2009_Book_FoodChemistry

874 19 Sugars, Sugar Alcohols and Honey
practically 100% sucrose. Washed raw beet
sugar has about 96% sucrose, <1.4% moisture,
0.9% ash and 1.5% nonsugar organic substances.
Berry sugar consists of 98.8% sucrose, 0.70%
moisture, 0.20% ash and 0.29% nonsugar
organic substances. The presence of raffinose,
a trisaccharide, is detected by high optical
rotation readings or by the presence of needle- or
spearlike crystals.
19.1.4.1.8 Molasses
The molasses obtained after sugar beet processing
contains about 60% sucrose and 40%
other components (both on dry basis). The
nonsucrose substances, expressed as percent
weight of molasses, include: 10% inorganic salts,
especially those of potassium; raffinose (about
1.2%); the trisaccharide kestose, an artifact
of processing; organic acids (formic, acetic,
propionic, butyric and valeric); and N-containing
compounds (amino acids, betaine, etc.). The main
amino acids are glutamic acid and its derivative,
pyrrolidone carboxylic acid. Molasses is used in
the production of baker’s yeast; in fermentation
technology for production of ethanol and citric,
lactic and gluconic acids, as well as glycerol,
butanol and acetone; as an ingredient of mixed
feeds; or in the production of amino acids.
The residual molasses after cane sugar processing
contains about 4% invert sugar, 30−40%
sucrose, 10−25% reducing substances, a very
low amount of raffinose and no betaine, but
unlike beet molasses, contains about 5% aconitic
acid. Cane sugar molasses is fermented to
provide arrack and rum.
19.1.4.2 Sugars Produced from Sucrose
Hydrolysis of sucrose with acids, or enzymes
(invertase or saccharase) results in invert sugar
which, after chromatographic separation, can
provide glucose and fructose. Invert sugar
syrup is a commercially available liquid sugar.
Invert sugar also serves as a raw material for
production of sorbitol and mannitol. Isomerization
of sucrose with isomaltulose synthase
(EC 5.4.99.11) gives isomaltulose. Apart from
6-O-α-glucopyranosidofructose (palatinose, Ia,
Formula 19.1), 1-O-α-glucopyranosidofructose
(Ib) is also formed, the ratio depending on the
reaction conditions. The process is operated
continuously with the immobilized enzyme. The
fructose component of palatinose is present as
furanose, the anomer ratio being α/β = 0.25
(34 ◦ C). The sweetening strength is 0.4, based on
a 10% sucrose solution. Palatinose is not cleaved
by human mouth flora; it undergoes delayed
cleavage by the glucosidases in the wall of the
small intestines.
Catalytic hydrogenation yields isomaltol
(palatinit), a mixture of the disaccharide alcohols
(19.1)