Effect of Bran Pre-Treatment with Endoxylanase on the Characteristics of Intermediate Wheatgrass (Thinopyrum intermedium) Bread.

Yaxi Dai,George Amponsah Annor,Jacob Jungers,Radhika Bharathi,Catrin Tyl

doi:10.3390/foods10071464

Yaxi Dai, George Amponsah Annor + Show 3 more

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https://doi.org/10.3390/foods10071464

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Abstract

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.

Highlights

Whole grains and products thereof are integral parts of diets that are healthy and have low environmental impact [1]
Indigestible carbohydrates that qualify as dietary fiber are considered one of the main contributors to the positive health effects associated with the consumption of whole grains and cereal brans
intermediate wheatgrass (IWG) breads without pretreatments had specific loaf volumes slightly below the range reported for breads made from whole wheat (2.43–3.64 mL/g) or spelt (2.94–3.87 mL/g) [15]

Summary

Introduction

Whole grains and products thereof are integral parts of diets that are healthy and have low environmental impact [1]. In a recent study, participants who adhered to a diet with a low index for healthiness and sustainability consumed significantly fewer whole grains than individuals whose diet scored high on both aspects [2]. Indigestible carbohydrates that qualify as dietary fiber are considered one of the main contributors to the positive health effects associated with the consumption of whole grains and cereal brans. The incorporation of cereal bran into food products can decrease consumer acceptance and the decline in acceptability with increasing fiber levels appears to be especially pronounced for indulgence products [5]. Numerous studies have focused on devising novel processing strategies for cereal bran such as particle size reduction or fermentation [6]

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