The effect of seven-day cold storage on the protein and lipid content of white muscle and microbial count in the gastrointestinal tract of Katsuwonus pelamis (gulyasan) and Thunnus albacares (tambakol)

• Main Authors: Castro, Samuel Paul M., Cuaso, Janice Claire C., Discaya, Wilson T., Endencia, Timothy, Herrela, Chad Albert V., Simbol, Maria Monina C., Tengco, Christopher J.
• Format: text
• Language: English
• Published: Animo Repository 1994
• Subjects: Proteins; Cold storage; Fish, Frozen; Microbial growth; Lipids; xx4 Bacterial growth
• Online Access: https://animorepository.dlsu.edu.ph/etd_bachelors/9799
• Institution: De La Salle University

Changes in protein content (myofibrillar protein nitrogen, sarcoplasmic protein nitrogen and non-proteinous nitrogen), dimethylamine nitrogen (DMA-N) content, lipid content (free fatty acid, total lipid content and peroxide value) and bacterial growth in Katsuwonus pelamis (gulyasan) and Thunnus albacares (tambakol) during 7 day cold storage were determined.Protein content was determined using the Bradford Protein Analysis. Both species showed a generally decreasing pattern in myofibrillar protein nitrogen (MPN), sarcoplasmic protein nitrogen (SPN), and non-proteinous nitrogen (NPN).In Katsuwonus pelamis, myofibrillar protein nitrogen concentration decreased from 4.695 mg/mg muscle at day 1 to 0.861 mg/mg muscle at day 7 sacroplasmic protein nitrogen concentration decreased from 8.696 mg/mg muscle to 4.513 mg/mg muscle and non-proteinous nitrogen concentration decreased from 1.168 mg/mg muscle to 0.000 mg/mg muscle.In Thunnus albacares, myofibrillar protein nitrogen concentration decreased from 5.977 mg/mg muscle at day 1 to 0.433 mg/mg muscle at day 7 sarcoplasmic protein nitrogen increased from 1.170 mg/mg muscle to 33.555 mg/mg muscle and non-proteinous nitrogen concentration decreased from 0.681 mg/mg muscle to 0.055 mg/mg muscle.Dimethylamine Nitrogen (DMA-N) was detected using Dyer's Colorimetric Method. Its concentration showed a general increase in both species. DMA-N concentration in Katsuwonus pelamis (gulyasan) increased from 0.00227 mg/100g muscle on day 1 to 0.0.01304 mg/100g muscle on day 7, while in Thunnus albacares (tambakol) the DMA-N concentration increased from 0.00269 mg/100 g muscle to 0.00455 mg/100 g muscle on day 7.Lipid content was determined using Modified Folch's Method. It showed a generally increasing pattern for total lipid content, free fatty acid and peroxide value in both species.In Katsuwonus pelamis (gulyasan), total lipid content on day 1 was 12.628 percent and on day 7 was 17.975 percent free fatty acid on day 1 was 2.909 percent and on day 7 was 6.082 percent and peroxide value on day 1 was 11.051 meq/100 g and on day 7 was 18.639 meq/100g muscle.In Thunnus albacares (tambakol), total lipid content on day 1 was 12.197 percent and on day 7 was 17.779 percent free fatty acid on day 1 was 2.652 percent and on day 7 was 5.812 percent and peroxide value on day 1 was 12.600 meq/100 g and on day 7 was 1 6.111 meq/100g muscle.Bacterial growth in the fish gastrointestinal tract was quantified using the Aerobic Plete Count. It experienced onsets of increase on specific days of storage. Bacterial count in Katsuwonus pelamis (gulyasan) increased from 4.66 X 10 CFU/g on day 1 to 3.65 X10 CFU/g on day 7, with the onset of rapid increase occuring on day 5. Bacterial count in Thunnus albacares (tambakol) increased from 3.60 X 10 CFU/g on day 1 to 2.6 X 10 CFU/g on day 7, with the onset of rapid increase occurring on day 3.