Turmeric is used extensively as a spice, colorant and food preservative, and also in traditional medicine. The active principles of turmeric are mainly polyphenols, namely curcuminoids such as curcumin, and are responsible for its characteristic yellow colour. Curcumin also possesses anti-inflammatory, antioxidant, antimicrobial, anticancer and immunomodulatory properties.

Herbs and spices can lose their vital principles and important biological activities during processing. Various methods have been employed for preparing turmeric extracts, including organic solvent extraction or supercritical carbon dioxide extraction. However, these processes can adversely affect the bioactivity and quality of the extracted spice, such that loss of aroma, flavour, pigments and antioxidants, such as flavonoids, may occur. Trace residues of the non-edible extraction solvents used can also be difficult to remove.

Methods are therefore needed that can achieve good yields, quality and optimal concentrations of active principles using an edible solvent, without undesirable thermal degradation, hydrolysis and reduced stability. It would also be advantageous to produce a water-soluble extract by improving the aqueous solubility of highly lipophilic curcuminoids. Polyglycolized glycerides, which are commercially available as food-grade excipients, could have potential for producing water-soluble turmeric extracts.

A study by Gilda et al.¹ investigated the use of food-grade polyglycolized glycerides to obtain water-soluble turmeric extracts containing lipophilic curcuminoids. The extracts produced were characterized in terms of their composition, antioxidant activity, radical scavenging activity, effect on cell proliferation and protection afforded to DNA against radical scavengers. The excipients used were Gelucire 44/14, Gelucire 50/13 and PEG 6000, with the former providing the best yield of curcuminoids. It is concluded that this edible polyglycolized glyceride can be used to produce aqueous extracts of curcuminoids and other constituents from turmeric.
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1 Gilda, S; Kanitkar, M; Bhonde, R; Paradkar, A (2010). Activity of water-soluble turmeric extract using hydrophilic excipients. Food Science and Technology 43 (1) 59-66.

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