Effect of water unextractable solids on gluten formation and properties: mechanistic consideration.

A miniaturised set-up for gluten-starch separation was used to systematically study the effect of water unextractable solids (WUS) on the formation and properties of gluten. The results showed that WUS not only have a negative effect on gluten yield, but also affect gluten and glutenin macropolymer (GMP) composition and rheological properties. The negative effect of WUS on gluten yield could be compensated for to a large extent, but not completely, by increasing mixing time and mixing water. Adding xylanase can effectively counteract the effect of WUS. On the basis of these results we hypothesize that WUS interfere with gluten formation in both a direct and an indirect way. WUS interfere indirectly by competing for water and thus changing conditions for gluten development. This effect can be corrected for by the combination of adding more 0·2% NaCl solution during dough mixing and a longer mixing time. The particulate nature of WUS requires that the direct effect occurs through an interaction between WUS particles and gluten particles. Both effects of WUS can be counteracted through the use of xylanase.