<p>The use of native arenga starch is limited, therefore modification is needed. The objectives of this study was to obtain the optimum concentration of mixed sodium trimetaphospate (STMP) and sodium tripolyphospate (STPP) ratio in the acetylated-cross linked combination that based on the physicochemical characteristics of the modified arenga starch. The study was conducted in March-August 2018 at the Agroindustry Laboratory, Faculty of Agriculture, Tadulako University Palu, Central Sulawesi. This research was compiled using a Completely Randomized Design (CRD) consisting of seven levels of treatment and repeated three times, 21 experimental units in total. The treatments used were native arenga starch and concentration of mixed STMP:STPP (99:1). The level of treatment used were 2%, 4%, 6%, 8%, 10% and 12%. Analysis variables included viscosity, emulsion separation volume, water and oil holding capacity, swelling power and solubility. The results showed that the best concentration of STMP and STPP ratio was 2%. The physicochemical characteristics produced in viscosity, swelling power, and solubility of starch phosphate acetate arenga starches were smaller than native arenga starch. However, in the emulsion separation volume, water and oil holding capacity of phosphate acetate arenga starches are greater than native arenga starch. Viscosity and solubility of phosphate acetate arenga starches increase as the concentration of STMP and STPP ratios is rising. However, the emulsion separation volume, water holding capacity, oil holding capacity and swelling power decrease concentration of the mixed STMP and STPP ratios is rising.</p><p align="center"><strong>ABSTRAK</strong></p><p align="center"><strong> </strong></p><p>Penggunaan pati aren alami masih terbatas, sehingga perlu dilakukan modifikasi. Penelitian ini bertujuan untuk mendapatkan konsentrasi campuran rasio <em>Natrium Trimetafosfat</em> (NTMF) dan <em>Natrium Tripol</em><em>ifosfat </em>(NTPF) yang optimum pada kombinasi asetilasi-ikat silang berdasarkan karakteristik fisikokimia pati aren hasil modifikasi. Penelitian dilaksanakan pada bulan Maret-Agustus 2018 di Laboratorium Agroindustri, Fakultas Pertanian Universitas Tadulako Palu, Sulawesi Tengah. Penelitian ini disusun dengan menggunakan Rancangan Acak Lengkap (RAL) yang terdiri dari tujuh taraf perlakuan dan diulang sebanyak tiga kali sehingga terdapat 21 unit percobaan. Perlakuan yang digunakan berupa pati aren alami dan konsentrasi campuran rasio NTMF:NTPF (99:1). Adapun taraf perlakuan yang digunakan yaitu 2%, 4%, 6%, 8%, 10% dan 12%. Variabel analisis meliputi viskositas, volume pemisahan emulsi, daya menahan air dan minyak, daya mengembang dan kelarutan. Hasil penelitian menunjukkan bahwa konsentrasi rasio NTMF dan NTPF yang terbaik adalah 2%. Karakteristik fisikokimia yang dihasilkan pada viskositas, daya mengembang, dan daya kelarutan pati aren asetat fosfat lebih kecil dibandingkan pati alami. Namun pada volume pemisahan emulsi, daya menahan air dan minyak memiliki pati aren asetat fosfat lebih besar dibandingkan pati alami. Viskositas dan daya kelarutan pati aren asetat fosfat meningkat seiring meningkatnya konsentrasi rasio NTMF dan NTPF. Namun pada volume pemisahan emulsi, daya menahan air, daya menahan minyak dan daya mengembang menurun seiring meningkatnya konsentrasi campuran rasio NTMF dan NTPF.</p>