Some standard content:
National Standard of the People's Republic of China
Analytical methods for butter
GB/T 541685
This standard applies to the cream separated from milk, which is a fat product obtained by sterilization, maturation, stirring and pressing.
1 Sample preparation
The sample should be kept away from air and sunlight, and analyzed as quickly as possible. Place the sample in a sealed container with a lid, dissolve it in a water bath at 32-37℃, take it out of the water bath and shake it frequently until the cream becomes a uniform paste-like liquid, and cool it to room temperature before testing. 2 Test method
2.1 Determination of moisture
2.1.1 Apparatus and preparation: Same as GB5413-85 "Public Test Method for Milk Powder" 2.3.1, 2.1.2 Weigh 2g of sample (accurate to 0.2mg) from the constant weight aluminum blood, place in a 98~100℃ oven, dry for 1h, take out, put in a desiccator, cool for 25min or 30min, and weigh. Place in the oven to dry for 1h, take out, cool, and weigh. Repeat this process until the weight difference between the two times does not exceed 2mg. Calculation is the same as GB5413-852.3.2.
The parallel error of the test should not be greater than 0.05%.
If other methods are used for determination, the method used must be indicated after the determination results. Note: The blood and samples after the water test should be reserved for non-fat solids. 2.2 Determination of non-fat solids
2.2.1 Apparatus: No. 2 or No. 3 bacterial funnel, clean, dry in an oven at 100℃, cool, and weigh. 2.2.2 Reagents: Petroleum ether, analytical grade, boiling range 30～60℃. 2.2.3 MethodbZxz.net
Add 25ml of petroleum ether to the blood sample after the water content has been measured, stir thoroughly with a glass rod, and transfer the solution and residue into the bacterial funnel with constant weight. Wash the blood several times with 15～20ml of petroleum ether, and add the washing liquid to the funnel, drain it in a suction filter bottle, and use a washing bottle (with petroleum ether in the bottle) to wash away the fat on the inner and outer walls of the funnel. Take out the funnel and dry it in a drying oven at 98～100℃, take it out after 30 minutes, cool it, and weigh it. Repeat drying, cooling, and weighing until the difference between the two weights is less than 2mg. Non-fat solids are calculated according to formula (1). Non-fat solids (%) -0.
Wr—weight of funnel and residue after drying, g;
weight of funnel, g.
2.3 Determination of fat
2.3.1 Rozgothi method
2.3.1.1 Apparatus: Same as item 2.4.1.1 of GB5413-85. 2.3.1.2 Reagents
a. Ether: analytical grade
b. Petroleum ether: analytical grade, boiling range 30～60℃C. 95% ethanol.
.....*.... (1)
d. 10% ammonium hydroxide solution.
2.3.1.3 Method
Weigh about 1g of sample (accurate to 0.2mg) into a liposuction bottle, add 10ml of water, place in a warm water bath to melt the fat, add 1ml of 10% ammonium hydroxide solution, and shake well. Heat in a 60℃ water bath for 2min, take out, and shake well. Then add 10ml of ether, shake well again, and extract with ethanol and petroleum ether after cooling. The method and result calculation are the same as GB5413852.4.1.3. 2.3.2 Gerber Creamer Method
2.3.2.1 Apparatus: Except for the Gerber Creamer, the rest are the same as GB5413-852.4.2.1.1. Sixin
017: 0.5
2.3.2.2 Reagents
a. Sulfuric acid: specific gravity 1.60.
b. Isoamyl alcohol: specific gravity 0.8090～0.8115. 2.3.2.3 Method
Weigh 4.5g of sample (accurate to 10mg) in the weighing tube of the butterfat meter. Add 2ml of water and 18ml of sulfuric acid with a specific gravity of 1.60 to the butterfat meter. Add 1ml of isoamyl alcohol, insert the weighing tube tightly into the butterfat meter, mix, and heat in a water bath at 80℃ to completely dissolve the butter. Centrifuge for 5min (the centrifugation factor is the same as that of milk powder), keep warm at 65℃ for 15min, and read the scale number occupied by the fat column. Where: a-
Cream (%)
Read the scale number occupied by the fat column;
Sample weight;
0.0511—conversion factor of the butterfat meter. 2.3.3 Calculation of fat
Fat (%) = 100-(W+X)
Wherein: W-
Water content in sample, %;
Non-fat solid content in sample, %.
Determination of acidity
Cream acidity (°T) is measured by the milliliters of 0.1N sodium hydroxide solution consumed to neutralize 100g of cream.
2, 4.1 Reagents
Same as GB5413-852.5.2.
2.4.2 Method
Weigh 10g (accurate to 0.01g) butter, add 15ml of neutral ethanol and ether, add 3 drops of 0.5% phenolic acid indicator, and titrate with 0.1N sodium hydroxide solution until it turns slightly red and does not fade within 1min. Calculate:
Acidity (.T) = VX10...
Where: V is the amount of 0.2N sodium hydroxide solution consumed, ml. 2.5 Determination of salt
2.5.1 Reagents
2.5.1.10.1N silver nitrate standard solution: Weigh about 17g of silver nitrate, dissolve it in water, transfer it into a 1000ml brown volumetric flask, dilute it to the mark with water, and store it in a dark place. Calibration method: Accurately weigh 0.15-0.16g sodium chloride (or potassium chloride), add 30ml of water to dissolve it, then add 0.5ml of 10% potassium chromate indicator, and then titrate with the prepared silver nitrate solution until it turns red brick color. Calculation formula:
Where: N
equivalent concentration of silver nitrate solution;
-weight of sodium chloride, g;
volume of silver nitrate solution consumed during titration, ml; (5)
0.0585-grams of sodium chloride equivalent to each ml of 1N silver nitrate solution (if potassium chloride is used, this number should be 0.07455).
2.5.1.210% potassium chromate.
2.5.2 Method
Weigh 1g of sample (accurate to 1mg), place it in a separatory funnel, wash it with 50℃ warm water for no less than 5 times, 20-30ml each time, transfer the washing liquid into a 250ml volumetric flask, cool it to 20℃ and dilute it to the mark, then draw 25ml into a 250ml conical flask, add 3 drops of 10% potassium chromate, and titrate it with 0.1N silver nitrate standard solution until it turns red brick color. Calculation:
Salt (%) = N×V×0.0585
Where: N—
equivalent concentration of silver nitrate standard solution; V—consumed 0.1N silver nitrate standard solution, ml; W sample weight, g;
0.0585 grams of sodium chloride equivalent to each ml of 1N silver nitrate solution. Determination of mercury
Same as GB5413-852.10.
Determination of hexachlorobenzene
Same as GB5413-852.11.
Determination of drip boiling
Same as GB5413-852.11.
Microbiological inspection
The inspection of cream microorganisms includes the total number of live bacteria, mold, coliform group and pathogenic bacteria, etc., which shall be carried out in accordance with Appendix B (supplement) of GB5408-85 "Disinfected Milk". Additional remarks:
This standard was proposed by the Ministry of Light Industry of the People's Republic of China and is under the jurisdiction of Heilongjiang Dairy Industry Research Institute. This standard was drafted by Heilongjiang Dairy Industry Research Institute. The main drafters of this standard are Zhang Baofeng, Li Yuxian and Yu Yunhua. From the date of implementation of this standard, the former Ministry of Light Industry standard QB39-60 "Cream Inspection Method" shall be invalidated.
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