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Formation of dityrosine cross-links during breadmaking
Ana Rodriguez-Mateos1, Sam J Millar, Dhan G Bhandari
1School of Food Biosciences, The University of Reading, P.O. Box 226, Whiteknights, Reading, RG6 6AP, United Kingdom.
Journal of Agricultural and Food Chemistry
|March 30, 2006
Summary
Dityrosine formation occurs during breadmaking, with higher levels in good quality flours. Ascorbic acid inhibits this process, suggesting a radical mechanism involving peroxidases.
Area of Science:
- Food Science
- Biochemistry
- Wheat Quality
Background:
- Dityrosine is a cross-linking amino acid formed by oxidation.
- Its role in commercial breadmaking, particularly the Chorleywood Bread Process, is not fully understood.
Purpose of the Study:
- To quantify dityrosine formation in different wheat flours during breadmaking.
- To investigate the relationship between dityrosine content and bread quality.
- To explore factors influencing dityrosine formation, such as additives and enzymes.
Main Methods:
- Quantification of dityrosine in wheat flours and doughs using High-Performance Liquid Chromatography (HPLC).
- Analysis of six commercial wheat types at various stages of the Chorleywood Bread Process.
- Assessment of the effects of ascorbic acid and hydrogen peroxide on dityrosine formation.
Main Results:
- Dityrosine formed primarily during mixing and baking stages, at nmol/g dry weight levels.
- Higher dityrosine content was observed in final bread from good quality flours.
- No correlation was found between gluten yield and dityrosine concentration.
- Ascorbic acid inhibited dityrosine formation during mixing and proving but not in final bread.
- Hydrogen peroxide promoted dityrosine formation.
Conclusions:
- Dityrosine content in bread is influenced by flour quality and processing conditions.
- Dityrosine cross-links are not a primary determinant of gluten formation.
- A radical mechanism involving endogenous peroxidases likely contributes to dityrosine formation during breadmaking.
- Ascorbic acid can modulate dityrosine formation during bread processing.
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