Limonene encapsulation in freeze dried gellan systems

- Limonene encapsulated in gellan gels and solutions.
- Type and concentration of salts used to induce gelation were important.
- Surface limonene content was measured.
- Mechanical properties of the matrix were not important.
- Experimental conditions and limonene's physicochemical properties were critical.

The encapsulation of limonene in freeze-dried gellan systems was investigated. Surface and encapsulated limonene content was determined by measurement of the absorbance at 252 nm. Gellan matrices were both gels and solutions. For a standard gellan concentration (0.5 wt%) gelation was induced by potassium or calcium chloride. Furthermore, gellan solutions of varying concentrations (0.25-1 wt%) were also studied. Limonene was added at two different concentrations (1 and 2 mL/100 g sample). Gellan gels encapsulated greater amounts of limonene than solutions. Among all gellan gels, the KCl gels had the greater encapsulated limonene content. However, when the concentration of limonene was doubled in these KCl gels, the encapsulated limonene decreased. The surface limonene content was significant, especially for gellan solutions. The experimental conditions and not the mechanical properties of the matrices were the dominant factor in the interpretation of the observed results.