Judul: Kajian Hidrolisis Enzimatik Minyak Ikan untuk Produksi Omega-3 Menggunakan Lipase dari Aspergillus niger pada Media yang Ditambahkan Toluena
Abstrak: Omega-3 is an essential fatty acid that is needed for our brain and other organs development. Our body could not produce omega-3 itself, so we should consume it from our food. Omega-3 is found mostly from sea fish that eat phytoplankton that can produce omega-3 within their body. Many researches had been done to find an effective and efficient way to extract omega-3 from fish oil through hydrolysis, esterification, interesterification, acidolysis, or transesterification reaction. Omega-3 is usually produced in these three common forms: methyl ester, free fatty acid and acylglycerol. Acylglycerol form is considered better as food chemical material because it is easily digested by human digestive system. Selection of lipase as catalyst of hydrolysis reaction because of its easiness to get, it does not need cofactor, its stability and tolerance with solvent. Organic solvent could modify the original form of enzyme, so that it could change catalytic efficiency and specificity of enzyme. This research had aim to get reaction factor condition that could produce the best degree of hydrolysis of fish oil in a media without and with toluene-added media. Besides, this research’ aim was to figure out the correlation between optimum degree of hydrolysis of fish oil and sum amount of omega-3 fatty acid. The variations of factor reaction those were used here were temperatures (25-65)o Enzymatic hydrolysis of fish oil in this research was used a no-toluene-added media and a toluene-added media. Factors those were analyzed in hydrolysis in a no-toluene-added media are temperature and pH treatment. Factors those were analyzed in hydrolysis in a toluene-added media are water addition, pH and temperature treatment. Parameter that was used here to determine the effect of each factor was degree of hydrolysis. C, pH (5-9) and water addition (1-5)%v/v. Highest degree of hydrolysis in media without toluene addition on temperature treatment was 6,02% that was reached at 45o In water addition treatment, there were no significant effects of degree of hydrolysis for every stage of water addition. Otherwise, there was significance of degree of hydrolysis was decreasing. In pH treatment, degree of hydrolysis was decreasing while the value of pH was increasing. When it was reached pH 7, degree of hydrolysis had reached stationer phase for another stage of pH. C, while on pH treatment was 23,42% that was reached on pH 5. Highest degree of hydrolysis in media with toluene addition in a media with toluene addition on water addition treatment was 15,69%, while on pH treatment was 10,66% and on temperature treatment was 11,59%. According to the result of GC-MS analysis, highest omega-3 content was reached from enzymatic hydrolysis in a media without toluene addition on pH 5, whereas its EPA content was 12,43% and its DHA content was 0,86%. Omega-3 content in the result of enzymatic hydrolysis in a media with toluene addition consist of EPA content of 3,01% and DHA content undetected. Toluene addition into hydrolysis media could not increase the catalytic activity of Aspergillus niger lipase. So, it is better to hydrolyze fish oil with Aspergillus niger lipase in a no-toluene-added-media to reach higher degree of
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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