Judul: Pengaruh Aplikasi Edible Coating dengan Penambahan Carboxymethyl Cellulose (CMC) pada Pisang Barangan (Musa acuminata L)
Abstrak: Pisang memiliki kandungan vitamin C yang cukup tinggi. Gas etilen yang membuat proses oksidasi menjadi cepat itu perlu dikontrol agar daya simpan dan umur buah bisa menjadi lebih lama hingga sampai ke tangan konsumen. Edible coating bertindak sebagai lapisan ekstra yang melapisi stomata yang mengarah pada pengurangan transpirasi. Untuk meningkatkan kekuatan serta perbaikan struktur permukaan edible coating yaitu ditambahkan CMC (Carboxymethyl Cellulose). Penelitian ini bertujuan mengetahui pengaruh penambahan CMC pada edible coating untuk melapisi bagian luar buah pisang Barangan (Musa acuminata L) terhadap kualitas buah. Pengamatan dilakukan di laboratorium pascapanen AGH dengan menerapkan metode rancangan acak lengkap dengan satu faktor pengamatan yaitu perlakuan konsentrasi CMC yang terdiri atas 4 taraf percobaan dan tiap taraf percobaan dilakukan sebanyak 5 ulangan dan setiap ulangan terdapat 3 satuan percobaan dengan total sampel 60 buah. Hasil Percobaan menunjukkan bahwa penambahan CMC dalam edible coating dapat memperpanjang umursimpan. Penggunaan edible coating dengan tambahan 1 g CMC dapat meningkatkan umur simpan buah selama 2 hari dibandingkan dengan kontrol. Edible coating dengan tambahan 3 g CMC mampu memperpanjang umur simpan hingga 17,04 hari, sedangkan edible coating dengan tambahan 5 g CMC memperpanjang umur simpan hingga 18,6 hari., Bananas have a relatively high content of vitamin C. Ethylene gas, which accelerates the oxidation process, needs to be controlled to extend the shelf life and freshness of the fruit until it reaches the hands of consumers. Edible coating acts as an extra layer that covers the stomata, leading to reduced transpiration. To enhance the strength and improve the surface structure of the edible coating, Carboxymethyl Cellulose (CMC) is added. This study aims to determine the effect of CMC addition to the edible coating for covering the outer part of Barangan bananas (Musa acuminata L) on the fruit quality. Observations were conducted in the post-harvest laboratory of AGH using a completely randomized design method with a single observational factor, namely the concentration of CMC treatment consisting of 4 experimental levels. Each experimental level was repeated 5 times, and each repetition consisted of 3 experimental units, resulting in a total sample of 60 fruits. The experimental results indicate that the addition of CMC in the edible coating can extend the storage time. The use of edible coating with an addition of 1 g CMC can increase the fruit's shelf life by 2 days compared to the control. Edible coating with an addition of 3 g CMC can extend the shelf life to 17.04 days, while edible coating with an addition of 5 g CMC can extend the shelf life to 18.6 days.
Keyword: CMC, edible coating, shelf life

Judul: Edible Coating Application From Sugar Palm Fruit To Extend Cucumber’s Shelf Life
Abstrak: Mentimun merupakan sayuran berbentuk buah yang memiliki umur simpan yang sangat pendek, yaitu 3-4 hari setelah dipanen. Pengaplikasian edible coating adalah salah satu upaya untuk memperpanjang umur simpan buah tersebut. Kolang-kaling mengandung galaktomanan yang mampu membentuk larutan dengan viskositas tinggi dalam konsentrasi yang rendah, sehingga diduga dapat menjadi bahan baku edible coating yang baik. Penelitian ini dilakukan untuk mengetahui pengaruh aplikasi edible coating dari kolang-kaling terhadap umur simpan buah mentimun. Penelitian dilakukan dengan cara mencelupkan buah mentimun ke dalam suspensi edible coating selama ±5 menit, buah kemudian dikeringanginkan selama ±2 jam dan disimpan di wadah PET berongga. Analisis yang dilakukan adalah perubahan susut bobot, total padatan terlarut, kekerasan, dan warna pada buah yang dilapisi oleh edible coating dengan konsentrasi 1 : 9, 1 : 12, dan 1 : 15 dan diamati setiap hari ke-3, 6, 9, 12, dan 15. Hasil penelitian menunjukkan penambahan edible coating dari kolang-kaling dengan konsentrasi 1 : 15 mampu memberi perbedaan yang signifikan terhadap laju perubahan warna buah selama 12 hari penyimpanan. Hasil penelitian tidak menunjukkan perbedaan yang signifikan terhadap laju perubahan susut bobot, total padatan terlarut, dan kekerasan pada penyimpanan buah mentimun selama 3, 6, 9, 12, dan 15 hari., Cucumber is a fruit-shaped vegetable that has a very short shelf life, which is 3-4 days after harvest. The application of edible coating is one of the efforts to extend the shelf life of the fruit. Sugar palm fruit contains galactomannan which is able to form solutions with high viscosity in low concentrations, so it is suspected that it can be a good raw material for edible coatings. This research was conducted to determine the effect of edible coating application from sugar palm fruit on the shelf life of cucumber. The research was conducted by dipping cucumbers into edible coating suspension for ± 5 minutes, then drying the fruit for ± 2 hours and storing in a hollow PET container. The analysis carried out was the change in weight loss, total soluble solids, hardness, and color of the fruit coated with edible coating with concentrations of 1 : 9, 1 : 12, and 1 : 15 and observed every 3rd, 6th, 9th, 12th, and 15th day. The results showed that the addition of edible coating from sugar palm fruit with a concentration of 1: 15 was able to give a significant difference to the rate of change in fruit color during 12 days of storage. However, the results did not show a significant difference in the rate of change in weight loss, total dissolved solids, and hardness on cucumber fruit storage for 3, 6, 9, 12, and 15 days.
Keyword: edible coating, sugar palm fruit, cucumber, shelf life

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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