Effect of different ratios of maltodextrin/gelatin and ultrasound in the microencapsulation efficiency of turmeric oleoresin

Despite of turmeric oleoresin having many advantages over ground turmeric roots, its sensitivity to light, heat and oxygen is a disadvantage. One approach to overcome this problem is microencapsulation. The objective of this work was to investigate the influence of different ratios of maltodextrin/gelatin used as wall materials, as well as the use of ultrasound during the emulsification step on encapsulation efficiency of turmeric oleoresin by freeze drying. The results showed that increasing gelatin concentration in the polymeric matrix increased the encapsulation efficiency of turmeric oleoresin (p < 0.05), whereas the maltodextrin content in the wall material did not show significant effect at a 5 % level of significance. On the other hand, the effectiveness of ultrasound to improve encapsulation efficiency was more pronounced for a higher content of maltodextrin in the wall material: for the encapsulant matrix formulated with 18 % maltodextrin and 6 % gelatin, the encapsulation efficiency increased from (81.1 ± 0.3) % without ultrasound to (90.4 ± 1.0) % when applying ultrasound. In the case of the encapsulant matrix formulated with 12 % maltodextrin and 6 % gelatin, the increase in the encapsulation efficiency was lower: (77.6 ± 0.4) % without ultrasound to (80.6 ± 0.1) % when applying ultrasound. These results indicate the effectiveness of gelatin as an encapsulant for turmeric oleoresin and that ultrasound may be particularly effective for improving the emulsification properties of maltodextrin.