Judul: Physical, Chemical, Sensory Characteristics, and Shelf Life of Tempe Chips
Abstrak: Keripik tempe merupakan salah satu bentuk diversifikasi dari pengolahan tempe sehingga produk tempe lebih awet. Di Indonesia, jenis keripik tempe yang beredar di pasaran adalah keripik tempe konvensional dan keripik tempe tapioka. Penelitian ini bertujuan membandingkan karakteristik fisik, kimia, dan sensori serta menentukan umur simpan keripik tempe yang dikemas dalam kemasan standing pouch aluminum foil. Analisis dilakukan dengan membandingkan keripik tempe produksi Rumah Tempe Azaki dengan keripik tempe komersial yang sudah beredar di pasaran yang akan dijadikan sebagai kontrol. Hasil penelitian ini menunjukkan bahwa semakin tinggi proporsi tapioka yang digunakan sebagai bahan baku, maka semakin tinggi nilai oHue, kerenyahan, kadar karbohidrat, dan penilaian panelis terhadap karakteristik sensorinya. Selain itu, semakin tinggi proporsi kedelai yang digunakan sebagai bahan baku, maka semakin tinggi kadar abu, kadar lemak, kadar protein, dan kadar serat kasar. Keripik tempe tapioka dengan perbandingan kedelai dan tapioka sebesar 50:50 (b:b) cenderung lebih disukai dari segi warna, aroma, rasa, tekstur, dan keseluruhan, sedangkan keripik tempe konvensional cenderung kurang disukai dibandingkan kontrol (komersial). Umur simpan keripik tempe tapioka dan keripik tempe konvensional ditentukan berdasarkan parameter kritis kadar asam lemak bebas. Umur simpan keripik tempe tapioka yang dikemas dalam kemasan standing pouch aluminum foil pada suhu 27 dan 30 oC berturut-turut selama 71 dan 69 hari. Umur simpan keripik tempe konvensional yang dikemas dalam kemasan standing pouch aluminum foil pada suhu 27 dan 30 oC berturut-turut selama 68 dan 66 hari, Tempe chips are one of diversification of tempe processing so that tempe products are more durable. In Indonesia, the types of tempe chips on the market are conventional tempe chips and tapioca tempe chips. This study examines to compare the physical, chemical, and sensory characteristics and determine the shelf life of tempe chips that packaged in standing pouch aluminum foil. The analysis was carried out by comparing tempe chips produced by Rumah Tempe Azaki with commercial tempe chips already sold in the market which will be used as control. The results of this study showed that the higher the proportion of tapioca used as raw material, increased oHue values, crispness, carbohydrate content, and panelists assessment of sensory characteristics. In addition, the higher the proportion of soybean used as raw material, increased the ash content, fat content, protein content, and crude fiber content. Tapioca tempe chips with a ratio of 50:50 (w:w) soybean and tapioca tend to be preferred in terms of color, aroma, taste, texture, and overall, while conventional tempe chips tend to be less favorable than control (commercials). The shelf life of tapioca tempe chips and conventional tempe chips was determined based on the critical parameter of free fatty acid content. The shelf life of tapioca tempe chips that packaged in standing pouch aluminum foil at temperatures of 27 and 30 oC was 71 and 69 days respectively. The shelf life of conventional tempe chips that packaged in standing pouch aluminum foil at a temperature of 27 and 30 oC for 68 and 66 days respectively
Keyword: fisik, keripik tempe konvensional, keripik tempe tapioka, kimia, umur simpan, physical, conventional tempe chips, chemical, shelf life, tapioca tempe chips

Judul: Physicochemical and Microbiology Changes of Beverage Powder Based on Tempe Protein Concentrate at Various Storage Temperature
Abstrak: Tempe merupakan makanan khas Indonesia yang dihasilkan melalui proses fermentasi kacang kedelai oleh kapang Rhizopus spp. Adapun upaya pengembangan produk dan diversifikasi pangan yaitu memanfaatkan tempe sebagai bahan utama dalam pembuatan serbuk minuman berbasis konsentrat protein tempe. Pengolahan tempe menjadi serbuk minuman diharapkan dapat meningkatkan konsumsi tempe dan memenuhi kebutuhan protein masyarakat. Sebuah produk pangan akan mengalami penurunan mutu seiring dengan lama waktu penyimpanan. Oleh karenanya penting untuk diketahui perubahan karakteristik fisikokimia dan mikrobiologi agar produk tetap layak dikonsumsi. Penelitian ini bertujuan untuk mengetahui perubahan mutu karakteristik fisikokimia dan mikrobiologi produk SMBKPT selama penyimpanan pada berbagai suhu. Karakteristik fisikokimia yang diuji yaitu nilai proksimat, aw, pH, aktivitas antioksidan dan derajat putih. Karakteristik mikrobiologi yang diuji yaitu total kapang dan angka lempeng total. Nilai kadar air mengalami peningkatan pada suhu penyimpanan 35⁰C dan 45⁰C, sedangkan pada suhu penyimpanan 55⁰C nilai kadar air cenderung menurun. Kandungan protein dan lemak cenderung stabil selama penyimpanan. Aktivitas antioksidan mengalami peningkatan pada suhu penyimpanan 25, 35 dan 45⁰C dan mengalami penurunan pada suhu penyimpanan 55⁰C. Nilai total kapang mengalami peningkatan pada suhu penyimpanan 25 dan 35⁰C. Selanjutnya pada parameter kadar abu, aw, pH, derajat putih, angka lempeng total mengalami penurunan pada setiap suhu penyimpanan. Kata kunci: fisikokimia, mikrobiologi, mutu pangan, serbuk minuman, tempe, Tempe is a typical Indonesian food produced through the fermentation process of soybeans by the fungus Rhizopus spp. As for product development efforts and food diversification, namely utilizing tempe as the main ingredient in the manufacture of beverage powders based on tempeh protein concentrate. Processing tempeh into beverage powder is expected to increase the consumption of tempeh and meet the protein needs of the community. A food product will experience a decrease in quality along with the length of storage time. Therefore, it is important to know the changes in physicochemical and microbiological characteristics so that the product remains fit for consumption. This study aims to determine changes in the quality of the physicochemical and microbiological characteristics of SMBKPT products during storage at various temperatures. The physicochemical characteristics tested were proximate value, aw, pH, antioxidant activity and whiteness degree. The microbiological characteristics tested were total mold and total plate count. The value of water content increased at a storage temperature of 35 and 45⁰C, while at a storage temperature of 55⁰C the value of the water content tended to decrease. Protein and fat content tends to be stable during storage. Antioxidant activity increased at storage temperatures of 25, 35 and 45⁰C and decreased at storage temperature of 55⁰C. The value of molds increased at storage temperatures of 25 and 35⁰C. Furthermore, the parameters of ash content, aw, pH, degree of whiteness, total plate number decreased at each storage temperature. Keywords: beverage powder, food quality, microbiology, physicochemical, tempe
Keyword: beverage powder, food quality, microbiology, physicochemical, tempe

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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