Ivory nut mannan

These last two mucilages have been examined in some detail. Gum gatto in some respects has a structure which resembles that of salep mannan and ivory nut mannan. Lucerne seed mucilage, on the other... 

Lamellar, single crystals of ivory-nut mannan were studied by electron diffraction. The base-plane dimensions of the unit cell are a = 0.722 nm and b = 0.892 nm. The systematic absences confirmed the space group P212121. The diffraction pattern did not change with the crystallization temperature. Oriented crystallization ofD-mannan with its chain axis parallel to the microfibril substrates, Valonia ventricosa and bacterial cellulose, was discovered ( hetero-shish-kebabs ). 

Ivory nut mannan such as that from palm seed is the only identified water insoluble food reserve polysaccharide which occurs in nearly pure form. It dissolves in 5% alkaline solution, and its food reserve nature is indicated by its disappearance when the seed germinates. Perhaps its lack of solubility permits the palm seeds to withstand rather long soaking periods before germination. Most other mannans found in other biological sources are branched and more readily water soluble. 

Two mannans may be isolated from ivory nuts. Mannan A, which is extracted with alkali, occurs in granular form,94 96 and x-ray diffraction photographs of both the native and the extracted polysaccharide show distinct crystalline patterns.96 Mannan B cannot, however, be extracted directly, and it is separated from cellulose by precipitation from cupram-monium solution.91 In the plant, mannan B is built up of microfibrils analogous to those of cellulose, but the extracted polysaccharide shows no tendency to crystallize on precipitation.95... 

An enzyme preparation from guar,236 described as exo-jS-D-(l— 4)-mannanase, hydrolyzed ivory-nut mannan almost completely to D-mannose. The purified (1,000-fold) enzyme from pineapple300 hydrolyzed the substrates in the order p-nitrophenyl /3-D-mannopy-ranoside >/3-D-Man-(GlcNAc)2-Asn (a core glycopeptide) > methyl /3-D-mannopyranos ide > /3-D-Man-(l—>4)-d-G1c > /3-D-Man-(l—>4)-D-mannitol. 

The structure of the mannan, or mannans, in wood cannot be described with certainty. Hess and Liidtke isolated a mannan from pine sulfite pulp identical with ivory-nut mannan-A in optical rotation and x-ray diagram. Husemann prepared, from spruce hemicellulose, fractions having rotational values in agreement with those for the mannan from pine sulfite... 

While all of the natural products just referred to were heteropolysaccharides (although several of the hemicelluloses were largely xylose-based), some attention was paid to compounds composed of single hexoses. A minor amount of research was conducted on cellulose and starch chemistry, and callose, an unusual />-(T 3)-linked glucan, found in small amounts in the sieve plates of the phloem of the grape vine, was characterized. Two papers were published on ivory nut mannan and several on fructose-based polymers. 

Ivory nut mannan, poly (W)-g-p-mannose, Is a well-known reserve polysaccharide which is water insoluble... 

Carbon atoms of neutral polysaccharides may be converted into carboxyl groups by oxidation with dinitrogen tetraoxide, and the mechanism, at least for cellulose, possibly involves an intermonomeric contribution to the transition state by adjacent C-6 groups. Cellulose " " and ivory-nut mannan have been oxidized in this way, and, in both products, keto groups are formed at secondary carbon atoms in side reactions. Oxidation with dinitrogen tetraoxide has also been employed in the pro-... 

A polysaccharide containing 95% or more mannose units which are (1 4) linked in the P-pyranosyl form with some a-D-galactopyranosyl units (1 6) linked along the main chain. The type of mannan depends on the ratio i> mannose D-galactose Galactomannan 1.04-5.26 1 Mannan A 50 1 Mannan B 90 1. Polymeric. Minimum formula given. Occurs in custard apple, ebony and palms. Ivory nut mannan is a major product. Used in prepn. of i>Mannose by hydrol. of ivory nut meal. Widely used in industry, notably in food, pharmaceuticals, paints and explosives. [a]i -44.58 (c, 0.83 in N NaOH). 

C18H32O16 504.441 Isol. from the partial acid hydrolysate of ivory-nut mannan Phytelephas macrocarpa). Cryst. (EtOH aq.). 

The presence of mannans in the crude cellulose of softwoods has frequently been reported but it is probable that in most of these instances the polysaccharide involved is a glucomannoglycan (see p. 225). A true mannan (ivory nut mannan) forms about 60% of the endosperm of the seed of the tagua palm [Phytelephas macrocarpa) and its X-ray diffraction pattern resembles that of cellulose. The D-mannose units are mainly /S-D-(i -> 4)-linked in a linear molecule. Similar mannans are found in the tubers of some Orchidaceae species (salep mannan) and in the green coffee bean. 

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