Adhesive gluten

Wood adhesives, gluten, NMR, wood, particleboard, panel products... 

Abs, Antibodies CD, celiac disease EM, endomysial antibodies GFD, gluten-free diet HLA-DQ2, human leukocyte antigen ICAM, intercellular adhesion molecule IFN, interferon IL, interleukin Lab laboratory tTG, tissue transglutaminase antibodies. 

Electrostatic charges due to ionized acidic or basic amino acids influence protein solubility. At extremes of pH, many poorly soluble proteins are dissolved and their molecular structures unfolded due to surplus of similar repelling charges. Gluten proteins have few charged groups and so are poorly soluble in neutral solution (15). Dispersions of other proteins must be adjusted to their isoelectric point or have salt added to optimize cohesion and adhesion. 

Gluten is used in many other foods where its adhesive and cohesive properties provide beneficial value (29). In breakfast... 

The cohesive-elastic character of gluten is the basis for many vegetarian-simulated meat products where it holds ingredients and provides chewy texture. It must be cautioned that, because of its highly cohesive properties, native gluten may not be compatible with and serve as an adhesive for some ingredients. 

High molecular weight and random coil structure of protein result in more associations and thereby enhance adhesive and cohesive properties. Although these characteristics are inherent in native gluten proteins, functional properties of other proteins may be improved by chemical or thermal processing. 

Increased intestinal permeability in untreated celiac disease that is reversible on withdrawal of gluten from the diet has been recognized since the early 1980s. Recent evidence suggests that this may be mediated by increased expression of zonulin, a protein that opens small intestinal tight junctions, or to decreased expression of intercellular epithelial cell adhesion molecules, such as ZO-1, catenin, and cadherin. It is currently unclear whether these findings are... 

This paper thus deals with different approaches to the formulation of liquid wood adhesives predominantly based on gluten for wood particleboards and other particulate wood panels, in an easily applied liquid form. 

Internal bond (IB) strength results of particleboards prepared with different gluten protein adhesive formulations. GA = gluten-formaldehyde. GB = gluten alkali treated. GC = gluten-glyoxal... 

Figure 1. Modulus of elasticity (MOE) variation as a function of temperature obtained by thermomechanical analysis (TMA) of different gluten protein-formaldehyde and gluten protein-glyoxal adhesive formulations. Gluten protein hydrolysate produced chemically (G). GA(form) = gluten reacted with...

Compared to previous gluten based adhesives the present resins are applicable in liquid form, thus without any need for modifications of the application systems in particleboard factories. Relative to other protein adhesives such as soy-based adhesives based on reaction with formaldehyde some of the resins presented here have several advantages (i) they cannot and do not produce any aldehyde emission as neither formaldehyde nor any other volatile aldehyde was used in some of the formulations (ii) the percentage of natural materials was increased up to 70% for one type of formulation and up to 95% for others. Furthermore, in relation to resin formulations based on different cross-linking reactions other than those with formaldehyde the resins presented here have other advantages they are competitive with alternate natural resin systems such as those based exclusively on tannins and/or lignins. 

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