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UPV Theses and Dissertations

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Degree: search.filters.degree.Bachelor of Science in ChemistrySDG: search.filters.sdg.SDG 1 - No poverty

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    Isolation and partial characterization of globulin from Cassava (Manihot esculenta Crantz) tubers
    Barbosa, May R. (Division of Physical Sciences, College of Arts and Sciences, University of the Philippines Visayas, 2007-04)
    Soluble globulin was isolated using an extraction buffer (0.4 M NaCl in 35 mM potassium phosphate buffer, pH 7.6 with 0.02% Na azide). The isolated globulin was subjected to solubility tests with different NaCl concentrations. It has the highest solubility in 1.25M NaCl (1.09%), but no significant differences existed among the NaCl concentrations by analysis using one-way ANOVA at a = 0.05. Three major bands existed at LOOM NaCl dissolved globulin with molecular weight ranges of 28-33kDa, 38- 43kDa, and 65-70kDa relative to BSA. Two of these bands (38-43kDa and 65-70kDa) were observed in 0.50M and 0.75M NaCl soluble globulin. The 1.25M and 1.50M NaCl concentrations gave a single band (28-33kDa) each, while no clear bands were observed in other NaCl concentrations. Amino acid analysis revealed glutamic acid (12.09%) as the most abundant amino acid component of cassava globulin. Nine (9) essential amino acids were present. Of these nine, lysine (10.50%) is the most predominant. Cystine (0.39%) has the lowest percentage, followed by methionine (1.76%).
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    Development of a high-performance thin layer chromatography (HPTLC)-densitometric method for the estimation of quercetin and kaempferol in Euphorbia hirta (Tawa-tawa) extract
    Baladjay, Diane Monique S. (Department of Chemistry, College of Arts and Sciences, University of the Philippines Visayas, 2017-06)
    A sensitive, fast, efficient, and repeatable high-performance thin-layer chromatographic (HPTLC) method has been developed for simultaneous analysis of quercetin and kaempferol from the extracts of the aerial parts of Euphorbia hirta. In the development of the HPTLC method, different extraction parameters were evaluated and quantification of quercetin and kaempferol in the extract of E.hirta was performed using a densitometric software, Quantiscan™. Among the different combinations of mobile phases used, best separation was achieved in toluene: ethyl acetate: formic acid: methanol (5: 6: 2: 1) solvent system. E.hirta was extracted using the developed extraction method which involves the use of 80% ethanol, 8 minutes of sonication and serial extraction until 3rd extraction. This determined method provides a maximum yield of the compounds at minimum time and cost. The method was also validated for linearity and precision specifically repeatability. The results show that the produced calibration is linear, as supported by the obtained correlation coefficient (r) of > 0.999 and coefficient of determination (R2) of > 0.997. Moreover, the obtained slopes of the calibration curves show that the method is most sensitive towards quercetin and least sensitive to gallic acid. The method was also found out to be repeatable and precise as the %RSD for both the inter-day and intra-day trials obtained a value less than <2%. The present method is being reported for the first time and can be used for routine quality control and quantification of quercetin and kaempferol in various plant samples, extracts, and market formulations.
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    Antioxidant property of anthocyanin from malatinta (Phyllanthus reticulatus Poir.) fruits obtained by static and microwave-assisted extraction
    Baldonasa, RB Hera Angelica R. (Department of Chemistry, College of Arts and Sciences, University of the Philippines Visayas, 2015-06)
    Fresh fruits of Phyllanthus reticulatus Poir. were analyzed for anthocyanin by spectrophotometric method. The antioxidant activity using 1,1 -diphenyl-2-picrylhydrazyl (DPPH ) free radical scavenging activity (FRSA) and reducing power (RP) through FeCl3 assay were determined. The use of two extraction processes, namely, the static method and microwave-assisted extraction, using two extraction solvents, acidified methanol and aqueous ethanol (1:1) were compared. The total anthocyanin content (TAC) of P. reticulatus fruit was highest in extract using static method of extraction in acidified methanol solvent (279.94 ±17.31 mg/lOOg), comparable to levels found in plants rich in anthocyanins, (e.g., berries genotypes, grapes and red cabbages). In microwave-assisted extraction, TAC using acidified methanol was higher (278.01 ± 18.76 mg/lOOg) compared to using aqueous ethanol (210.96 ± 2.02 mg/100g). P. reticulatus fruits exhibited high antioxidant activity as revealed by its RP and DPPH FRSA results when compared to ascorbic acid. These findings highlight the usefulness of P. reticulatus as a source of anthocyanins with good antioxidant properties, which, in turn, gives importance to the undervalued and underutilized plant.
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    Determination of heavy metal (Cu, Cd, and Pb) concentration in musclemeat of fish from different areas in Batan Bay, Aklan
    Bagarinao, Cathrina F. (Department of Chemistry, College of Arts and Sciences, University of the Philippines Visayas, 2014-04)
    Food safety is of utmost importance but it is usually compromised by the presence of pollutants in the environment such as heavy metals. This study was conducted to investigate heavy metals concentrations in fish musclemeat collected from different areas of Batan Bay, Aklan. A total of 22 fish species were analyzed for Cu, Cd and Pb using Flame Atomic Absorbance Spectroscopy. Pb concentration in the musclemeat of fish ranged from 0.0292 ± 0.2070- 2.09 ±1.15 mg/kg wet weight and was found to be highest in Mugil cephalus (flathead grey mullet), while Cd concentration ranged from 0.0075 ± 0.0016-0.157 ± 0.209 mg/kg wet weight with highest value in Megalops cyprinoides (Indo-pacific tarpon), and Cu concentration ranged from 0.0605 ± 0.0667-2.76 ± 0.05 mg/kg wet weight, with highest concentration in Leiognathus equulus (common ponyfish). Among the metals, only Pb concentration in flathead grey mullet exceeded the maximum permissible concentration in food as indicated by the Joint FAO/WHO Codex Alimentarius (1984). Assessment of Noncarcinogenic Hazard Quotient (NHQ) gave NHQ values less than 1, indicating that the risk of developing adverse effects due to fish intake is low.