Skip to main content
ARS Home » Midwest Area » Peoria, Illinois » National Center for Agricultural Utilization Research » Plant Polymer Research » Research » Publications at this Location » Publication #90449
Title: STARCH DEBRANCHING WITHOUT ENZYMES: EXTRUSION AND HYDROLYSIS EFFECTS ON STARCH BRANCHING

Author
item Dunn Jr, Larson

Submitted to: Corn Utilization Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 6/3/1998
Publication Date: N/A
Citation: N/A

Interpretive Summary: Starch is one of the most important and plentiful renewable resources for food and industrial products in the world today. Starch is a mixture of two substances: a straight-line or linear substance called amylose and a crooked or branched substance called amylopectin. Many starch applications, both food and industrial, are improved by using a more linear rstarch, or starch high in amylose. High amylose starch can be made from special corn, but it is expensive. And, it is very difficult and costly to convert normal cornstarch to starch without branches unless special debranching enzymes are used to break the branch points and leave the rest of the starch intact. If extruders, or simply adding acid and water to the starch, called hydrolysis, can accomplish the same thing as enzymes, then it would be much easier to make debranched or linear starch. The research described in this paper suggests that it may be possible to use extruders or hydrolysis to make linear starch. Easily obtained linear starch would increase its use in many food and industrial uses, especially in thermoplastics and degradable materials.

Technical Abstract: Starch consists of two types of alpha-glucans: amylose, which is mostly linear and has only a low level of branching, and amylopectin, which is highly branched. Many starch applications, both food and industrial, are improved by using a more linear starch. High amylose cornstarches have found increasing use because of their enhanced linearity versus normal starches. Higher prices for such specialty starches and the complexity an cost of debranching normal cornstarch using specific debranching enzymes has limited the use of highly linear starches. However, it appears that certain extrusion conditions leads to debranching of starch, even when starting from highly branched starches, such as waxy cornstarch. Conditions under which starch is apparently debranched will be described in terms of screw design, screw speed and temperature conditions. In addition, hydrolysis of starch using common acids will be examined as another possibility for making starch more linear without the use of debranching enzymes.