Judul: Tinjauan Sistematis: Pengaruh Garam-Garam Pengemulsi Terhadap Mutu Processed Cheese dan Processed Cheese Spread
Abstrak: Pengembangan processed cheese dilatarbelakangi oleh kebutuhan mendapatkan produk keju yang stabil pada suhu ruang dan dapat disimpan untuk waktu yang lama tanpa perubahan kualitas. Bahan-bahan yang umumnya digunakan dalam processed cheese dan processed cheese spread adalah natural cheese, air, garam pengemulsi dan bahan pilihan tertentu sesuai jenis produk. Penelitian mengenai pengaruh garam pengemulsi terhadap mutu processed cheese dan processed cheese spread masih bervariasi, sehingga perlu dilakukan tinjauan sistematis. Penelitian ini menggunakan metode telaah pustaka. Sumber pustaka kemudian diseleksi berdasarkan kriteria. Setelah melalui proses identifikasi, penyaringan dan uji kelayakan, diperoleh 12 artikel sebagai data sekunder. Hasil tinjauan menunjukkan, garam pengemulsi berpengaruh terhadap mutu processed cheese dan processed cheese spread. Garam pengemulsi bertindak sebagai penstabil yang berkontribusi dalam pengolahan processed cheese dan processed cheese spread yang lembut, homogen dan stabil secara fisik-kimia. Perubahan tersebut mencakup pergeseran dan stabilisasi pH, penyerapan kalsium dan demineralisasi kasein, hidrasi kasein, emulsifikasi lemak bebas serta perbaikan struktur. Berdasarkan keefektifan garam pengemulsi dalam melakukan berbagai perubahan fisik-kimia seperti penyerapan kalsium, penyesuaian dan stabilisasi pH, hidrasi dan dispersi kasein, kemampuan emulsifikasi, stabilitas, efek bakteriostatik dan pengaruh terhadap rasa, polyphosphate dinilai memiliki potensi terbaik. Kemampuan polyphosphate dinilai akan lebih efektif pada produk processed cheese dan processed cheese spread jika digunakan bersama dengan orthophosphate. Kata Kunci: garam pengemulsi, keju olahan, keju olahan oles, tinjauan sistematis, The development of processed cheese was motivated by the need to develop cheese-like products that were stable at ambient temperatures and could be stored for a long time without a change in quality. The ingredients generally used in processed cheese and processed cheese spread are natural cheese, water, emulsifying salts and optional ingredients that determined by the product type. Research on emulsifying salts to enhance the quality of processed cheese and processed cheese spread are still varied, so a systematic review is needed. This study uses systematic literature review method. Literature sources are the selected based on criterias. After going through identification, screening and eligibility test, 12 articles were obtained as secondary data. The results showed that emulsifying salts affects the quality of processed cheese and processed cheese spread. Emulsifying salts acts as a stabilizer which contribute to the formation of a smooth, homogeneous and physco-chemically stable processed cheese and processed cheese spread during processing. These changes include upward adjustment and buffering of the pH, calcium sequestration and casein demineralization, casein hydration, emulsification of free fat and structure formation. Based on the effectiveness of emulsifying salts in promoting various physic-chemical changes such as calcium sequestration, adjument and buffering of pH, hydration and dispersion of casein, ability to promote emulsification, stability, bacteriostatic effects and flavor effects, polyphosphates is considered to have the highest potential, this generally requires that polyphosphates are used in conjuction with orthophosphates for this influence to be manifested. Key Words: emulsifying salt, systematic review, processed cheese, processed cheese spread
Keyword: emulsifying salt, systematic review, processed cheese, processed cheese spread

Judul: Pengaruh penambahan garam kalsium dalam pembuatan keju cottage yang dibuat dengan metode pengasaman langsung menggunakan asam laktat
Abstrak: Terbatasnya ketersediaan rennet sapi sebagai koagulan utama dalam pembuatan keju mendorong untuk mencari alternatif sumber koagulan lain. Salah satu alternatif pemecahannya adalah dengan menggunakan koagulan asam secara langsung dalam pembuatan keju. Keju yang dibuat dengan metode pengasaman langsung menghasilkan curd yang rapuh dan mudah pecah (Scott, 1981). Sementara itu penambahan garam kalsium pada pembuatan keju, baik secara enzimatis maupun menggunakan asam, biasa dilakukan untuk memperbaiki tekstur. Oleh sebab itu dalam penelitian ini dilakukan percobaan untuk mengetahui pengaruh penambahan garam kalsium dalam pembuatan keju cottage yang dibuat dengan metode pengasaman langsung menggunakan asam laktat. Perlakuan yang diberikan meliputi (A) jenis garam kalsium, yaitu kalsium laktat, kalsium fosfat, kalsium klorida, dan kalsium karbonat, (B) konsentrasi garam kalsium, yaitu 0 (kontrol), 0.005, 0.010, dan 0.015%, dan (C) nilai pH koagulasi yaitu 4.6 dan 5.2. Keju yang dihasilkan dihitung rendemennya dan dianalisis kadar air (AOAC, 1984), kadar abu (AOAC, 1984), nilai pH (AOAC, 1970), total asam (Newlander, 1949), serta dilakukan uji organoleptik (Soekarto, 1985) yakni uji hedonik, meliputi parameter warna, rasa, aroma, tekstur, dan uji perbandingan jamak, meliputi parameter rasa dan tekstur.
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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.
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