Judul: Seaweed Cellulose Microfiber Aerogel: Application  of Active Packaging Material to Absorb Carcinogenic Polycyclic Aromatic  Hydrocarbon Compounds in Smoked Fish
Abstrak: Polisiklik aromatik hidrokarbon (PAH) pada ikan asap cenderung mencapai tingkat yang tinggi bahkan melebihi batas maksimum, dan berpotensi sebagai senyawa karsinogenik. Aerogel sebagai alternatif ideal untuk menyerap senyawa PAH dan membuka peluang baru melalui pengembangan kemasan aktif. Penelitian bertujuan menentukan karakteristik aerogel mikrofiber selulosa dari rumput laut dengan teknik pengeringan berbeda dan aplikasinya sebagai material kemasan aktif penyerap senyawa karsinogen polisiklik aromatik hidrokarbon pada ikan asap. Metode berfokus pada pembuatan dan penentuan karakteristik aerogel mikrofiber selulosa dari rumput laut Sargassum sp. menggunakan freeze drying dan dehydrator serta efektivitas penyerapan senyawa PAH pada ikan asap. Aerogel mikrofiber selulosa dari rumput laut melalui freeze drying memperlihatkan keunikan struktur 3D berpori dengan ukuran 16,250 nm, sedangkan dengan dehydrator cenderung memiliki struktur yang padat dengan ukuran pori 12,081 nm. Aerogel mikrofiber selulosa dari rumput laut secara umum cukup efektif dalam menyerap senyawa PAH, yaitu anthracene., Polycyclic aromatic hydrocarbons (PAH) in smoked fish tend to reach high levels, even exceeding the maximum limit, and have the potential to be carcinogenic compounds. Aerogel is considered an ideal alternative to absorb PAH compounds and opens up new opportunities through the development of active packaging. This research aims to determine the characteristics of cellulose microfiber aerogel from seaweed using different drying techniques and its application as an active packaging material to absorb polycyclic aromatic hydrocarbon carcinogenic compounds in smoked fish. The method focuses on making and determining the characteristics of cellulose microfiber aerogel from seaweed Sargassum sp. using freeze drying and dehydrator and the effectiveness of absorption of PAH compounds in smoked fish. Cellulose microfiber aerogel from seaweed through freeze drying shows a unique 3D porous structure with a size of 16,250 nm, whereas with a dehydrator it tends to have a dense structure, but has a pore size of 12,081 nm. Cellulose microfiber aerogel from seaweed is generally quite effective in absorbing PAH compounds, including anthracene.
Keyword: absorbents, biomaterials, food safety, freeze drying, hydrogels

Judul: Kajian Penggunaan Asap Cair Tempurung Kelapa terhadap Daya Awet Bakso Ikan
Abstrak: The study investigated safeties and antibacterial activity of coconut shell liquid smoke and its applications of fishball preservation. The safeties of liquid smoke studied by identification of volatile compounds of liquid smoke by means of Gas Chromatography-Mass Spectroscopy (GC-MS) and determination acute toxicity of liquid smoke. A high number of compounds was detected. They were identified as ketones, carbonyl, acids, furan and pyran derivatives, phenol and derivatives, guaiacol and derivatives, syringol and derivatives, and alkyl aryl ethers. Neither benzo[a]pyrene nor other polycyclic aromatic compounds with carcinogenic properties were found in this liquid smoke. Acute toxicity test of these product assessed by determination of LD50 dose (the dose which causes the death of half the test animals). Results indicated that LD50 dose of this liquid smoke are more than 15.000 mg/kg body weight of mice. The Minimum Inhibitory Concentration (MIC) of liquid smoke against Pseudomonas aeruginosa and Staphylococcus aureus determined using broth or agar dilution methods. Liquid smoke showed antibacterial activities againts P. aeruginosa and S. aureus with MIC value 0,22% and 0,40%, respectively. Applications of 2,5% liquid smoke in fishball at 27–28 0C increased shelflife from 16 to 32 hours, whereas at 4±1 0C until 20 days storage were better accepted, and retarded the decreased of pH and moisture content compared to control. The results indicated that liquid smoke was an effective preservative agent for fishball.
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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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