Sodium Carboxymethyl Cellulose(SCMC) is one type of most popular thickener, emulsifier and is widely used in various types of foods, such as ketchup, mayonnaise, yogurt and milk, etc. Viscosity is the most critical index of food grade CMC, so we would like to introduce the testing method of food grade Sodium CMC here.
Viscosity can be measured in 1%, 2%, 4% and 10% aqueous solutions based on customer production requests. Normally, lower viscosity CMC is measured in 4% or 10% solution; Middle and high viscosity ismeasured in 1% or 2% solution. Besides, if you have special requests, we can also do test based on your suggestion. Eg: Hoppler viscometer, Brookfield LVT, DVT viscometer, NDJ-79 viscometer, etc.
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1. Viscosity testing steps.
1.1 Test equipments
1). Rotary viscosimeter: Numerical rotary viscosimeter or pointer rotary viscosimeter.
2). Glass cup: diameter is about 90mm, height is about 120mm. The diameter of the top is the same as the diameter of end, volume is 500mL.
3). Thermostatic water bath
4). Blender: stainless steel or glass (see the following picture), under the different load connected in a to 900 r/min and 100 r/min variable speed motor rotation.
1.2 Steps:
1). Weigh about 5g sample of 1% solution or 10g sample of 2% solution , accurate to 1mg.
2). Add 495g of 1% solution or 490g of 2% solution water into glass bottle.
3). Put the blender into glass bottle, mixing blade is about 10mm far from the bottom of the cup.
4). Start stirring and add the test sample slowly, adjust the speed to 900 r/min士100r./min, stirring for 2 hours.
5). If the sample is not dissolved completely, continue to stir for 0.5 hour.
6). Move off the blender and put the glass bottle into thermostatic waterbath(25℃士0.2℃) for 1 hour.
7). Take out of the thermostatic waterbath and stir by hand for 10s.
8). Use the Viscometer LVT to test the Viscosity. Firstly put the rotor of the viscometer into the sample solution and then start the viscometer, rotating for 1 min, when the display value is stable, read the viscosity.
1.3 Testing result calculating:
1). Numerical viscometer
Direct reading, that is, the viscosity of the sample value.
2). Analog viscometer
Viscosity η, the value in milliseconds (mPa · s), according to formula (A.1) calculation:
η = S × k ………… (A.1)
S — Rotary viscometer pointer indicates the reading number in milliseconds (mPa · s);
k – the coefficient of rotor and speed selected for determination.
The test results shall indicate the concentration of the test solution and the rotor number and speed of the rotor used.
The results of the test are based on the arithmetic mean of the parallel determination results, and the absolute difference of the two independent determinations results under the repeatability condition.
The value should not exceed 5% to 10% of the arithmetic mean.
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If you have any question about Sodium CMC viscosity, please contact SINOCMC freely.
SINOCMC Team