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: Perbaikan Stabilitas Mutu Keju Cheddar Olahan Blok
Melalui Kombinasi Garam Pengemulsi di PT XYZ
Abstrak: Keju cheddar olahan blok adalah salah satu produk pengembangan keju natural dengan tambahan bahan lain. Emulsi oil in water pada keju olahan dapat mengalami destabilisasi. Fraksi olein keluar dari matriks kasein keju sehingga permukaan keju menjadi greasy dan oily. Dibutuhkan kombinasi garam pengemulsi yang tepat untuk meminimalisir oiling off. Tujuan penelitian ini ialah menentukan jenis dan jumlah garam pengemulsi serta mengamati pengaruh reformulasi terhadap fisikokimia keju. Variabel bebas penelitian ini ialah jumlah disodium phosphate (DSP), sodium hexametaphosphate (SHMP), dan trisodium citrate (TSC) dengan variabel terikat meliputi kadar air, lemak, protein, garam, pH, kekerasan, dan oil separation index. Optimalisasi formula dilakukan menggunakan response surface methodology (RSM) dengan Design Expert 13 dan analisis data melalui ANOVA. Hasil penelitian menunjukkan bahwa penggunaan garam pengemulsi tunggal menghasilkan produk keju dengan oil separation index tertinggi hingga terendah secara berturut-turut ialah DSP (3,3495%), SHMP (1,3171%), dan TSC (0,56245%). Berdasarkan verifikasi, formula optimum 2 dengan kombinasi DSP (12,3014 g), SHMP (4,3706 g), dan TSC (13,328 g) serta nilai desirability 0,204 berhasil meminimalisir oiling off dari 1,7838% menjadi 0,785446%. Oil separation index dikaitkan dengan kemampuan garam pengemulsi dalam mengkelat kalsium. Formula optimum ini memiliki kadar air 44,7483%, lemak 23,7%, protein 4,002%, garam 1,8472%, pH 5,70, dan kekerasan 627,998 N., Block processed cheddar cheese is a product of developing natural cheese with the addition of other ingredients. Oil in water emulsions in processed cheese can experience destabilization. The olein fraction comes out of the cheese casein matrix so that the surface of the cheese becomes greasy and oily. The right combination of emulsifying salts is needed to minimize oiling off. The aim of this research is to determine the type and amount of emulsifying salt and observe the effect of reformulation on the physicochemistry of cheese. The independent variables of this research are the amount of disodium phosphate (DSP), sodium hexametaphosphate (SHMP), and trisodium citrate (TSC) with the dependent variables including water content, fat, protein, salt, pH, hardness, and oil separation index. Formula optimization was carried out using response surface methodology (RSM) with Design Expert 13 and data analysis via ANOVA. The results of the research show that the use of a single emulsifying salt produces cheese products with the highest to lowest oil separation index respectively, namely DSP (3,3495%), SHMP (1,3171%), and TSC (0,56245%). Based on verification, optimum formula 2 with a combination of DSP (12,3014 g), SHMP (4,3706 g), and TSC (13,328 g) and a desirability value of 0,204 succeeded in minimizing oiling off from 1,7838% to 0,785446%. Oil separation index is associated with the ability of emulsifying salts to chelate calcium. This optimum formula has a water content of 44,7483%, fat 23,7%, protein 4,002%, salt 1,8472%, pH 5,70, and hardness 627,998 N.
Keyword: keju olahan, emulsi, garam pengemulsi, kasein, oiling off, casein, emulsion, emulsifying salt, processed cheese

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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