UPV Theses and Dissertations
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Item 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.Item Bioactivities of protein hydrolysates from Chlorella sorokinianaTejano, 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.Item Effects of different levels of Pinus tebulaeformis pollen on growth and stress resistance of milkfish fry (Chanos chanos)Baldove, Analyn B. (University of the Philippines Visayas, 2010-06)The present study investigated the effects of different inclusion levels of pine pollen from Pinus tabulaeformis Carr. on the growth performance and stress resistance of milkfish fry (Chanos chanos). Milkfish fry with average body weight of 0.02 g were stocked in 15 tanks (40 fish per tank). A control diet (without pine pollen) and four experimental diets were prepared containing different levels of pine pollen at 0 g kg-1, 1.3 g kg-1, 2.6 g kg-1, 3.8 g kg-1, and 5.1 g kg-1 was fed to the experimental fish for 60 days. At the termination of the experiment, milkfish were subjected to acute ammonia and high salinity shock test. The result of feeding trial revealed that milkfish fed diets containing different levels of pine pollen stowed significantly higher growth (p < 0.05) in terms of weight gain, specific growth rate, feed conversion ratio, and protein efficiency ratio than the control diet. Survival of the milkfish during the trial were not significantly different among treatments (p > 0.05). Survival rates of milkfish groups exposed to high salinity stock test for 72 h were not significantly different from each other (p > 0.05). In contrast, results of the ammonia stress test revealed that the survival rates of milkfish fed with the diets containing (2.6 to 5.1 g kg-1) were significantly higher (p <0 .05) than those fed with diets containing 1.3 g kg-1 and the control diet Optimum dietary PP level was estimated using the quadratic model by using SGR and FCR values and found to be is 2.9 g kg-1 and 3.0 g kg-1, respectively. conclusion, pine pollen can be used as a supplement in milkfish diet to enhance growth and stress resistance against environmental stressors like ammonia.