Arabinoxylans in einkorn are non-starch polysaccharides belonging to the hemicellulose fraction of cereal cell walls [1]. Their structure consists of a main chain of \u03b2-(1\u21924)-D-xylose residues, to which \u03b1-L-arabinose residues are attached laterally in different positions [1]. The degree of substitution and the distribution of arabinosyl groups determine their solubility, water-binding capacity, and the rheological properties of the flour system [2].<\/p>\n
In wheat flours and ancient cereals, including diploid wheats such as Triticum monococcum, arabinoxylans represent a significant component of the non-starch fraction and play an important role in the technological properties of dough [1;2]. They are generally classified into water-extractable arabinoxylans (WE-AX) and water-unextractable arabinoxylans (WU-AX) [2].
\nWater-extractable arabinoxylans contribute to the viscosity of the liquid phase of the dough, promoting gas retention and influencing the stability of the fermentative foam [3]. Water-unextractable arabinoxylans, on the other hand, are more closely associated with the structure of the grain cell wall and can mechanically interfere with the continuity of the gluten network, especially in wholemeal or less refined flours [3].<\/p>\n
From a rheological perspective, arabinoxylans exert a dual effect: on one hand they increase the water absorption capacity of the flour, competing with gluten proteins for hydration; on the other hand, they can contribute to the stabilization of the dough matrix through physical interactions and, in some cases, through bonds mediated by phenolic acids such as ferulic acid [4].
\nIn the context of baking with ancient grains and flours with limited gluten development capacity, such as einkorn, the presence and behavior of arabinoxylans are particularly relevant because they can influence the balance between matrix hydration, protein mobility, and fermentative gas retention [3;5], thus contributing significantly to the final crumb structure.<\/p>\n
Studies on arabinoxylans in einkorn (Triticum monococcum) exist, but they are less numerous than those on common wheat. However, the literature clearly shows three important points:
\n1\ufe0f\u20e3 the arabinoxylan content in einkorn differs from that of modern wheats
\n2\ufe0f\u20e3 there is genetic variability among genotypes and cultivars
\n3\ufe0f\u20e3 the distribution and solubility of arabinoxylans influence dough technology<\/p>\n
1. Arabinoxylan content in einkorn compared to other wheats<\/span><\/strong> For example, a study on fiber in hulled wheats (einkorn, emmer, spelt) shows that: 2. Variability among einkorn genotypes<\/span><\/strong> 3. Distribution of arabinoxylans in the grain<\/span><\/strong> 4. The most important factor: genotype + environment<\/span><\/strong> 5. Direct link with baking<\/span><\/strong> \u2705 Concise scientific conclusion (arabinoxylans in einkorn)<\/span><\/strong> Bibliography<\/span><\/strong> [2]. Courtin, C. M., & Delcour, J. A. (2002). [3]. Saulnier, L., Sado, P.-E., Branlard, G., Charmet, G., & Guillon, F. (2007). [4]. Oudgenoeg, G., Dirksen, E., Ingemann, S., Hilhorst, R., Gruppen, H., Boeriu, C. G., Piersma, S. R., & Voragen, A. G. J. (2001). [5]. Shewry, P. R., & Hey, S. J. (2015). [6]. Abdel-Aal, E.-S. M., Hucl, P., Sosulski, F. W., & Bhirud, P. R. (1998). [7]. Hidalgo, A., & Brandolini, A. (2014). [8]. Gebruers, K., Dornez, E., Boros, D., Fras, A., Dynkowska, W., Bed\u0151, Z., Rakszegi, M., Delcour, J. A., & Courtin, C. M. (2008). Arabinoxylans in einkorn are non-starch polysaccharides belonging to the hemicellulose fraction of cereal cell walls [1]. Their structure consists of a main chain of \u03b2-(1\u21924)-D-xylose residues, to which \u03b1-L-arabinose residues are attached laterally in different positions [1]. The degree of substitution and the distribution of arabinosyl groups determine their solubility, water-binding capacity, and the rheological […]<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[73],"tags":[3129,3125,3135,3139,3127,3131,3137,3133],"class_list":["post-13197","post","type-post","status-publish","format-standard","hentry","category-article","tag-arabinoxylans-dough-rheology","tag-arabinoxylans-einkorn","tag-einkorn-baking-properties","tag-einkorn-dough-structure","tag-einkorn-fiber-composition","tag-einkorn-vs-modern-wheat-fiber","tag-non-starch-polysaccharides-wheat","tag-we-ax-wu-ax-wheat"],"yoast_head":"\n
\nSeveral comparative studies on cereal fiber show that:
\n1 – the total arabinoxylan content in einkorn is generally lower than in modern bread wheat [6].
\n2 – but the fiber composition may be richer in low molecular weight soluble fractions<\/p>\n
\n1 – in bran, arabinoxylans in common wheats are about 12.7\u201322.1% of dry matter
\n2 – whereas in einkorn and emmer they are about 6.1\u201314.4% [6].
\nThis means that einkorn has on average:
\n1 – less structural arabinoxylans
\n2 – a slightly different cell wall structure.
\nThis is consistent with the fact that einkorn doughs are often:
\n1 – more extensible
\n2 – less structurally rigid [3].<\/p>\n
\nVariability among cultivars is documented.
\nA study on hulled wheats analyzed different einkorn genotypes grown in the same environment and found:
\n1 – statistically significant differences among genotypes in soluble fiber fractions
\n2 – differences in low molecular weight soluble dietary fiber fractions (SDF-LM) [7].
\nIn practice:
\n1 – some einkorn lines have:
\n2 – more soluble fiber
\n3 – others more insoluble fiber
\n4 – and this changes dough behavior.
\nThis is very important for baking.<\/p>\n
\nMicroscopy and spectroscopy studies have shown that:
\n1 – arabinoxylans are distributed in the cell walls of the endosperm and bran [2].
\n2 – there are two main forms:
\nLS-AX (low substituted arabinoxylan)
\nHS-AX (high substituted arabinoxylan) [2].
\nThis difference affects:
\n1 -solubility
\n2 – interaction with water and proteins [2;3].
\n3 – dough viscosity.<\/p>\n
\nOne of the clearest findings in the literature is this:
\nthe content and properties of arabinoxylans depend on:
\n1 – genotype (cultivar)
\n2 – environmental conditions
\n3 – year of cultivation [8].
\nFor this reason, two different einkorns can behave very differently in baking.<\/p>\n
\nArabinoxylans mainly influence:
\n1\ufe0f\u20e3 water absorption [2].
\n2\ufe0f\u20e3 dough viscosity [3].
\n3\ufe0f\u20e3 gas retention [3].
\n4\ufe0f\u20e3 interaction with gluten [4].
\nIn cereals with weaker gluten (such as einkorn), arabinoxylans in einkorn<\/strong> can become an important structural factor, because the network is not supported only by proteins but also by the polysaccharide matrix.<\/p>\n
\nThe literature indicates that in einkorn:
\n1 – the total arabinoxylan content is on average lower than in modern wheat [6].
\n2 – there is significant variability among genotypes [7].
\n3 – the composition of soluble and insoluble fractions can influence hydration, viscosity, and dough behavior [2;3].<\/p>\n
\n[1], Izydorczyk, M. S., & Biliaderis, C. G. (1995).
\nCereal arabinoxylans: Advances in structure and physicochemical properties.
\nCarbohydrate Polymers, 28(1), 33\u201348.
\nDOI: 10.1016\/0144-8617(95)00077-1
\nSintesi: defines structure, degree of substitution, and relationship with solubility and functionality.<\/p>\n
\nArabinoxylans and endoxylanases in wheat flour bread-making.
\nJournal of Cereal Science, 35(3), 225\u2013243.
\nDOI: 10.1006\/jcrs.2001.0433
\nSintesi: distinction WE-AX\/WU-AX and key role in hydration, viscosity, and dough.<\/p>\n
\nWheat arabinoxylans: Exploiting variation in amount and composition to develop enhanced varieties.
\nJournal of Cereal Science, 46(3), 261\u2013281.
\nDOI: 10.1016\/j.jcs.2007.06.014
\nSintesi: technological role of arabinoxylans in gas retention and dough structure.<\/p>\n
\nHorseradish peroxidase-catalyzed oligomerization of ferulic acid on arabinoxylans.
\nJournal of Agricultural and Food Chemistry, 49(5), 2503\u20132510.
\nDOI: 10.1021\/jf000595x
\nSintesi: demonstrates the role of ferulic acid in cross-linking and network stability.<\/p>\n
\nThe contribution of wheat to human diet and health.
\nPhilosophical Transactions of the Royal Society B, 370(1679), 20140271.
\nDOI: 10.1098\/rstb.2014.0271
\nSintesi: highlights differences between ancient and modern wheats and the role of the non-starch matrix.<\/p>\n
\nKernel, milling and baking properties of spring-type spelt and einkorn wheats.
\nJournal of Cereal Chemistry, 75(5), 736\u2013742.
\nDOI: 10.1094\/CCHEM.1998.75.5.736
\nSintesi: comparison between hulled and modern wheats, including fiber and arabinoxylan content.<\/p>\n
\nNutritional properties of einkorn wheat (Triticum monococcum L.).
\nJournal of the Science of Food and Agriculture, 94(4), 601\u2013612.
\nDOI: 10.1002\/jsfa.6382
\nSintesi: highlights genetic variability and differences in fiber composition.<\/p>\n
\nVariation in the content of dietary fiber and components thereof in wheats in the HEALTHGRAIN diversity screen.
\nJournal of Cereal Science, 48(3), 845\u2013857.
\nDOI: 10.1016\/j.jcs.2008.01.012
\nSintesi: demonstrates the combined effect of genotype and environment on fiber (including arabinoxylans).<\/p>\n","protected":false},"excerpt":{"rendered":"