Judul: Kualitas Dadih Susu Sapi Berkalori Rendah yang Diperkaya Jamur Shiitake Bubuk sebagai Sumber Serat
Abstrak: Dadih merupakan bahan pangan tradisional hasil fermentasi alami susu kerbau dari Sumatera Barat. Modifikasi pengolahan dadih yang berbasis susu sapi rendah kalori dan penambahan jamur shiitake bubuk, diharapkan dapat meningkatkan kualitas dadih terutama serat makanan yang dihasilkan dan meningkatkan nilai guna sebagai pangan fungsional. Penelitian ini bertujuan untuk mempelajari penambahan jamur shiitake bubuk pada pembuatan dadih terhadap kualitas nutrisi khususnya serat makanan dadih yang dihasilkan. Penelitian ini dilakukan dalam dua tahap, yaitu persiapan penelitian dan penelitian utama. Persiapan penelitian meliputi identifikasi jamur shiitake, pembuatan jamur shiitake bubuk dan analisis nutrisi jamur shiitake bubuk. Penelitian utama meliputi analisis fisik, kimia, mikrobiologi serta uji organoleptik. Bahan baku berupa susu sapi berkalori rendah dipanaskan hingga penguapan 50% pada suhu 80- 90°C dan didinginkan sampai suhu 37 °C kemudian diinokulasi dengan starter Lactobacillus plantarum (4%) selama 6-8 jam pada suhu 37 °C di dalam inkubator. Penambahan jamur shiitake bubuk dilakukan diawal proses pemanasan dengan konsentarsi penambahan 1%, 2%, 3% (g/v) dan tanpa penambahan jamur shiitake bubuk sebagai kontrol. Parameter yang diamati meliputi waktu koagulasi, nilai pH, total asam tertitrasi, kadar air, kadar abu, kadar lemak, kadar protein, kadar karbohidrat, kadar laktosa, viskositas, kadar serat makanan tidak larut, kadar serat makanan larut dan total serat makanan serta uji organoleptik. Rancangan percobaan yang dilakukan adalah rancangan acak lengkap pola searah dengan tiga kali ulangan untuk mempelajari pengaruh perlakuan terhadap karakteristik fisik dan kimia dadih yang dihasilkan. Hasil penelitian menunjukkan bahwa waktu koagulasi dadih yang ditambahkan jamur shiitake bubuk berkisar 6-7 jam lebih cepat daripada dadih tanpa penambahan jamur shiitake bubuk (7 jam 40 menit). Penambahan jamur shiitake bubuk tidak mempengaruhi nilai pH, total asam tertitrasi, kadar air, kadar abu, kadar protein, kadar lemak dan kadar karbohidrat tetapi penambahan jamur shiitake bubuk memberikan pengaruh terhadap kadar viskositas (P<0,05). Kadar laktosa, serat makanan larut, kadar serat makanan tidak larut dan kadar total serat makanan dadih yang dihasilkan sangat dipengaruhi (P<0,01) oleh penambahan jamur shiitake bubuk. Penambahan jamur shiitake bubuk juga berpengaruh (P<0,01) terhadap tingkat kesukaan pauclis untuk aroma, rasa, warna dan tekstur dadih yang dihasilkan. Tingkat kesukaan panelis dari dadih yang mengalami penambahan jamur shiitake bubuk menyatakan kisaran suka sampai netral terhadap kriteria warna dan aroma sedangkan tingkat kesukaan panelis terhadap rasa dan tekstur dalam kisaran suka sampai agak tidak suka. Uji deskripsi menunjukkan bahwa intensitas warna dadih yang paling tinggi adalah dadih tanpa penambahan jamur shiitake bubuk. Aroma dadih cenderung memberikan aroma khas jamur shiitake bubuk, semakin tinggi konsentr asi penambahan jamur shiitake bubuk maka aroma jamur shiitake bubuk semakin tajam. Tekstur dadih yang paling lembut adalah tekstur dadih tanpa penambahan jamur shiitake bubuk. Semakin tinggi penambahan jamur shiitake bubuk maka tekstur dadih semakin kasar. Dadih tanpa penambahan jamur shiitake bubuk juga mempunyai intensitas rasa manis dan asam yang paling tinggi. Penambahan jamur shiitake bubuk cenderung meningkatkan rasa pa.hit pada dadih. Dadih dengan konsentrasi jamur shiitake bubuk 3% mempunyai intensitas rasa pa.hit yang paling tinggi. Kekentalan dadih juga sernakin tinggi dengan semakin meningkatnya konsentrasi penambahan jamur shiitake bubuk dengan intensitas kekentalan paling tinggi adalah dadih dengan penambahan 3% jarnur shiitake bubuk. Kesimpulan dari penelitian ini adalah penambahan jamur shiitake
Keyword: dadih, jamur shiitake bubuk, susu berkalori rendah, serat makanan

Judul: Pengaruh Penambahan Bahan Pengental terhadap Kualitas Dadih Susu Sapi dengan Starter Lactobacillus casei.
Abstrak: Dadih is one of the fermented milk products from West Sumatra, Indonesia, and made by fermenting buffalo milk naturally in the bamboo for 48 hours. Limited of raw materials and inconsistency product make dadih difficult to be developed. Improving of process and adding thickening agent hopefully can increase quality of dadih so it will be able to be accepted by people and become one of functional industrial food product that could be commercialized. This study aims to study the influence of thickening agent for quality of dadih and to decide the correct type and concentration of thickening agent. The design of study used completely randomized design factorial, consisted of two factors; they were the type and concentration thickening agent. There are two types of thickening agent, are gelling agent and non gelling agent. The treatment with Gelling Agent was used seaweed and pectin with concentration 0,10%, 0,15%, and 0,20% while the treatment with non gelling agent was used CMC and Arabic Gum with concentration 0,6%, 0,8%, and 1,0%. Parameter of Research were Physical–chemistry analysis which included moisture content, carbohydrate content, protein content, pH, acidity total, and viscosity; microbiology included total plate count bacteria; and organoleptic included hedonic test, same/different test and ranking test. Based on physical-chemistry analysis and microbiologiy of dadih the addition of Thickening Agent and concentration did not give the different result. While, t-test, which used thickening agent with gelling agent and non-gelling agent did not give the different result. Based on hedonic test, the addition of thickening agent gave different result. Panelist graded that adding pectin 0,1% gave better color while they prefer dadih with pectin 0,1% for the flavor. The most delicious of taste were dadih with pectin 0,15%, while dadih with pectin 0,2% gave the best texture by panelist. In generally, dadih with pectin 0,1% more preferable than the other treatments. Based on chi–square test list, organoleptic testing with the same/different test and ranking test showed the result was not different (P>0,05). In the same and different test, dadih with adding thickening agent with gelling agent and non-gelling agent gave the different result with the real dadih. While ranking test showed that dadih with pectin 0,2% gave the best response from panelist was compared the other treatments. From the result of this study it could be concluded that dadih from cow milk with the addition of the pectin thickening agent 0,2% gave the best result than the other treatments in process for making dadih cow milk.
Keyword: 

Judul: Hamiltonian formulation for linear waves motion in two layers fluid
Abstrak: The surface wave could be considered as a wave that separates two fluids, namely water and air. Based on this assumption, it is introduced the interfacial wave, a wave between two layers of fluid with different density. The formulation of interfacial waves motion begins with deriving the base equation of irrotational ideal fluid. Furthermore, according to irrotational fluid assumption, the base equation can be stated in velocity potential. In this derivation, the fluids domain is assumed to be restricted by rigid lid boundary conditions, both at the upper and lower limit. Therefore, the interfacial waves motion can be explained in a hamiltonian formulation. In the hamiltonian formulation, total energy is defined as the sum of kinetic and potential energy. The hamiltonian system is obtained from reduction of kinetic energy by using the Dirichlet Neumann Operator. The resulted kinetic energy equation is nonlinear. Therefore, this form is linearized by first part of the Taylor expansion. This linearization gives a dispersion relation of linear wave. Based on this dispersion relation, the phase speed of the linear wave depends on the density ratio of the two layers fluid.
Keyword: