Akademik Veri Yönetim Sistemi
Tezin Türü: Yüksek Lisans
Tezin Yürütüldüğü Kurum: Orta Doğu Teknik Üniversitesi, Mühendislik Fakültesi, Gıda Mühendisliği Bölümü, Türkiye
Tezin Onay Tarihi: 2015
Öğrenci: MELTEM KARADENİZ
Danışman: SERPİL ŞAHİN
Özet:Wheat germ oil is a rich source of omega 3 and omega 6-fatty acids, octacosanol and tocopherol which has vitamin E activity. Due to these properties it is very beneficial for health but it is prone to oxidation in free form. Encapsulation provides protection of food ingredients from environmental stresses and increases the stability and functionality of the ingredient, which makes it possible to be used in functional foods. The main objective of this study was to encapsulate wheat germ oil and to investigate its physicochemical properties and stabilities during storage. In encapsulation, aqueous solutions of maltodextrin (MD), gum arabic (GA), whey protein concentrate (WPC), chitosan (CS) and sodium caseinate (NaCa) at different concentrations were used as wall material. Core to coating ratio was constant as 1:8.The effects of different homogenization techniques (ultrasonication (US), high speed blending by silent crusher (SC) and microfluidization (MF)) on particle size distributions of emulsions and efficiency of microcapsules were investigated. The effect of different treatment passes in MF was also studied. In addition, the capsules prepared at the optimum conditions were studied for their storage stability by determining totox value and α tocopherol concentration during storage at 15°C and 45°C at 33.3% RH and 31.10% RH, respectively. NaCa was found to have better encapsulation properties than CS, WPC and GA in encapsulation of wheat germ oil. The SC and MF techniques were better in the formation of stable emulsions as compared to US. The change in treatment passes of MF did not have significant effect on encapsulation efficiencies; on the other hand, the increase in treatment passes decreased particle size of the emulsions. When storage temperature was 15°C, even the non-encapsulated oil was stable to oxidation. Storage stability analyses showed that rate of oxidation of fresh oil was higher than that of encapsulated oil stored at 45°C and microcapsules could maintain their stability for 20 days.