Biomedical Engineering Reference
In-Depth Information
TABLE 7.10
Shelf-Life of Standard Bread as Estimated from Compressor
Readings (in grams load), in the Presence of Shortening (SH) and
SSL at Various Levels (Weight Percentage on Flour Basis) After
1 to 5 Days of Storage at Room Temperature and in the Open
Shelf Life from Compressometer Readings in Gram Load
Storage Period (days)
Additive
wt% a
0
1
3
5
0
40
61
118
125
SH b
1
35
74
109
122
SH
2
36
70
100
121
SH
3
32
64
106
115
SSL
0.25
33
62
91
111
SSL
0.5
38
62
81
105
SL
1.0
36
63
84
96
a On flour basis.
b SH stands for shortening from tallow.
by solvent extraction once the bread has been baked. When the emulsifiers complex
with wheat gluten, as in yeast-raised doughs, a strong protein network is formed
that allows the carbon dioxide produced during processing to be retained. The
reaction results in better texture and increased volume of the baked products.
In addition to complexing with protein, CSL has also been shown to inhibit the
transition temperature of dilute starch-water mixes in the amylograph and sharply
increases the maximum paste viscosity. 131 These authors also suggested that the
effect of starch gelatinization is associated with the observed reduction in the rate
offirming in bread containing CSL. In general, stearoyl lactylates form complexes
with both protein and starch. The latter property allows for effective antistaling
agents in bread ( Table 7.10 ), while their interaction with gluten results in a finer
crumb structure, increased volume, and better crust in the finished loaf. 133 Further-
more, SSLs under certain conditions can be used in imitation sour cream to improve
heat stability and resistance against melting down. 105 SSL has been found to be
beneficial in many other applications.
Sorbitan Esters and Ethoxylated Sorbitan Esters
Sorbitol, a sugar alcohol, belongs to the group of hexahydric alcohols made by
hydrogenation of glucose. When esterified, water is split off and the hydroxylated
tetrahydrofuran, 1,4-anhydrosorbitan, is formed as the main product. The free
hydroxyl groups can react with fatty acids to form sorbitan esters. 134 Another product
formed is 1,5-anhydrohydroxypentahydropyran which can dehydrate further to iso-
sorbitude. The synthesis of sorbitan esters was comprehensively reviewed over
30 years ago by Markley, 127 who described interesterification of triglycerides and
sorbitol at several temperatures, with different catalysts, and under a variety of
 
 
Search WWH ::




Custom Search