Judul: Optimasi Metode Ekstraksi dalam Identifikasi dan Karakterisasi Molekuler Protein Penyebab Alergi pada Terasi
Abstrak: Terasi sebagai penyedap makanan digemari oleh masyarakat, namun terasi mengandung alergen tropomiosin dari udang yang berpotensi menyebabkan alergi pada sebagian orang. Pemilihan buffer yang tepat diperlukan untuk mengidentifikasi alergen pada terasi dengan baik. Tujuan penelitian yaitu menentukan buffer ekstraksi yang baik dalam memperoleh protein udang pada terasi sehingga dapat diidentifikasi dan dikarakterisasi. Sampel penelitian terdiri dari satu jenis udang rebon dan delapan jenis terasi yang berbeda. Metode ekstraksi terdiri atas tiga jenis buffer dengan pH berbeda yaitu pH 7,4 phosphate buffered saline, pH 8,5 coca solution, dan pH 10,6 carbonate buffered saline yang dilakukan kepada sembilan sampel. Konsentrasi dan profil protein dianalisis dengan uji Bradford dan SDS-PAGE. Konsentrasi protein menggunakan tiga buffer yang berbeda menunjukkan hasil yang bervariasi. Analisis SDS-PAGE pada sampel memiliki bobot molekul berkisar 15-200 kDa. Hasil ekstraksi terbaik didapatkan pada penggunaan buffer CBS. Tropomiosin tidak teridentifikasi pada sampel terasi. Pemrosesan udang menjadi olahan terasi dapat menurunkan alergen udang., Terasi as a food flavoring is popular among people, but it contains the tropomyosin allergen from shrimp, which has the potential to cause allergies in some people. The right buffer selection needs to be used to identify allergens in shrimp paste correctly. This research aimed to determine a suitable extraction buffer for obtaining shrimp protein in shrimp paste so that it could be identified and characterized. The research sample included one type of rebon shrimp and eight different shrimp pastes. The extraction method used three types of buffers with different pH, phosphate buffered saline pH 7.4, coca solution pH 8.5, and carbonate buffered saline pH 10.6 which were carried out on nine samples. The protein concentration and profile were determined using the Bradford test and SDS-PAGE. Protein concentration using three different buffers showed varying results. SDS-PAGE analysis of the samples revealed molecular weights ranging from 15-200 kDa. The best extraction results were obtained by using the CBS buffer. Tropomyosin was not identified in the sample of shrimp paste. Shrimp allergens can be reduced by processing shrimp into processed shrimp paste.
Keyword: alergen, bobot molekul, ekstraksi, protein, tropomiosin

Judul: Influence of Fermentation Time on Tropomyosin Content as Allergen Protein of Shrimp Paste (Terasi Udang Rebon)
Abstrak: Terasi udang merupakan produk olahan hasil perikanan dengan bahan baku udang rebon atau udang segar, atau kering atau campurannya yang difermentasi. Penelitian ini bertujuan menentukan pengaruh lama waktu fermentasi terhadap karakteristik terasi dan kandungan protein alergen tropomiosin. Analisis protein alergen tropomiosin menggunakan metode SDS-PAGE dan dihitung kandungannya melalui intensitas pita tropomiosin. Kadar protein pada produk akhir terasi sebesar 16.74% pada terasi 7H, 16.46% pada terasi 14H, dan 16.03% pada terasi 21H. Hasil pengukuran protein terlarut pada sampel terasi 7H, 14H, dan 21H berturut-turut sebesar 1.504, 1.106, dan 1.069 mg/mL. Penilaian organoleptik terasi memiliki rata-rata nilai berkisar 6 – 7 yang memiliki arti cukup spesifik jenis terasi. Pita bobot molekul hasil analisis SDS-PAGE memperoleh hasil protein alergen tropomiosin berkisar 34,41 – 35,68 kDa. Ketebalan intensitas pita protein tropomiosin semakin memudar pada sampel 14H dan 21H sehingga konsentrasi tropomiosin semakin berkurang pada waktu 14H dan 21H., Shrimp paste (terasi) is a processed fishery product made from raw, fresh or dried small shrimp or its fermented mixture. This study aims to determine the effect of fermentation time on the characteristics of shrimp paste and the content of tropomyosin allergen protein. Tropomyosin allergen protein analyzed using SDS- PAGE method and its content was calculated by the intensity of the tropomyosin band. The protein content in the final shrimp paste product was 16.74% for 7H shrimp paste, 16.46% for 14H shrimp paste, and 16.03% for 21H shrimp paste. The highest results of dissolved protein content obtained in fresh rebon shrimp samples were at 3,013 mg/mL, 7H, 14H, and 21H shrimp paste at 1,504, 1,106, and 1,069 mg/mL, respectively. The organoleptic results of shrimp paste have an average value ranging 6 to 7 which have a fairly specific meaning for the type of shrimp paste. Molecular weight bands from SDS-PAGE analysis obtained tropomiosin allergen protein ranges from 34.41 – 35.68 kDa. The thickness of the tropomyosin protein band intensity faded in sample 14H and 21H suggesting the tropomyosin concentration decreases at 14H and 21H.
Keyword: Alergen tropomiosin, Fermentasi, Terasi udang, fermentation, shrimp paste, tropomyosin allergen

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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