Importance of zein composition in quality protein maize (QPM) to microstructural and chemical modifications of proteins during extrusion and their impact on texture of corn-based extrudates
type: CreativeWork
description: Although several studies have been already carried out to clarify the importance of endosperm corn proteins in corn grain hardness and vitreousness, the role that protein compositional differences plays on the physical properties of texturized corn-based products is still poorly understood. Considering that protein has been shown to have an important impact in extruded food systems, it is important to understand how differences in composition or spatial arrangement of corn endosperm proteins, such as observed in Quality Protein Maize (QPM), can influence changes in polymers and structures during extrusion processing. Therefore, the overall objective of this project was to investigate the effect of the high γ-zein content in QPM to chemical, physical, and microstructural changes that occurs in zeins during extrusion and its impact on texture of intermediate corn-based extrudates. Three experiments were designed to test the overall scientific hypothesis that high γ-zein content in QPM influences chemical modifications of proteins during extrusion and provides different textural properties in corn-based extrudates as compared to normal corn. Overall results of thermal and pasting properties for starch isolated from QPM and normal maize grits showed either no or negligible differences between starch of normal and QPM maize types. This finding allowed maize grits to be used in prospective studies for comparison of possible modifications in proteins during processing. Extrusion caused significant changes in the microstructural organization of major components of the grits and the chemistry of maize proteins. Starch granules lost their orderly structure, gelatinized, and melted to form a continuous matrix, whereas, proteins aggregated into large masses diffused in the gelatinized starchy network. The high γ-zein content in QPM seems to confer resistance to disruption of protein bodies during extrusion. Therefore, high γ-zein rich protein bodies require higher energy input …
abstract: Although several studies have been already carried out to clarify the importance of endosperm corn proteins in corn grain hardness and vitreousness, the role that protein compositional differences plays on the physical properties of texturized corn-based products is still poorly understood. Considering that protein has been shown to have an important impact in extruded food systems, it is important to understand how differences in composition or spatial arrangement of corn endosperm proteins, such as observed in Quality Protein Maize (QPM), can influence changes in polymers and structures during extrusion processing. Therefore, the overall objective of this project was to investigate the effect of the high γ-zein content in QPM to chemical, physical, and microstructural changes that occurs in zeins during extrusion and its impact on texture of intermediate corn-based extrudates. Three experiments were designed to test the overall scientific hypothesis that high γ-zein content in QPM influences chemical modifications of proteins during extrusion and provides different textural properties in corn-based extrudates as compared to normal corn. Overall results of thermal and pasting properties for starch isolated from QPM and normal maize grits showed either no or negligible differences between starch of normal and QPM maize types. This finding allowed maize grits to be used in prospective studies for comparison of possible modifications in proteins during processing. Extrusion caused significant changes in the microstructural organization of major components of the grits and the chemistry of maize proteins. Starch granules lost their orderly structure, gelatinized, and melted to form a continuous matrix, whereas, proteins aggregated into large masses diffused in the gelatinized starchy network. The high γ-zein content in QPM seems to confer resistance to disruption of protein bodies during extrusion. Therefore, high γ-zein rich protein bodies require higher energy input …
author: Dias Paes, Maria Cristina, author
author: Stone, Martha B., advisor
author: Hamaker, Bruce, advisor
author: Yu, Lucy Liangly, committee member
author: Chandler, John, committee member
language: eng
language: English
keywords: agricultural engineering
date published: 2002
date modified: 2026-07-27T19:12:52Z
provider: Colorado State University
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: Colorado State University. Libraries

PropertyValue
property ID: Handle
value: https://hdl.handle.net/10217/244637

PropertyValue
property ID: DOI
value: 10.25675/3.027086