*4.2. Methods*

### 4.2.1. Synthesis of Pectin Aerogels

Pectin aerogels were prepared by ethanol-induced gelation, a method designed in our laboratory [20]. A weighed amount of pectin was dissolved in miliQ water to obtain a 4% (*w*/*w*) solution. The solution was strengthened by addition of a known amount of ethanol (not more than 10%). The hardened solution was transferred into molds and soaked in ethanol to obtain gels. The gels were cut into tablet form using a precise cutter with a diameter of 12.5 mm.

### 4.2.2. Synthesis of Chitosan-Coated Pectin Aerogels

For the preparation of pectin aerogels coated with a chitosan layer, a coating procedure was designed. Pectin core gels were prepared as described above. Chitosan solution, 1.5% (*w*/*w*), was prepared by dissolving a known amount of chitosan into 0.2 M CH3COOH. Pectin core gels were soaked in a chitosan solution to bring the solution over the core. To attach the chitosan layer, soaked pectin cores were immediately transferred into 2 M NaOH. 2 M NaOH was prepared in ethanol. As pectin cores covered with chitosan solution were transferred into the NaOH solution, they immediately attached, since NaOH triggers the gelation of chitosan. After 20 min, the samples were transferred into ethanol to wash out the remaining NaOH.

### 4.2.3. Loading of Curcumin

The addition of curcumin was conducted using ethanol during the synthesis of pectin aerogels or chitosan-coated pectin aerogels. Since curcumin is highly soluble in ethanol (10 mg/mL), the molecules of the drug were easily diffusing inside the gel pore network. Once the curcumin was loaded, the samples were subjected to supercritical drying. Supercritical drying was conducted for 6 h at 120 bar and 40 ◦C, the conditions optimized for polysaccharides drying [21]. Since curcumin is poorly soluble in supercritical carbon dioxide (2 × 10−<sup>8</sup> mole fraction for given drying conditions) [22], there was no risk of washing it out during drying.
