Judul: Physiological study of hardening and color changes of pericarp in relation to climacteric respiration and moisture content in mangosteen (Garcinia mangostana) after harvest
Abstrak: Mangosteen is a high economic value fruit in Indonesia. The problems encountered are the fruit pericarp quickly harden and the color immediately changed to dark purple-black, and sepals quickly turned into brown in color after harvest, so shelf life is short, especially at room temperature. This research aimed to study the process of change in hardness, pericarp and sepal color, and the sepal freshness of the mangosteen fruit and the factors that influence the physiology and biochemistry during storage. The research consisted of five experiments: (1) hardening physiology of mangosteen pericarp, (2) effect of exogenous ethylene and storage temperature on quality changes of mangosteen, (3) effects of 1-methylcyclopropene (1-mcp) and storage temperature on hardening of and color change of pericarp of mangosteen, (4) Effect of cytokinin and CoSO4 on physical quality of mangosteen during cool storage, and (5) Effect of coating material and cytokinin CPPU (N-(2-chloro-4-pyridyl)-N-phenylurea (Forchlorfenuron)) on the quality of mangosteen on cool storage. The results showed that the peak rate of ethylene production one day earlier than the respiration climacteric. The peak rate of ethylene production occurred on day 11 while the respiration climacteric peak occurred on day 12. Climacteric respiration will lead to biochemical changes in the mangosteen fruit pericarp, such an increase in protein content, increased activity of the enzyme phenylalanine ammonia lyase (PAL), cinnamyl alcohol dehydrogenase (CAD), and peroxidase (POD), and increasing the amount of lignin. Pericarp hardening occured due to water content decrease in the mangosteen and increased content of lignin. Fruit stored at a temperature of 15oC can last up to 28 days after treatment (DAT). Whereas fruit stored at room temperature only last up to 14 DAT. Mangosteen fruit stored at a temperature of 15oC had lower level of resistance and hardness. had a higher water content, lower weight loss, slower color change, and had a higher total soluble solids (TSS) and titratable acidity (TA). Exogenous ethylene treatment did not provide a marked influence on all the variables observed, which means that the mangosteen fruit wass less sensitive to exogenous ethylene treatment. 1-MCP treatment at various doses did not prolong the shelf life of the mangosteen fruit. This treatment is consistent in both room temperature and at a temperature of 15oC. 6% beeswax better reduce weight loss than other types of coating materials.
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Judul: Pelapisan Buah Manggis (Garcinia mangostana L.) dan Adaptasi Suhu terhadap Perubahan Karakteristiknya selama Penyimpanan
Abstrak: Mangosteen (Garcinia mangostana L.) as an exotic tropical fruit is the one commodity of fruits that have high economic value and popular society. The main factor that limits the export potential of the mangosteen fruit including the decline in fruit quality during storage.Constraints exporters mangosteen fruit is the speed of the next petal wilting is assumed as a decrease in quality by consumers that makes the decline in sales value. Efforts that have been done on the mangosteen fruit to reduce the granting of transpiration is beeswax, giberelic acid, benomyl or a combination. Other efforts also can be done is by storage at low temperatures. But these efforts also have the disadvantage that the temperature changes that occurred from ambient temperature to low temperature can affect the quality of mangosteen fruit, mangosteen, especially sepals which is a major factor in determining the quality mangosteen exports. For thar, there should be efforts and new technologies that can reduce the shock effect of this temperature so that the mangosteen will be in export quality and better durability. The purpose of this study was to determine the effect of coating the fruit mangosteen and adaptation temperature on its characteristics change during storage. Characteristics that were observed during storage is the physical properties (appearance of sepals, weight loss, skin color, and the level of violence). Based on the results of regression analysis to the treatment performed, to appearance of sepals, coating treatment without or with adaptation temperature kept at cold temperatures (8-10)°C shows the value of a relatively smaller slope (2,17987 and 2,17676) compared with coating treatment without or with adaptation temperature stored at room temperature (29-31)°C. This indicates that treatment with adaptation temperature coating on cold temperature storage has sepals damage level is lower than other treatments. For weight loss treatment characteristics without adaptation temperature coating that is stored at room temperature (29-31)°C and cold temperatures (8-10)°C showed slope values (0,00832 and 0,00162), relatively lower than those treated with adaptation temperature coating stored at room temperature (29-31)°C and cold temperatures (8-10)°C showed slope values (0,00628 and 0,00158).Based on these characteristics can be seen that treatment with adaptation temperature coating has a churn rate of weight loss is much smaller than without adaptation temperature coating treatment on the same storage temperature. Based on the parameters of the texture or hardness, for each treatment, such treatment without adaptation temperature coating that is stored at room temperature (29-31)°C, without adaptation temperature coating that is stored at cool temperatures (8-10)°C, with adaptation temperature coating stored at room temperature (29-31)°C and with adaptation temperature coating that is stored at cold temperature (8-10)°C showed slope values (0,0006049; 0,0002076; 0,0008072; 0,0002053). This showed that the mangosteen are given preferential treatment temperature adaptation that is iv stored in cold temperatures have a smaller increase in violence compared to other treatments. Mangosteen fruit shelf life stored at room temperature (29-31)°C lasted only 15 days, while the mangosteen that are stored at a temperature (8-10)°C can reach 35 days. The smallest percentage change in the characteristics contained in the mangosteen fruit mangosteen with the treatment
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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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