Theses and Dissertations

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Browsing Theses and Dissertations by Subject "Research Subject Categories::NATURAL SCIENCES::Chemistry"

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    Extraction and characterization of fish oil from milkfish (Chanos chanos), tilapia (Oreochromis niloticus) and sardines (Sardinella fimbriata) fish wastes
    (2020) Christine Joy Ann V. Padiernos
    Fish processing industry produces large scale of waste (entrails, head, tails, fins and scales) from the production processes. These by-products can be a source of bioactive components that can be commercially produces. Fish oil which contain saturated and unsaturated fatty acids can also be produced through extracting oil from fish wastes without the use of chemical solvents. In this study, water is used as the solvent for the oil to separate from the mixture using centrifuge. Characterization of soil such as peroxide value, free fatty acid, acid value and fatty acid profile are important parameters to determine if the oil can be possibly commercially produced. Peroxide value of the 3 samples both for crude and purified oil meet the standard for about <10meq/kg standard. peroxide value determines if the oil already reacted to oxygen or reached rancidity. Free fatty acid is the result of hydrolysis of fats and oil present in the sample. Free fatty acid having the standard value ranging from 1% to 7% milkfish, sardines and tilapia both for crude and purified also falls within the range. For the acid value, milkfish crude oil contains 4.86 mg/KOH and sardines purified oil both contain 4.86 mg/KOH only meet the standard < 5 mg/KOH. Acid number determines how much base is needed to neutralize the acid present in the sample. Saturated fatty acids such as lauric (C12), myristic (C14), palmitic (C16), stearic (C18), arachidic (C20) and lignoceric (C24) are detected among the samples using the method AOAC Official method, 963.22, 19th ed., 2012. Unsaturatede fatty acids such as oleic (omega-9), linoleic (omega-6) and linolenic acid (omega-3) are the essential fatty acids that should be included in diet. Omega-9 is the highest unsaturated fatty acid that exist between the milkfish, sardines and tilapia. Omega-6, omega-3 ratio differs from its contribution to human health and dietary requirement for ech individual. Tilapia (7:1) and sardines (3:1) can be beneficial to Asian dietary requirement while milkfish (12:1) is qualified for Western countries.
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    Green synthesis of gold nanoparticle using paragis (Eleusine indica) and Makahiya (Mimosa pudica) leaf extracts
    (2019) Alexander C. Datuin
    Gold nanoparticles were traditionally synthesized using expensive and toxic chemicals. An alternative way of synthesizing Gold nanoparticles is to use a locally available plant extract which may serve as reducing and stabilizing agent that is eco-friendly and inexpensive. In this study, Gold Nanoparticles were synthesized using leaf extracts of Paragis (Eleusine indica) and Makahiya (Mimosa pudica) as reducing and stabilizing agents for the reduction of HauCl43H2O. The leaf extract from each plant sample was prepared by mixing 1 gram of fresh leaf and 100 mL of distilled water and was boiled for 15 minutes. The gold nanoparticle produced was characterized using UV-Vis spectrophotometer, fourier transform infrared spectroscopy (FTIR), particle size analyzer (Nanopartica, Horiba) and scanning electron microscopy (SEM). The synthesized Gold nanoparticle was effectively produced by mixing 1 mL of leaf extract and 1 mL of 1mM HAuCl4+3H2O. The gold nanoparticle produced was confirmed by measuring its Surface Plasmon Resonance (SPR) at 520 nm to 550 nm using UV-Vis Spectrophotometer. The particle size was evaluated using particle size analyzer (nanopartica, Horiba). Makahiya leaf extract reduced the gold nanoparticles with mean size of 55.60 nm+19.6, while Paragis leaf extract reduced gold nanoparticle with mean size of 159.47 nm +60.9 respectively. The surface morphology of the synthesized Gold nanoparticle was analysed using SEM. Micrograph obtained at 50 nm and 1x10-1 um magnification of SEM image showed spherical AuNPs reduced by leaf extract having approximate size ranging from 20-80 nm for Makahiya and 30-70 nm Paragis. FTIR analysis of both leaf extracts showed a peak at 1100 cm which indicates at C-O stretching band, a peak at 1620-1680 cm -1 which indicates a sp3 C-H stretching band and a broad peak at 2500-3000 cm-1 indicates O-H group. Although these peaks were also observed in the IR spectrum of the Gold Nanoparticle their transmittance were reduced. This observation suggests that those functional groups obtained might be responsible for the reduction the gold salt solution to gold nanoparticles.
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    Isolation and characterization of collagen from the by-products of milkfish (Chanos chanos) processing
    (2019) Abbie Louise E. Cajucom
    Considerable amounts of fish processing by-products are discarded each year from the 100 million tonnes of fish harvested globally in a year, approximately 30% of it ends up as waste. This amount of waste can be used as source of collagen for several applications. Fish such as milkfish plays a significant role as nutrient source in Asian countries. This study extracted, isolated and characterized the collagen from skin, scales, bones, head, tails and fins of Milkfish (Chanos chanos), and the yield of the collagen was taken. The amount of collagen extracted ranged from 0.2433-1.0367% for freeze dried and 0.2133-1.9667%, for silica dried. The denaturation temperature of freeze dried collagen from head, tail, skin, scale and fins were 17° C, 15°C, 15°C, 15°C, 14.33°C and 16°C respectively. For the silica dried, denaturation temperatures were 16.67°C, 16.33°C, 15°C, 15.67°C, 17°C and 16°C respectively. The Fourier Transform Infrared Spectra (FTIR) of the extracted with the standard collagen from bovine source. The collagen was identified to be Type 1 but since it is not yet purified, the diversity from the standard type 1 collagen may be due to the presence of other types of collagen. The spectra is characterized by the amide bond in the 1,650cm⁻1 and 1,550cm⁻1. The difference in the peak may be due to the amount of the amino acid present for it plays a major role in the secondary structure distribution. The presence of proline and hydroxyproline in the collagen were positively, identified qualitatively. Milkfish waste from the skin, scale, bone, fin, tail and head had collagen with similar characteristics as the commercial bovine collagen and thus can be alternative source.
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    Isolation and characterization of protein hydrolysate from tilapia (Oreochromis niloticus) by-products for potential application as fish flavouring
    (2019) Cherrie Mae J. Martinez
    The processing of fish into various products result in the accumulation of a large amount of by-products such as heads and viscera. The proper disposal of these wastes poses environmental concerns. However, these by-products are proven to be rich in nutrients and bioactive properties that can be a good source of high nutritive value in food industry. This study aimed to ultimately minimize the fish processing waste disposal by using tilapia wastes as a source of proteolytic enzyme to produce protein hydrolysates. The enzymes were extracted from tilapia viscera by using acetone and were dried overnight. The pH of the dried powder was adjusted and subjected to dialysis. The dialyzed solution solution are purified by using ammonium sulphate precipitation followed by gel filtration. The crude and purified enzyme extracted was used for enzymatic hydrolysis under the same condition of pH=2.37 degrees celcius at 1% E/S ratio for 120 min and undergone centrifugation. The oven dried hydrolysate were tested for proximate composition degree of hydrolysis, protein solubility and qualitative test for amino acids. The purified protease extracted exhibits an activity of 66.54 U/mg while the crude proteases is 23.16 U/mg. the degrees of hydrolysis of the hydrolysate from purified and crude were found to be 8.50% and 17.13% respectively. Fish protein hydrolysates from crude enzyme yielded 93.85% while the hydrolysate from purified only yielded 58.57%. The protein content, fat, ash and moisture content of hydrolysate from crude enzyme and purified enzymes are 1.05%, 22.89%, 13.46+0.59%, 10.72+0.5% and 4.03% , 16.96%, 8.44+0.43%, 12.71+0.42% respectively. The protein hydrolysate from crude enzyme has the highest solubility at pH=5 to 6 while the protein hydrolysate from purified enzyme is at pH=4. This indicates that both protein hydrolysate were soluble at acidic condition. Both hydrolysates were tested positive to have tyrosine, tryptophan, and cysteine crude enzyme without undergoing purification can be used as a substitute to commercial enzymes to produce protein hydrolysate. The presence of essential amino acids gives a space for hydrolysate from crude enzyme to be used as fish flavoring under more study.
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    Partial isolation and characterization of secondary metabolites of Selliguea taeniata and its antioxidant and antibacterial activity
    (2019) Abigail L. Dela Cruz
    This current study presents chemical exploration on the methanolic leaf extract of Selliguea taeniata, a fern species endemic in certain regions in the Philippines, such as Ifugao where it is used to treat cough. Although botanical data of this fern are reported, there are still no reports, as of the time this thesis was conducted, regarding its chemical properties, such as phytochemicals and biological activities. For this to be conducted, the air-dried leaves of S. taeniata were extracted using absolute methanol. Crude extract was concentrated and subjected to Folin-Ciocalteu method to determine the total phenolic content (TPC), 2.2diphenyl-1 picrylhydrazyl (DPPH) free radical scavenging assay to evaluate its antioxidant activity, disc diffusion method to assess antibacterial activity, and phytochemical screening. Subsequently, various chromatographic techniques and 1H Nuclear Magnetic Resonance spectroscopy were applied to partially isolate and characterize its secondary metabolites. Methanolic leaf extract of S. taeniata had TPC of 1669.11±0.07 mg GAE/gram of dried sample. It also exhibited antioxidant activity of (EC50=85.79±0.023 ppm), which was lower than ascorbic acid (EC50 = 0.51±0.66ppm). However, it was found ineffective against Escherichia coli and Staphylococcus aureus. The crude extract was found to contain alkaloids, falvonoids, cardiac glycosides, saponins, phenols and tannins. Partial isolation of its secondary metabolites suggested that the crude extract may contain a mixture of proanthrocyandins and/ or its monomer units, and glycosides. In conclusions, S. taeniata was considered as strong antioxidant, but was inactive against E. coli and S. aureus. It contained high amount of phenolic compounds that could be proanthrocyanidins and/or monomer units of it and glycosides.