2009_Book_FoodChemistry

462 8 Food Additives
Unlike acetem and lactem, citrem is an acid (cf.
Formula 8.43).
8.15.3.4 Polyoxyethylene Sorbitan Esters
Polyoxyethylene groups are introduced into the
molecules to increase the hydrophilic property of
sorbitan esters:
8.15.3.2 Sugar Esters
(8.43)
They are obtained, among other methods, by
transesterification of fatty acid methyl esters
(14:0, 16:0, 18:0 and/or 18:1, double bond position
9) with sucrose and lactose. The resultant
mono- and diesters are odorless and tasteless.
Depending on their structure, they cover an
HLBrange of 7–13, and are used in stabilization
of o/w emulsions, or in stabilization of some
instant dehydrated and powdered foods.
8.15.3.3 Sorbitan Fatty Acid Esters
Esters of sorbitan (cf. 19.1.4.6) with fatty acids
(Span’s) serve the stabilization of w/o emulsions.
Sorbitan tristearate is used in the production of
chocolate to delay the fat bloom formation.
(8.45)
Polyoxyethylene sorbitan monoesters (examples
in Table 8.22) are used to stabilize o/w emulsions.
8.15.3.5 Polyglycerol – Polyricinoleate
(PGPR)
In the production of the emulsifier PGPR (cf.
Formula 8.46), oligomeric glycerol is made by
attachment of 2,3-epoxy-l-propanol (glycid) to
glycerol and at the same time ricinoleic acids
are esterified with each other under controlled
heating conditions. In a third step, the oligomeric
glycerol is esterified with polyesterricinoleic
acid.
The emulsifier has a very complicated composition:
apart from different types of esters,
oligomeric glycerol and free ricinoleic acid are
present.
Together with lecithin, PGPR is used in the production
of chocolate. It completely eliminates the
flow point of a molten chocolate mass, but hardly
lowers the viscosity.
(8.44)
(8.46)