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Carotenoid Pigments of Pineapple Fruit. I. Acid‐Catalyzed Isomerization of the Pigments a
Author(s) -
SINGLETON L.,
GORTNER WILLIS A.,
YOUNG H. Y.
Publication year - 1961
Publication title -
journal of food science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.772
H-Index - 150
eISSN - 1750-3841
pISSN - 0022-1147
DOI - 10.1111/j.1365-2621.1961.tb00039.x
Subject(s) - isomerization , pigment , chemistry , carotenoid , hypsochromic shift , absorbance , epoxide , photochemistry , organic chemistry , catalysis , biochemistry , chromatography , physics , quantum mechanics , fluorescence
SUMMARY The total carotenoid pigments of pineapple fruit contain a high proportion of epoxide groups which are readily isomerized to furanoid forms in an acid but not an alkaline environment. This isomerization causes a characteristic hypsochromic shift in the absorption maxima of the pigment extract. The absorbance at 425 mμ remains relatively unchanged as isomerization proceeds, and thus can serve as a measure of the total carotenoid pigment regardless of its isomeric form. The sharp maximum at 466 mμ is lost as isomerization progresses. Thus, the ratio of absorbances at 466 and 425 mμ can serve as a measure of the extent of isomerization of the pigments.