Chemistry Reference
In-Depth Information
500
450
400
350
300
250
200
150
100
50
0
0
123
Degree of hydrolysis (%)
456789 0
Fig. 13.10
Emulsifying capacity of soya protein at different DH produced by hydrolysis with Alcalase
and Neutrase.
24
between soya protein to caseinate; the change in soya protein emulsifying properties was
much larger.
In a study of the effect of the glutamic acid-specific protease V8, Chobert
et al.
32
found
that the emulsifying properties of casein decreased at DH 2% and 6.7%. This indicates the
importance of the specificity of the protease used for the hydrolysis. However, the result
may have been different for other proteins. When trypsin was tested using casein and whey
proteins Chobert
et al.
33
concluded that the emulsifying activity was improved in the DH
range up to 10%, whereas the stability of the emulsion was lower than control.
Hydrolyzing whey proteins up to a DH of 20% using Alcalase and Protamex, two
Bacillus
endoproteases, revealed differences mainly in the emulsion stability.
34
Data are presented in
Fig. 13.11, showing a decline in both emulsifying capacity and stability at increasing DH
above 5% and that the emulsion stability of Protamex-hydrolyzates is significantly better
than when Alcalase was used.
Va n d e r Ve n
et al.
35
made an extensive study of casein and whey protein hydrolyzates
produced by 11 different commercially available proteases. The hydrolyzates represented a
range in DH from 1% to 24%. They concluded that there is no direct relation between DH
and emulsifying properties. Whey protein hydrolyzates had similar emulsifying properties in
DH range of 5.5-24%. Casein hydrolyzates showed a different picture. These hydrolyzates
were grouped into three groups which formed different emulsions. One group had a narrow
emulsion droplet size distribution (DH
<
6%). Another set of emulsions made with similar
100
Alcalase
capacity
Alcalase
stability
Protamex
capacity
Protamex
stability
80
60
40
20
0
0
5
10
15
20
25
Degree of hydrolysis (%)
Fig. 13.11
Emulsifying capacity and stability of whey protein hydrolyzed with Alcalase and Protamex
(adapted from Ref. [34]).
