Judul: Physico-chemical Characteristics of Cassava Flour and Mocaf from Several Cassava Varieties
Abstrak: Singkong merupakan tanaman yang banyak dibudidayakan di Indonesia dengan beragam varietas. Tepung singkong dan tepung mokaf adalah produk intermediet dari singkong yang banyak dibutuhkan untuk keperluan Industri. Penelitian ini bertujuan mengkarakterisasi sifat fisiko-kimia tepung singkong dan tepung mokaf dari varietas lokal meliputi, UK 1 Agritan, IR Jonggol, Manalagi, Adira 4, Malang 4, dan Vati 1. Penelitian ini dilakukan dengan dua tahapan yaitu, proses pembuatan tepung singkong dan tepung mokaf dan proses analisis tepung tersebut. Metode analisis yang dilakukan antara lain kadar air, kadar abu, kadar protein, kadar lemak, kadar karbohidrat, kadar amilosa, profil gelatinisasi pati, analisi total pati, dan derajat putih. Secara keseluruhan, perbedaan varietas singkong terhadap karakteristik fisikokimia tepung yang dihasilkan menunjukkan hasil yang berbeda nyata kecuali pada kadar pati dan amilosa. Perlakuan fermentasi memberikan pengaruh yang signifikan pada karakteristik tepung yang dihasilkan pada beberapa parameter uji. Analisis kimia menunjukkan tepung mokaf dari varietas Vati 1 menghasilkan karakteristik terbaik. Sedangkan tepung singkong varietas Manalagi menghasilkan profil gelatinisasi terbaik dan tepung mokaf varietas Manalagi menghasilkan derajat putih tertinggi.
Keyword: Cassava, Physico-chemical Characteristics, Cassava Flour, Mocaf Flour, Singkong, Karakteristik Fisiko-kimia, Tepung Singkong, Tepung Mokaf

Judul: Karakterisasi dan Analisis Kluster Tepung Singkong Terfermentasi Varietas Indonesia
Abstrak: Indonesia has various types of cassava with different physicochemical characteristics. Cassava can be processed into fermented cassava flour (FCF), which is an intermediate cassava-based product used as a raw material in food industries. To enhance the database of cassava varieties in Indonesia, this study aimed to characterize the chemical composition and pasting profiles of FCF produced from 28 different Indonesian cassava varieties. The FCF samples were analyzed in terms of chemical composition (moisture, ash, protein, fat, carbohydrate, starch, amylose, amylopectin, and cyanide content) and their pasting properties (peak viscosity, hot paste viscosity, breakdown viscosity, final viscosity, setback viscosity, pasting temperature, peak time, and gel strength). The chemical composition data were subsequently analyzed using Principal Component Analysis (PCA) and Agglomerative Hierarchical Clustering (AHC). This research discovered that the 28 cassava varieties had a significant effect on moisture, ash, protein, fat, carbohydrate, starch, amylose, amylopectin, cyanide content, and gel strength (p<0.05). The highest productivity value of cassava was in UK 1. However, when combined with the FCF yield, the most efficient variety for FCF production was Barokah. The most potential cassava variety in FCF production had high cyanide and ash content that exceeded SNI. Thus, further decreasing method is needed. A decrease in ash content is needed for UK1, Darul Hidayah, Manggu Bogor, and Kubar B, while a decrease in cyanide content is needed for Barokah, Gajah B, Randu, and Genjah Bayam. Some varieties were potential for tapioca raw material, namely UK 1, Barokah, and Malang 4. The result of pasting properties showed a relatively wide range of each parameter, indicating a potential wide range of food application. The PCA of chemical composition visualized the relationships and similarities among the different cassava varieties based on their ash, starch, amylose, amylopectin, and cyanide content. Based on the same factors, three clusters of FCF were identified: the first cluster had the lowest level of ash, starch, and amylopectin content but has the highest amylose and cyanide content; the second cluster displayed demonstrated the highest ash content and the lowest cyanide content, and the last cluster exhibited the highest levels of starch, amylopectin, but intermediate ash, amylose, and cyanide content. These findings successfully identified cassava varieties with a potential application as a food ingredient., Indonesia memiliki berbagai jenis singkong dengan karakteristik fisikokimia yang berbeda-beda. Singkong dapat diolah menjadi tepung singkong terfermentasi atau fermented cassava flour (FCF) yang merupakan produk antara untuk bahan baku industri makanan. Untuk meningkatkan data varietas singkong di Indonesia, penelitian ini mengkarakterisasi komposisi kimia dan sifat pasta pada FCF yang dihasilkan dari 28 varietas singkong berbeda yang ada di Indonesia. Sampel FCF dianalisis kandungan kimianya (kadar air, abu, protein, lemak, karbohidrat, pati, amilosa, amilopektin, dan sianida) dan sifat pasta (viskositas puncak, viskositas jatuh, viskositas pasta panas, viskositas akhir, viskositas balik, suhu pasting, waktu puncak, dan kekuatan gel). Data komposisi kimia selanjutnya dianalisis menggunakan Principal Component Analysis (PCA) dan Agglomerative Hierarchical Clustering (AHC). Penelitian ini memperlihatkan bahwa 28 varietas ubi kayu berpengaruh signifikan terhadap kadar air, abu, protein, lemak, karbohidrat, pati, amilosa, amilopektin, sianida, dan kekuatan gel (p<0,05). Nilai produktivitas umbi singkong tertinggi ada di
Keyword: cassava, characterization, cluster, fermented, flour

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