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Changes in Water‐Soluble Calcium and Magnesium Content of Pear Fruit Tissue During Maturation and Ripening in Relation to Changes in Pectic Substances
Author(s) -
ESAU PAUL,
JOSLYN M. A.,
CLAYPOOL L. L.
Publication year - 1962
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.1365-2621.1962.tb00135.x
Subject(s) - magnesium , pectin , ripening , calcium , pear , chemistry , food science , botany , horticulture , biology , organic chemistry
SUMMARY Changes were determined in total and water‐soluble calcium and magnesium content and in the pectic substances of Bartlett pears during maturation and storage. The data indicate a change in metabolic processes when the fruit is removed from the tree. In maturing fruit, about 48% of calcium and 65% of magnesium are present in soluble form. Both cations generally decreased during maturation. The Mg/Ca ratio varied with growing conditions and may be related to soil composition. The data indicate that mare, total pectin, water‐soluble pectin, total calcium, and total magnesium arc correlated with firmness. The relationship of soluble calcium and magnesium to firmness is radically different in detached fruit from that in fruit on the tree. Analyses of data indicate that the “bound” calcium and magnesium are present in concentrations far greater than the total available carboxyl groups of pectin, and that protopecin content is not related to calcium‐ or magnesium‐bound pectinic acid chains. In detaching ripening fruit, when a general breakdown begins there is a good correlation of all data with firmness.