Carotenoids in corn gluten

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1940
Authors
Nagy, Daniel
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Chemistry
Abstract

Existing methods for the isolation of carotenoid pigments have been modified to make them more suitable for the isolation of the isomerized pigment derivatives from corn gluten. Greater recovery of pigments from saponification mixtures may be obtained by the use of concentrated aqueous alkali and centrifuging;Closely related pigments are separable only on mild adsorbents. Deactivated alumina is not suited for such separations. Calcium carbonate showing the necessary selective adsorption has been made by precipitation. The presence of acidic and saponifiable materials hinders adsorption, particularly on mild adsorbants;Acetone is of value as a developing agent. Adsorbents treated with acetone are not deactivated, and the complete removal of pigments with this solvent can be used to advantage with the microchromatograph;The original pigment of the corn kernel is almost wholly carotenoid in nature;Processing corn gluten under conditions which involve exposure to heat, air, and acid transform the carotenoids partly into heat and acid isomerized derivatives. No large amounts of colored, partly oxidized pigments are present;Neozeaxanthin B, prepared according to Zechmeister's procedure, differed markedly both in melting point and in adsorption spectra from the values he records;A brief study of the acid isomerization products of zeaxanthin has been made. Dilute acetic acid results mainly in the formation of neozeaxanthin A. Dilute hydrochloric acid causes the formation of at least ten isomerized pigments. With the exception of neozeaxanthins A and B, these are oils. One of the pigments was found to be almost identical with cryptoxanthin both in partition and adsorption affinity;The presence of beta-carotene in corn has been confirmed by the isolation of the material in crystalline form;The suggestion is made that the chromatographic adsorption of carotenoids is fundamentally an acid-base reaction occurring in non-aqueous media.

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Mon Jan 01 00:00:00 UTC 1940