This standard applies to the inspection of crude lactose. QB/T 3779-1999 Inspection method for crude lactose QB/T3779-1999 Standard download decompression password: www.bzxz.net

Classification number: x16
Light Industry Standard of the People's Republic of China
QR/T3779-—1999
Crude Lactose Test Method
Published on April 21, 1999
Published by the State Bureau of Light Industry
Implemented on April 21, 1999
QB/T3779
This standard is the original national standard D/T54231985 Crude Lactose Test Method The standard number of the film is QB/T3779-1999 after the publication of the document No. 112 of the Light Industry (1999) issued by the Ministry of Light Industry of the People's Republic of China. This standard is proposed by the National Dairy Standardization Center. The technical standard is jointly produced by the Heilongjiang Provincial Institute of Food Industry and Hailar Dairy Factory. The drafters of this standard are Zhang Chubei, Zhang Baofeng, Li Gongxian and Neng Lihua. Industry Standard
Test Method for Crude Lactose
This standard is applicable to the test of lactose.
Product Preparation
QB/T3779-1999
542315
The sample should be mixed carefully before separation. When the product is stored for a long time and the sample is lumpy, it should be crushed in a mortar: In order to mix it well, the small sample can be transferred to a large narrow container, and the ore slices can be mixed quickly. After recording, Re-pack into the small energy, and add some to 2 Inspection methods
2.1 Determination of moisture
2.1.! Install a pot with a lid or a glass weighing plate (straight 50mm*70mm), clean the L, dry the sample at 108℃~110℃ for 0.5h, cool it in a dryer for 25min~-3Umim, and weigh it. Focus on flat drying (accurate to 0.2mz), and put it in the dryer for use:
2. 1.2 Method
In a drill with known weight, weigh 5 samples (accurate to 0.2 g) and place them in a 108℃ 110℃ oven: dry for 2 h, take out, cool and re-weigh. Repeat the drying, cooling and weighing until the difference between the two weights is within 2 mm: Calculate the moisture content using formula (1):
Moisture (%) = weight × 100
Where:
weight of empty sample,
limit, "weight of empty sample after drying", wwW.bzxz.Net
weight ratio, g.
2.2 Determination of ash content 2.2.1 The apparatus is the same as that of GB5425-1985, which specifies the test method 2.2.4.1. 2.2.2 The test method is to place the sample in a high temperature furnace, burn for 3 hours at 600°C or above, cool for more than 200°C, cool in a gasifier for 30 minutes, weigh accurately, weigh 1~1.5 grams of milk firewood, and heat it on a low fire in an electric furnace. The following operations and calculation results can be in accordance with 2.2.4.3 of GB5425-1985. 2.3 Determination of salt 2.3.1 Apparatus 1) 20 mL porcelain: 2) electric furnace: 3) 25 mL burette; 4) 250 mL conical flask.
Approved by the State Bureau of Light Industry on April 21, 1999
Implemented on April 21, 1999
2. 3.2 Preparation
QB/T3779—1999
a) 0.1N silver nitrate solution, prepare the method specified in GB54161985 "Cream Test Method 2.5.1.1: b) 10% potassium chromium (K,Cr) solution.
2.3.3 Method
Put 2g-3g of accurate sample (accurate to 0.2mg) in a porcelain mixing medium with a capacity of about 20mL, and carefully carbonize the ten substances in the sample on the furnace. No product is lost during carbonization. After the fuming is completed, it can be burned. The carbonized material is soaked in hot water for at least 5 times, and the carbon is ground with a glass with a stable tip. The residue is filtered into a 2501ml conical flask, and the filter paper is washed with water for 3 times. The total volume of hot water is 100ml. 0.5mT. 10% potassium hydroxide solution is used as an indicator, and all the liquid is titrated to a reddish color with 0.1N silver nitrate. The calculation formula for salt content is the same as that of G5416-1985 Cream Formula 2.5.2. 2.4 Determination of lactic acid 2.4.1 Apparatus a) 25-40 mL volumetric flask b) 10 mL aspirator 25 mL volumetric flask d) 300 mL beaker 2.4.2 Reagents 2.4.2.1 Sodium hydroxide solution: weigh 34.66 g sodium sulfate and dissolve in water, dilute to 500 mL. 2.4.2.2 0.5 N sodium hydroxide solution 2.4.2.0.1 N potassium iodide: weigh 20 g to 25 g potassium iodide (accurate to 1 g), dissolve in a small amount of water in a beaker, add 12.7 g potassium iodide (accurate to 0.1% g), dilute to 1000 mL. 2.4.2.41.1N sodium iodide solution
2.4.2.4.19.1N sodium iodide solution preparation: weigh about 25g sodium iodide Na2SO4,5H2O3 on a hot plate and place in a 500ml beaker. Add 400ml of hot water that has just been boiled. After the gold is completely dissolved, add 0.052 sodium carbonate (to prevent precipitation) and 0.01g mercury iodide (to prevent mold). Then add 100Um 2.4.2.4.2 Calibration method: Weigh 0.10g~0.12g (accurate to 0.2mg) of dichromic acid (KC2O) stored at 105℃ and dried, add 3mL of water to dissolve it, add 5mL of concentrated hydrochloric acid and 10mL of 15% potassium iodide solution, fully dilute to 200mL, and then Use the prepared sodium thiosulfate solution to stabilize until it turns yellow-green (straw color). After stabilization, add 5 mL of 0.05% starch solution and continue to stabilize until the pale color disappears and turns into monovalent chromium ion green: Calculate:
Vx0.04904
The equivalent salt concentration of thiosulfate solution:
G-weight,
yThe number of liters of 0.1N sodium thiosulfate solution consumed. 2.4.2.52 N sulfuric acid solution.
2.4.2. 1% starch solution
2.4.3 Method
Put 1g of sample (0.2mg) in a beaker, add a small amount of water to dissolve, add 10mL of sulfuric acid solution, 0.5% hydrogenated solution to 8mL. After the sample is fully dissolved, transfer it to a 250mL storage bottle, add water to the mark, mix, precipitate and pass through the port. Absorb and filter 25mL in iodine store 2
TTKANY KA
QB/T3779-1999
, 25mL of phosphorus solution, add 37.5ml of 0.1N potassium hydroxide. Tighten the core to double the pressure, and after 15mm, add 5mL of 2H2O and 0.1N sodium thiosulfate to light yellow, add 1mL of 1% starch indicator, and continue to fill until colorless. Calculate by formula (3) and do the reagent blank test by the sample method.
(4-B)×Vx0.18
Lactose (%):
Wu Zhong:
0.18·Lactose conversion factor,
A-sample. Consumed sodium thiosulfate solution. m: B blank digestion sodium thiosulfate solution, mL: A. Equivalent concentration of sodium thiosulfate solution
w-sample weight, g.
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