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Structural and textural changes in brown onions during pickling
Author(s) -
JEWELL G. G.
Publication year - 1972
Publication title -
international journal of food science and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.831
H-Index - 96
eISSN - 1365-2621
pISSN - 0950-5423
DOI - 10.1111/j.1365-2621.1972.tb01674.x
Subject(s) - turgor pressure , plasmolysis , chemistry , pickling , chewiness , pectin , brine , food science , protoplast , cell structure , cell wall , horticulture , biology , biochemistry , organic chemistry , biological system
Summary The morphological and textural changes which occur during the pickling of brown onions have been studied using the electron microscope and Instron Universal Testing Rig. The structural studies revealed that the brining process gradually degraded the cell contents to leave just cell walls. The rate of degradation was shown to be dependent on the brine strength used: the most rapid rate being produced by the strongest brine. Electron histochemical staining showed that the cell walls were also degraded, with the pectin and hemicellulose components being modified. During the initial 24 hr in brine the marked changes in the texture parameters: hardness, elasticity and cohesion correspond to plasmolysis of the tissue and reorganization of cell wall materials. A recovery of texture values observed after 3 and 4 days’brining was attributed to the stabilization of turgor pressure. After 5 days’brining, rupture of the protoplast and subsequent loss of turgor pressure resulted in lower texture values. It was concluded that the optimum treatment for onions which would be stored in vinegar for 1 month was a brining period of between 3 and 4 days.