GEA Niro Method No. A 1 e

Revised: September 2006

 

 1.        Definition

The water of crystallization (%) of a powder is the difference between total moisture and free moisture.

 

2.         Scope

This method may be used for any kind of dried milk products containing crystallized lactose (α-lactose-monohydrate), e.g. whey powder.

 

3.         Principle

Sample total moisture (determined by Karl Fisher titration) and free moisture (determined by oven drying 87°C/6h) is measured. The water of crystallization is calculated.

 

4.         Apparatus

4.1   As given in GEA Niro Method № A 1 c.

4.2   As given in GEA Niro Method № A 1 d.

 

5.         Reagents

As specified in GEA Niro Method № A 1 d.

 

6.         Procedure

6.1   Determine the free moisture content as described in
GEA Niro Method № A 1 c.

6.2   Determine the total moisture content as described in
GEA Niro Method № A 1 d.

 

7.         Calculation

       Water of crystallization   =   % total moisture - % free moisture

      

8.         Reproducibility

± 0.2%

 

9.         Remarks

The water of crystallization of whey powders provides a good indication of the ‘Degree of Crystallization’ of the lactose content.

Degree of Crystallization

%L = the content of lactose in whey powder (%), expressed as anhydride. For rapid routine test of sweet whey, the %L ≈ 74%. 

 

10.       Literature

GEA Niro Research Laboratory