Pentose content

The other carbohydrates in cane juice are the soluble polysaccharides vaguely classified under the terms "hemi-celluloses, soluble gums and pectins. It is possible that some of these polysaccharides may enter the juice during the milling of the cane as the plant cell structure is destroyed. A gummy product has been isolated from cane fiber by alkali extraction followed by alcohol precipitation. Acid hydrolysis of this substance yielded crystalline D-xylose and L-arabinose.10 Such gums in Trinidad cane juices were isolated by alcohol precipitation at suitable hydrogen ion concentration and assayed for pentose content by the Tollens 2-fural-dehyde assay the results showed an apparent pentosan content of 0.04-0.07%u of the Brix solids. 

The pentose content in carrageen was estimated as 1-1.4% (cold extract)68 82 and 1-1.9% (hot extract)68-82 methylpentose was found only in the hot extract82 and to the extent of about half that of the pentose content. 

The chemistry of tuberculinic acid (the nucleic acid of the tubercle bacillus) was investigated by Brown and Johnson. The acid was purified by conversion to the copper salt. Distillation with hydrochloric acid yielded small amounts of furfural, indicating the presence of only a trace of pentose in the residue. Levulinic acid was identified, and it was thought on this evidence that the sugar associated with the acid was a hexose. Tuberculinic acid is unique in that it does not contain uracil, has a low pentose content and contains an unusual pyrimidine derivative. The tuberculinic acid was considered to be more nearly related to deoxyribonucleic acid than to ribonucleic acid. ... 

The second fraction had a high optical rotation, was insoluble in alcohol and contained a large quantity of D-mannose. It had only a weak precipitation power with immune serum the biological activity therefore seemed to be associated with the pentose content of the fractions. 

Needless to say, the same test procedure can be employed to determine the pentose content of a solution, in which case 150.130 g of pentose yield 96.082 g of furfural, so that each gram of furfural produced in the test corresponds to 1.56252 g of pentose. 

Unless otherwise specified, reaction conditions were substrate (100 mg) and CrCb -OHrO (10 mg, 0.0375 mmol) were added to 2.0 g of [C4mim]Cl, followed by Ml at 400 W for the desired time. Yields of HMF from corn stalk, rice straw and pine wood were based on a hexose content of 36.1 %, 37.5% and 54%, and yields for furfural were based on a pentose content of 21.4%, 21.2% and 7.6%, respectively. [QmimJBr was used as a reaction medium. Reaction conditions were 20 mg of hydrochloric acid, 2.0 g of [OmimJCl, 30 mg of HrO, 0.1 g of pine wood, 1(X) C with an oil-bath. Reaction conditions were 10 mg of CrCb 6H2O, 2.0 g of [C4mim]Cl, 0.1 g of pine wood, 100 "C with an oil-bath. Otherwise was the same as in Entry 11 except for the reaction temperature at 200 "C. 

The major biochemical features of neutrophils are summarized in Table 52-8. Prominent feamres are active aerobic glycolysis, active pentose phosphate pathway, moderately active oxidative phosphorylation (because mitochondria are relatively sparse), and a high content of lysosomal enzymes. Many of the enzymes listed in Table 52-4 are also of importance in the oxidative metabolism of neutrophils (see below). Table 52-9 summarizes the functions of some proteins that are relatively unique to neutrophils. 

Iowa. Modem industrial prepns start with agricultural residues such as oat hulls, corn cobs, rice hulls, bran, etc, which have a relatively high pentosan content (Ref 10). In these processes pentosans are hydrolyzed to pentoses by acid digestion, and these split out water internally to form forfurals ... 

Minimum amounts of 2-3 /ig of sialic acids can be determined in, for example, the orcinol-Fe3+ assay, if the volumes of the Bial reagents23 are one-fifth of those originally described.107 By using this method, sialic acids can be accurately determined only if they have been prepurified, as free or glycosidically bound pentoses, hexoses, or alduronic acids interfere with the reaction by giving green chromo-phores.107 In our experience, an approximate determination of the sialic acid in a complex carbohydrate is only possible if its sialic acid content is >5%. 

Niacin, a water-soluble vitamin vital for oxidation by living cells, functions in the body as a component of two important coenzymes nicotinamide adenine dinucleotide (NAD) and nicotinamide adenine dinucleotide phosphate (NADP). NAD and NADP are involved in the release of energy from carbohydrate, fat, and protein, and in the synthesis of protein, fat, and pentoses for nucleic acid formation. Milk is a poor source of preformed niacin, containing about 0.08 mg per 100 g. However, milk s niacin value is considerably greater than indicated by its niacin content (Horwitt et al. 1981). Not only is the niacin in milk fully available, but the amino acid tryptophan in milk can be used by the body for the synthesis of niacin. For every 60 mg of tryptophan consumed, the body synthesizes 1 mg of niacin. Therefore, the niacin equivalents in 100 g milk equal 0.856 mg including that from pre-... 

The hexose monophosphate (Helly, 1976) and pentose phosphate (Hochachka and Hayes, 1962 Yamaguchi et al., 1976 Walsh, 1985 Malinovskaya, 1988 Kudryavtseva, 1990) shunts have also been found to increase in importance. The activity of transketolase, the enzyme which inhibits the peptide-phosphate pathway, is greater in fish from cold water, e.g. trout and smelt, than in those from warm water (Kudryavtseva, 1990). In the Black Sea horse-mackerel, a sharp decline in adenine nucleotide content (AMP, ADP and ATP) in white and red muscle tissues and in liver occurs at low temperature (Trusevich, 1978). In this case, the ATP is mosdy resynthesized by glycolysis. The increase in the glucose content of the blood of fish at low ambient temperatures may be of the same nature (Prosser, 1967 ... 

The material used in the present study contained higher amounts of carbohydrates. The higher sugar content can, to some extent, be ascribed to the fact that the material was withdrawn before the saccharification step in the factory, in contrast to the old material. As already mentioned, starch saccharification releases some pentoses as well. If these monosaccharides, released in the saccharification step, are subtracted from the sugar yields obtained with the new material, the difference in yield between the two materials diminishes. However, the new material still has a higher amount of carbohydrates. 

From the reported data (Figs. 1 and 2, Table 1) the optimum condition to obtain a pentose-rich hydrolysate from dilute-acid hydrolysis of BSG at 130°C was 15 min (CS 1.94). Such hydrolysate contains about 43.5 g/L of glucose, xylose, and arabinose (ratio of 10 67 32), together with a low content of furfural, HMF, acetic acid, formic acid, and total phenolic compounds (Table 2). This condition was chosen for subsequent production of hydrolysates for fermentation. 

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