Numerous dough improvers are used alone or in combination to enhance the quality of baked goods such as breads. While modern consumers demand consistent quality, the expectations for ingredients have changed over the past few years, and reformulations have taken place to provide "clean label" options. However, the effects and mechanisms of blended dough conditioners suitable for such baked products have not been systematically summarized. In this review, dough and bread properties as affected by different improver combinations are examined, with a focus on additive or synergistic interactions between enzymes or between enzymes and ascorbic acid. The combination of enzymes that hydrolyze starch and cell wall polysaccharides has been shown to reduce textural hardness in fresh and stored bakes goods such as breads. Enzymes that hydrolyze arabinoxylans, the main nonstarch polysaccharide in wheat, have synergistic effects with enzymes that result in cross-linking of wheat flour biopolymers. In some studies, the effects of bread improvers varied for wheat flours of different strength. Overall, bread products in which wheat is used in whole grain form or in a blend with other flours especially benefit from multiple improvers that target different flour constituents in doughs.
Previous work indicated that bran removal promotes network formation in breads prepared from intermediate wheatgrass (IWG) flour. However, refinement reduces yields as well as contents of nutritionally beneficial compounds such as fiber. This study evaluated xylanase pretreatment of IWG bran as a processing option to enhance the properties of bread made with half of the original bran content. Xylanase pretreatment did not affect stickiness but significantly reduced hardness and increased specific loaf volumes compared to negative (without xylanase) and positive controls (with xylanase but without pretreatment). However, the surface of breads with pretreated bran was uneven due to structural collapse during baking. Fewer but larger gas cells were present due to pretreatment. Addition of ascorbic acid modulated these effects, but did not prevent uneven surfaces. Accessible thiol concentrations were slightly but significantly increased by xylanase pretreatment, possibly due to a less compact crumb structure. Endogenous xylanases (apparent activity 0.46 and 5.81 XU/g in flour and bran, respectively) may have been activated during the pretreatment. Moreover, Triticum aestivum xylanase inhibitor activity was also detected (193 and 410 InU/g in flour and bran). Overall, xylanase pretreatment facilitates incorporation of IWG bran into breads, but more research is needed to improve bread appearance.
Background and objectives
To benefit from ecosystem services provided by intermediate wheatgrass (IWG, Thinopyrum intermedium) cultivation, its processing conditions require optimization to facilitate its use in foods. This study assessed tempering as a strategy to improve IWG flour properties relevant for dough making.
Findings
Tempered IWG samples had significantly higher maximum torque in the GlutoPeak, which strongly correlated with lower contents in total and water‐extractable arabinoxylans (p < .05, r = −0.481; p < .01, r = −0.611) and phosphate buffer‐soluble proteins (p < .01, r = −0.893). While higher maximum torque was observed when IWG was tempered to 14% (compared to 12%), target moisture and tempering time did not have any effect. Tempering induced significant reductions in accessible thiols, which also negatively correlated with maximum torque (p < .05, r = −0.473). SDS‐PAGE analysis, however, did not indicate a shift in flour protein profiles.
Conclusions
Tempering significantly increased maximum torque and significantly reduced the contents of phosphate buffer‐soluble proteins, accessible thiols, and arabinoxylans. Together, these findings imply increased protein aggregation and an improved IWG protein network.
Significance and novelty
This work demonstrates that the interaction between proteins and arabinoxylans is crucial for IWG dough properties and can be influenced by processing methods.
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