THESIS

However, it was discovered that a removal of lipids from the starch
resulted in higher RS yields. This is probably due to an increase of lipid-depleted
“free” amylose crystallized (Berry et al. 1988 and Cerletti et al. 1993). Derived from
heat treated starches, RS displays endothermic transitions between 120 and 177°C in
DSC studies that seem to be due to melting of recrystallized amylose (Sievert and
Pomeranz, 1989). RS exhibits a B-type X-ray diffraction pattern at low retrogradation
temperatures and a mixture of A-type with B-type or V-type pattern if retrograded at
high temperatures (95°C) (Siljeström et al. 1989, Sievert et al.1991, Eerlingen et al.
1993 and Shamai et al. 2003).
Table 1 Classification of RS and factors affecting their resistance to digestion in the
colon
Type Description Food sources Resistant
RS I Physically protected Whole or partially milled
RS
II
RS
III
RS
IV
Non gelatinized granules
with B-type crystallinity
and are hydrolyzed
slowly by α-amylase
seeds, legumes, pasta
Raw potatoes, green
banana, some legumes,
high amylose starch
Retrograded starch Cooked and cooled cereal
Chemically modified
starches due to cross-
bonding with
chemical reagents.
products with prolong and/
or repeated moist heat
treatment
Source: Asp, (1992) and Englyst et al. (1992)
Some fiber drink, foods in
which modified starches
has been used (e.g. certain
breads and cakes)
reduced by
Milling and
Chewing
Food processing
and Cooking
Processing
condition
Less susceptible
to in vitro
digestibility
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