Maillard Reaction Products in Gluten-Free Bread Made from Raw and Roasted Buckwheat Flour.

Artur Szwengiel,Krzysztof Dziedzic,Aleksander Siger,Maria Barbara Różańska,Sylwia Mildner-Szkudlarz

doi:10.3390/molecules26051361

Artur Szwengiel, Krzysztof Dziedzic + Show 3 more

Open Access

https://doi.org/10.3390/molecules26051361

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Abstract

The formation of Maillard reaction products (MRPs) in gluten-free bread made from roasted and raw buckwheat flour was examined. The levels of phenolic compounds such as flavonoids (catechin, naringenin, quercetin, rutin, and others) and phenolic acids (like 4-hydroxybenzoic, caffeic, dihydroxybenzoic, ferulic, gallic, syringic, vanillic, and p-coumaric) were measured using reversed-phase ultra-high performance liquid chromatography-electrospray ionization mass spectrometry (RP–UHPLC–ESI-MS). Early and advanced Maillard reaction products were analyzed using HPLC, whereas spectrofluorimetric analysis was used to determine the levels of fluorescent intermediate compounds (FIC). The total levels of phenolic compounds were higher in the case of buckwheat bread prepared from roasted buckwheat flour (156 and 140 µg/g of crumb and crust, respectively). Rutin, gallic acid, and catechin were the most abundant phenolic compounds detected in roasted buckwheat bread. The roasting process resulted in significantly lower radical scavenging capacities (ABTS) of the total phenolics and flavonoids in the buckwheat bread. Taking into consideration these Maillard reaction products, we observed a significant increase in FIC level in roasted buckwheat crumb and crust (at about 40%, and 38%, respectively). At the same time, the Nε-(carboxymethyl)lysine (CML) level did not change in roasted or raw buckwheat bread crumb, though in roasted buckwheat crust the concentration of CML increased by about 21%.

Highlights

Bread is one of the most popular cereal products in the world
In the case of crust and crumb of roasted buckwheat bread, the total phenolic compound content was 158% and 187% higher, respectively, than in bread produced with raw buckwheat flour
These findings can be related to the fact that the steaming processing in the production of roasted buckwheat flour led to a transfer of water-soluble substances from buckwheat husk to the grain [15]

Summary

Introduction

Bread is one of the most popular cereal products in the world. An increase in interest in gluten-free (GF) products was observed. Numerous studies have being conducted to improve the quality of gluten-free (GF) bread [1] given its poor nutritional value (manifesting as insufficient levels of protein and the minerals Ca, Fe, Mg, and Zn) [2], poor aroma [3], and poor textural quality. Like other pseudocereals (e.g., amaranth, quinoa), buckwheat flour does not contain proteins with the ability to trigger the auto-immune response observed in celiac disease, and can be used in the production of gluten-free bread [4]. Two types of buckwheat flour are commercially available with high variability in the composition of nutrients. The first is raw buckwheat flour, produced by using raw dehulled grains; the second is roasted buckwheat flour, which is obtained from buckwheat grains roasted at 130 ◦C under 5–6 bars pressure for 1 h, and dehulled [5]

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