Formation of Dityrosine Cross-Links during Breadmaking

摘要

To establish its significance during commercial breadmaking,dityrosine formation was quantified in flours and doughs of six commercial wheat types at various stages of the Chorleywood Bread Process.Dityrosine was formed mainly during mixing and baking,at the levels of nmol/g dry weight.Good breadmaking flours tended to exhibit a higher dityrosine content in the final bread than low quality ones,but no relationship was found for dityrosine as a proportion of flour protein content,indicating that the latter was still a dominant factor in the analysis.There was no correlation between gluten yield of the six wheat types and their typical dityrosine concentrations,suggesting that dityrosine cross-links were not a determinant factor for gluten formation.Ascorbic acid was found to inhibit dityrosine formation during mixing and proving,and it has no significant effect on dityrosine in the final bread.Hydrogen peroxide promoted dityrosine formation,which suggests that a radical mechanism involving endogenous peroxidases might be responsible for dityrosine formation during breadmaking.