Judul: Karakterisasi Komponen Aroma Aktif Pada Belimbing Wuluh (Averrhoa Bilimbi L.) Dan Produk Fermentasinya
Abstrak: Indonesia memiliki kekayaan alam yang berlimpah ruah. Aceh salah satu provinsi di Indonesia yang terletak diujung utara Pulau Sumatra memiliki bumbu tradisional yang dikenal dengan nama asam sunti. Asam sunti banyak digunakan dalam kuliner Aceh karena rasa dan aromanya yang khas. Asam sunti terbuat dari belimbing wuluh (Averrhoa bilimbi L.) yang dijemur, diberi garam, dan dibiarkan mengalami fermentasi secara spontan. Penelitian ini merupakan penelitian pertama yang mengkaji mengenai komponen aroma aktif pada belimbing wuluh dan asam sunti. Tahapan penelitian ini terdiri dari: penentuan sampel yang representatif; karakterisasi secara fisik, kimia, dan sensori; analisis komponen volatil menggunakan gas kromatografi-spektroskopi massa (GC-MS); analisis komponen aroma aktif dengan gas kromatografi-olfaktometri (GC-O) dan perhitungan odor active value (OAV); dan rekonstitusi komponen aroma aktif menggunakan senyawa standar. Belimbing wuluh yang digunakan dalam penelitian ini memiliki warna hijau, tekstur keras, dan tidak bercacat. Asam sunti yang digunakan dalam penelitian ini memiliki rasa asam dan asin yang dominan, aroma asam, berwarna coklat, berbentuk oval pipih, dan tidak berjamur. Pengukuran karakteristik fisik menunjukkan belimbing wuluh memiliki nilai kecerahan yang lebih tinggi dibandingkan asam sunti. Belimbing wuluh memiliki warna dominan kuning dan hijau, sedangkan asam sunti memiliki warna dominan kuning dan merah. Analisis proksimat menunjukkan belimbing wuluh memiliki 94.78% kadar air, 0.35% lemak, 1.37% protein, 0.30% abu, dan 3.19% karbohidrat. Asam sunti memiliki 62.16% kadar air, 1.27% lemak, 4.24% protein, 11.38% abu, dan 20.94% karbohidrat. Analisis sensori QDA dengan 10 panelis terlatih menyimpulkan bahwa belimbing wuluh memiliki aroma green yang lebih kuat dari asam sunti secara signifikan, sedangkan asam sunti memiliki aroma rancid dan rasa asin yang lebih kuat dari belimbing wuluh secara signifikan. Hasil analisis GC-MS menunjukkan belimbing wuluh terdeteksi memiliki 35 komponen volatil, sedangkan asam sunti memiliki 82 komponen volatil. Analisis GC-O menunjukkan 4 komponen aroma aktif untuk belimbing wuluh dan 22 komponen aroma aktif untuk asam sunti. Alpha-pinena (OAV=3.33) dan etil (2E)-3-(4-hidroksi-3-metoksifenil)-2- propenoat (OAV=2) merupakan komponen volatil yang berperan dalam pembentukan aroma belimbing wuluh. (E)-2-tetradekanal (OAV=49000), (E,Z)- 2,4-dekadienal (OAV=18428), nonanal (OAV=4850), metil isoheksadekanoat (OAV=3970), alpha-metil ionon (OAV=1301), (E)-2-oktenol (OAV=1040), etil benzoat (OAV=17.33), asam pentanoat(OAV=14), asam heptadekanoat (OAV=3.39), vanilin (OAV=3.35), asam 2-furankarboksilat (OAV=1.15), dan asam dekanedioat (OAV=1.13) merupakan komponen volatil yang berperan dalam pembentukan aroma pada asam sunti. Asam sunti memiliki komponen volatil yang lebih kompleks serta membentuk aroma yang lebih kuat dibandingkan dengan belimbing wuluh.
Keyword: asam sunti, belimbing wuluh, bumbu, komponen aroma aktif, OAV

Judul: Kajian Pembuatan Bubuk Asam Sunti dari Belimbing Wuluh (Averrhoa bilimbi. L) Menggunakan Alat Pengering Kabut (Spray Dryer)
Abstrak: Asam sunti is a kind of unique and popular seasoning in tradisional food that made of the dried “wuluh” starfruit. Recently, asam sunti become popular widely, not limited only in Aceh, therefore it is need to produce asam sunti in powder form such as tumeric powder, pepper, chili and some other spices. The problems in making asam sunti powder is the lack of quality standards of semi-wet asam sunti to be the raw material for powder asam sunti. The quality of wet asam sunti is greatly influenced by the level of ripeness of “wuluh” starfruit and its moisture content. Hence necessary to study the influence of fruit maturity level and mechanically drying temperature to produce of a semi-wet asam sunti which is the raw material of powder asam sunti. The purpose of this research is to determine a maturity level of fruit and the best drying temperature to produce semi-wet asam sunti and then to define of spray dryer temperature and addition of dextrin to produce asam sunti powder that meet with consumer preferences. The study was began by measuring the physicochemical properties of “wuluh” starfruit at three levels of maturity fruit, with parameter of color, size, firmness, total acid, and oxalic acid as the preliminary data from fresh sampel. The second stage of research was done to determine of drying time based on the final moisture content which is close with the moisture content of the control sampel (asam sunti from Aceh). The third stage of research was done to perform drying process of “wuluh” starfruit using a cabinet dryer with drying time based on the results of the second stage, and follow by the last stage to study of producing asam sunti powder using a spray dryer. The best semi-wet asam sunti according to consumers’ preferences are made from a half-mature starfruit (green-yellow) with the drying temperature 50 °C for 8 hours, where it has total acid 37.80%, oxalic acid 4.76% and will perform a rendemen of 50.74%. After that, semi-wet asam sunti is processed into asam sunti powder. The best asam sunti powder which is based on consumer preferences is combination of addition dextrin 30%, drying temperature 180 °C, and will produce the products with moisture content 5.14%, total acid 48.40%, oxalic acid 6.10%, and rendemen 11.28%. Meanwhile, when the local asam sunti is used as raw material for asam sunti powder, the best result based on consumer preferences should be produced by add 30% of dextrin with drying temperature of 170°C.
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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