Physical modifications of wheat gluten protein: An extensive review

Abstract

AbstractGluten protein, as plant resource, is susceptible to physical, genetic, chemical, and enzymatic treatments. In this study, we reviewed physical modifications such as heating‐ freezing, irradiation, high pressure, ultrasonication, shear, and extrusion of gluten. The mode of action of each modification process was investigated. Conformational changes (secondary and tertiary structure) of gluten protein upon physical modification process were described. Functional, morphological, textural, and rheological properties of gluten and their subunits through physical modification were studied. Among physical modifications, the gluten structure was affected by extrusion (heating‐shearing) process. The combination of additives (oxidative and reducing compounds) and alkaline pH upon the extrusion process result in concomitantly dissociation or/and aggregation of gluten via various interactions mainly covalent (disulphide, isopeptides bonds, and dityrosine), noncovalent (hydrogen, ionic, and hydrophobic bonds) interactions and other bonds, such as, dehydroalanine (DHA), lanthioalanine (LAN), and lysinoalanine (LAL).Practical applicationsAttaining an environment friendly and resource protecting provide global value chain and keep on economic development, which has properly been the major target of the most countries. The physical modifications of protein structure are more widely employed since it is safer and without impurities, which have strong effects on different component functionalities. Today, there is a highly increased demand for applying modification‐using technologies; such as ultrasound, extrusion cooking, high hydrostatic pressure, irradiation, which do not rely on chemical treatment for altering ingredient functional and reological properties. We underscored the importance of filling the gaps of knowledge concerning various kinds of physical modification research to alter the disulphide and other interactions, which modified gluten will be suitable in different food and nonfood applications. The additional point is that a better understanding of the correlation between structure and functionality of gluten proteins when they undergo physical modification in combination with additives, such as dough improvers, gums, and surfactant.