Characterization of fish muscle tissue from Lake Taal, Batangas

• Main Author: Delima, David John Eliezar P.
• Format: text
• Language: English
• Published: Animo Repository 2019
• Subjects: Freshwater fishes > Philippines > Batangas > Taal; Fisheries > Philippines > Batangas > Taal; Chemistry
• Online Access: https://animorepository.dlsu.edu.ph/etd_bachelors/2977
• Institution: De La Salle University

Lake Taal is one of the largest producers of inland fish in the Philippines and has one of the largest freshwater markets in Luzon. These unregulated markets post threat to the consumers health as the fish produce coming from the aquacultures and fisheries were not assessed through quality assurance and control. There were a lot of reported fish kills in this lake that contribute to a hundred million financial loss; consequently, the biomonitoring of fish kills, as well as the heavy metal concentrations of the inland waters and muscle tissues, are not intensive and extensive. Conservation management is also not heavily imposed as fundamental data are lacking. Similarly, price values are not regulated as nutritional values are not well characterized. This study focused on the characterization of a) Pb and Cd through GFAAS; b) protein concentrations through three protein quantification methods via UV-Vis; c) relative lipid-protein-carbohydrate through FTIR analysis; and, d) physicochemical properties through thermogravimetric analysis for the 12 fish samples. Cd concentrations were below the 30 ppm-limit which was the accepted limit of cadmium intake per day, but all the lead concentrations were greater than 0.1 and 0.05 ppm thresholds for adults and children, respectively. It is strongly recommended to have a tighter regulations of the fish markets, aquacultures, and commercial fisheries in Lake Taal as the levels of lead in the muscle tissues were above the accepted values. Among the protein quantification methods utilized, Bradfords assay showed highest precision of less than 1% with the protein values ranging from 15 to 20%. Otip has the most proteins. Moreover, banak, in terms of its FTIR spectral transmittances, showed to be the most nutritious fish among the given samples. The FTIER analyses revealed five fish groups based on spectral arrangement which was supported by the results of TGA analyses on its thermogravimetric transition curves when five fish groups were observed. Both the FTIR and TGA analyses supported the genetic relationships according to the 3 superorders, 6 orders, 7 suborders, and 11 families of 12 fish species. Banak, biang bato, arroyo, and guno were the species that were not highly commercialized among the samples. It is recommended that aquacultures and fisheries should cultivate more of these species. This is the first time thermogravimetry was used to validate the ideal pre-digestion parameters in AAS, the ashing and charring temperatures. The TGA analyses confirmed that the optimum charring temperatures for the fish samples must be around 366 to 395 degrees Celsius. It also confirmed that the optimum ashing temperatures for the fish samples must be around 564 to 647 degrees Celsius. The glass transition temperatures obtained suggests the optimum temperature for cooking fish which was at 262 to 395 degrees Celsius. The TGA analyses also revealed melting points, thermal transitions unique to the molecular profile of the species, and the Curie point transition.