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National Starch and Chemical Company,
10 Finderne Avenue, Bridgewater, NJ 08807
USA.
Correspondence should be addressed to Stephen A. Jobling Steve.Jobling@Unilever.com.
biotechnologystarch structureamylopectinbranching enzyme
High-amylose starch is in great demand by the starch industry for its unique
functional properties. However, very few high-amylose crop varieties are commercially
available. In this paper we describe the generation of very-high-amylose potato
starch by genetic modification. We achieved this by simultaneously inhibiting
two isoforms of starch branching enzyme to below 1% of the wild-type activities.
Starch granule morphology and composition were noticeably altered. Normal,
high-molecular-weight amylopectin was absent, whereas the amylose content
was increased to levels comparable to the highest commercially available maize
starches. In addition, the phosphorus content of the starch was increased
more than fivefold. This unique starch, with its high amylose, low amylopectin,
and high phosphorus levels, offers novel properties for food and industrial
applications.
