Curcumin recovery from alginate-pectin hydrogel: exploration of extraction parameters

Ana Maria Velasquez Giraldo
Graduate (PhD)
Gonul Kaletunc
Food, Agricultural and Biological Engineering

Curcumin is a nutriceutical compound with yellow color present in turmeric. It has been shown to have antioxidant properties leading to its potential use as a therapeutic agent for various diseases. Curcumin use is limited due to sensitivity to environmental conditions which results in degradation upon exposure to oxygen, light, alkaline pH, and metals. Encapsulation of curcumin provides an excellent opportunity for protection from undesirable environment and targeted delivery in the human body with the additional benefit of masking the flavor of curcumin which broadens its incorporation into various food systems. In this study, curcumin, a hydrophobic compound is encapsulated in a hydrophilic system, pectin-alginate gel. A method for quantification of encapsulated curcumin is essential for determination of encapsulation efficiency and to assess the stability of encapsulated curcumin during storage. 
The objectives are to develop and evaluate extraction methods for curcumin from alginate-pectin hydrogel particles for maximum extraction efficiency and preventing curcumin degradation.
Two extraction approaches were compared in terms of extraction efficiency and curcumin stability. Ethanol was used as solvent. Curcumin was extracted by ethanol with sonication. Sonication was provided by using a bath sonicator and probe sonicator. Hydrogel particles were used as is and also by crushing under the frozen conditions. Extraction parameters included particle weight to solvent ratio, particle size, sonication time, total contact time. The curcumin concentration was determined with UV-Vis spectrophotometry at 426 nm.
Particle weight to solvent ratio was determined to be 1 g to 10 ml of ethanol. Extraction efficiency increased by using sonication. Extraction efficiency of 86%±2% were obtained by using whole particles with 20 minutes of bath sonication. Under the same sonication conditions, a slightly higher extraction efficiency of 89%±3% was observed when frozen crushed particles were used. 
The extraction approach developed can be implemented for other organic soluble compounds sensitive to environmental conditions to prevent structural changes in the material. This method provides an accurate determination of encapsulation efficacy and stability of the compound.