, and heat at 18~20℃ for 4-5h, or heat to 45 and keep at this temperature for 30min, then add 1ml of water, mix well, and pass through a dry paper filter. Absorb 50ml of the filter, add 6 drops of 2% phenol-ethanol solution in a conical flask, and use 0.1N sodium hydroxide solution to turn it to a slightly red color, and it will not disappear within [min].
Will the consumed! .1N sodium hygroscopicity multiplied by 40 to get the formaldehyde content of dry alkali, 2.2.4. or determination of the content
2.2,4, instrument
, 25ml porcelain.
b. High-lid furnace,
2.2.4.2 method
Take the temperature full, put it in a high-temperature furnace, and burn it at 650℃ for half an hour. Cool to below 200℃, take it out and cool it in a desiccator for half an hour. Weigh accurately, weigh 1-1.5g (accurate to 0.2mg) of the prepared casein, put it on an electric furnace, heat it with a low fire, fully carbonize it until it is smokeless, then place it in a high-temperature furnace and burn it at 550℃ to become white ash, cool it to below 200℃, take it out, put it in a dryer to cool for half an hour, weigh it, repeat the burning for 30 minutes, and weigh it until the difference between the two times is no more than 2mg, which is constant weight. 2.2.4.8 Calculate
Find the difference [】
W,——the amount of carbon and egg, g! After the first ignition, if there is still a long smell in the middle, add a little water to replace the decomposed material, and the undecomposed material will come out of the surface, and then burn it again. If decomposition occurs during the ignition, add micro-decomposition.
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