Judul: Physicochemical Characterization of Starch from Several Types of Tubers
Abstrak: Salah satu tanaman alternatif sumber karbohidrat berasal dari tanaman umbi-umbian. Pati merupakan sumber karbohidrat terbesar pada tanaman. Tujuan dari penelitian ini adalah mempelajari karakteristik fisikokimia pati dari beberapa jenis umbi, seperti singkong, ubi jalar, talas bogor, talas beneng, dan anuwun sehingga dapat diketahui potensi pemanfaatannya. Karakterisasi fisikokimia yang dilakukan pada penelitian ini yaitu analisis proksimat, kadar pati, amilosa dan amilopektin, serat kasar, bentuk dan ukuran granula pati, kristalinitas pati, profil gelatinisasi pati, dan kestabilan panas pati. Kelima jenis pati umbi memiliki kadar pati basis kering yang tinggi, seperti pati singkong yaitu 96,04%; ubi jalar yaitu 89,98%; talas bogor yaitu 89,86%; talas beneng yaitu 87,45%; dan anuwun yaitu 90,11%. Kadar amilosa basis kering pati singkong yaitu 35,45%; ubi jalar yaitu 36,88%; talas bogor yaitu 15,33%; talas beneng yaitu 27,15%; dan anuwun yaitu 32,84%. Kelima jenis pati umbi memiliki kadar serat kasar basis kering yang rendah. Pati singkong, ubi jalar, dan anuwun memiliki bentuk granula hampir bulat dan berukuran sedang. Sementara itu pati talas bogor dan talas beneng memiliki bentuk poligonal dan berukuran kecil. Kelima jenis pati memiliki profil gelatinisasi pati tipe A dan kristalinitas pati tipe A. Kristalinitas pati singkong yaitu sebesar 10,21%; ubi jalar yaitu 10,92%; talas bogor yaitu 12,89%; talas beneng yaitu 12,86%; dan anuwun yaitu 10,14%. Analisis kestabilan panas dari kelima jenis pati menunjukkan puncak endotermik sekitar 59,45 – 66,89°C dan entalpi transisi sekitar 145,4284 - 191,8308 J/g. Berdasarkan analisis multivariat menggunakan Principle Component Analysis (PCA) pati singkong dan pati ubi jalar memiliki karakteristik fisikokimia yang mirip. Sementara itu pati talas bogor, talas beneng, dan anuwun memiliki karakteristik fisikokimia yang berbeda., One of the alternative sources of carbohydrates comes from root crops. Starch is the largest source of carbohydrates in plants. The purpose of this study was to study the physicochemical characteristics of starch from several types of tubers, such as cassava, sweet potato, bogor taro, beneng taro, and anuwun so that their potential utilization can be identified. The physicochemical characterizations carried out in this study were proximate analysis, starch content, amylose and amylopectin, crude fiber, starch granule shape and size, starch gelatinization profile, starch heat stability, and starch crystallinity. The five types of tuber starch have high dry base starch content, such as cassava starch which is 96.04%; sweet potato is 89.98%; taro bogor is 89.86%; taro beneng is 87.45%; and anuwun is 90.11%. The dry base amylose content of cassava starch was 35.45%; sweet potato is 36.88%; taro bogor is 15.33%; taro beneng is 27.15%; and anuwun is 32.84%. The five types of tuber starch have low dry base crude fiber content. Cassava, sweet potato, and anuwun starch have almost round granule shape and medium size. Meanwhile, bogor taro and beneng taro strach have a polygonal shape and are small in size. The five types of starch have a starch gelatinization profile type A and starch crystallinity type A. The crystallinity of cassava starch was 10.21%; sweet potato is 10.92%; taro bogor that is 12.89%; taro beneng is 12.86%; and anuwun is 10.14%. Heat stability analysis of the five types of starch showed endothermic peaks around 59.45 –
Keyword: Karakteristik fisikokimia, Pati, Principle Component Analysis (PCA), Physicochemical characteristics, Principle Component Analysis (PCA), starch

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: A Continuous Vaccination Strategy in the SVIR Epidemic Model
Abstrak: Vaccination is conducted to minimize the spread of a disease. The vaccination is usually done several times within a fixed time interval. In the SVIR model, it is assumed that individuals do not get immediate immunity following a vaccination program. So according to process of vaccination on SVIR model, there are two strategies, i.e. the continuous vaccination strategy (CVS) and the pulse vaccination strategy (PVS). In this study, only the CVS strategy in epidemic model SVIR is considered. Results of the study indicate that dynamics of the CVS system depends on the basic reproductive number. If the basic reproductive number is less than one, then the disease-free fixed point is asymptotically stable. It means that the disease will eventually disappear from the population. Conversely, if the basic reproductive number is greater than one, then the endemic fixed point is asymptotically stable, which means that the disease will remain exist in the population. Simulation result shows that the vaccination would minimize the spread of disease by reducing the basic reproductive number. If the time for the vaccinated recipients to obtain the immunity, as well as a possibility of vaccinated recipients to be infected are neglected, then the disease will be eradicated. This condition is called an over-evaluating effect of vaccination.
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