THIN LAYER CHROMATOGRAPHIC ANALYSIS OF STABILITY OF CURCUMIN AND CURCUMIN IN TURMERIC AFTER REFLUXING IN WATER AND USING DOUBLE MOBILE PHASE AFTER HEATING IN EDIBLE OILS

Turmeric is a popular curry spice widely used in cooking ethnic foods around the world. The active ingredient of turmeric is curcumin which has strong antioxidant and anti-inflammatory properties. These properties make curcumin a candidate for therapeutic investigations for many diseases including cancer and Alzheimer’s. The objective of this study is to study the effect of heat on reference curcumin and curcumin in turmeric in both water and edible oil, as well as isolated curcumin in water. This investigation will help determine the stability of curcumin in turmeric in domestic cooking. Typically, curcumin dissolved in oil cannot be analyzed successfully using thin layer chromatography (TLC) due to interference from the oil. A new TLC method was developed using two different mobile phases: hexane followed by a mixture of dichloromethane (98.5%) and methanol (1.5%). The TLC plates were then scanned with a standard desktop scanner and used for quantification via Quantity One 1-D analysis software (Bio-Rad Laboratories). It was found that when refluxed in water, reference curcumin and isolated curcumin were fairly stable, but curcumin in turmeric degraded by as much as 47% in 60 minutes. It was also found that at increasing temperatures from ambient temperature to 2500C, by 2500C, reference curcumin dissolved in oil had degraded by 25%, but curcumin in turmeric had degraded by 70%. Finally, it was found that when samples dissolved in oil were held at a maintained temperature for 60 minutes, all samples remained relatively stable until 2250C, at which point about 45% degradation was observed in both reference curcumin and curcumin in turmeric.