THESIS

McCleary and co-workers developed an official AOAC method for the determination
of RS in plant and starch materials (McCleary and Monaghan, 2002).
The main step of any method to measure the content of RS in foods must
first remove all of the digestible starch from the product using thermostable α-
amylases (McCleary and Rossiter 2004). At present, the method of McCleary and
Monaghan (2002 and AOAC method 2002.02) is considered the most reproducible
and repeatable measurement of RS in starch and plant materials, but it has not been
shown to analyze all RS as defined (Champ et al. 2003). It is based on the principle of
enzymic digestion and measures the portions of starch resistant to digestion at 37 o C
that are typically not quantities due to the gelatinization at 100°C followed by
digestion at 60 o C.
In the US and some other countries such as Japan and Australia, the
Association of Official Analytical Chemists (AOAC) method 985.29 for Total Dietary
Fiber Determination in Foods (Prosky et al. 1985), a gravimetric determination of
dietary fiber quantity after enzymic digestion, mimicking human digestion) is
commonly used to measure total dietary fiber (De Vries, 2004). This method accounts
for some (RS III, the retrograded portion, and RS II as found in high amylose maize)
RS present as part of the total dietary fiber value. Therefore, while it does measure
some RS as part of the total dietary fiber figure, additional methods are needed for
quantification of the other categories of RS (Champ et al. 2003). Again, this
highlights the need for a universally agreed definition and method of analysis for all
of the components of dietary fiber, including RS.
1.7 Commercially manufactured sources of resistant starch
In addition to the natural food sources of RS, some commercially
manufactured forms of RS are also available. Hi-maize® was originally obtained
from a maize hybrid grown in Australia. It originally contained 80–85% amylose with
approximately 30% dietary fiber when commercially released in 1993 but it has since
been improved to provide ingredients containing approximately 60% dietary fiber
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