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    Surface Modification of Magnetic Iron Oxide Nanoparticles with Biodegradable Polymers for Plasma Protein Adsorption
    (Assumption University, 2017-09) Waralee Watcharin
    Magnetic iron oxide nanoparticles have been proposed as one of the most popular and efficient drug carrying magnetic materials used in human treatment and diagnosis due to their non-toxicity, high stability and high magnetic responses. Magnetic iron oxide nanoparticles (MNP) were obtained by chemical co-precipitation of iron salts in the presence of ammonia. The prepared magnetic particles were modified with gallic acid to reduce aggregation of particles, maintain magnetic stability, and slowdown degrading process under physiological conditions. Magnetic iron oxide nanoparticles coated with gallic acid (MNPG) were obtained with small particle size ranging from 10 nm to 80 nm and retained magnetization properties. The magnetic nanoparticles were characterized by scanning electron microscope (SEM) coupled with an energy dispersive X-ray detector (EDX), Fourier transform infrared (FTIR), and powder X-ray diffraction (XRD). Surface functionalization of magnetic nanoparticles was evaluated via adsorption of protein bovine serum albumin (BSA) on nanoparticles. The highest adsorption of BSA was obtained from MNP as BSA adsorbed up to 70% within 30 min of incubation, while the adsorption of BSA by MNPG within 30 min of incubation was observed at 50% approximately and MNPG showed the lower BSA adsorption rate within 4 h of incubation. After 4 h of incubation, the result indicated similar adsorption profile of BSA by MNP and MNPG.
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    Effect of encapsulation on Zymomonas mobilis survival rate from practical conditions and its levan polysaccharide production ability
    (Assumption University, 2017-09) Teeradate Kongpichitchoke
    Bioethanol is one of the good sources of liquid energy for automobiles and industries. The bioethanol market has continued to grow rapidly in recent years. Thai government aims to increase ethanol consumption from 1.2 billion liters in 2015 to 3.3 billion liters by 2021 and up to 4.1 billion liters by 2036. Z. mobilis, a gram-negative bacterium, is considered as an alternative organism in large-scale fuel ethanol production. The bacterium Z. mobilis is a highly potent ethanol producer already used in industrial-scale fermentations which converts sugars to ethanol and carbon dioxide. Levans are natural polymers of the sugar fructose found in many plants and microbial products. They are formed as an undesirable by-product of sugar juice processing. This project aimed to study survivor rate of Z. mobilis encapsulated at different concentration of sodium alginate 2%, 2.5% and 3%., from simulated practical conditions including simulated food tract condition (acidic pH at 1.55 and 0.6% bile salt) and high temperature environment (85°). The encapsulated beads were separated into four different sizes according to their average size by sieving process. Results indicated that survival rates of encapsulated cells of Z. mobilis were significantly higher (p < 0.05) from all simulated conditions compared to free cells. Furthermore, the highest survival rate was obtained from sieve 10 with 3% sodium alginate for both heat and bile salt tests, while the lowest survival rates were performed by 2% alginate beads obtained from sieve 70 with survival rate of 19.52% and 14.72%, and 0.22% and 0.77%, respectively. Levan production was also determined from encapsulated cells providing the highest survivor rate which was beads from sieve 10 of 3 % sodium alginate. Results showed they that there was no significant difference (p > 0.05) in levan production between free cell and encapsulated cells from high temperature condition test.
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    Formation and stability study of flavor oil emulsions stabilized by polyglycerol esters and by sucrose esters
    (Assumption University, 2016-05) Suwimon Ariyaprakai
    In this work, flavor oil emulsions contained 5 wt% oil and 0.75 wt% emulsifier were formulated by using different combinations between flavor oils and food emulsifiers. Orange oil (00), peppermint oil (PO), polyglycerol monostearate (PGE), and sucrose monostearate (SE) were employed to form emulsions by ultrasonic homogenization. Heat stability (storage at 100°C for 30 min) and freeze-thaw stability (storage at -20°C for 22 h. and at 30°C for 2 h.) of emulsions were investigated by observing droplets under a microscope, determining mean droplet sizes, and measuring amounts of destabilized oil. Ostwald ripening stability of emulsions was determined by measuring the droplet size distribution changes over 48 days of storage. The results showed that flavor oil emulsions stabilized by PGE and by SE were heat stable. Interestingly, flavo.r oil emulsions stabilized by PGE had better freeze- thaw stability compared to emulsions stabilized by SE. This property of PGE was suggested from polyglycerol interfacial layers reduced ice crystallization and reduced coalescence. The flavor oil emulsions stabilized by either PGE or SE underwent through Ostwald ripening destabilization and the ripening stability was improved by using mixed emulsifiers between PGE and SE. The information from this study could be useful for creating formulations of flavor oil emulsions that suitable for future applications in foods and beverages.
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    The Development of Centella asiatica Extract-Loaded BSA Nanoparticles Production to Improve Bioavailability
    (Assumption University, ) Patchanee Yasurin
    Centella asiatica cBao-bog) is used as a traditional drug widely in Asia. C. asiatica crude extracts showed excellent potential in-vitro but less or no in-vivo activity due to their poor lipid solubility or improper molecular size or both, resulting in poor absorption, poor dosing and poor bioavailability. The Bovine serum albumin cBSA) can attract macromolecular and carry wide variety of molecule. So this research was aimed to develop C. asiatica extract-loaded BSA nanoparticles cCBNP) to improve bioavailability. CBNP was prepared by the desolvation method using three different ratio C. asiatica crude chloroform extracts: BSA cl:2, 1:3, and 1:4). The well agar diffusion method was used for evaluating antibacterial activity of CBNP with different concentration (100, 200, and 300 µg!Illl) against five food borne pathogens cEscherichia coli ATCC25822, Salmonella enterica Typhimurium U302 cDT104b), S. enterica Enteritidis chuman), S. enterica 4,5,12:i:- chumall) US clone, and Bacillus cereus). The results showed that the antibacterial activity of CBNP did not show significant different on three different ratio and concentration in all food borne pathogens except S. enterica Enteritidis chuman) and B. cereus cP < 0.05). The highest antibacterial active of CBNP was 1.07±0.46 cm against S. enterica Enteritidis (human) on ratio 1 :4, 200 µg!Illl. The antibacterial activity of CBNP gave almost 2 times highe than free crude C. asiatica chloroform extracts. The modified Folin-Ciocalteu method, Ferric reducing antioxidant potential assay and DPPH assay were used for evaluating antioxidant activity. The highest antioxidant activity represented by the amount of phenolic content of CBNP was 14.59±6.74 µgGAEIIllg using ratio 1:2. The amount of phenolic content of CBNP did not show significant different between ratio 1 :2 and others cP < 0.05). For Ferric reducing antioxidant potential assay and DPPH assay, crude chloroform extract showed significantly higher activity than CBNP were 1.00 ± 0.15 mmol Fe2 + 1Illg and 29.44 ± 8.20 % DPPH radical scavenging respectively cP < 0.05). The entrapment efficiency and loading efficiency of CBNP showed highest value on ratio 1 :4 which were 96.94 ± 1.48% and 42.05 ± 5.68% respectively. It's also showed highest in release kinetic In Vitro approximately 12% during the whole period of 6 hours in both artificial gastric and intestinal juice. C. asiatica crude chloroform extract have higher solubility in water than CBNP but CBNP have higher stability in releasing crude chloroform extract. The results indicated that CBNP showed the promising to increase bioavailability of C. asiatica.