Abstract:
The objective of this research is the studying of xeazanthin encapsulation with chitosan and polylactic acid (PLA) by emulsion method. The encapsulation efficiency, amount of encapsulated zeaxanthin in chitosan particles and PLA particles as well as shape, size and
thermal stability of the encapsulated were evaluated. The results showed that, amount of xeazanthin encapsulated with chitosan by the emulsion method is 1.075% (w/w) where the ratio of chitosan to standard zeaxanthin was 1: 0.6 and the concentration of tri-polyphosphate solution was 2% (w/v). The encapsulated chitosan particle was spherical shape, approximately 30-48 nm. Its temperature decompose was slightly higher than the free zeaxanthin. The encapsulated PLA particle particles was a fine powder size in the range of 22-42 nm when measured by TEM technique and 5,445-10,100 nm when measured by a particle size analyzer. The ratios of PLA to xanthophyll provided the highest load capacity (% LC) and the encapsulated (%EE) values are 1: 1.0 and 1: 5.0. The decomposition of encapsulated PLA particle of xanthophyll was found by 3-steps. The first step is at temperatures below 100°C. The
second step occurs at 240.7-243.8oC and the third step occurs at 348.3-370.4oC. The thermal decomposition of the encapsulated PLA particles of xanthophyll revealed 12.47. -26.01% and 24.26-38.14% in the first step and in step 2, respectively. The encapsulated PLA particles in the ratios of PLA to xanthophyll 1:1.0, 1:1.5, 1:2.0 and 1:5.0 are decomposed 10.52-25.69% at 598°C while the free form was decomposed 98.64%. A shelf life of the encapsulated particles of marigold petals extract with chitosan and PLA kept in aluminum foil with vacuum sealing and stored under room temperature are less than 5 months and at least 12 months, respectively.