Judul: Optimasi Preferensi Sensori  dan Kekenyalan Plant-Protein Substitute Nugget Berbasis Tempe Edamame (Glycine Max (L.) Merrill)
Abstrak: Produk Plant-Protein Substitute Nugget (PPSN) berbasis tempe edamame ditujukan untuk menggantikan penggunaan kedelai impor. PPSN kedelai memiliki preferensi sensori yang baik namun teksturnya kurang kenyal. Penelitian ini bertujuan untuk memperoleh formula optimum pada nugget ayam dengan substitusi tempe edamame yang secara preferensi sensori dan kekenyalan baik. Optimasi formula dilakukan menggunakan mixture design pada piranti lunak Design Expert 13.0®. Variabel bebas yang digunakan adalah daging ayam dan tempe edamame. Respon pada proses optimasi adalah warna, aroma, rasa, tekstur, overall, nilai warna (CIE L*a*b*), kekenyalan, dan WHC (expressible water). Hasil penelitian berhasil memperoleh PPSN dengan nilai preferensi keseluruhan setara dalam nilai PPSN tempe kedelai, dan nilai kekenyalan lebih baik. Komposisi formula optimum adalah daging ayam 34% dan tempe edamame 26% dengan nilai desirability sebesar 86,1%. Formula optimum memiliki nilai rating hedonik pada atribut warna sebesar 5,8, aroma 5,9, rasa 5,6, tekstur 5,2, overall 5,6, L* 65,94, a* -1,89, b* 29,40, kekenyalan 0,6861, dan expressible water sebesar 5,6219. Atribut sensori aroma, nugget tempe edamame formula optimum memiliki kesukaan yang lebih baik daripada nugget tempe kedelai sedangkan pada atribut sensori warna, rasa, tekstur, dan overall tidak ada perbedaan signifikan diantara keduanya. Nilai kekenyalan dan WHC nugget tempe edamame formula optimum lebih baik daripada nugget tempe kedelai., Edamame Tempe-based Plant-Protein Substitute Nugget (PPSN) has been developed to replace the soy-tempe PPSN. The sensory preference of the Soy-Tempe PPSN is good, but the texture is less chewy than the chicken nugget. Tempe edamame nuggets were developed to replace soy tempe in PPSN products. This study aims to obtain the optimum formula for chicken nuggets substituted with edamame tempe, which can successfully replace soy tempe in tempe nugget products based on sensory preference and chewiness. Formula optimization was done using a mixture design on Design Expert 13.0® software. The independent variables used were chicken meat and edamame tempeh. Responses to the optimization process are color, aroma, taste, texture, overall sensory acceptance, color value (CIE L*a*b*), elasticity, and WHC (expressible water). This research has successfully replaced the soy-tempe with the edamame-tempe. The optimum formula composition is 34% chicken meat and 26% edamame tempeh, with a desirability value of 86.1%. The optimum formula has a hedonic rating value on the color attribute of 5.8, aroma 5.9, taste 5.6, texture 5.2, overall 5.6, L* 65.94, a* -1.89, b* 29 .40, elasticity 0.6861, and expressible water 5.6219. On the sensory attributes of aroma, the optimum formula edamame tempe nuggets have a better preference than soybean tempe nuggets, while on the sensory attributes of color, taste, texture, and overall there is no significant difference between the two. The optimum formula elasticity and WHC values of edamame tempeh nuggets were better than soybean tempeh nuggets.
Keyword: edamame, formula optimization, nuggets, sensory preference, soybeans

Judul: Quality Development of Tempe that Made from Cowpeas and Soybeans
Abstrak: Tempe merupakan pangan tradisional Indonesia yang umumnya terbuat dari kedelai yang difermentasi oleh kapang Rhizopus spp. Indonesia memiliki ketergantungan terhadap kedelai impor yang cukup tinggi. Penggunaan kacang tunggak (Vigna unguiculata) sebagai bahan baku tempe akan mengurangi impor kedelai dan mendukung diversifikasi pangan. Penelitian ini bertujuan untuk menghasilkan formula optimum tempe kombinasi kacang tunggak dan kedelai dengan parameter mutu yang setara dengan tempe kedelai (golden standard). Optimasi formula dilakukan berdasarkan rancangan response surface methodology menggunakan program aplikasi lunak Design Expert 12. Rekomendasi formula optimum yaitu kombinasi kacang tunggak 30% dan kedelai 70% dengan nilai desirability 0,87. Formulasi optimum bahan baku tersebut menghasilkan tempe dengan nilai L (tingkat kecerahan)= 77,01, a (merah-hijau)= 0,55, b (kuning-biru)= 12,55, kekerasan = 12,62 Kgf, aktivitas air= 0,99, dan pH= 6,16. Komposisi proksimat tempe kombinasi optimum memenuhi mutu SNI 3144:2015, yaitu kadar air 60,28, abu 0,64, lemak 11,67, protein 17,67, dan karbohidrat 10,28 %bb. Uji sensori rating hedonik mengggunakan skala 1-7 (sangat tidak suka-sangat suka) pada tempe segar kombinasi optimum menghasilkan skor atribut warna= 4,38, aroma= 4,89, tekstur= 4,81, dan overall= 5,02, sedangkan pada tempe goreng menghasilkan skor atribut warna= 4,38, aroma= 5,34, tekstur= 4,91, rasa= 5,09, dan overall= 5,02., Tempe is a traditional Indonesian food which is generally made from soybeans fermented by Rhizopus spp. Indonesia has a high dependence on imported soybeans. The use of cowpeas (Vigna unguiculata) as a raw material for tempe will reduce soybean imports and support food diversification. This study aims to produce the optimum formula for tempe combination of cowpeas and soybeans with quality parameters equivalent to soybean tempe (golden standard). The optimization of the formula was carried out based on the response surface methodology design using the Design Expert 12 software application. The recommended optimum formula is a combination of 30% cowpea and 70% soybean with a desirability value of 0,87. The optimum formulation of these raw materials produces tempe with a value of L (brightness level)= 77,01, a (red-green)= 0,55, b (yellow-blue)= 12,55, hardness= 12,62 Kgf, water activity= 0,99, and pH= 6,16. The proximate compositions of the optimum combination tempe qualify SNI 3144:2015, which are water content 60,28, ash 0,64, fat 11,67, protein 17,67, and carbohydrates 10,28 %ww. Sensory rating hedonic test using 1-7(very dislike – very much like) scale. The optimum combination of fresh tempe results in a color attribute score= 4,38, aroma= 4,89, texture= 4,81, and overall= 5,02, while fried tempe results in a color attribute score= 4,38, aroma= 5,34, texture= 4,91, taste= 5,09, and overall= 5,02.
Keyword: design expert, kacang tunggak, kedelai, optimasi formula, tempe, cowpea, soybean, formula optimization

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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