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: Aplikasi Semi-Cutting dan Pelilinan (Waxing) dalam Penyimpanan Dingin Buah Manggis
Abstrak: Peel hardening of mangosteen fruit is one of the problems in storage, especially for long term storage at low temperature. Peel hardening of mangosteen fruit makes it difficult to open before consumption. One attempt to solve this problem isthe application of semi-cutting treatment before storage of the fruits. Semi-cutting application requires a combination with waxing and cold storage to prevent faster quality deterioration, because it provides a way for microorganisms to enter the fruits, and increases the respiration as well. Waxing helps to cover the pores, and especially in this case, the cut opening, of mangosteen fruit and cold storage helps to slow down the respiration and metabolism. The purpose of this research is to study the effect of semi-cutting treatment in combinations with waxing treatment to increase shelf life, and provides easier opening of the fruits at the end of long storage. Treatment of semi-cutting was conducted on two depth, 3 mm and 5 mm whereas waxing treatment was conducted by 2 concentrations, 6% and 10%. Mangosteen fruit which has been semi-cutted and waxed, stored at 8oC and 27oC for 60 days. It was observed that application of semi-cutting 5 mm and waxing 6% in mangosteen fruit stored at 8oC provided ease opening until 33 days of storage while maintaining fruit quality, which is the best result compared with other treatments, because the treatment was able to reduce the peel hardening.
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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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