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DECOMPOSITION OF TURMERIC CURCUMINOIDS AS AFFECTED BY LIGHT, SOLVENT AND OXYGEN 1
Author(s) -
PRICE LISA C.,
BUESCHER R.W.
Publication year - 1996
Publication title -
journal of food biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.507
H-Index - 47
eISSN - 1745-4514
pISSN - 0145-8884
DOI - 10.1111/j.1745-4514.1996.tb00577.x
Subject(s) - pigment , methanol , chemistry , solvent , curcumin , acetic acid , nitrogen , chromatography , oxygen , organic chemistry , biochemistry
Turmeric curcuminoids are important natural pigments but their instability limits their use in many foods. This study was conducted to examine light‐induced degradation of turmeric curcumin as affected by solvent system and oxygen. The rate constants and half‐lives were determined for purified curcumin, demethoxycurcumin and bis‐demethoxycurcumin exposed to 1450 lux using reversed‐phase HPLC. Rates of degradation of each pigment followed first‐order kinetics. Differences in rate constants and half‐lives between the individual pigments were minor in an acetic acid‐NaCl solution; however, in methanol, large differences in stability to light of the individual pigment were observed. Stability of all the pigments to light was several fold greater in methanol than in acid brine. In methanol sparged with air, stability to photooxidation was curcumin > demethoxycurcumin > bis‐ demethoxycurcumin. In methanol, curcumin was more stable than the other curcuminoids when sparged with air than when sparged with nitrogen. In methanol sparged with nitrogen, demethoxycurcumin was the most stable pigment. All of the pigments were stable in the dark .