1:30 pm - 2:30 pm
A graduate exam seminar is a presentation of the student’s final research project for their degree.
This is an ALES MSc Final Exam Seminar by Andrea Vilchez Athanasopulous. This seminar is open to the general public to attend.
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Conference ID: 471012027
Thesis Topic: Adsorptive precipitation of vitamin D3 and vitamin E on gum arabic and sodium alginate using supercritical carbon dioxide
MSc with Dr. Feral Temelli.
Functional food products are formulated with added ingredients that provide health benefits beyond basic nutrition function. However, there are different challenges in the manufacturing of these products with fat-soluble vitamins, such as, vitamin D3 (VitD3), an essential nutrient responsible for increasing intestinal absorption of calcium and phosphorus, and vitamin E (VitE), a powerful antioxidant that plays an important role in the prevention of many disorders. Some challenges are their high tendency to be degraded or oxidized by heat, light and presence of oxygen, and also their hydrophobic nature limits their further use in aqueous-based products. To overcome these limitations, water-soluble biopolymers can be used as delivery systems. The polysaccharides, gum arabic (GA), and sodium alginate (SA), were dried using the Pressurized Gas eXpanded (PGX) liquid technology, a drying method for high molecular weight water-soluble biopolymers to produce unique morphologies of micro or nano-sized particles. Then, adsorptive precipitation, an environmentally friendly technology to load hydrophobic bioactives homogeneously onto the biopolymers without the use of any organic solvents, was used to develop novel delivery systems. The objectives of this MSc thesis research were to investigate the effect of adsorptive precipitation process parameters on the loading of fat-soluble bioactive compounds (VitD3 and VitE) on water-soluble biopolymers (GA and SA), and to characterize the powders obtained to ultimately increase the application of these hydrophobic compounds in aqueous-based products. The VitD3 and VitE loaded PGX-GA and PGX-SA particles obtained by adsorptive precipitation under different recirculation flow rates and times were investigated in terms of the vitamin loading content, particle morphology, molecular interactions, thermal behavior, storage stability, and release kinetics. In addition, adsorption kinetics were evaluated for VitE.
The highest loading of the VitD3 on the biopolymers were achieved at different recirculation flow rates (10.1 ± 0.2% for GA at 190 mL/min and 13.7 ± 0.1% for SA at 250 mL/min), but the same recirculation time (45 min). Uniform coating of VitD3 on the surface of biopolymers was demonstrated by helium ion microscopy (HIM). VitD3 retained some crystalline form on the loaded gum arabic (L-GA). After an initial drop, loaded samples showed storage stability of VitD3 after 21 days for L-SA and after 28 days L-GA. Sustained release of VitD3 was demonstrated for L-GA sample in simulated intestinal fluid. For VitE, the highest loading contents were achieved at the same processing conditions (135 mL/min and 45 min) for both biopolymers with maximum values of 14.95 ± 0.2% for GA, and 22.35 ± 0.1% for SA. Homogeneous coating of VitE on the biopolymers surface was displayed by HIM images. Loaded samples were quite stable over storage for 28 days with a drop of VitE loading to 91% for L-GA and 96% for L-SA. Adsorption kinetics results showed a difference in the rate of the concentration increase up to 50 min for both biopolymers, indicating differences in the surface areas of the biopolymers as well as the interactions between VitE and biopolymers.
The findings on adsorptive precipitation of VitD3 and VitE on the PGX-processed gum arabic and sodium alginate powders demonstrated the great potential of this technology and these food biopolymers for use as delivery systems of fat-soluble vitamins, targeting subsequent aqueous-based product applications.