Novel Rhamnogalacturonan I and Arabinoxylan Polysaccharides of Flax Seed Mucilage

Abstract

The viscous seed mucilage of flax (Linum usitatissimum) is a mixture of rhamnogalacturonan I and arabinoxylan with novel side group substitutions. The rhamnogalacturonan I has numerous single nonreducing terminal residues of the rare sugar L-galactose attached at the O-3 position of the rhamnosyl residues instead of the typical O-4 position. The arabinoxylan is highly branched, primarily with double branches of nonreducing terminal L-arabinosyl units at the O-2 and O-3 positions along the xylan backbone. While a portion of each polysaccharide can be purified by anion-exchange chromatography, the side group structures of both polysaccharides are modified further in about one-third of the mucilage to form composites with enhanced viscosity. Our finding of the unusual side group structures for two well-known cell wall polysaccharides supports a hypothesis that plants make a selected few ubiquitous backbone polymers onto which a broad spectrum of side group substitutions are added to engender many possible functions. To this end, modification of one polymer may be accompanied by complementary modifications of others to impart functions to heterocomposites not present in either polymer alone.

XAX1 from glycosyltransferase family 61 mediates xylosyltransfer to rice xylan

“…Whereas O-3 substituted arabinose is characteristic of the grasses, many dicot species have O-2 substituted arabinose (38,41,42). In addition, flax and psyllium seed mucilage have been shown to contain α-(1,2) α-(1,3) disubstituted or α-(1,3) monosubstituted arabinose on xylan, respectively (39,40). Thus, having dicot orthologs in Clade C.II is not surprising.…”

Structure–activity relationship of immunomodulating pectins from elderberries

“…Linkages normally found in HG and RG-I backbone were identified in all the fractions (Table 3 and Table 4) [95]. The most acidic fraction from the 50 °C water extract, 50WSnFl-I-S4, Small amounts of 1,4-Xyl, 1,4-Glc, t-Xyl and 1,3,4-GalA could be due to xyloglucans and xylogalacturonans [94,97].…”

Flaxseed Soluble Dietary Fibre Enhances Lactic Acid Bacterial Survival and Growth in Kefir and Possesses High Antioxidant Capacity

“…Overall, after the day 14, kefir samples supplemented with flaxseed mucilage provided significantly (P < 0.001) higher viability of bacteria in comparison with their respective samples without flaxseed mucilage. These results demonstrated the potential ability of pure mucilage as well as crude flaxseed mucilage in kefir systems with or without probiotics to enhance the microbial survival and growth.The polysaccharides of flaxseed mucilage have been classified in two groups of neutral and acidic fraction which mainly composed of arabinoxylan and rhamonogalacturonan I, respectively (Naran, Chen, & Carpita, 2008;Warrand et al, 2003). Our findings confirm the results reported by (Fodje et al, 2009) which showed the highest fermentation rate of flaxseed mucilage in comparison to wheat or rye bran, due to higher soluble fibre content in flaxseed mucilage.…”