Effect of Differently Extracted Arabinoxylan on Gluten-Free Sourdough-Bread Properties

Abstract

e role of arabinoxylans (AXs) in bread-making has gained interest due to their positive contribution to bread quality. erefore, the e ect of di erently extracted (water, alkaline, or enzymatic) rye AXs on gluten-free (GF) buckwheat and millet batter rheology and bread properties was evaluated. e results showed that the addition of AXs in uenced most of the batter and bread properties di erently, which depended on the chemical and structural properties of the AXs. All batter systems displayed a typical weak gel behavior. Enzyme-(Pentopan Mono BG-) extracted AXs (PEAXs) were able to strengthen both millet and buckwheat batter structures to a greater degree, as seen by the increase in storage modulus. Regarding bread properties, in buckwheat breads, calcium hydroxide-extracted AX (CEAX) was able to improve the speci c volume (from 1.73 to 1.93 cm 3 /g) and rmness (from 10.88 to 4.69 N) the most, compared to the control. e AXs extracted successively with water and the enzyme Pentopan Mono BG (WPEAX) produced the highest loaf volume (2.39 cm 3 /g) and one of the lowest crumb rmness values (5.51 N) but caused larger pores and a ruptured crust. In millet breads, water-extracted AXs (WEAXs) and CEAX produced lowest crumb hardness (WEAX: 6.94 N; CEAX: 8.53 N). Speci c volume was highest in breads with WEAX (2.35 cm 3 /g), but CEAX displayed a better pore structure. Overall, water-extracted AXs improved the GF bread properties to a higher extent than alkaline-extracted AXs. Only CEAX displayed a comparable e ect in some cases, and considering the fact that alkaline extraction of AX is much more e cient (much higher yield), its application compared to other AXs could be more favorable. Overall, AXs hold great potential as baking improvers for GF bread; the extent of their improvement will be de ned by their functional properties.

Cross-Linking of Wheat Bran Arabinoxylan by Fungal Laccases Yields Firm Gels

“…Laccases are part of a large group of multi-copper oxidases acting on polyphenols, methoxy-substituted phenols, aromatic diamines, and a range of other compounds [17]. They were suggested as processing aids for wine, beer, and bakery products, and for improving sensory parameters of food [18][19][20]. Laccase catalysis occurs by reduction of oxygen to water accompanied by the oxidation of the substrate.…”

Improving gluten-free buckwheat bread by sourdough fermentation and addition of arabinoxylan and pyranose 2-oxidase

“…The chemical composition of wholemeal buckwheat flour was 14.27 ± 0.02% dm (= % dry matter) protein, 2.87 ± 0.01% dm fat, 67.07 ± 0.09% dm starch, 0.42 ± 0.04% dm soluble dietary fibres, 5.42 ± 0.20% dm insoluble dietary fibres and 2.27 ± 0.03% dm ash; while for refined buckwheat flour, it was 2.27 ± 0.03% dm protein, 2.27 ± 0.03% dm fat, 82.54 ± 4.26% dm starch, 0.13 ± 0.03% dm soluble dietary fibres, 1.51 ± 0.05% dm insoluble dietary fibres and 0.99 ± 0.00% dm (the sum of soluble and insoluble dietary fibre is total dietary fibre). These properties were derived from Bender et al (2018b), except for the starch content, which was calculated by differences. Rye AX was extracted with calcium hydroxide following the procedure of Bender et al (2017b) and POx was recombinantly expressed from the white rot fungus Phanerochaete chrysosporium and purified, as explained by Spadiut et al (2010).…”

“…The ratio of water, flour and starter culture was 1:1:10. The resulting batter was fermented in a fermenter (60/rW, MANZ Backtechnik GmbH, Creglingen, Germany) at 30 °C and 85% R.H. for 20 h. A simplified recipe, as described by Bender et al (2018b), was used for wholemeal and refined buckwheat bread, based only on buckwheat flour (100%), water (100%), salt (1.9%), sugar (1.9%), instant yeast (1.9%) and sourdough (82%) without any further additives (% of total flour weight, including flour of sourdough and bread preparation). AX was added to the dry ingredients, while POx was always added to the water.…”

“…AX was added to the dry ingredients, while POx was always added to the water. When AX was used, additional water was added to the formulation, according to its water holding capacity (= 1.64 g H 2 O/g AX) (Bender et al, 2018b). Subsequently, the sourdough and water was added to the batter and mixed at 300 rpm with a laboratory dough mixer (Bär Varimixer RN10 VL-2, Wodschow & Co., Denmark) for 1 minute and at 78 rpm for 4 minutes.…”

Ohmic Heating—a Novel Approach for Gluten-Free Bread Baking

“…Values of L* ((0 = black, 100 = white), a * (+value = red, −value = green), and b * (+value = yellow, −value = blue) were measured according to the CIELAb system definition. Crumb porosity was measured by taking an image of two slices by a digital camera D-90 Nikon (Tokyo, Japan) from the Digi-Eye® System (Verivide, Leicester, UK) and analyzing a 2 × 2 cm crumb square with an image analyzer software (ImageJ 1.47v, National Institute of Health, Bethesda, USA) as described by Bender et al (2018). This software uses the contrast between two phases (pores and solid part) to estimate the pores.…”