Judul: Kajian Konsentrasi dan Metode Pelilinan Buah Manggis (Garciana mangostana L.) Semi-Cutting Selama Penyimpanan Dingin
Abstrak: Quality of mangosteen (Garcinia mangostana L.) fruit decreases due to the process of respiration and transpiration during storage after postharvest. Long term storage time causes peel hardening, semi-cutting might prevent this peel hardening from happening. However semi-cutting treatment would damage the fruit and it will quickly rot, and one of the solution to this problem is to do waxing. This study aimed to obtain a combination of concentration and most pelilinan method for semi-cuting the mangosteen fruit. This research result showed the concentration of 12% wax applied by using a brush sweeping was the best combination to assurance quality of semi-cutting mangosteen fruit during cold storage at 13°C until, day-45. Organoleptic test results showed a concentration of 12% with a combination of sweeping seemed tend to be accepted by panelists and the panellist preferred to do fruit mangosteen waxing method than other treatments until day-41.
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Judul: Kajian Semi-cutting dan Pelilinan terhadap Beberapa Parameter Mutu Buah Manggis (Garciana mangostana L.) selama Penyimpanan Dingin
Abstrak: Demand of mangosteen fruits (Garciana mangostana L.) is currently increasing both for local and export markets. As a fresh product, the quality of mangosteen fruit must be preserved through the application of post-harvest technology. There are various post-harvest technologies to prevent quality loss such as pre-cooling, cold storage, storage with controlled atmosphere, waxing, packaging and others. The objectives of this research are to knowing the effect of semi-cutting and waxing on shelf-life and quality of fresh mangosteen. Deterioration of quality parameters that observed in this experiment were weight loss, total dissolved solids, and fruit flesh color. The result showed that combination of semi-cutting and waxing influenced the rate of quality deterioration of mangosteen fruit. If semi-cutting may accelerate the weight loss due to small opening on peel, the combination with waxing prevented that from happening. Quality parameter that influenced during cold storage was weight loss, while it had effect on other quality parameters such as total dissolved solids and fruit flesh color. Semi-cutting treatment 5 mm and waxing 10% concentration could extend shelf life until 33 days when stored at 8°C, while those stored at 27°C experienced a shorter shelf life, 14 days only. In addition, this treatment makes opening the mangosteen fruit easier while able to maintain quality of the fruit flesh. Combination of semi-cutting treatment 5 mm and waxing 10% stored at 8°C was found the best treatment in this experiment, if with semi-cutting 3 mm and without semi-cutting stored at temperatures of 8°C and 27°C.
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Judul: Pengaruh vaksinasi terhadap dinamika populasi pada model SIR (Susceptible-Infected-Recovered)
Abstrak: SIR model can be used to model the spread of diseases in a closed population based on certain assumptions. In this research, the SIR model is formulated by including the factor of vaccination. As the result, the model has been shown to have two equilibrium points, i.e. disease free and endemic equilibrium. A simulation study is carried out to illustrate the model. The results show that some equilibrium points are asymptotically stable. Moreover, a minimum level of vaccination has been defined. For the vaccination level less than the minimum level, increase in the vaccination level results in decrease of the proportion of infected individuals in the corresponding equilibrium point. On the other hand, for the vaccination level greater than the minimum level, increase in the vaccination level results in decrease the proportion of susceptible individuals in the corresponding equilibrium point. Furthermore, when vaccination level is greater than the minimum level, it is found that the time needed for the disease to extinct is shorter.
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