ISI 05-2e Determination of Dry Matter in Oven at 105 oC

ISI 05-2e Determination of Dry Matter in Oven at 105 oC

1. Scope

The method is applicable to starch, dextrose - anhydrous and monohydrate - and total sugar.

LT 15. Dec- 1964

Rev. LT 21. Nov. 1997

2. Principle

The sample is dried at 105 oC



3. Apparatus

3.1 Analytical balance weighing to the nearest 1 mg.

3.2 Dish of aluminium or glass with tight-fitting lid

3.3 Electrically heated oven.

3.4 Desiccator with dry drying agent



4. Procedure

Dry dish (3.2) 1/2 hours in oven (3.3) at 105 oC.

Cool dish in desiccator (3.4) to room temperature and weigh on balance (3.1) to nearest 1 mg. Weight = w0 Cool 40 min

Weigh 2 g of sample in dish to the nearest 1 mg. Weight = w1. Take 5 g total sugar

Dry dish and sample over night (min. 16 hours) in vacuum at 105 oC With one dying step only time may be extended

Close lid and cool in desiccator for 1 hour. Weigh immediately after removal from desiccator to nearest 1 mg. Weight=w2



Possibly re-heat to constant weight

5. Calculation

Dry matter (DM) in percent of sample (average results of two samples to one decimal) =

DM % = 100 x (w2 - w0) / (w1 - w0)



6. Notes

Alternative method: Drying at 70 oC or 100 oC in vacuum.

The European Pharmacopoeia 4 specifies for potato and wheat starch drying at 130 oC for 90 min and for maize and rice starch drying at 100-105 oC to constant weight.



7. Reference International Standard: ISO 1741

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