Judul: Karakterisasi Produk Ekstrusi Dari Campuran Jagung, Umbi Ganyong Dan Umbi Garut
Abstrak: The objective of this study was to determine the most acceptable formulation of corn based extrusion product mixed with cowpea grits and canna flours or cowpea grits and arrowroot flours based on their chemical and physical qualities. In the first step, the ratio of corn grits with canna flours or arrowroot flours was determined. In the second step, the most acceptable mixture of corn grits and canna or arrowroot with cowpea grits were formulated. The product were analyzed in terms of chemical analyses (proximate, dietary fiber, and crude fiber) and physical analyses (degree of gelatinization, expansion ratio, crispiness, oil absorption capacity, water absorption index, water solubility index, and color). It was shown that the most acceptable ratio of corn grits with canna flours (Formula 1) or arrowroot flours (Formula 2) was 60:40 for both formulation. When the mixture was combined with cowpea grits, the acceptable ratios were 51:34:15 for Formula 1 and 57:38:5 for Formula 2. The chemical analysis showed that Formula 1 (corn grits, canna flours and cowpea grits) had high protein (8,50%), carbohydrate (81,78%), dietary fiber (19,43%), and fiber (8,31%). The physical analyses showed that the product had high degree of gelatinization (>100%), expansion ratio (505,56%), and crispiness (2167,20%). The oil absorption capacity, water absorption index, water solubility index and color of the product were 5,91 ml/g, 0,05 g/ml, 4,12 ml/g, and 52,48 (L value), respectively. The second Formula 2 (corn grits, arrowroot flours and cowpea grits) also contained high protein (7,89%), carbohydrate (82,83%), dietary fiber (9,94%), and fiber 5,37%. The degree of gelatinization, expansion ratio and crispiness of the products were >100%, 593,33%, 1733,80%, respectively. The oil absorption capacity, water absorption index, water solubility index and color of the products were 6,13 ml/g, 4,20 ml/g, 0,06 g/ml and 56,70 (L value), respectively.
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Judul: Formulation of High-Fiber Extruded Purple Sweet Potato (Ipomoea batatas L.) and Red Kidney Bean (Phaseolus vulgaris)
Abstrak: Rendahnya asupan serat pangan yang berkaitan erat dengan peningkatan risiko beragam penyakit tidak menular (PTM) masih menjadi masalah kesehatan terkait gizi pada masyarakat luas. Ubi ungu dan kacang merah merupakan pangan tinggi serat yang terjangkau dan mudah diakses di Indonesia. Penelitian ini bertujuan mengembangkan formulasi olahan ubi ungu dan kacang merah berupa ekstrudat tinggi serat. Tahapan penelitian terdiri dari optimasi formula, evaluasi sensori, uji karakteristik fisik yakni analisis warna dan tekstur, analisis proksimat, analisis serat pangan, baik larut dan tidak larut, dan analisis aktivitas air. Optimasi formula dilakukan menggunakan empat formulasi dengan perbandingan penggunaan tepung ubi ungu dan tepung kacang merah yang berbeda-beda yakni F0 (100:0), F1 (80:20), F2 (70:30), dan F3 (60:40). Ekstrudat diekstrusi pada suhu 60°C dan kecepatan ulir, umpan, serta pisau sebesar berturut-turut 45, 45, dan 50 Hz. Formula terpilih yakni formula F2 ditentukan berdasarkan hasil seluruh analisis. Satu takaran saji ekstrudat formula F2 diketahui mengandung mengandung energi, protein, lemak, karbohidrat, dan total serat pangan berturut-turut sebesar 129 kkal, 4,0 g, 0,3 g, 27,7 g, dan 6,0 g, serta memenuhi 6,0% kebutuhan energi serta 19,9% kebutuhan serat orang dewasa. Analisis aktivitas air menunjukkan bahwa formula terpilih memiliki aktivitas air sebesar 0,44%. Formula ekstrudat terpilih berpotensi memenuhi klaim sebagai pangan tinggi serat dan rendah lemak dengan umur simpan yang cukup panjang., The low intake of dietary fiber, which is closely related to the increased risks of various non-communicable diseases (NCDs), is still considered as a major health problem related to nutrition globally. Purple sweet potatoes and red kidney bean are high-fiber foods that are affordable and readily accessible in Indonesia. This research aimed to develop a formulation of high-fiber extrudate made from purple sweet potato and red kidney bean. This research was conducted through formula optimization, sensory evaluation, and analyses of color, texture, proximate, dietary fiber, and water activity. Optimization of the formula was carried out using four formulations with different ratios of purple sweet potato and red kidney bean flours, i.e. F0 (100:0), F1 (80:20), F2 (70:30), and F3 (60:40). The extrudate was extruded using a double-screw extruder at the temperature of 60°C, with the screw, feed and cutter speeds of 45, 45, and 50 Hz, respectively. The selected extrudate formula, formula F2, was determined based on the results of all analyses. A single serving of F2 extrudate was shown to contain energy, protein, fat, carbohydrates and total dietary fiber of 129 kcal, 4.0 g, 0.3 g, 27.7 g, and 6.0 g respectively, and contributes to 6.0% and 19.9% of energy and fiber needs for adults. Water activity analysis showed that the selected formula had a water activity of 0.44%. The results of all analyses showed that this extrudate was well accepted and may potentially be claimed as a high-fiber and low-fat food with long shelf life.
Keyword: analisis proksimat, makanan ekstrudat tinggi serat, kacang merah, optimasi formula, ubi ungu, formula optimisation, high-fiber extruded food, proximate analysis, purple sweet potato, red kidney bean

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