Judul: Karakteristik Tepung Talas (Colocasia esculenta (L) Schott) dan Pemanfaatannya dalam Pembuatan Cake
Abstrak: Taro has high carbohydrate content. Taro is mostly consumed in the form of fresh tubers. To increase the utilization of Taro as a carbohydrate source in food, taro tubers should be processed into flour. Therefore, understanding the characteristics of taro flour is required to be able to handle taro flour properly during production storage, packaging, and processing. The objective of this study were to examine the physical and chemical characteristics of taro flour, and to determine the consumer preference level of taro cake. The results showed that yield of taro flour was 19.7%. The density was 0.534 g/ml and launch angle was 34º. The gelatinization temperature was relatively high, at 82.9ºC, due to high content of protein that inhibits the starch gelatinization. Peak viscosity of taro flour was 2865.3 cP. Taro flour was less stable during heating, this was indicated by a high value of breakdown viscosity i.e. 1155.7 cP. Setback viscosity was 636.3 cP. The largest part of the chemical composition was carbohydrates. The energy contained in taro flour worth was 369.04 kcal per 100 g taro flour. Taro sponge cakes were made in two levels of taro flour composition, i.e. 50% and 100%. It was resulted that taste, texture, aroma, pores, color of crumb, and crust color, sponge cake of 50% taro flour was more acceptable than 100%.
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Judul: Optimasi Suhu dan Waktu Penggorengan Hampa (vacuum frying) Keripik Talas (Colocasia esculenta)
Abstrak: Taro is a carbohydrate crops potentially as subtitution of rice or for food diversification. Mentawai Islands have a great taro production. Post harvest handling of taro comonly is done by processing it into chips. Conventional frying has the disadvantage that the oil temperature is too high so it can stimulate the acrylamide compound that carsinogenic compound. One of suitable frying technology is called vacuum frying. The aim of this research were to determine the effect of temperature and frying time to physic-chemical characteristic of taro chips, to determine the best temperature and frying time, and to determine the production cost of taro chips. Taro was fried with temperature 102, 107, 112 °C and time of 25, 30, 35 minutes. Temperature and time treatment significantly influenced to physic-chemical parameters such as moisture content, carbohydrate content, hardness, and colors. The best temperature and time for frying taro chips is 112 °C for 30 minutes. The production cost of taro chips for every 100 grams is 5 750 Rupiahs
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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