Effect of the proteinaceous wheat xylanase inhibitor XIP‐I on the performances of an Aspergillus niger xylanase in breadmaking

Abstract

The functionality of the proteinaceous wheat xylanase inhibitor XIP-I in Aspergillus niger endoxylanaseaided breadmaking was investigated using small-scale breadmaking and in vitro experiments. At an optimal dosage for an increase in bread volume, the endoxylanase provoked a ∼15% increase of loaf volume in standard flour experiments, but the dough was significantly more sticky than in the control. No variations in bread volumes were observed in the presence of added XIP-I in endoxylanase dough but stickiness was much reduced. Arabinoxylan (AX) solubilisation from flour cell wall material was practically unaffected with XIP-I, and the viscosity of dough water extracts and AX intrinsic viscosity were slightly enhanced. In other breadmaking experiments using a flour from which water extractable material was inactivated, or a reconstituted flour (starch, gluten, water extractable arabinoxylans (WEAXs), water unextractable arabinoxylans (WUAXs)), no differences in loaf volumes were observed between control, endoxylanase and endoxylanase/XIP-I breads, but the high stickiness induced by endoxylanase was totally corrected by XIP-I. In these doughs, AX solubilisation was slightly affected by XIP-I whereas water extract viscosity and WEAX intrinsic viscosity were much higher than in endoxylanase doughs. In vitro experiments with purified AX and A. niger endoxylanase and XIP-I confirmed these findings, showing that the endoxylanase inhibition by XIP-I had more effect on the characteristics measured on WEAX (specific and intrinsic viscosities) than those measured on WUAX (AX solubilisation). Premixing substrate, endoxylanase and inhibitor in different combinationsshowed that XIP-I had a tendancy to bind WUAX, but not WEAX, which changed the balance between enzymic AX solubilisation and AX depolymerisation. As a result, a high viscosity of water extracts was preserved, which is beneficial for dough handling properties.

Effect of the addition of enzymes on the quality of frozen pre-baked French bread substituted with whole wheat flour

“…At excessive concentrations, dough/bread can collapse due to a reduction of the viscosity in dough aqueous extract, caused by the pronounced depolymerization of arabinoxylans (Rouau, Daviet, Tahir, Cherel, & Saulnier, 2006). This excessive amount was not achieved in this study.…”

Plant Cell Wall Polysaccharides in Storage Organs: Xylans (Food Applications)

“…275 They are in concentrations that can reduce significantly the activity of sensitive added endoxylanases, and a mutant endoxylanase resistant to inhibition exhibits improved bread-making functionality. 277,278 AXs, in spite of their low concentrations in wheat flours, are major actors in a bread-making process together with the enzymes able to transform them and inhibitors able in turn to modify enzyme action. 277,278 AXs, in spite of their low concentrations in wheat flours, are major actors in a bread-making process together with the enzymes able to transform them and inhibitors able in turn to modify enzyme action.…”

Mutational Analysis of Endoxylanases XylA and XylB from the Phytopathogen Fusarium graminearum Reveals Comprehensive Insights into Their Inhibitor Insensitivity

“…While, in recent years, much research effort has been directed towards evaluating and manipulating the influence of these inhibitors for applications of endoxylanases in biotechnological processes (11,18,27,32,40), little if anything is known about their role in plant physiology and defense. Their relevance in these contexts, though, should not be underestimated as both types of endoxylanase inhibitors described to date, i.e., Triticum aestivum xylanase inhibitor (TAXI) type (19) and xylanase inhibitor protein (XIP) type (26), are wound and pathogen inducible (23,24) and occur as multiple-isoform families widely represented within the plant kingdom (13,20,31).…”