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: Physical Characterization of Emulsions Stabilized by Proteins and Nanoparticle
Abstrak: Encapsulation of provitamin A in red palm oil has become a focus for both industry and researcher to support solutions for vitamin deficiencies that are still prevalent, especially in developing countries The main aim of the present work was to investigate the effect of combination of different emulsifier such as SiO2 nanoparticle, whey protein isolate, and soy protein isolate to produce a stable emulsion from red palm oil. Research consists of two stages: red palm oil characterization and comparison of three different emulsifier and its combination in emulsion system then Comparison of best stage 1 emulsion in various concentration. Combination of SiO2-SPI-WPI had the best characteristics therefore it was chosen for final stage sample. After 7 days of storage, combination of SiO2-SPI-WPI at 5% concentration had lowest creaming index at 5,2% for final stage sample was obtained. In rheological perspective, emulsion samples predominantly exhibit shear-thinning behavior following power law model. All stage 2 samples have reddish and yellowish color as measured by chromameter. Samples were considered as macro-emulsion as droplets size distribution obtained were above 100
Keyword: Emulsion, Nanoparticle, Whey Protein, Soy Protein, Red Palm Oil

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