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: Maintaining the Quality of Cavendish Bananas through the Application of Chitosan Edible Coating Using the Dip and Spray Methods
Abstrak: Penerapan teknologi pascapanen seperti edible coating diperlukan dalam memperpanjang umur simpan pisang. Kitosan merupakan bahan edible coating yang dapat melapisi permukaan kulit buah dengan baik sehingga menghambat respirasi dan memperpanjang umur simpannya. Jenis metode pelapisan menjadi faktor yang penting dalam aplikasi edible coating. Penelitian ini bertujuan mengevaluasi susut bobot, rasio bobot daging terhadap kulit, kekerasan, pH, padatan terlarut total, konversi pati menjadi gula, warna kulit, dan keparahan penyakit buah pisang cavendish yang dilapisi coating kitosan (1,25 %) dengan metode celup dan semprot. Penyimpanan pisang dilakukan pada suhu ruang (26 ± 2oC) dengan RH 80±5% selama 11 hari. Sprayer gendong bermotor digunakan untuk menyemprotkan larutan coating. Uji kinerja alat sprayer dilakukan untuk mengevaluasi efektivitasnya. Hasil uji menunjukkan tekanan semprot sebesar (4 ± 0,00) kgf/cm2, tinggi penyemprotan sebesar (58,5 ± 0,71) cm, diameter droplet sebesar (78,50 ± 12,02) μm, dan kerapatan droplet sebesar (733,5 ± 20,51) droplet/cm2. Pelapisan kitosan berpengaruh signifikan terhadap rasio bobot daging:kulit, kekerasan, padatan terlarut total, pH, nilai a* warna, dan keparahan penyakit buah pisang. Pisang coating metode semprot tidak mengalami kemunculan bintik coklat selama penyimpanan dan memiliki nilai keparahan penyakit terendah pada hari ke-11 penyimpanan yaitu sebesar 3,33 ± 0,00 dibanding metode celup sebesar 4,17 ± 0,71 dan tanpa pelapis sebesar 5,00 ± 0,00. Penghambatan susut bobot hanya terjadi pada pisang coating metode semprot, dengan nilai susut bobot pada hari ke-11 penyimpanan sebesar (14,51 ± 0,28)%, dibanding metode celup sebesar (15,32 ± 0,64)%, dan tanpa pelapis sebesar (15,25 ± 0,26)%. Pisang coating metode semprot memiliki nilai kekerasan pada hari ke-5 penyimpanan sebesar (29,11 ± 0,25) mm/50g/50dtk, lebih rendah dibanding metode celup sebesar (34,81 ± 0,43) mm/50g/50dtk, dan tanpa pelapis sebesar (37,58 ±0 ,01) mm/50g/50dtk. Pisang tanpa pelapis telah mengalami konversi pati seluruhnya pada hari ke-5 penyimpanan, sedangkan pati pisang coating metode semprot terkonversi sebesar 45%, lebih rendah dibanding metode celup sebesar >65%. Hal ini menunjukkan metode semprot menghasilkan sebaran larutan kitosan lebih merata dan mampu mempertahankan mutu buah pisang dibanding metode celup., Applying postharvest technology such as edible coating is needed to extend the shelf life of bananas. Chitosan is an edible coating material that has an excellent ability to coat the surface of fruit so that it inhibits respiration and extends its shelf life. The coating method is an essential factor in the application of edible coating. This study aims to evaluate the weight loss, pulp-to-peel ratio, firmness, pH, total soluble solids, starch-to-sugar conversion, peel color, and disease severity of cavendish bananas coated with chitosan solution (1.25 %) using the dip and spray method. A knapsack power sprayer was used to spray the coating solution. The sprayer performance test was carried out to evaluate its effectiveness. The result of the tests shows spray pressure (4 ± 0.00) kgf/cm2, spray height (58.5 ± 0.71) cm, droplet diameter (78.50 ± 12.02) μm, and droplet density (733.5 ± 20.51) droplet/cm2. Chitosan coating significantly affects the pulp:peel ratio, firmness, total soluble solids, pH, a* color value, and disease severity of bananas. Spray coated bananas do not experience the appearance of brown spots during storage and have the lowest disease severity value on the
Keyword: cavendish banana, chitosan, dip method, edible coating, spray method

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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