Encapsulation of rosemary essential oil


Thesis Type: Postgraduate

Institution Of The Thesis: Orta Doğu Teknik Üniversitesi, Faculty of Engineering, Department of Food Engineering, Turkey

Approval Date: 2014

Student: HAZAL TURASAN

Co-Supervisor: SERPİL ŞAHİN, SERVET GÜLÜM ŞÜMNÜ

Abstract:

Encapsulation protects sensitive food ingredients against oxygen, heat, moisture and pH until they are released to the system. In addition, it can mask the unwanted taste of nutrients that are added to the foods for fortification purposes. The studies about encapsulation of essential oils in micro or nano-size are very much limited. The objective of the study was to encapsulate the rosemary essential oil in micron size and to find the optimum coating material formulation by investigating the physicochemical properties and storage stability of microcapsules. In the wall material preparation two different ratios of maltodextrin (MD) and whey protein concentrate (WP) were used (3:1 and 1:3). The emulsions were prepared with four different core to coating ratios (1:80, 1:40, 1:20 and 1:10) and two different dextrose equivalent (DE) maltodextrins (DE:13-17 and DE:4-7). Freeze dried capsules were analyzed for their drying efficiencies, encapsulation efficiencies, surface morphologies and particle size distributions. In addition, concentrations of 1,8-cineole were determined during storage. vi Increasing WP:MD ratio was found to increase both drying and encapsulation efficiencies. Also, capsules having core to coating ratio of 1:20 gave the highest drying and encapsulation efficiency. Maltodextrin with DE:13-17 was proven to have better encapsulating properties than maltodextrin with DE:4-7. Changing DE value of MD did not have any significant effect on particle size distributions and surface morphologies of the capsules. Although maltodextrin with DE value of 4-7 provided better storage stability to the capsules for the first 30 days of storage, percent retention of 1,8-cineole in these capsules were similar to the capsules containing maltodextrin with DE value of 13-17 at the end of 40 days of storage.