Application of wheat gluten in non-food industry — wheat gluten as a natural cobinder in paper coating

Abstract

Although wheat gluten could be regarded to be an alternative to natural binders occasionally used in preparation of coating colours, its physical (e.g. elasticity and cohesiveness) and chemical (e.g. hydrogen bonding potential, apolar bonding potential, and low ionic character) properties impeded the application. Acylation of free functional groups of side chains of the protein was a suitable tool for modification of wheat gluten properties. This was expressed in practice by several characteristics of the coating colour (e.g. viscosity, and water retention behaviour) or of printability (e.g. gloss, and picking-up resistance). In comparison to a system introduced into industry and even more to commercially available plant proteins succinylated wheat gluten admixed to standardized coating colour formulations produced acceptable levels in water retention behaviour, gloss, and picking-up resistance. Only the viscosity of the coating colour increased too much. However, evidence exists for a successful reduction of viscosity while positive effects remain unchanged. Thus, the use of wheat gluten derivatives, in particular of succinylated wheat gluten, could be made feasible to offset coating formulations and seemed to be possible even in applications to paper and cardboard coatings.