Waxy corn has carved out a formidable position as a raw material for the production of amylopectin starch which is processed by certain wet millers in the USA, Canada, Europe, and other countries for industrial and food uses. Waxy corn is easy to identify. Since waxy is a single recessive gene, production fields must be isolated from normal dent corn. A majority of the commercially produced waxy grain is produced under contract to wet milling companies.
Amylomaize is the generic name for corn that has an amylose content of around 50% or greater. The single recessive amylose-extender gene, plus modifiers, gives a range in amylose content of 50 to 94%. Amylomaize hybrids require special management and cultural requirements to provide more assurance of optimum grain production of acceptable quality and purity. Production fields must be isolated from normal dent corn. High-amylose grain is grown exclusively under contract for wet milling. Amylose starch is utilized in a complexity of uses in various industries. The two major types of high-amylose grain are Class V (amylose percentages in the 50% range) and Class VII (amylose content from 70 to 80%). Class VIII amylomaize (80-90%) and Class IX (>90%) can be produced but presently they are not commercialized.
There are a number of genetically modified specialty corn varieties that offer several characteristics and produce value-added properties to the grain. These specialty corn strains possess unique structural and functional properties for utilization by the corn processing industry for the production of specialty starches. Specialty starches may be used in various industrial applications and food systems, for example in enhancing food products where these genetically diverse starches offer new and different functionalities and bases for chemical modifications that are currently not available. Examples of specialty corn varieties producing enhanced amylose starches with unique characteristics are: (1) amylose-extender dull, (2) amylose-extender waxy, (3) amylose-extender sugary-2 and (4) dull sugary-2. Examples of specialty corn varieties producing amylopectin-rich starches are: (1) dull waxy, (2) dull soft-starch, (3) waxyfloury and (4) waxy shrunken-1. The specialty corn products mentioned are approaching commercial distribution in the foreseeable future, although currently there are limited commercial quantities of some of these varieties grown.
Submitted by David V. Glover, Department of Agronomy, Purdue University