Judul: Kajian gejala chilling injury terhadap perubahan mutu buah mangga varietas Gedong Gincu selama penyimpanan dingin
Abstrak: Penyimpanan pada suhu rendah adalah cara yang umum digunakan untuk memperpanjang masa simpan dan mempertahankan kualitas produk pertanian segar. Permasalahan yang sering dihadapi untuk mempertahankan kualitas produk pertanian dengan cara pendinginan adalah kepekaan produk pertanian terhadap perlakuan suhu rendah sangat bervariasi. Penyimpanan pada suhu rendah dapat mengakibatkan terjadinya kerusakan dingin (chilling injury) yang berakibat pada kerusakan produk secara fisiologi baik secara eksternal maupun internal sehingga dapat menurunkan kualitas produk. Gejala kerusakan dingin terlihat dalam bentuk kegagalan pematangan, pematangan tidak normal, pelunakan prematur, kulit terkelupas, dan peningkatan pembusukan yang disebabkan oleh luka, serta kehilangan flavor yang khas. Gejala kerusakan dingin dapat diamati dari kenaikan kecepatan respirasi dan produksi etilen, terjadinya proses pematangan yang tidak normal dan lambat serta kenaikan jumlah ion yang dikeluarkan dari membran sel (ion leakage). Penelitian ini bertujuan untuk mengkaji gejala chilling injury dengan beberapa parameter mutu buah mangga varietas Gedong Gincu selama penyimpanan dingin yaitu, jumlah konsentrasi CO2 dan O2, susut bobot, perubahan warna, total padatan terlarut, kekerasan buah, uji organoleptik, dan ion leakage.
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Judul: Kajian Gejala Chilling Injury Terhadap Perubahan Mutu Buah Mangga Varietas Gedong Gincu Selama Penyimpanan Dingin
Abstrak: Low temperature storage is a common method to extend the self life and to maintain the quality of mango. However, low temperature storage may cause mango experience the chilling injury. Study on the chilling injury symptoms of mango stored under low temperature storage will be very important in order to understand better mathod to reduction of chilling injury. The objective of this study was to examine the chilling injury symptopms of mango fruits stored at 8, 13 °C and room temperature. Chilling injury symptoms was determined from the ion leagake which measured from the changes in the value of electric conductivity with time. The quality of mango during storage were evaluated from the changes in weight loss, respiration rate, colour, firmness, total soluble solid as well as organoleptic test. The result showed that mango fruits experienced chilling injury at days 4 at storage condition of 8°C. The chilling injury symptoms at days 4 was showed by the highest value of slope from graphic of total percentage of electric conductivity value with time. This phenomenon of chilling injury symptoms at 8°C was also indicated by quality parameter i.e respiration rate, weight loss, total soluble solid, change in colour, firmness and organoleptic test.
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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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