Processing induced changes in phenolic concentration and antioxidant capacity of corn for production of corn flakes

Zhong, Zhou

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https://hdl.handle.net/2142/88310 Copy

Description

Title

Processing induced changes in phenolic concentration and antioxidant capacity of corn for production of corn flakes

Author(s)

Zhong, Zhou

Issue Date

2015-07-24

Director of Research (if dissertation) or Advisor (if thesis)

Engseth, Nicki Jene

Department of Study

Food Science & Human Nutrition

Discipline

Food Science & Human Nutrition

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

M.S.

Degree Level

Thesis

Keyword(s)

• Phenolics
• Antioxidant Capacity
• Corn Flakes
• Processing

Abstract

Epidemiological studies have suggested that regular consumption of breakfast cereals would help in reducing the risk of obesity and cardiovascular disease. However, average nutritional quality of ready-to-eat breakfast cereals have been declining since late the 1980s. This study was designed to examine how phenolics and antioxidant capacity change during processing of corn into flakes, and to evaluate the effects of processing condition, corn genotype, and growing year on phenolics, with the ultimate goal of improving the nutritional quality of corn flakes. Three commercial corn hybrids grown in three different years with three replicates per year were dry-milled, cooked, baked, and toasted into corn flakes to determine the impact on phenolic content and antioxidant capacity. Genotype and processing effects were significant for phenolics, while the yearly effect was not. Cooking and toasting were the two critical processing points to induce phenolic changes. Total phenolic content significantly decreased during cooking, and significantly increased again during toasting. Significant losses of antioxidant capacity were observed during dry-milling and pressure cooking. Baking and toasting did not further alter the antioxidant capacity of corn. Significant linear correlations were observed between antioxidant capacity and phenolics in corn, while a higher correlation was observed for bound phenolics rather than soluble phenolics. Total phenolic content of corn was enhanced with higher cooking pressure, but decreased with extended pressure cooking time. Increased baking time and temperature both induced significant increases in phenolics. Extended toasting time could also liberate more bound phenolic compounds to increase total phenolic content, but higher toasting temperature did not facilitate in faster liberation. Our findings will provide a guide to optimize processing conditions and select proper corn hybrids for higher phenolic content and antioxidant capacity in corn flakes.

Graduation Semester

2015-8

Type of Resource

text

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http://hdl.handle.net/2142/88310

Copyright and License Information

Copyright 2015 Zhou Zhong

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