The rheological properties of wheat dough containing zeolite residue

Abstract

The use of natural zeolite - clinoptilolite, to protect wheat grain from storage insects within environmentally-friendly storage techniques can lead to the presence of small amounts of zeolite residues in flour. This study investigated the influence of as-received zeolite clinoptilolite (Z) and sodium-rich clinoptilolite (NaZ) in wheat dough on the dough rheological properties. Zeolites were added to dough at 0.5-1.5 wt% flour basis level, which is a range expected to remain in the grain (flour) after treatment to control storage pests. The effects were studied in two types of wheat, conventional (Triticum aestivum) and spelt (T aestivum spp. spelta) because they initially differ in rheological properties. NaZ was used to discern whether the presence of increased concentration of Na+ in the zeolite was able to exert a higher strengthening effect as compared to as-received zeolite (Z). NaZ exerted the highest dough strengthening effect which was mainly reflected as decreased dough softening and increased water absorption. The fact that the presence of NaZ was the most effective factor in improving the dough rheological profile suggested that the presence of movable cations in the zeolite lattice might have a pronounced role in the mechanism by which zeolite affects dough behaviour.