Acid Reversion in Relation to Isomaltose as a Starch Hydrolytic Product<sup>1</sup>

Thompson, A.; Wolfrom, M. L.; Quinn, Edwin J.

doi:10.1021/ja01108a062

Cited by 37 publications

(6 citation statements)

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“…Our figures for the yield of isomaltose on hydrolysis of glycogen are somewhat higher than those given by Wolfrom, Lassettre & O'Neill (1951). Ifone assumes that isomaltose amountsto about half the total oligosaccharide produced from glucose by condensation under the conditions used for glycogen hydrolysis, as in the more drastic conditions mentioned earlier, the yields recorded in our experiments are appreciably greater than those found by Thompson et al (1953).…”

Section: Discussioncontrasting

confidence: 66%

“…That glucose could be -condensed with aqueous mineral acid has long been known, if not widely recognized. It is evident from our observations and those of Thompson et al (1953Thompson et al ( , 1954) that with relatively dilute mineral acid isomaltose and gentiobiose are the main products, although a number of other disaccharides also arise. Chromatographic evidence and the fact that the reducing power is more than doubled by complete hydrolysis show that after treatment with concentrations of acid no greater than N some larger molecules are formed.…”

Section: Discussionsupporting

confidence: 63%

“…Even if an allowance of 1O % is made for contaminating substances in the isomaltose fraction the figures show that nearly half the condensation product is isomaltose. Inspection of chromatograms suggests that the amount of gentiobiose formed is of a comparable magnitude, and this is confirned by the isolation by Thompson et al (1953) of equal amounts of the two octaacetates. The greater part of the condensation products evidently consists of these two disaccharides.…”

Section: Discussionmentioning

confidence: 99%

“…While the present work was in progress Wolfrom and his collaborators published the results of several years' investigation of this problem (cf. Wolfrom, Georges & Miller, 1949): after acetylating the products of heating glucose in dilute acid solution they have isolated equal quantities of the octaacetates of isomaltose and gentiobiose (Thompson, Wolfrom & Quinn, 1953) and also smaller amounts of the octaacetates of other disaccharides (Thompson, Anno, Wolfrom & Inatome, 1954). The quantities of isomaltose octaacetate isolated in these experiments were much smaller than those obtained from the acetylated hydrolysis products of glycogen (Wolfrom, Lassettre & O'Neill, 1951) and amylopectin (Wolfrom, Tyree, Galkowski & O'Neill, 1951).…”

mentioning

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The occurrence of isomaltose among the products of heating glucose in dilute mineral acid

Bacon

1954

Biochemical Journal

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Section: Discussioncontrasting

confidence: 66%

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confidence: 63%

Section: Discussionmentioning

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The occurrence of isomaltose among the products of heating glucose in dilute mineral acid

Bacon

1954

Biochemical Journal

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Structure of a Synthetic Polyxylose

Bishop¹

1956

Can. J. Chem.

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In the presence of an acid catalyst monosaccharides may coilde~lse to form reversion products and there are many reports about the preparation and structures of low molecular weight oligosaccharides, mainly disaccharides, thus formed (11,17,19,20,22). There are a limited number of references to higher molecular weight polysaccharides, having a degree of polyinerization (D.P.) greater than 10, formed by reversion. Pacsu and Mora (12) reported the isolatioil of a polyglucose having a D.P. of 37-42 and claimed that similar products could be obtained from ~-l l l a~l i l~~e , D-fructose, L-arabinose, maltose, and cellobiose. However, no details were given of the polysaccharides formed from these latter sugars. Preparation of these polymers was accomplished by low temperature evaporation of a concentrated solution of the mo~zosaccharide in 5% hydrochloric acid. Kent (8) has synthesized glucose polyn~ers by heating glucose monohydrate with thioilyl chloride and Theobald and Twigg (18) also used this method. Ricketts (14, 15) improved on these inethods of polysaccharide syntheses by allowing crystalline D-glucose or its monohydrate to deliquesce in the presence of hydrogen chloride. I t was postulated that by this process, the molecules of D-glucose, which in the crystalline state are as near to each other as possible, must pass through the optimum distance for bond formation as they dissolve.The linkrages formed in the reversion of hexoses by acid in the experiments just summarized were primarily l+G and were predoininailtly in the aconfiguration. Of the glycosidic linkages other than l+6, the 1-+4 was prevalent but there was a notable absence of the 1+3. Since the final compositiorl of a system undergoing acid reversioil is determined by equilibria between hydrolytic and condensation reactions, the preferential occurrence of 1-6 over 1 -4 over 1-3 linkages could be caused by (a) differences in acid-stability of the linl;ages once formed or (b) differences in reactivities of hydroxyl groups. There is evidence in favor of both effects: (a) Wolfrom et al. (24) showed that for glucose disaccharides the a , 1 4 4 linkage is hydrolyzed by acid four times as rapidly as the a, l+G bond, and Ricketts and Rowe (13) found that maltose is not incorporated as such into a polyglucose on acid reversion but yields a product very similar to that obtained from glucose, with a predominance of ldlanuscript received il [ay 24, 1956.

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Carbohydrates in Malting and Brewing: Vii. Complex Carbohydrates of Infusion Wort and Their Enzymic Degradation

Harris

MacWilliam

1958

Journal of the Institute of Brewing

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The dextrins of infusion wort were separated into five fractions of increasing complexity of structure by successive precipitations by means of acetone and ethanol and by dialysis. The first fraction contained dextrins averaging four glucose units in chain‐length while fraction 2 had an average chain‐length of 13 and the less soluble fractions were still more complex and were contaminated with pentosans. The various groups of dextrins were all hydrolysed to a considerable extent by β‐amylase except in the case of fractions 2 and 3 where the degree of degradation was only about 20%. These fractions were of highly branched structures as confirmed by their yielding much isomaltose on partial hydrolysis with acid. Although the dextrins are incompletely degraded by α‐ and β‐amylase under normal brewing conditions, enzyme preparations from moulds and even from malt were able to degrade all fractions almost completely under certain circumstances to mono‐, di‐, and trisaccharides. The alcohol‐soluble carbohydrates from infusion wort contained small amounts of isomaltose and panose and the pentoses xylose, arabinose and ribose in addition to the major components previously noted.

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Acid Reversion in Relation to Isomaltose as a Starch Hydrolytic Product¹

Cited by 37 publications

References 1 publication

The occurrence of isomaltose among the products of heating glucose in dilute mineral acid

The occurrence of isomaltose among the products of heating glucose in dilute mineral acid

Structure of a Synthetic Polyxylose

Carbohydrates in Malting and Brewing: Vii. Complex Carbohydrates of Infusion Wort and Their Enzymic Degradation

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Acid Reversion in Relation to Isomaltose as a Starch Hydrolytic Product1

Cited by 37 publications

References 1 publication

The occurrence of isomaltose among the products of heating glucose in dilute mineral acid

The occurrence of isomaltose among the products of heating glucose in dilute mineral acid

Structure of a Synthetic Polyxylose

Carbohydrates in Malting and Brewing: Vii. Complex Carbohydrates of Infusion Wort and Their Enzymic Degradation

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Product

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Acid Reversion in Relation to Isomaltose as a Starch Hydrolytic Product¹