Title: Position of modifying groups on starch chains of octenylsuccinic anhydride-modified waxy maize starch Authors
Submitted to: Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 3, 2013
Publication Date: January 1, 2014
Citation: Bai, Y., Kaufman, R.C., Wilson, J.D. and Shi, Y. 2014. Position of modifying groups on starch chains of octenylsuccinic anhydride-modified waxy maize starch. Food Chemistry. 153:193-199. Interpretive Summary: Substituted starch is of great industrial and academic interest due to its significant improvements in starch functional properties. Octenylsuccinic anhydride (OSA)-modified starch has been suggested to affect many physical and chemical properties of starch, including the starch gelatinization behavior, as well as enhancing emulsifying properties and increasing hydrophobicity. This study utilized various starch degrading enzymes to study the position of octenylsuccinc anhydride (OS) substitutions on waxy corn amylopectin chains. Various chromatographic methodologies were utilized to evaluated these enzymatic hydolysates and develop a model for these substituted OS starch chains. OS-S-L (degree of substitution of 0.018%) had OS groups located close to the branching points of the amylopectin, whereas the OS substitution in OS-S-H (degree of substitution of 0.092%) occurred near the non-reducing ends as well as the branching points. This study provides us with critical information regarding food and industrial uses of OSA-modified waxy starches.
Technical Abstract: Octenylsuccinic anhydride (OSA)-modified starches with degree of substitution of 0.018 (OS-S-L) and 0.092 (OS-S-H) were prepared from granular native waxy maize starch in an aqueous slurry system. The substitution distribution of OS groups was investigated by enzyme hydrolysis followed by chromatographic analysis. Amyloglucosidase, ß-amylase, and isoamylase were used separately or combined to hydrolyze the starches. High-performance anion-exchange chromatography, gel permeation chromatography, and size exclusion chromatography with a multi-angle light scattering detector were used to analyze the enzyme hydrolysates. Native starch, OS-S-L, and OS-S-H had ß-limit values of 55.9, 52.8, and 34.4%, respectively. Weight average molecular weight of the ß-limit dextrin of OS-S-L was close to that of native starch, but for OS-S-H, it was approximately 7 times that of native starch. Debranching of OS starches was incomplete compared with native starch. Percentage hydrolysis of ß-amylase on debranched OS-S-L and OS-S-H was ca. 91 and 70%, respectively. OS-S-L had OS groups located close to the branching points, whereas the OS substitution in OS-S-H occurred near the non-reducing ends as well as the branching points.