Molecular Structure of a Low-Amylopectin Starch and Other High-Amylose Maize Starches

• Published in: Journal of cereal science Vol. 27; no. 3; pp. 289 - 299
• Main Authors: Shi, Yong-Cheng, Capitani, Terri, Trzasko, Peter, Jeffcoat, Roger
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01-05-1998; Elsevier
• Subjects: Agronomy. Soil science and plant productions; amylopectin; amylose; Applied sciences; Biological and medical sciences; chemical structure; corn starch; Exact sciences and technology; fractionation; Fundamental and applied biological sciences. Psychology; gelation; Genetics and breeding of economic plants; high amylose starch; maize starch; molecular structure; molecular weight; Natural polymers; Physicochemistry of polymers; polymerization; quantitative analysis; Starch and polysaccharides; Varietal selection. Specialized plant breeding, plant breeding aims; X-ray diffraction; Yield, quality, earliness, varia; molecular structure; maize starch; high amylose starch; Monocotyledones; Production quality; Material science; Property composition relationship; Molecular structure; Biochemistry; Gelatinization; Corn starch; Cereal crop; Molecular weight; Amylose; Gramineae; Angiospermae; Biopolymer; Branching; High content; Zea mays; Low content; Swelling; New product; Amylopectin; Storage carbohydrate; Starch crop; Chromatographic properties; Biophysics; Experimental study; X ray diffraction; Variant; Colloid properties; starch granules; Genetic improvement; Oside polymer; Spermatophyta; Property structure relationship; Polysaccharide; Cultivar; Structural analysis
• ISSN: 0733-5210; 1095-9963
• DOI: 10.1006/jcrs.1997.9998

The molecular structure of two commercially available high-amylose maize starches, HYLON® V starch and HYLON® VII starch, and of a newly developed low-amylopectin starch (LAPS) was examined. These high-amylose starches give three apparent fractions as determined by gel-permeation chromatography: a high-molecular weight (mol.wt) amylopectin fraction, a low-mol.wt amylose fraction, and an intermediate-mol.wt fraction which contains both linear and branched components. The low-mol.wt amylose fraction increases from 9·4% in HYLON V starch to 17·7% in HYLON VII starch and 26·5% in LAPS, whereas the high-mol.wt amylopectin fraction decreases from 31·1% in HYLON V starch to 13·8% in HYLON VII starch and 2·5% in LAPS. The percentage of linear components in HYLON V starch, HYLON VII starch, and LAPS are 42, 54, and 80%, respectively. High-amylose starches have a large proportion of long chains in their branched fractions compared to waxy-maize and normal-maize starch. Both HYLON VII starch and the LAPS give B plus V-type X-ray diffraction patterns, but the LAPS has even a higher gelatinization temperature, lower swelling power in hot water, and is more resistant to acid digestion. With the lack of amylopectin, amylose accounts for at least part of the double helical structure in the LAPS granules.