Photo-Induced Modification of Food Protein Structure and Functionality

Abstract

Light processing is nowadays recognised as an efficient technology to non-thermally inactivate a wide range of microorganisms to increase food safety. However, exposure of foods to light can provide further advantages associated with the development of photoreactions involving polymers. Proteins are major target polymers for photoreactions due to abundance of endogenous chromophores, ability to bind exogenous ones and rapid reactivity with other excited state species. As food structure and functions are the result of the status of food constituents, photo-induced structural modification of food proteins can lead to new product characteristics or improved functionalities. This review paper summarises recent developments of the application of light radiation to modify protein structure, inducing changes in their technological and biological functions

Exploring the Potentialities of Photoinduced Glycation to Steer Protein Functionalities: The Study Case of Freeze-Dried Egg White Proteins/Carbohydrates Mixtures

“…The energy of the radiation absorbed by the chromophores is transferred between the initial sites of oxidation and the part of the protein that controls its structure and function. This transfer is primarily directed to sulphur-containing amino acids through hydrogen bonding networks and protein backbone [ 2 , 3 ]. As a result, side-chain oxidation, backbone fragmentation and/or formation of cross-links and aggregates occur, leading to a modification in both protein structure and properties [ 4 ].…”

Modifying the Functional Properties of Egg Proteins Using Novel Processing Techniques: A Review

“…Light processing is based on the application of electromagnetic radiation in the nonionizing region of the spectrum between 170 and 1,100 nm, including UV‐C and pulsed light processing (Manzocco, ). UV‐C is the portion of the electromagnetic spectrum with wavelengths between 200 and 280 nm (Gómez‐López, Ragaert, Debevere, & Devlieghere, ), which can be obtained using low‐ or medium‐pressure mercury lamps as the light sources (Manzocco, ). UV‐C processing primarily relies on continuous nonthermal germicidal radiation to exert photochemical effects on biomolecules that are abundant in highly conjugated double‐bond systems, such as proteins and microbial DNA.…”

“…UV‐C and pulsed light share similarities in their underlying mechanisms of photo‐induced damage to proteins (that is, chemical modification of protein molecules when exposed to light). When exposed to light, proteins undergo chemical modification known as protein photoreaction, which is associated with (i) the abundance of endogenous chromophores (for example, tryptophan, tyrosine, phenylalanine, and so on) within the protein structure, (ii) the ability of some proteins to bind exogenous chromophores, and (iii) their rapid reactivity with other excited state species (for example, singlet oxygen; Manzocco, ). Photooxidation of proteins can occur either by direct or indirect means (Davies & Truscott, ; Pattison, Rahmanto, & Davies, ).…”

“…The former involves direct absorption of UV radiation by the protein or bound chromophore groups, whereas the latter involves indirect protein oxidation via the formation and subsequent reactions of singlet oxygen generated by the transfer of energy to ground state molecular oxygen. In addition to its photochemical effects, pulsed light has been reported to result in photothermal (that is, local heating upon intense pulsed light) and photophysical (that is, disturbance due to high peak power pulses) effects that can potentially result in structural damage to biomolecules (Gómez‐López et al., ; Manzocco, ).…”

Processamento UV-C de proteínas do soro do leite: Efeitos na estrutura e digestibilidade

“…aumento nos tióis livres acessíveis após exposição da β-lactoglobulina à luz na região do UV-C em 254 nm. Além disso, a formação de tióis livres para proteínas expostas a luz na região do UV-C (200-280 nm) é um fato bem consolidado na literatura (MANZOCCO, 2015;NEVES-PETERSEN et al, 2009) e ocorre, principalmente, para proteínas que tem um triptofano espacialmente próximo a uma ponte de dissulfeto. Para as medidas de tióis livres acessíveis foi usado o DTNB que reage estequiometricamente com os tióis livres acessíveis ao solvente presentes na proteína.…”