Judul: Pembuatan Tepung Ubi Jalar Ungu (Ipomoea batatas varietas Ayamurasaki) dan Aplikasinya dalam Pembuatan Roti Tawar
Abstrak: Purple sweet potato (Ipomoea batatas cultivar Ayamurasaki) contains high amount of anthocyanin. Purple sweet potato flour will be more available to be used in bakery products and more effective in storage condition. This study was designed to produce purple sweet potato flour that has good appearance characteristic and high anthocyanin, then its application in bread making. The result showed that flour steamed 7 minutes of fleshed (1 cm) purple sweet potato and dried with tray drying has the highest total anthocyanin (188,11 mg Cy-3-glucoside/100 g flour) and the best colour appearance (L 42.08, a 13.04, b -2.88, and hue 347.7). Substituted bread by 40% purple sweet potato flour has the highest acceptability by 70 untrained panellists. This bread has L 38.11-39.41, a 21.22-21.84, b -0.37- -0.33, hue 358.3-359.1, and contains 96.41 mg Cy-3-glucoside/100 g bread. Physical analysis showed that loaf bread technique has specific volume 2.44 cm3/g and 0.13 kgF firmness. Based on the data, loaf bread technique is more suitable method in bread making that is substituted with purple sweet potato flour.
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Judul: Effect of Flour Processing and Steaming on Physicochemical and Sensory Characteristic of Purple Sweet Potato Analog Rice
Abstrak: Beras analog ubi jalar ungu memiliki peluang untuk dikembangkan sebagai alternatif makanan pokok. Ubi jalar ungu sebagai bahan dasar dikenal memiliki karbohidrat dengan indeks glikemik rendah serta kandungan antosianin dan senyawa fenolik yang cukup tinggi. Proses pembuatan beras analog ubi jalar ungu dari tepung menghasilkan beras yang cenderung berwarna gelap akibat degradasi senyawa antosianin selama proses pengolahan. Upaya untuk menghasilkan beras analog ubi jalar ungu dengan karakteristik warna dan total fenolik yang lebih baik dapat dilakukan dengan proses pengukusan. Pengukusan ubi jalar ungu dapat mencegah terjadinya oksidasi antosianin dan memperkuat warna pigmen. Penelitian ini bertujuan membandingkan karakteristik beras analog ubi jalar ungu dengan proses penepungan dan proses pengukusan berdasarkan parameter fisik, kimia, dan sensori. Pembuatan beras analog menggunakan dua formula dengan bahan utama yang berbeda, yaitu tepung dan pasta ubi jalar ungu. Karakteristik beras analog didapatkan dengan melakukan analisis fisik, kimia dan sensori. Hasil analisis menunjukkan formula menghasilkan beras dengan warna yang berbeda. Beras analog dengan proses pengukusan mengandung total fenolik dan aktivitas antioksidan yang lebih tinggi. Uji RATA menunjukkan beras analog dengan penepungan didominasi oleh atribut brown color, sedangkan beras analog dengan proses pengukusan didominasi oleh atribut purple color, sweet, purple sweet potato aroma, dan chewiness. Kedua formula beras memiliki tingkat kesukaan yang sama dan masih dapat diterima oleh panelis.
Keyword: analog rice, flour processing, steaming, sweet purple potato, total  phenolic

Judul: Dynamical System of Hepatitis B in Three Groups with Vaccination
Abstrak: The aim of this study is to modify the hepatitis B transmission model in three age groups involving vaccination from the model conducted by Zhoe and Zhang.The method used is to analyze the stability of the fixed point and its basic reproduction number (R_0). Performed stability analysis and numerical simulation to see population dynamics. Next, a sensitivity analysis of the parameters was carried out to see its effect on R_0. From the analysis obtained two fixed points, namely non-endemic and endemic fixed points. Non-endemic fixed points are locally asymptotically stable if R_0 <1 Meanwhile, the endemic fixed point is locally asymptotically stable if R_0 > 1. Hepatitis vaccination affects the number of susceptible population, because the more successful the vaccination, the smaller the number of susceptible populations so that the smaller the population will be infected.
Keyword: Dynamic, Hepatitis B, Vaccine, Mathematical model