Antioxidant properties and potential mechanisms of hydrolyzed proteins and peptides from cereals

Abstract

Cereals like wheat, rice, corn, barley, rye, oat, and millet are staple foods in many regions around the world and contribute to more than half of human energy requirements. Scientific publications contain evidence showing that apart from energy, the regular consumption of whole grains is useful for the prevention of many chronic diseases associated with oxidative stress. Biological activities have mostly been attributed to the presence of glucans and polyphenols. In recent years however, food proteins have been investigated as sources of peptides that can exert biological functions, promote health and prevent oxidative stress. This review focuses on the role of hydrolyzed proteins and peptides with antioxidant properties in various models and their mechanisms which include hydrogen or electron transfer, metal chelating, and regulation of enzymes involved in the oxidation-reduction process.

Keywords: Food science; Nutrition.

Fig. 1

Radical scavenging mechanisms of peptides. HAT: hydrogen atom transfer, SET: single electron transfer, SAPL: solvent-assisted proton loss. Proposed scheme for tyrosine (a), cysteine (b) and histidine (c) containing peptides.

Fig. 2

Formation of peroxyl radical from linoleic initiated by hydroxyl radical (HO^·) hydroperoxide (HOO^·), transition metal (Mn⁺), lipoxygenase (LOX), or radiation.

Fig. 3

Proposed mechanism for the chelating of metal by peptide with multiple histidine. DHHQ (a) and FRDEHKK (b). residues like DHHQ (a) and peptides that contain a single histidine residue (b).

Fig. 4

Proposed mechanism of the reduction of linoleic hydroperoxide by cysteine (a) or methionine (b) containing peptides.