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EDTA promoted extraction

AA is susceptible to both chemical and enzymatic oxidation [1]. Chemical oxidation is catalyzed by minerals, such as Cu(II) and Fe(III), in the presence of oxygen at a pH-dependent rate enzymatic oxidation by the ascorbate oxidase occurring in plant tissues. Light and heat are other factors that promote its degradation. For these reasons, the extraction procedure should be designed to stabilize the vitamin for example, metaphosphoric acid [63—66] denatures proteins, inactivates enzymes, provides a medium below pH 4 (degradation rate is minimal at pH 2), and inhibits metal catalysis, whereas EDTA [67,68] chelates the minerals efficiently. [Pg.488]

Ascorbic acid is known to play a role in both in vitro and in vivo hydroxy-lation. Udenfried et al. (1954) observed promotion of tyramine hydroxy-lation by adrenal extracts. A mixture of vitamin C, Fe++ (Fe +), and EDTA can be substituted for the extract. A mixture of vitamin C and Cu++ or Cu+ is less efficient. Oxygen can be replaced by hydrogen peroxide. As much as 2 moles of hydrogen peroxide are required per mole of ascorbic acid. HjOj without ascorbic acid added is ineffective. [Pg.392]


See other pages where EDTA promoted extraction is mentioned: [Pg.32]    [Pg.32]    [Pg.286]    [Pg.120]    [Pg.405]    [Pg.905]    [Pg.269]    [Pg.73]    [Pg.581]    [Pg.588]    [Pg.20]    [Pg.430]    [Pg.53]   
See also in sourсe #XX -- [ Pg.31 ]




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