Degradation of bioactive spice compound: curcumin during domestic cooking

Many of the health beneficial physiological effects of the spice-turmeric (Curcuma longa), documented in recent years are attributable to the major flavour and colouring compound curcumin. Considerable decrease in the concentration of bioactive compound curcumin has been observed during the heat processing of turmeric. This study was aimed at understanding the nature of altered/degraded compounds formed from the bioactive spice compound-curcumin as a result of heat treatment encountered during domestic cooking. Among several of the degradation compounds of curcumin, three major ones were characterized as ferulic acid, vanillin and vanillic acid on the basis of their UV absorption, proton NMR spectra and mass spectral data of LC fractions, as well as by comparison of the three identified compounds with respective standards. The study confirmed the vulnerability of the diketone bridge in curcumin molecule to heat. In addition, formation of vanillic acid and vanillin indicated that the molecule is sensitive to heat at the first carbon atom of the alkyl chain which is connecting the two phenyl moieties.