Wheat gluten components

In this paper, we will explore the measurement of and the basis for the cohesive and elastic properties of a commonly used component of foods that excels in these characteristics, wheat gluten. Gluten constitutes from 10 to 16% of wheat flour, from which it may be separated by Martin, batter, or Raisio processes (2, 3). The separated wheat gluten is 70 to 80% protein, of which 85% is insoluble in saline solution. We shall also seek to correlate some of the basic concepts developed in studies of gluten to other protein systems, such as those of soybean protein isolates and concentrates. 

Amino acids are not only the building blocks of proteins but also occur in the free form. Amino acids commonly found in proteins have the L-conflguration. Of these amino acids (Table 1), Asn was first discovered in asparagus in 1806, and Thr, the most recently discovered, was Isolated from the hydrolysates of fibrin in 1935. Most of them were Isolated from hydrolysates of various proteins. Glu, first obtained from wheat gluten hydrolysate in 1886, was found to be the most important taste component in sea tangle by Ikeda in 1908. Later, industrial production of MSG was undertaken to utilize it as a seasoner. 

Monolayer techniques have been used with much success to study the interaction of proteins with surfactants (11, 12, 13), ions and lipids (14), and other proteins (15). This paper investigates, through well-established procedures, the surface chemistry of monolayers of a major component of heterogeneous wheat gluten protein, gliadin, and explores these interactions with various surface-active agents. 

It must be point out that wheat gluten is present as a network in dough, where it is intimately associated with other dough components. These interactions are still not completely understood, but there are reported correlations of breadmaking quality with polar lipid content, so lipids are potentially of great importance in modulating the functionaUty of the gluten proteins [39]. 

Wheat gluten is a protein carbohydrate complex of which proteins are the major component. Two main fractions are present gliadin, which is soluble in neutral 70% ethanol, made of single chain polypeptides with an average molecular... 

Taylor N.W. and Cluskey, J.E. Wheat gluten and its glutenin component Viscosity, diffusion and sedimentation studies. Am/i. Biochem. Biophys. 97 399-405, 1962. 

Wheat gluten — the plastic and elastic mass which is obtained by washing out wheat flour with water — has for a lor time been considered as a mixture of two proteins containing water or better of two groups of protein components which to distinguish them are denoted by the terms gliadin and glutenin,... 

The thermoplasticity and good-film forming properties of wheat gluten may be used to produce natural adhesives [73]. Gluten s adhesive properties make it useful in pressure-sensitive medical bandages and adhesive tapes. Gluten has the ability to provide edible protection for food or food components from interactions with the environment as they can serve as barriers to mass transfer (e g. oxygen, water vapour, moisture, aroma, lipids) [73]. 

Glutamic acid is the most abundant amino acid in the nervous tissue. In conventional proteins, both amino acids are usually found in larger quantities (especially in globulins) in cereal and legume proteins (18-40%). Wheat gluten (in its component gliadin) contains about 40%, soy protein contains about 18% and milk proteins contain about 22% of glutamic acid. 

Proline ProKne is present in most proteins in amounts of 4-7% the average content is 4.6%. Its content in the component of wheat gluten, gliadin, is about 10%, and about 12% of proline contains casein. Proline content in gelatine can be up to 13%. In bacteria, plants and animals it also plays a role as an osmoprotectant that helps stabilise proteins and ceU membranes from the damaging effect of high osmotic pressure. 

Methionine can be oxidised by reactive oxygen spedes, fatty acid hydroperoxides and oxidised polyphenols. The primary oxidation product, methionine sulfoxide (free or bound in proteins), is a frequent component of various proteins. The contents of methionine sulfoxide in protein sources used for foods and feeds usually vary from 0 to 30% of the total methionine content (e.g. up to 11% methionine sulfoxide apparently occurs in milk powder, 13% in lean beef, 16-28% in wheat gluten and 50% in orange juice). It is fuUy available as a source of methionine as it can be reduced back to methionine by sulfoxide reductases, but the final oxidation product, methionine sulfone, is unavailable as a source of methionine (Figure 2.34). The oxidation of the methyl group to... 

More recently, succinic acid deamidated wheat gluten microspheres for encapsulation of fish oil via O/W/0 doubleemulsion followed by heat-polymerization of emulsified WG was reported (Liao et al., 2012). During microspheres formation, dramatically elevated intermolecular a regation caused the formation of a compact network structure of succinic acid deamidated WG molecules, in which fish oil was encapsulated. Heat-pol5mierization at the same time increased interactions (hydrogen bonds and hydrophobic interactions) between the two components. 

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