Reactions between dicarbonyls and food proteins: when lipid oxidation and the maillard reaction meet protein oxidation

Over the recent decades, clear evidence showed that protein carbonylation has a significant influence on food quality and human health. The chemical nature and mechanism of food protein carbonylation remain poorly understood. One obstacle is the routine DNPH method lacks accuracy and consistency and it is unable to distinguish between primary and secondary carbonylation since DNPH can label both of them. Another obstacle is that within food systems, two major reactions (the Maillard reaction and lipid oxidation) can lead to generation of a range of reactive substances which interact with protein and add complexity to protein carbonylation. This review focuses on the mechanisms and factors governing the chemistry behind protein carbonylation in connection with lipid oxidation and the Maillard reaction. The consequences of the chemical and structural changes in proteins will also be covered. This review will shed light on the complicated mechanism of protein carbonylation in foods and empower future studies in this area.