Judul: Study on dry fractionation behaviour and crystallization kinetics of coconut oil
Abstrak: Dry fractionation of oils consists of two stages, namely crystallization to produce solid crystals in a liquid matrices and filtration to separate the crystals formed from a liquid matrix. Changes that occur at the molecular level during the crystallisation process such as nucleation, crystall growth and changes in the phase behavior (folymorphism, solid-solutions). The overall changes at the molecular level is highly influenced by the treatment at the physical level in the form of heat removal. Methods of cooling (crystallization temperature, cooling rate and duration of the crystallization is applied) will largely determine the success of coconut oil fractionation process. This research aims to study the typical fractionation method for coconut oil at pilot plant scale (120 kg) and identify the conditions and essential requirements that must be managed and maintained in a dry fractionation stages of coconut oil; establish the crucial cooling systems in the dry fractionation of coconut oil as a guide in designing practical coconut oil fractionation; establish an effective cooling procedure to produce coconut oil fractions with a high content of MCT; determine the effect of cooling rate and crystallization temperature on the composition and profile of TAG, the kinetics of crystallization and melting properties of coconut oil fractionation products ; determine the relationship (model equations) between the parameters of fractionation with cooling procedure during the crystallization process, to predict the TAG composition, physical and thermal-mechanical properties of fractions produced. Coconut oil is dominant with lauric (C12:O), miristic (C14:0) and caprilic (C8:0)acid which composed the main trilaurin (LaLaLa), caprodilaurin (CaLaLa) and dilauromiristin (LaLaM) TAG. The content of lauric, miristic and caprilic acid in coconut oil are 51.73; 15.57 and 10.61%, respectively; while LaLaLa, CaLaLa and LaLaM TAG are 20.43; 16.23 and 15.38%, respectively. Coconut oil contains medium chain trigliserides (MCT) of 53.71%, trisaturated (St3) of 82.54%, disaturated (St2U) of 14:24%, monosaturated (StU2) of 3:22% and the proportion of high/low-melting TAG (S/L) by 49.25%. Coconut oil has a high SFC at low temperatures and a sharp decline to a temperature of 25 °C and then constant up to a temperature of about 30 ºC. Coconut oil’s SFC with about 32% was measured in temperature interval 21-22 °C, indicating that coconut oil has a good spreadibility at ambient temperature for countries that have 4 seasons. Coconut oil has SMP ranged between 24.5-26.2 °C, the water content of 0.021% and a free fatty acid content of 0.018%. Our study showed that there were three distinct cooling regimes critical to crystallization process, i.e. initial cooling, critical cooling and crystallization regime. Initial cooling was cooling from certain temperature that the oil has been rejuvenated and there was no more crystalized TAG (in this study rejuvenation was done at 70 oC for 10 minutes) to the onzet of oil crystallization temperature. For coconut oil the onzet of crystallization temperature was found at 29 oC. Critical cooling was cooling from the onzet of crystallization temperature (29 °C) to crystallization temperature. We predicted that during the critical cooling regime the crystal nucleation process was intensively occured (propagation). Crystallization regime was cooling to keep the oil temperature
Keyword: 

Judul: Karakterisasi dan Analisis Fisiko-Kimia Terhadap Minyak Kelapa dengan Penambahan Ragi roti, Enzim Papain Kasar, Enzim Bromelin Kasar dan Starter Ragi Tape.
Abstrak: Coconut plants (Cocos nucifera L) are grouped into two main varieties of Coconut (tall variety) and Coconut Elephant (dwarf variety). Coconut meat used as raw material in the manufacturing of coconut oil. Coconut oil is generally divided into three types ie: RBD (Refined, Bleached, and Deodorized), VCO (Virgin Coconut Oil) and Traditional Coconut Oil. Coconut oil contains lauric acid which are categorized as an acid medium chain saturated fatty acid. Lauric acid in coconut oil contained approximately 53%, which is efficacious as a natural antibiotic that can kill many types of germs, viruses and parasites such as HIV and hepatitis C virus. Coconut milk is an oil and water emulsions stabilized by proteins and possibly by some ions are adsorbed on the surface of the boundary between oil and water, in this study coconut milk obtained was treated with additions such as yeast breads, crude enzyme papain, crude enzyme bromelain, tape yeast starter. Use of yeast, starter and crude enzyme is intended to break the emulsion which were with components degrade proteins such as emulsion stabilizer. The Randomized Complete Design Group was used for analysis the obtained onto, followed by analysis of variance and Duncan Multiple Range Test showed that crude enzyme bromelain treatment was meet effective for breaking the emulsion, having a yield of oil and water, 31.51 and 0.251 percent, respectively. A good extraction was obtained by using water at 700C that had peroxide number of 1.16 O2/100 g oil.
Keyword: 

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