Judul: Pengaruh Ratio Dt/Di dan Kecepatan Pengadukan terhadap Hidrolisis Enzimatik Minyak Ikan Lemuru Menggunakan Lipase Aspergillus Niger untuk Produksi Asam Lemak Omega-3
Abstrak: Lemuru is one of fish that found in Indonesia which can be processed into canned fish (sardine), cue, and fish meal. Fish oil is by- product of fish meal processing that is containing unsaturated fatty acid named omega-3, specially eicosapentanoic acid (EPA) and docosahexanoic acid (DHA). Research objectives are obtaining the optimum process conditions for enzymatic hydrolysis of lemuru fish oil using lipase from Aspergillus niger and determining the Dt/Di ratio and optimum stirring speed for enzymatic hydrolysis of fish oils produce omega-3 fatty acids.. Hexane added into 527,625ml of fish oil that have been rinsed by nitrogen and lipase enzyme that is dissolved with phosphat buffer 0,1 M and hydrolyzed at optimum condition for 48 hour. Product separated from water and analyzed with Gas Chromatography Mass Spectromerty. Scales that used in this research are 5, 10, 20, and 50, which each volumes are 52,7625 ml; 105,525 ml; 211,05 ml; and 527,625 ml. The product at last scale contain 1,16% EPA. DHA does not formed at this scale caused by non-ideal parameter. Stirring speed and ratio of stirrer diameter and container diameter are the parameters that influence production of omega-3. Ideal stirring speed using propeller with 3 blades calculated based on 250 rpm as initial stirring speed. Ideal ratio of container diameter and stirrer diameter is 1,1538.
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Judul: Kajian Hidrolisis Enzimatik Minyak Ikan untuk Produksi Omega-3 Menggunakan Lipase dari Aspergillus niger pada Media yang Ditambahkan Heksana.
Abstrak: Nowadays utilization of sea fish is limited for human consumption only. This is made solid waste and fish oil that is produced during the process could not be utilized further. Besides, fish oil is the source of important fatty-acid, especially polyunsaturated fatty acid (PUFA) omega-3, those are eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). These kinds of fatty acids have important roles in fulfilling human nutrition, preventing and curing few diseases. Omega-3 fatty acid in acylglycerol form is considered better as food chemical form because it is digested easily by human digestive system. Production of omega-3 fatty acid in acylglycerol form with high products could be reached through enzymatic hydrolysis reaction. Aspergillus niger lipase has positional specificity that could break down triacylglycerols chain on stereochemical numbering position (sn) 1 and 3. Usage of this lipase in hydrolysis reaction could produce a lot of omega-3 fatty acid, especially eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Catalytic activity of Aspergillus niger lipase is low when it is used in hydrolysis reaction of fish oil. That is the reason that it is needed to find a way to increase catalytic activity of Aspergillus niger lipase by adding organic solvent of hexane into its hydrolysis media. Besides, during hydrolysis process, activity and stability of enzyme is affected by environment condition, such as temperature, pH and water addition. This research had aim to determine reaction factor condition that could produce highest degree of hydrolysis of fish oil in a media without or with added-hexane media. Besides, this research aim was to determine the correlation between highest degree of hydrolysis of fish oil and sum amount of omega-3 fatty acid. The variation of factor reaction that was used here were temperatures (25-65)oC, pH (5-9), and water addition (1-5)%v/v. This research stage was began with fish oil characterization, measurement of activity of Aspergillus niger lipase with spectrofotometri method, enzymatic hydrolysis of fish oil in media without solvent addition, and hydrolysis in media with solvent addition using optimum temperature and pH from the result of hydrolysis in media without hexane addition. Analysis of end product was included measurement of degree of hydrolysis and gas chromatography mass spectrometry (GC-MS) analysis. Results of fish oil characterization of physiochemical characteristic showed that it had acid value of 3,26 mg KOH/g, free fatty acid content of 1,49%, and saponification value of 204,81 mg KOH/g. On the other hand, results of fish oil characterization of component analysis showed that it had saturated fatty acid content of 23,2%, unsaturated fatty acid content of 34,98%, alkenes 11,19%, squalenes 4,75%, aldehide 0,88% and lanol 24,96%. Result of measurement of activity of Aspergillus niger lipase was 7939,97 U/g.
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Judul: Closed Knight’s Tour pada Papan Catur Berbentuk Persegi Panjang dengan Ukuran Maksimal 8 × 8
Abstrak: Closed Knight’s Tour merupakan langkah kuda yang mengunjungi setiap kotak pada papan catur tepat satu kali dengan langkah kuda berawal dan berakhir pada kotak yang sama. Graf yang terbentuk dari closed knight’s tour dinotasikan sebagai graf G(m,n), dengan m adalah banyaknya baris dan n adalah banyaknya kolom. Graf tersebut memuat Hamiltonian cycle. Sebuah graf terhubung G adalah graf bipartite jika dan hanya jika graf tersebut tidak memiliki cycle dengan panjang ganjil. Papan catur yang memenuhi syarat cukup untuk memiliki closed knight’s tour adalah papan catur berukuran 5 × 6, 5 × 8, 6 × 6, 6 × 7, 6 × 8, 7 × 8, dan 8 × 8.
Keyword: bipartite, closed knight’s tour, hamiltonian cycle, knight’s tour, teori graf