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: Kajian pemanfaatan tepung ubi jalar ungu (Ipomoea batatas (L) Lam.) dalam pembuatan spreads ubi jalar
Abstrak: Purple sweet potato (Ipomoea babatas cv. Ayamurasaki) contains high amounts of anthocyanin. Processing purple sweet potato becoming flour will make it more available to be used in various product, like spreads. Aim of this research is to obtain flours with highest color intensity and anthocyanin content, an optimal recipe for producing sweet potato spreads, and describe characteristic of sweet potato spreads. The results showed that flour steamed 10 minutes and dried with sun light has the highest total anthocyanin (183,44 mg cyE/100g) and the best color appearance (L 40.25; a 13.29; b -3.74; ohue 344.37o; and C 13.81). Then, the purple sweet potato flour was used to make sweet potato spreads. Addition of 9% purple sweet potato flour and 0.6% glycerol monostearate with 30 minutes of mixing at 500C and 15 minutes of homogenization gave optimum emulsion stability for sweet potato spreads. Sweet potato spreads was divided into three different formula based on the ratio of shortening and oil. The result showed that ratio of shortening and oil had significant effect to spreadability, brightness, consumer acceptance, and emulsion stability of sweet potato spreads. Based on the fourth parameter, it was concluded that sweet potato spreads with 2:1 ratio of shortening to oil was the most optimum formula.
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Judul: Kajian Model Epidemik SIS Deterministik dan Stokastik Waktu Diskret dengan Total Populasi Tidak Konstan
Abstrak: Model epidemik SIS merupakan salah satu model penyebaran penyakit menular. Pada model ini, individu yang terinfeksi (infective) dapat menjadi rentan kembali (susceptible). Model epidemik SIS yang dibahas dalam penelitian ini yaitu model deterministik dan stokastik. Pada model stokastik dibandingkan saat total populasi tidak kontan dan konstan. Pada model deterministik diperoleh dua titik tetap yaitu titik tetap bebas penyakit dan titik tetap endemik. Dalam penelitian ini diperoleh bahwa pada model stokastik populasi tidak konstan dengan populasi awal lebih besar dari daya dukung lingkungan, peluang untuk terjadi bebas penyakit lebih besar dibandingkan pada model dengan populasi konstan. Sebaliknya jika populasi awal lebih kecil dari daya dukung lingkungan, peluang untuk terjadinya bebas penyakit lebih besar pada model dengan populasi konstan dibandingkan saat populasinya tidak konstan.
Keyword: daya dukung lingkungan, model epidemik determinstik, model epidemik stokastik, populasi konstan, populasi tidak konstan, titik tetap