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Undergraduate Theses

Permanent URI for this collectionhttps://hdl.handle.net/20.500.14583/13

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Degree: search.filters.degree.Bachelor of Science in ChemistrySDG: search.filters.sdg.SDG 12 - Responsible consumption and production

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    Effects of alginate coating loaded with lemongrass essential oil-cyclodextrin inclusion complex on the postharvest quality of calamansi(Citrus microcarpa)
    Astorga, Krizzia Anne B. (Department of Chemistry, College of Arts and Sciences, University of the Philippines Visayas, 2018-06)
    Calamansi (Citrus microcarpa) is locally grown in the Philippines and is considered to be an important commodity because of its wide range of uses. Losses of this fruit in the country already reached up to 30% because of postharvest degradation. To address this problem, three coating treatments (1% alginate, 1% alginate loaded with lemongrass essential oil-B-cyclodextrin inclusion complex, and 1% alginate loaded with lemongrass essential oil-hp-B-cyclodextrin inclusion complex) were made for the purpose of examining their potential in the preservation of the postharvest quality of calamansi. Quality parameters such as color and weight loss of calamansi, as well as pH, FTIR spectra, total soluble solids, and titratable acidity of the fruit juice were evaluated in a span of 15 days at room temperature storage. Results show that the prepared edible coatings did not significantly preserve the postharvest quality of calamansi (p > 0.05) as coated samples resulted to earlier appearances of yellow and brown peel color, higher weight loss percentages, pH, and total soluble solids content. Out of the three coating treatments, fruit samples coated with 1% alginate resulted to lower weight loss percentages, pH, TSS, and TA. Fruit samples coated with 1% alginate loaded with lemongrass essential oil-hp-B-cyclodextrin inclusion complex resulted to the highest pH, TSS, and TA, while those coated with 1% alginate loaded with lemongrass essential oil-B-cyclodextrin inclusion complex resulted to the highest weight loss percentages. Data on the titratable acidity weren’t conclusive since the results obtained were not in agreement to the expected outcome. The ineffectiveness of the coatings may be a result of unfavorable storage conditions and incompatibility of the coating materials or formulations on the calamansi.
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    Preparation and characterization of chitin-humic acid hybrid and chitin-humic acid hybrid hydrogel as absorbent for Cu(II)
    Balgos, Blyth Angela C. (Department of Chemistry, College of Arts and Sciences, University of the Philippines Visayas, 2017-06)
    Gelatinous chitin was functionalized with humic acid to produce a chitinhumic acid hybrid. The gelatinous chitin was protonated using HC1 and humic acid was deprotonated by using NaOH in separate containers. The protonated gelatinous chitin and the deprotonated humic acid were then mixed to form Hie chitin-humic acid hybrid. A portion of the chitin-humic acid hybrid was used to prepare the chitin-humic acid hydrogel. The chitin-humic acid hybrid hydrogel was then prepared using 1,2,3,4- butanetetracarboxylic dianhydride(BTCA) as crosslinker. The chitin-humic acid hybrid hydrogel was then characterized using FT-IR and swelling test. The degree of swelling of the chitin-humic acid hydrogel was found to be 38.10 ± 3.06. It can also be inferred from the results of the swelling test that the chitin-humic acid hybrid hydrogel has a low crosslink density. Characterization by FT-IR suggested successful immobilization for the hybrid and BTCA crosslinking for the hydrogel. The potential of chitin-humic acid hybrid and chitin-humic acid hybrid hydrogel to adsorb Cu(II) in a solution was then evaluated. The process was done by subjecting the chitin-humic acid hybrid to Cu(II) adsorption. The results for Cu(II) adsorption test was subjected to a Shapiro- Wilk test for normality and was determined to have normally distributed data. One- sample T-test was then used to compare the adsorption capacity of the hybrid and hydrogel. The mean % Cu(II) Removal of the chitin-humic acid hybrid and chitinhumic acid hybrid hydrogel were 41.36 ± 2.35% and 51.21 ± 1.32%, respectively. Results suggested that the chitin-humic acid hybrid hydrogel has significantly higher % Cu(II) Removal compared to the chitin-humic acid hybrid
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    Anti-inflammatory and antibacterial activities of Batuan (Garcinia binucao) fruits
    Albano, Zella Faye (Department of Chemistry, College of Arts and Sciences, University of the Philippines Visayas, 2010)
    In this study, fresh fruits of batuan (Garcinia binucao) was evaluated for its antiinflammatory and antibacterial activities. The anti-inflammatory assay using Carrageenan-Induced Paw Edema Method showed that n-hexane extracts (65.79%) and dichloromethane extracts (64.91%) exhibited anti-inflammatory activities comparable to Indomethacin, the positive control (67.11%). The antibacterial assay using Paper Disk Diffusion Method showed that crude methanolic extracts, n-hexane extracts and dichloromethane extracts at 1000pg/mL were most effective against Staphylococcus aureus. The microbial indexes were 0.39, 0.47 and 0.50 respectively. The positive control, Amoxicillin has a 3.39 microbial index. The components of the three most active extracts (crude methanolic, n-hexane and DCM extracts) from both assays were separated through Thin Layer Chromatography and subjected to phytochemical tests. Crude methanolic extracts contained alkaloids, phenolic compounds and cardiac glycosides. Both n-hexane and DCM extracts contained terpenes, alkaloids, saponins, phenolic compounds and cardiac glycosides. These bioactive compounds present may have been responsible for the antiinflammatory and antibacterial activities of the extracts.
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    Antibacterial activity, antioxidant property and photochemical analysis of crude ethanolic extract from Dalanghita (Citrus nobilis) peels
    Aglobo, Jastine S. (Division of Biological Sciences, College of Arts and Sciences, University of the Philippines Visayas, 2015-05)
    The crude ethanolic extract of Dalanghita (Citrus nobilis) was studied for their antibacterial activity, antioxidant and phytochemical properties. The DPPH free radical scavenging assay of extracts with varying concentrations showed strong antioxidant activity with a maximum % inhibition of 92.30 at 80.70 ug/mL concentration. The IC50 was calculated to be 26.26 pg/mL against 12.48 ug/mL for Ascorbic acid, the positive control. The antibacterial activity of the extract was determined against Escherichia coli and Staphylococcus aureus by measuring the mean zones of inhibition using the paper disc diffusion assay at different concentration of crude ethanolic extract. The crude ethanol extract at 100% concentration yielded the highest inhibition for E. coli at 21.50±0.50 mm which is comparable to tetracycline, the positive control. The presence of phytochemicals in the extract were evaluated and the phytochemicals identified were: alkaloids, flavonoids, saponins, steroids, tannins, and terpenes.
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    Partial purification of pH indicator extracted from Rhoeo spathacea
    Apa, Junna T. (Department of Chemistry, College of Arts and Sciences, University of the Philippines Visayas, 2009-04)
    pH test papers are still utilized nowadays despite the prevalence of pH meters, because it is more convenient to use in measuring the pH of a certain substance. The use of natural dye as a pH indicator can serve as a good substitute for an expensive commercial dye that most high schools cannot afford. The pH test papers were prepared by impregnation of 0.03% pure dye extracted from Rhoeo spathacea. TLC was performed to partially remove other plant dye components from the pH active ingredient. The color transition chart was then created at pH ranging from 1.0-13.0 at one unit interval using phosphate buffer. The color transition chart of pure dye extract was compared to the color transition chart of crude dye extract at different pH. Paper impregnated with 0.03% partially purified indicator dye extracted from Rhoeo spathacea showed color transitions from pink to red violet at pH 1.0-3.0; red violet to lavender at pH 3.0-4.0; lavender to blue at pH 4.0-7.0; blue to blue green at pH 7.0-8.0; blue green to green at pH 8.0-11.0; green to yellow green at pH 11.0-12.0; and yellow green to yellow at pH 12.0-13.0. Results also showed that the purified dye extract is a better pH indicator in comparison with the crude dye extract. Spectrophotometric determination of pKa of the indicator was unsuccessful due to the strong overlapping of the UV-Vis spectrum of the acidic and basic forms of the plant dye extract. Titration results showed that the plant indicator can serve as a substitute for the methyl red and phenolphthalein indicators for strong acid-strong base and weak acid-strong base titration, but not for weak acid-weak base titration.
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    Determination of the concentration of essential minerals (Ca, Fe, K, Mg, Na, Zn) in honey samples from Negros Occidental
    Arellano, Lory Mae F. (Department of Chemistry, College of Arts and Sciences, University of the Philippines Visayas, 2018-06)
    Honey is a natural, sweet and highly nutritional substance produced by bees through a series of nectar collection and chemical processes. Due to the popularity of the product, certain regions in the Philippines has been producing honey and recently, different apiaries from Negros Occidental has been producing its own share of popular product in the market. The products are well received by the consumers, but the problem is the lack of characterization which gives the product doubtful and unconfirmed nutritional value. This study focuses on the quantification of essential minerals (Ca, Fe, K, Mg, Na, Zn) present in local honey samples from Negros Occidental. Eight honey samples were obtained from the different apiaries including an external sample from Mindoro. Samples were acid digested using HNO3/H2O2 solution at 130 °C. The concentration of each minerals in the honey samples were analyzed using AAS. The data reported high concentration (5.71 to 93.20 ppm) of K on most of the samples. The second most abundant mineral in the local honey is Ca ranging from 13.67 to 45.88 ppm. The Mg concentration ranges from 1.19 to 4.09 ppm while Na is in between 0.82 to 3.14 ppm. The mineral Zn and Fe contained the lowest concentration in most of the samples with Zn at 0.46 to 0.86 ppm and Fe at 0.04 to 0.30 ppm.
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    Antibacterial agent-loaded water-in-oil-water (W/O/W) emulsion
    Aguilar, Ma. Arianne Lou C. (Department of Chemistry, College of Arts and Sciences, University of the Philippines Visayas, 2018-06)
    In this study, a water-in-oil-in-water (W/O/W) emulsion incorporated with an antibacterial agent using polyglycerol polyricinoleate (PGPR), whey protein isolate (WPI) and lecithin as emulsifying agents under ultrasonication was prepared. Micrographs of the emulsions formed showed small droplet sizes with an average range of 0.07 — 8.7 μm which indicates that the emulsification process was effective. However, the emulsion was only stable for 7 days. Natural and synthetic antibacterial agents were then loaded into the W/O/W emulsion. A solution of chlorhexidine gluconate (CHG) was chosen as the synthetic antibacterial agent to be loaded into the W/O/W emulsion because of its established stability and antibacterial efficacy against Gram—positive and Gram—negative bacteria. On the other hand, Psidium guajava (guava) was chosen as the natural antibacterial agent to be loaded because of its abundance and folkloric use to treat wounds. The CHG—loaded emulsion showed a mean zone of inhibition equal to 11.3 ± 2.1 mm against Staphylococcus aureus and 12.0 ±1.0 mm against Escherichia coli. The Psidium guajava (guava) — loaded emulsion on the other hand showed no inhibitory activity which suggests that the bioactive component of the guava may have been destroyed during sonication process. The results of this study showed that a synthetic antibacterial agent loaded - W/O/W emulsion was more effective than the natural antibacterial agent loaded — W/O/W emulsion.