Physicochemical attributes of irradiated proteins

In this book chapter, the effects of irradiation on the physicochemical properties of animal- and plant-based proteins were investigated. Studies in the literature showed that different methods such as γ-irradiation, electron beam irradiation, X-ray irradiation, and UV irradiation could be used to irradiate food proteins. Animal proteins studied were egg products such as liquid egg or dried egg or egg-based proteins such as globulin, ovalbumin, and lysozyme; meat-based proteins such as gelatin or myofibrillar proteins; and milk-based proteins such as casein, α-lactoalbumin, β-lactoglobulin. Irradiated plant-based proteins were mostly rice protein, watermelon seed kernel proteins, wheat germ protein hydrolysates, etc. The physicochemical properties affected by irradiation were solubility, foaming capacity, foaming stability, emulsifying activity, emulsion stability, gelling capacity, film-forming properties, viscosity, water holding capacity, as well as hydrophobicity. These properties were highly interrelated and affected by changes in protein structure, such as protein degradation, protein cross-linking, or amino acid side chain modifications, particularly carbonyl formation and oxidation of S-containing amino acids as a result of irradiation.