Judul: Study of Morphometric Corelation Some Fish Species on Chemical Composition, Amino Acid, and Activity of Trypsin Enzyme
Abstrak: Morfometrik merupakan metode pengukuran bentuk tubuh ikan yang dapat digunakan sebagai pembanding ukuran ikan, menentukan pola pertumbuhan ikan, kebiasaan makan, dan identifikasi ikan. Kebiasaan makan ikan dewasa terbagi menjadi tiga kategori yaitu herbivora, karnivora, dan omnivora. Kebiasaan makan dari ikan tersebut mempengaruhi enzim pencernaan dalam tubuh ikan. Tripsin termasuk dalam kelompok protease serin yang merupakan enzim yang memecah protein. Penelitian ini bertujuan untuk mengetahui morfometrik, komposisi kimia dan asam amino ikan laut (tuna sirip kuning, kakap merah, baronang, tembang, cucut, ikan sebelah) dan ikan air tawar (gabus, nila dan gurame), mengetahui aktivitas tripsin dari jeroan (usus, hati, limpa) ikan laut dan air tawar, serta untuk mengetahui hubungan morfometrik dengan kebiasaan makan, hubungan komposisi kimia dan asam amino terhadap aktivitas tripsin menggunakan Principal Component Analysis (PCA). Berdasarkan analisis diketahui bahwa parameter morfometrik ikan memiliki korelasi yang erat dan dapat mengkatagorikan ikan gabus, cucut dan tuna termasuk dalam jenis ikan karnivora, baronang, gurame dan nila termasuk jenis ikan herbivora, ikan sebelah, kakap dan tembang termasuk ikan omnivora. Komposisi kimia dan asam amino daging ikan bervariasi pada setiap jenis dan kebiasaan makannya. Asam amino yang paling dominan pada semua jenis ikan yang diamati adalah asam glutamat. Setiap jenis ikan memiliki komposisi asam amino nonesensial dan esensial yang bervariasi. Aktivitas spesifik enzim tripsin dari usus ikan tuna sirip kuning (4,98±0,52 U/mg) lebih tinggi dibandingkan tripsin dari bagian hati dan limpa. Ikan tuna sirip kuning, gabus, dan ikan sebelah berkorelasi positif dengan kandungan asam amino lisina, asam aspartat, asam glutamat, alanina, valina, histidina, isoleusina, dan leusina, kadar protein, abu dan karbohidrat yang juga mencirikan enzim tripsin dari limpa dan usus. Ikan gurame berkorelasi positif dengan asam amino prolina, serina, treonina, glisina, tirosina, arginina, fenilalanina, dan kadar lemak serta berkorelasi negatif dengan kadar air dan tripsin dari limpa., Morphometric is a method of measuring fish body shape that can be used as a comparison of fish size, determine fish growth patterns, eating habits, and fish identification. Adult fish eating habits are divided into herbivores, carnivores, and omnivores that can affect digestive enzymes in the fish's body. Trypsin belongs to the group of serine protease which are enzymes that cleavage protein. This study aims to determine the morphometric, chemical composition and amino acids of marine fish (yellowfin tuna, red snapper, rabbitfish, sardine, spiny dogfish, flatfish) and freshwater fish (snakehead fish, tilapia and giant gourami), determine the activity of trypsin from the viscera (intestine, liver, spleen) of marine and freshwater fish, and to determine the correlation of morphometrics on eating habits, correlation chemical composition and amino acids on trypsin activity using Principal Component Analysis (PCA). Based on the analysis, it is known that the morphometric parameters of fish have significant correlation and able to categorized snakehead fish, yellowfin tuna and spiny dogfish as carnivorous fish, rabbitfish, giant gouramy and tilapia as herbivorous fish, flatfish, red snapper and sardine as omnivorous fish. The chemical and amino acid composition of fish meat varies with each type and eating habits. The most dominant amino acid in all types of fish observed was glutamic acid. Each type of fish has a different composition of
Keyword: asam amino, enzim, kebiasaan makan, amino acids, enzymes, fish diets, amino acids, enzymes, fish diets

Judul: Characteristics and Stability of Trypsin Enzyme in NaCl Isolated from Intestine, Liver, and Spleen of Tuna
Abstrak: Kebutuhan enzim di Indonesia sangat tinggi dan masih diimpor dari negara lain. Tripsin komersial biasanya diekstraksi dari pankreas babi dan sapi, sehingga diperlukan sumber alternatif lainnya yang bersumber dari ikan, yaitu usus, hati, dan limpa ikan tuna. Penelitian ini bertujuan menentukan karakteristik dan stabilitas enzim tripsin dalam NaCl, serta hubungan usus, hati, dan limpa ikan tuna terhadap aktivitas tripsin menggunakan Principal Component Analysis (PCA). Aktivitas tripsin berada pada kondisi optimum pada suhu 60 ̊C dan pH 8 dengan nilai aktivitas spesifik pada usus sebesar 0,948±0,114 U/mg; hati sebesar 0,610±0,029 U/mg; dan limpa sebesar 0,605±0,159 U/mg. Kecepatan reaksi maksimum (Vmaks) menunjukkan nilai usus yang paling besar sebesar 0,248 mmol/s, diikuti oleh hati 0,138 mmol/s, dan limpa 0,096 mmol/s, sedangkan nilai konstanta (Km) yang diperoleh usus sebesar 2,342 mM; hati sebesar 2,268 mM, dan limpa sebesar 1,276 mM. Bobot molekul pada tripsin berkisar antara 20-30 kDa. Konsentrasi NaCl yang tinggi akan menyebabkan aktivitas semakin menurun. Bagian usus, hati, dan limpa memiliki korelasi positif., The need for enzymes in Indonesia is very high and they are still imported from other countries. Commercial trypsin is usually extracted from the pancreas of pigs and cattle, so that other alternative sources are needed from fish, namely the intestines, liver and spleen of tuna. The relationship between intestine, liver and spleen of tuna trypsin activity using Principal Component Analysys (PCA) was used to determine characterisics and stability of the trypsin enzyme in NaCl as the study aims. Trypsin activity was at its optimum at a temperature of 60 ̊C and pH 8 with a specific activity value in the intestine of 0,948 ± 0,114 U/mg; liver of 0,610 ± 0,029 U/mg; and spleen of 0,605 ± 0,159 U/mg. The maximum reaction speed (Vmax) showed the largest intestinal value of 0,248 mmol/s, followed by the liver 0,138 mmol/s, and the spleen 0,096 mmol/s, while the constant value (Km) obtained by the intestine was 2,342 mM; liver of 2,268 mM, and spleen of 1,276 mM. The molecular weight of trypsin ranges from 20-30 kDa. The high concentration of NaCl decreased the activity. Sections of intestine, liver, and spleen had a positive correlation.
Keyword: karakteristik enzim tripsin, stabilitas NaCl, jeroan tuna

Judul: Bifurkasi Hopf pada Model Siklus Bisnis Kaldor Kalecki tanpa dan dengan Waktu Tunda
Abstrak: Business cycle model is one of dynamical system models in economic. One of the business cycles model is Kaldor-Kalecki model. Kaldor-Kalecki business cycle model that is written in delayed defferential equations, is a business cycle model that involves gross product and capital stock of a company. In this paper Kaldor-Kalecki business cycle model is analyzed using both nondelay and delay in time of capital stock. By Taylor expansion for the time delayed model, an analysis of stability around the fixed points has been done. Furthermore, by using Hopf bifurcation theorem, it can be shown that there exists periodic orbits and limit cycle. In the nondelayed model, changing the parameter of goods market could lead to the occurrence of Hopf bifurcation and the existence of limit cycle. Similarly, for the delayed model, it has been shown that changing the time delay parameter may result in the occurrence of Hopf bifurcation and limit cycle.
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