Judul: Karakteristik Kerenyahan Pilus dari Dua Tepung Tapioka
Abstrak: Quality of a product is one of the most important aspects to determine consumer’s acceptance. Final product quality closely related to the quality of raw materials used. Garudafood as one of the leading food and beverage companies in Indonesia, has pilus as its main snack product. Pilus is a fried round-shaped snack made from tapioca with a mixture of other spices, ready to be consumed as a snack or side dish companion. Pilus is supposed to has a crispy texture. Garudafood needs 2000 tons of tapioca for pilus production per month. However, this necessity could not be filled with a consistent quality of the material supply. Thus, characterise the tapioca used in production to determine the test parameters that can predict pilus crispness need to be done. The parameters tested are analysis of starch level, amylose, amylopectin, swelling power, starch gelatinization profiles, texture analyzer, and organoleptic test. Moreover, the test be repeated at each arrival tapioca to see the consistency of raw materials quality. The research showed that most relevant tests to specify pilus crispness are the ratio of amylose amylopectin and peak viscosity on starch gelatinization profiles. In addition, the data indicates that the quality of raw materials used are not consistent.
Keyword: tapioca, starch, pilus, amylose, Bogor Agricultural University (IPB)

Judul: Pembuatan Tepung Tapioka dengan Pengering Semprot dan Pengering Kabinet serta Aplikasinya pada Produk Pilus di PT Garudafood Putra Putri Jaya
Abstrak: Tapioca produced by means of modern method is not suitable for making of pilus. Pilus which is produced by using the so called “modern tapioca” will have a hard texture and not fluffy. Traditional tapioca flour is made with a long time to get a distinctive taste. However, traditional process of tapioca production could not be applied in large production scale. Therefore, experiments were conducted to produce tapioca starch of industrial scale by means of spray drying and cabinet drying process. During drying with spray dryer, three inlet temperature levels in range 140-160 °C, 170-190 °C, 200-220 °C were applied, whereas during drying with cabinet dryer, three levels of temperature in range 40-60 °C, 60-70 °C, 70-90 °C and three levels of drying time 0.75 hour, 1.5 hours, 2.5 hours were applied. The starch properties analysed were tapioca starch yield, moisture content, whiteness, fineness and gelatinization pattern of starch. The tapioca starch obtained will be applied in manufacturing of “pilus”. The characteristics of “pilus” evaluated is crispiness.
Keyword: pilus., cabinet drying, spray drying, tapioca

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