The possibility of preparing a RS concentrate from isolated pea
starch was investigated, and sorption of hydrophobic substances
(indicative of health-benefiting properties) by such a concentrate
was studied by Soral and Wronkowska (2000). By use of a thermally
stable -amylase, a preparation of up to 70% RS containing a
mixture of mineral and organic N compounds was obtained. The
pea RS concentrate had an affinity to bile acid, deoxycholic, and
cholesterol; however, its affinity to cholesterol was not as efficient as
that of native pea starch. The results concluded that the pea RS concentrate
may be potentially used as a food component in special
diets, or for preventive, prophylactic, and therapeutic purposes.
Readily fermentable heat-stable RS of optimal chain length from
poly-1,4--D-glucan useful in various functional foods can be
obtained by in vitro synthesis by adding an enzyme extract containing
the amylosucrase of Neisseria polysaccharea to sucrose
solutions, followed by incubation at 37 °C over several hours
(Buttcher and others 1997).
A method has been discovered to produce an RS product that
retains the same cooking quality as found in untreated rice starch
or flour, but has a higher percentage of starch resistant to -amylase
digestion (King and Tan 2005). This method uses a debranching
enzyme, that is, pullulanase, to digest the starch, but does not
require pretreating the starch source before enzymatic treatment.
This method produced RS from low amylose starches, rice starch
(24%), and rice flour (20%). Surprisingly the RS product formed
by this method retained the pasting characteristics of the untreated
flour or starch and was heat stable. This method may also be
used to produce RS from other botanical sources, that is, corn,
wheat, potato, oat, barley, tapioca, sago, and arrowroot