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: Experimental Investigation on Physical Stability of RPO-in-Water  Emulsion Stabilized by Protein and SiO2 Nanoparticles
Abstrak: As a source of Vitamin-A precursor, the stability of red palm oil (RPO) against oxidation was addressed to be improved. Emulsion containing 10% (v/v) RPO was produced using two-step homogenization, namely at 9000 rpm and 18000 rpm. This research aims to study the effect of emulsification process of RPO to enhance its stability. The used emulsifiers are whey protein concentrate (WPC), soy protein isolate (SPI), and SiO2 nanoparticles with concentration from 2.5% to 15%. The physical stability of the resulting emulsion is analyzed based on the parameters of surface colour, separation index, flow properties, and droplet size distribution. Results showed that higher emulsifier concentration (c) contributes to improve emulsion stability during storage. In this study, emulsion stabilized by SiO2/SPI 15% (SSP15) and SPI 5% (SPI5) were found as the most stable emulsion based on tested physical attributes.
Keyword: emulsion, red palm oil, SiO2 nanoparticle, whey protein concentrate, soy protein isolate

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