Judul: Formulation and Characterization of Rice Analog Porang (Amorphophallus muelleri) with the Addition of Spirulina platensis
Abstrak: Konsumsi beras di Indonesia selalu meningkat setiap tahunnya sehingga dapat menyebabkan krisis pangan bahan pokok, untuk itu dilakukan pembuatan beras analog yang memanfaatkan umbi porang sebagai alternatif penggunaan beras padi. Penambahan Spirulina platensis pada beras analog diharapkan mampu meningkatkan kandungan gizi dan komponen bioaktif. Penelitian ini bertujuan menentukan karakteristik fisik, proksimat, fitokimia, dan aktivitas antioksidan dalam beras analog porang spirulina. Rancangan Acak Lengkap (RAL) digunakan dengan perlakuan empat konsentrasi penambahan Spirulina platensis (0%, 1,5%, 3%, dan 4,5%). Beras analog porang spirulina yang terpilih adalah beras analog porang dengan penambahan S. platensis 1,5% memiliki kandungan karbohidrat 39,6%, protein 1,17%, dan serat pangan 24,5%. Aktivitas antioksidan beras analog porang spirulina 1,5% tergolong kuat setelah diolah menjadi nasi dengan nilai IC50 sebesar 38,96 ??g/mL., Rice consumption in Indonesia always increases every year, which can cause a food crisis for the staple food, for this reason, analog rice is being made which uses porang tubers as an alternative to paddy rice. The adding of Spirulina platensis to analog rice is expected to increase the nutritional content and bioactive components. This research aims to determine the physical, proximate, phytochemical characteristics and antioxidant activity of porang spirulina analog rice. A Completely Randomized Design (CRD) was used with four additional concentrations of Spirulina platensis (0%, 1.5%, 3%, and 4.5%). The selected porang spirulina analog rice is porang analog rice with the addition of 1.5% Spirulina platensis which has a carbohydrate content of 39.6%, protein 1.17% and dietary fiber 24.5%. The antioxidant activity of 1.5% porang spirulina analog rice is classified as strong after being processed into rice with an IC50 value of 38.96 ??g/mL.
Keyword: antioxidant activity, dietary fiber, porang, analog, potato starch

Judul: Formulation and Characterization of Analogue Rice made of Sweet Potato (Ipomoea batatas), Sago Starch (Metroxylon sp), and Maize Flour (Zea mays)
Abstrak: Rice as the main carbohydrate source in Indonesia has created an unavoidable dependency. Constraints in consuming other carbohydrate sources are caused by unavailability of easy processed product, lack of nutrition knowledge and psychological readiness, and also lack of food product that can fulfill people’s taste. Therefore, food diversification needs a precise means so it can be consumed as staple food. Analogue rice is artificial rice made of non-rice and non-wheat raw material using twin screw extruder. Analogue rice made of sweet potato, sago starch, and maize flour has been formulated and characterized using hedonic test and physicochemical analysis. This analogue rice excellences are using low-processed sweet potato roots as one of the main ingredient, which consume less energy and consequently lower production cost, and high in thiamin, riboflavin, niacin, K, P, Fe, and Ca 2-3 times than polished rice from the combination of sweet potato, sago starch, and maize flour. The formulation for sweet potato pulp: sago starch: maize flour was 3: 1.5: 2.5. The analogue rice processing used cooking twin screw extruder at , furthermore its chemical compositions were examined. The result showed that the analogue rice contains 82.61% of carbohydrate, 0.83 ± 0.01 % of fat, 4.60 ± 0.16 % of protein, 10.26 ± 0.76 % of moisture, and 0.83 ± 0.02 % of ash. Addition of 0.1 % gelling agent hydrocolloid (alginate, carrageenan, konjac) improved the texture quality with carrageenan 0.1% decreased the hardness also konjac 0.1% increased the stickiness, however did not improve the hydration properties of analogue rice.
Keyword: gelling agent hydrocolloid, sago starch, sweet potato, analogue rice

Judul: Bifurkasi Hopf pada Model Siklus Bisnis Kaldor Kalecki tanpa dan dengan Waktu Tunda
Abstrak: Business cycle model is one of dynamical system models in economic. One of the business cycles model is Kaldor-Kalecki model. Kaldor-Kalecki business cycle model that is written in delayed defferential equations, is a business cycle model that involves gross product and capital stock of a company. In this paper Kaldor-Kalecki business cycle model is analyzed using both nondelay and delay in time of capital stock. By Taylor expansion for the time delayed model, an analysis of stability around the fixed points has been done. Furthermore, by using Hopf bifurcation theorem, it can be shown that there exists periodic orbits and limit cycle. In the nondelayed model, changing the parameter of goods market could lead to the occurrence of Hopf bifurcation and the existence of limit cycle. Similarly, for the delayed model, it has been shown that changing the time delay parameter may result in the occurrence of Hopf bifurcation and limit cycle.
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