Aqueous Extraction of Curcuminoids from Curcuma longa: Effect of Cell Disintegration Pre-treatment and Extraction Condition

Cell structure modification techniques have the potential to improve curcuminoid recovery in Curcuma longa. In this study, different pre-treatments such as high hydrostatic pressure (HPP, high pressure processing), ultrasound (US), pulsed electric field (PEF), and ohmic heating (OH) were used on dried C. longa before aqueous extraction at pH 2.0, 5.0, and 8.0. The released curcuminoids, cell disintegration index (Z(p)), particle size distribution (PSD), and color (CIE L*, a*, b*) were used to evaluate the different pre-treatment impacts on plant structure and extract properties. In untreated turmeric, the highest amount of released curcuminoids (3.89 mg/g dry matter) was obtained after extraction for 30 min at 95 degrees in the aqueous phase. After pre-treatments, the acidic conditions showed a considerable improvement in curcuminoid recovery; PEF, HPP, and OH improved the curcuminoid recovery by 3.39-, 3.13-, and 1.24-fold, respectively; while US did not lead to an increased release of curcuminoids compared to the untreated material. The highest curcuminoid recovery (with PEF and extraction at pH 5.0) was 6.6% w/w of the total curcuminoids. The non-thermal pre-treatments have less impact on the extract's color compared to the extraction pH, with alkaline conditions reducing the lightness of the extract.

Automated summary

In this study, different pre-treatment techniques were used to improve the recovery of curcuminoids in Curcuma longa. Acidic conditions and non-thermal pre-treatments such as pulsed electric field (PEF), high hydrostatic pressure (HPP), and ohmic heating (OH) showed significant improvement in curcuminoid recovery. Ultrasound (US) did not lead to increased release of curcuminoids. Non-thermal pre-treatments had less impact on extract color compared to extraction pH, with alkaline conditions reducing the lightness of the extract.