Diferulates as structural components in soluble and insoluble cereal dietary fibre

Abstract

Cell wall cross-linking can have a substantial effect on the properties of the wall. To estimate cross-linking (between arabinoxylans) in cereal ®bres, dehydrodiferulate levels were measured in soluble and insoluble dietary ®bre (SDF and IDF) isolated from whole grains of maize (Zea mays L), wheat (Triticum aestivum L), spelt (Triticum spelta L), rice (Oryza sativa L), wild rice (Zizania aquatica L), barley (Hordeum vulgare L), rye (Secale cereale L), oat (Avena sativa L) and millet (Panicum miliaceum L). After saponi®cation of the cereal ®bres the extracts were investigated for dehydrodimers of ferulic acid using GLC±MS and GLC±FID. From most cereal IDF the whole spectrum of dehydrodiferulic acids (DFAs) (8-5'-, 8-8'-, 5-5'-, 8-O-4'-and 4-O-5'-coupled) could be identi®ed. The absolute contents of total DFAs ranged between 2.4 and 12.6 mg g À1. With the exception of 4-O-5'-coupled DFA, the whole range of DFAs was also detected from cereal SDF but only in amounts of 40±230 mg g À1. It was estimated that arabinoxylans of cereal IDF contain 8±39 times more diferulates than arabinoxylans of cereal SDF (where measurement of DFA levels in SDF was possible). In cereal IDF, 8-5'-coupled dimers dominated, whereas in cereal SDF, 8-8'-coupled dimers were relatively enhanced and often became the major dimers.

Health benefits of finger millet (Eleusine coracana L.) polyphenols and dietary fiber: a review

“…Water-insoluble fibre (IDF) contains lignin, cellulose, hemicelluloses (Bingham 1987;Marlett 1990), and NSP such as water-unextractable arabinoxylan. In millets, NSP form the quantitatively most important source of both soluble and insoluble dietary fibers (Bunzel et al 2001). In cereal botanical components, the majority of dietary fibres generally occur in decreasing amounts from the outer pericarp to the endosperm, except arabinoxylan, which is also a major component of endosperm cell wall materials.…”

Plant-derived antifungal agent poacic acid targets β-1,3-glucan

“…One understudied class of compounds found in grasses and their hydrolysates is the dehydrodiferulates and compounds derived from them (hereafter all simply termed diferulates) (16,17). In grasses, diferulates are produced by radical dimerization of ferulates that acylate arabinoxylan polysaccharides and function as powerful cell wall cross-linkers (16); derivatives of diferulates are released during the hydrolysis of biomass (16,18,19). At present, the structures of a range of diferulates have been described (16,18), but the biological activities of isolated diferulates (beyond their function in the plant cell wall) have not been explored.…”

Ferulic acid in cereals - a review

“…The highest diferulic acid contents in cereals were found in popcorn, followed by maize, rye, barley, oats, and wheat (ranging between around 250 and 475 µg/g of flour) (Jilek & Bunzel 2013). Diferulic acids may play an important role in dietary fibre by influencing the chemical structure of dietary fibre components (Bunzel et al 2001). Studies have shown that esterified diferulates can be released from cereals by intestinal enzymes, and that free diferulic acids can be absorbed and enter the circulatory system (Andreasen et al 2001).…”