Judul: Efektivitas antioksidan dalam sistem emulsi oil in water (O/W), The effective of antioxidants in Oil-in-Water emulsion system
Abstrak: Reaksi oksidasi lipid dalam sistem ernulsi lebih kompleks dari pada minyak utuh. Dalam sistem emulsi, lebjh banyak variabel yang mempengaruhi te jadinya oksidasi, " yakni meliputi kadar minyak, konsentrasi pengemulsi serta pH larutan. Penelitian ini bertujuan untuk mempelajari pengaruh kadar minyak, konsentmsi pengemulsi serta pH larutan terhadap stabilitas oksidatif sistem emulsi serta mempelajari pengaruh polaritas terhadap efektivitas antioksidan., The oxidation of lipids in emulsified form is more complex than that in bulk lipids. In emulsified from, there are more variables influencing lipid oxidation, including oil proportion, type and concentration of emulsifier, pH and buffer system. The aims of this research were (1) to study the effect of corn oil proportion, emulsifier concentration and pH on oxidative stability of emulsion system, and (2) to study the influence of antioxidant polarity on effectiveness.
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Judul: Pengaruh Jenis dan Konsentrasi Emulsifier terhadap Kestabilan dan Sifat Reologi Emulsi Oil in Water Minyak Sawit Merah
Abstrak: Oil in water (o/w) emulsion are a system where an oil is dispersed in an aqueous phase. Preliminary study was fractionation of red palm oil. This process was hold at 60°C for 10 minutes to obtain olein which used as raw material of oil in water emulsion. Futhermore, an optimal oil in water emulsion formulation was selected from the best water and oil ratio that was blended with several concentration of emulsifier. The ratio of water and oil were 6:4, 7:3, 7,5:2,5 and 8:2. This study used Carboxymethylcellulose (CMC), Arabic gum and Tween 80 as emulsifier in various concentrates. The result showed that Carboxymethylcellulose (CMC) at 0,55%, 0,60%, 0,65% and 0,70% (w/v) of concentration combined with 6:4 water and oil ratio was optimal o/w emulsions formulation. The optimal formulation were evaluated for emulsion stability (colour, carotene content and droplet size distribution) and rheology properties. The result of emulsion stability indicated that 0,65% and 0,70% (w/v) of CMC concentrations were stabilized. The rheology properties showed that all of optimal o/w emulsions formulation behaved as pseudoplastic (non-newtonian). This study indicated that viscosity of o/w emulsion was significantly affected by heat. However, the stirring on viscosity of o/w emulsions effect could be ignored. Based on stability and rheology evaluation, 0,65% (w/v) of CMC concentration was the best formulation for oil in water red palm oil emulsion.
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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