Modified eggshell catalyst for transesterification of sunflower oil: The effects of catalyst loading on FAMEs content

Modified highly active CaO catalyst (ESCHC-600) derived from waste chicken eggshells were prepared and used in the transesterification of sunflower oil. Eggshells were subjected to calcination-hydration-calcination (CHC) cycles described in detail previously [1]. After CHC treatments, highly active CaO was obtained, which indicates its great potential for biodiesel synthesis. The transesterification reaction was carried out in a batch reactor at 60 ºC, methanol to oil molar ratio of 12:1, and different catalyst concentrations ranging from 2 to 8 wt%. Fatty acid methyl esters (FAMEs) content was determined by the HPLC analytical technique. The highest triacylglycerols (TAGs) conversion to FAMEs was achieved at a catalyst loading of 4 wt% (Fig. 1a). A further increase in catalyst loading (> 4 wt%) led to a decrease in TAGs conversion. The higher catalyst loadings (6 and 8 wt%) limited mass transfer of the TAGs and reaction products (FAMEs, DAGs and MAGs) due to the higher reaction mixture density and viscosity of the complex multiphase system. Compared to raw eggshell calcined at 900 ºC (ES-900) (Fig. 1b), the synthesized ESCHC-600 catalyst showed a higher activity, which could be attributed to a more favourable pore structure of CHC treated catalyst and better availability of the active sites.Conference of the Young Chemists of Serbia, Belgrade, 2nd November 201

Biodiesel synthesis over green catalyst: The effect of thermal treatment of CaO/Zeolite precursor on catalytic activity

The green CaO/Zeolite catalyst for methanolysis of fatty oils was synthesized entirely from the waste materials. CaO derived from chicken eggshell was loaded onto fly ashbased zeolite catalyst carrier by the wet impregnation method using an alcohol solution. The effect of thermal activation at different temperatures ranging from 450 to 600 °C on catalytic activity was studied. The precursor and catalyst samples were characterized by XRD, FTIR, SEM, and Hg-porosimetry techniques. The catalytic tests were performed in a stirred batch reactor at the following reaction conditions: 60 °C - reaction temperature, 12:1 - methanol/oil molar ratio, and 4 wt% - catalyst concentration. The obtained results showed that the synthesized CaO/Zeolite catalyst has preserved alumosilicate framework-cancrinite type [1], with uniformly distributed calcium oxide (CaO) on its surface (Fig. 1c). It is shown that the catalyst sample calcinated at 550 °C exhibited the highest FAME content of 96.46%, which was achieved in 2 h (Fig. 2). Increasing temperature of calcination above 550 °C led to the formation of inactive calcium alumosilicate forms causing a decrease in the FAME content

Design of the new particles for controlled release of bioactive peptides

Bioactive peptides carry antioxidative activity and have the potential to be used as additives in food formulation. When incorporated, major instability of peptides is imposed within heterogeneous products, as well as the loss of biological activity in the gastrointestinal system before absorption into the bloodstream and manifestation of biological activity at the target site in the body. A good solution as a controlled release system is liposomes – particles made out of phospholipids, natural molecules and a building block of the cell membrane. Therefore, the aim of this study was to prepare new systems for the encapsulation and controlled release of soybean antioxidant peptides. Liposome preparation was performed by forming a uniform thin film of phospholipon 90-G and hydrating it with an aqueous solution of soy protein concentrate hydrolyzate prepared by a two-step enzymatic process. The last step of liposome preparation was ultrasonic treatment. The size distribution, surface charge, degree of encapsulation and stability of multilamellar liposomes were characterized. A thin film method provided a satisfying percentage of encapsulation of soybean antioxidant peptides (19%). The ultrasonic homogenizer proved to be three times better than the ultrasonic bath while reducing the size of the particles. The antioxidant activity was tested by neultralization of the ABTS • + radical cation method and by Fe2+ ion chelation method. The test have shown that encapsulation of the peptide activity was partially retained. In the simulated gastrointestinal system, diffusion experiments have shown that liposomes slow down the release of antioxidant peptides. The presented results represent important information for the specific application of liposomes with encapsulated soybean peptides in functional food products