Glutelin wheat

Koehler, P. 2003. Effect of acid in dough Reduction of oxidised glutathione with reactive thiol groups of wheat glutelin. J Agric Food Chem 51 4954-4959. 

Glutelins. Soluble in very dilute acid or base and insoluble in neutral solvents. These proteins occur in cereals, such as glutenin in wheat and oryzenin in rice. 

Glutelins are insoluble in water and absolute alcohol but soluble in dilute alkalies and acids. They are plant proteins. Example - Glutenin of wheat. 

Keywords Wheat, maize, barley, rye, gluten, gliadin, glutelin, HMW, LMW... 

Cereal kernels contain about 70% carbohydrates and 8 to 17% proteins. About 80% of wheat proteins are gluten. Gluten from the cereals named previously is composed of prolamins (high in prohne and glutamine) and glutelins, which are storage proteins... 

Some cereal proteins are quite soluble in aqueous solution (albumins, globulins) but the functional proteins—prolamins and glutelins—are difficult to solubilize. This is important because, for example, we do not want wheat gluten proteins to be soluble in a dough system. However, in order to characterize proteins, it is usually necessary to have them in solution. Because the property of solubility is such an important one with respect to cereal proteins, we will dedicate this chapter to the topic. In keeping with the objectives of the book, we will attempt to approach the subject from the most general and fundamental basis. 

Glutelins a group of simple proteins from grain. Hiey are generally insoluble in water, salt solutions and dilute ethanol, but at extreme pH values they do become soluble. Ihey contain up to 45% glutamic acid. The best known are glutenin in wheat, orycenin in rice and hordenin in barley. 

Protein molecules that are highly solvated and flexible, resulting in a disordered coil-like structure. This group comprises some proteins of which the natural function is nutritional, such as glutelins in wheat grains and caseins in milk. 

Extraction of Unreduced Glutelins. Protein molecular sizes or size distributions often influence functional properties, necessitating extraction and characterization of native proteins. Various procedures have solubilized and fractionated unreduced wheat glutenin using dilute acetic acid [34], solutions differing in HCl concentration [35-37], or 50% and 70% I-propanol [38]. 

The glutelin fraction of cereal protein is more heterogeneous than the other storage proteins and consists of several different proteins. Wheat gliadin, for example, is separable into four major fractions a, j3, y and a> but, in all, the gliadin may have as many as 46 components revealed by gel electrophoresis... 

Wheat protein fractionation by the Osborne method provides prolamins and glutelins in a ratio of 1 1. Both fractions, in hydrated form, have different effects on the rheological characteristics of dough prolamins are responsible, preferentially, for viscosity, and glutelins for dough strength and elasticity. 

The high-molecular subunits of wheat glutelins show a protein pattern typical of the cultivar (Fig. 15.8). 

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