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UPV Theses and Dissertations

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Degree: search.filters.degree.Master of Science in Fisheries (Fish Processing Technology)

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    Production and bioactivity characterization of protein hydrolysate from Portuguese oyster (Crassostrea angulata)
    Gomez, Honey Lyn R. (University of the Philippines Visayas, 2019-06)
    ABSTRACT It has been shown that oysters represent diversified peptides with a variety of biological importance. In the present study, the use of proteomics techniques and bioinformatics tool was carried out to predict the potential bioactivities of Portuguese oyster (Crassostrea angulata). Mascot database search have identified 8 proteins from C. angulata and 5 of which were selected for in silico analysis. Interestingly, BIOPEPUWM database analysis predicted that pepsin (pH > 2) can theoretically release highest number of peptides with biological activities, predominantly angiotensin-1 converting enzyme (ACE) and dipeptidyl peptidase (DPP-IV) inhibitory activities, followed by stem bromelain and papain. To confirm the reliability of these predictions, C. angulata proteins were assessed in vitro. Results showed that all the hydrolyzed samples possessed inhibitory effect against ACE and DPP-IV, with pepsin hydrolysate (PEH) having the strongest activity of 78.18% and 44.34%, respectively. Further fractionation of PEH revealed that fractions with low molecular weight (MW) such as <1 kDa fraction (Fl) and 1-5 kDa fraction (F2) can demonstrate higher ACE and DPP-IV inhibitory activity compared to crude PEH and >5 kDa fraction (F3), but not to a great extent. Overall, the results obtained from in vitro analyses corresponded with the in silico predictions. Findings of this study thereby suggest the applicability of in silico technique for rapid and reliable identification of bioactive peptides from food proteins and determination of suitable enzyme capable for the release of these peptides. Moreover, proteins from C. angulata can be considered as potential sources of peptides with potential pharmaceutical and nutraceutical application.
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    Antioxidative activities and lactic acid bacteria composition of fermented frigate tuna at different salt-fish ratio
    Ortizo, Rhessa Grace G. (University of the Philippines Visayas, 2019-06)
    ABSTRACT The antioxidative activities and lactic acid bacteria (LAB) composition of fermented frigate tuna (Auxis thazard), locally known as tinabal, at different salt-fish ratios were investigated. Fresh frigate tuna were degutted and cleaned before the addition of salt at different salt-fish ratio (w/w), (1:3), (1:4), (1:5), (1:6), and then fermented at ambient temperature. Samples were taken on day 0, 1, 4, and 7 for the pH determination, total titratable acidity measurement, and the different antioxidant activity assays that include testing for radical scavenging activity of ABTS+, ferric reducing power, hydrogen peroxide and singlet oxygen radicals. Isolation of lactic acid bacteria (LAB) for bacterial identification was also conducted as well as the measurement of the degree of hydrolysis for peptide profile analysis of fermented product. Results show that the LAB viable count in the fermented samples increased, and the pH levels decreased with increasing % titratable acidity during the 7 days of fermentation. Isolated LAB and LAB-like species with gram positive, catalase negative, and non-spore forming properties were presumptively identified as Lactobacillus casei, Lactobacillus fermenti, Lactobacillus delbrueckii subsp. delbrueckii, Pediococcus pentosaceus, Leuconostoc spp., Enterococcus faecalis and Streptococcus spp. In this study, the free amino acids due to hydrolysis increased with fermentation time for the different salt-fish ratios and DH was influenced by the length of fermentation. The ethanolic extracts from F3 (1:6) sample showed strong antioxidative activities against ABTS+ radical, while sample Fl (1:4) showed high reduction of ferric ions, and sample F2 (1:5) exhibited high antioxidative activities against 1O2 radical which is the major cause of damage to bioactive compounds that leads to oxidative stress in fermented products. Results further revealed that tinabal could be a potential source of natural antioxidants for industrial uses. In addition, presence of important LABs in F2 (1:5) indicated that this fermented product could serve as a good source of LAB for applications to other fermented products as starters for improved product quality. In particular, tinabal fermented with F2 salt-fish ratio (1:5) has potential to be a functional food product that could benefit the consumers.
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    Influence of various photobleaching conditions on algar quality from Gracilariopsis heteroclada
    Endoma, Leonilo Jr. F. (University of the Philippines Visayas, 2016-06)
    ABSTRACT The photobleaching agar extraction technology stems from public health, environmental, economic, and issues concerning agar stability. With the hypothesis that photobleaching reduces the total inorganic sulfate content in the alkaline-treated seaweed prior to agar extraction, the influence of various photobleaching processes on agar quality was tested. The 5-hour photobleaching agar extraction process using solar irradiation (SLA) effectively increased agar gel strength (1,038.61 g cm-2) and 3,6-anhydrogalactose content (41.44%), and decreased total inorganic sulfate content (1.87%) without compromising agar yield (19.37%). The agar extracts of SIA was found superior compared to samples from other bleaching methods tested (i.e., CBA: conventional chemical-bleaching agar extraction process using using NaOCl; UVA: ultraviolet agar photobleaching extraction process; and VLA: visible light agar photobleaching extraction process) in terms of carbohydrate content (90.50%), neutral gel pH (6.93), gel rigidity (815.31 g cm'1), gel cohesion (10.95 mm), breaking strength (7.99 N), apparent viscosity (19.67 cPs), melting temperature (92.67°C), thermal hysteresis (50°C) and has the lowest syneresis index (73.00 mm). The results also show that SIA produced agars with properties at par with the commercial bacteriological agar sample. With the recommendation to further improve gel clarity, the application of solar photobleaching agar extraction process for Gracilariopsis heteroclada is very promising.
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    Isolation of Hyaluronic acid from yellowfin tuna (Thunnus albacares) eyeball
    Sumogod, Angeleca A. (College of Fisheries and Ocean Sciences, University of the Philippines Visayas, 2019-06)
    ABSTRACT Hyaluronic acid (HA) is commonly extracted from terrestrial and bacterial sources. However, due to the risk associated with either animal- and/or bacterial- derived contaminants and the laborious production processes that tend to compromise the quality of HA, research studies have recently shifted to the exploration of the presence of this polymer in marine resources and the enhancement of the protocols for HA production. Hence, this study focused on the isolation of HA from yellowfin tuna eyeballs. Results of the study showed that the optimum conditions for the isolation of HA from yellowfin tuna eyeballs are as follows: pretreatment of the raw material (acetone, formaldehyde and sodium acetate solution) prior to water extraction and incubation of the mixture for 24 h; tissue hydrolysis for a maximum of 6 h; a 3% CPC: 3M NaCl concentration for recovery and fractionation; and the use of 1:3 v/v supernatant: ethanol ratio for alcoholic precipitation. These results are expected to help maximize the benefits of the utilization of the tuna processing wastes in the country. Likewise, these findings may open a new opportunity for more cost-effective production of a valuable bioactive compound from marine source.
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    Nutritional value of fish silage, with Gracilaria Sp. and Abalone Viscera as poultry feed
    Patadjai, Andi Besse (University of the Philippines Visayas, 2004-11)
    ABSTRACT Study on fish silage prepared with Gracilaria sp., with and without abalone viscera was conducted to evaluate the rate of hydrolysis during the ensiling process. The fish-Gracillaria sp.-abalone viscera silage was further subjected to nutritional value test as poultry feed. Three silage were prepared using 5% propionic acid and formic acid (ratio 1:1) to contain: a) 100% fish by catch (Silage F), b) 70% fish by catch and 30% Gracilaria sp. (Silage FG) and c) 70% fish by catch, 25% Gracilaria sp. and 5% abalone viscera (Silage FGA). These silage were stored for 15 days and stirred daily. Chemical components such as pH, amino nitrogen, polypeptide, and monosaccharide content were determined at regular intervals within the 15-day ensiling period. Isonitrogenous feeds were then formulated to contain fish-Gracillaria sp.- abalone viscera silage Feed (II) and fish silage (Feed III). Nutritional value of these diet (i.e. Feed II and Feed III) were compared with that of commercial feed (Feed I) which was used as the control, based on the growth response of chickens. Results showed that rate of decrease in pH value was sufficiently rapid to stabilize the three silage. Silage F showed significantly higher pH value throughout the ensiling period, compared with Silage FG and Silage FGA. No significant difference (P<0.05) was, however, found between Silage FG and Silage FGA. Results can be attributed to incorporation of Gracilaria sp. in silage production, which provided favorable condition to decrease the pH value. Amino nitrogen content of all silage increased with ensiling time. Silage F exhibited the highest amino nitrogen content during 15 days of ensiling, followed by that of Silage FGA. Although the amino nitrogen content of Silage FGA was higher than that of Silage FG, significant differences (P<0.05) were noted only after 12 days of ensiling. Polypeptide content of all silage decreased after 3 days of ensiling. Silage FGA exhibited the highest polypeptide content after 9 days of ensiling. Monosaccharide content of all silage fluctuated during the ensiling period. However, the highest value was noted with Silage FGA, followed by Silage FG on the 3rd day of ensiling. This could be attributed to the highest polysaccharide hydrolysis rate exhibited by Silage FGA throughout the ensiling period. The best feed conversion ratio (FCR) and protein efficiency ratio (PER) were obtained with chickens given feed containing fish-Gracilaria sp. -abalone viscera silage (Feed II) during the 3-week feeding time. Body weights of chickens given Feed II were significantly higher than those given Feed III until the 3rd week of feeding. Reduction of fish content by as much as 30% and its substitution with 25% of Gracilaria and 5% of abalone viscera in silage (Feed II) gave the same effect on growth rate of chickens as that of silage made up of 100% fish (Feed III), and commercial feed (Feed I) without any mineral deficiency symptoms (e.g. slipped tendon or leg weakness and abnormal feather growth). Fish-Gracilaria .sp.-abalone viscera silage could be used as an ingredient for the production of an acceptable/palatable and nutritious feed for poultry.
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    Bioactivities of protein hydrolysates from Chlorella sorokiniana
    Tejano, Lhumen A. (College of Fisheries and Ocean Sciences, University of the Philippines Visayas, 2018-06)
    ABSTRACT Microalgal proteins can be a good source of nutrients and compounds with bioactivities. In this study, proteins from Chlorella sorokiniana were isolated by pH shift technology and enzymatically hydrolyzed using pepsin, bromelain, and thermolysin to produce hydrolysates. Molecular characteristics of the hydrolysates were determined by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and amino acid analysis. After membrane ultrafiltration, bioactivities of the hydrolysates and peptide fractions were determined. Results revealed that thermolysin exhibited the highest degree of hydrolysis with 18.08 + 1.13%, followed by bromelain, and lastly by pepsin, after 4 h of hydrolysis. SDS-PAGE results showed that the hydrolysis generated peptides exhibited molecular weights of mostly <10 kDa of the hydrolysates, much less than those of the large and diverse proteins of the protein isolate. The essential amino acid indices (EAAIs) suggest that the hydrolysates could be considered as good quality protein sources. In vitro bioactivity assays, on the other hand, revealed that the pepsin peptide fraction of <5 kDa showed the highest DPPH radical scavenging activity (48.86 + 1.95%). Only pepsin hydrolysates and pepsin peptide fractions displayed inhibition to Staphylococcus aureus and Escherichia coli. However, there are no significant differences among the Angiotensin I Converting Enzyme (ACE) inhibitory and reducing power activities of the hydrolysates and peptide fractions. Both the protein hydrolysates and peptide fractions were observed to have satisfactory pH and heat stabilities. Overall, the results suggest that C. sorokiniana proteins can be a good alternative source of valuable compounds with pharmaceutical and nutraceutical application potentials.