Judul: Storage of minimally processed crystal guava coated by glucomannan in modified atmosphere packaging
Abstrak: There had been many studies on minimally processed fruits in Indonesia, but none had been conducted on crystal guava. Research had also been done for edible coated minimally processed mango (Wuryani et al., 1999), and snake fruits (Rusmono et al., 1998) using soybean protein isolate as the major ingredient for the edible coating. The objective of this research was to observe the respiration rates, the quality changes, and the shelf life of edible coated minimally processed crystal guava using glucomannan as the major ingredient for edible coating. Preliminary experiment resulted in the selection of 1% glucomannan for the edible coating selection due to the lowest respiration of the edible coated minimally processed crystal guava stored at 5 oC. Storage temperature at three levels 5 oC, 10 oC, and temperature room, and atmosphere composition at also three levels 16-18% O2 and 3-5% CO2, 14-16% O2 and 3-5% CO2, 16-18% O2 and 5-7% CO2 were applied to the edible coated minimally processed crystal guava. The results indicated that storage temperature of 10 oC, and atmosphere composition of 14-16% O2 and 3-5% CO2 were favored compared to the room condition. The packaging films appropriate for the selected condition were stretch film and polypropylene film. Validation experiment used a packaging made of LDPE no.4 for the bottom container accommodating 166-277 g edible coated minimally processed crystal guava which were then covered by stretch film and polypropylene film. It was concluded that edible coated minimally processed crystal guava was best to be stored at 10 oC in a modified atmosphere packaging using stretch film with the ratio of weight to area 200 g/ 240 cm2 since it would be still accepted on the sixth day storage with an organoleptic score of 3.5 in the range of 1-5.
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Judul: Pelapisan Manggis Segar (Garcinia mangostana L.) dengan Lilin Lebah, Hormon Giberelin, dan Benomil
Abstrak: Mangosteen (Garcinia Mangostana L) is one of fruit which has high economic value. The constraint of Mangosteen selling is wilt speed of fruit calyx, that could be assumed as decrease of quality by consumer thinking. Because of that condition, selling activity also decreased. One of way of to lengthen the fruit shelf-life is coating. Coating has known as a protecting substance of food, reduce the transpiration of product, and protect products from microbial contamination. So, the constrain which faced aspecially for seller and exporter for maintain mangosteen quality and freshness can be solved. The purpose of this research are knowing maturity degree of mangosteene which use as a raw material for next research that is knowing organoleptyc and physical effects of coating consentrations during storage. This research consists of two phases. Phase I decide of maturitie’s degree (2 , 3, and 4) and temperature’s storage (room and cool). Phase II decide consentration of coating agent. Types of concentration agent are consisted two levels of beeswax (4 and 6%), three levels of giberelic acid (5, 10, and 15 ppm), and two levels of benomyl (500 and 1000 ppm). The parameters were observed during storage involve physical parameter (visual sheath, weight reduce, husk hardness, and husk colour) and organoleptyc test (kernel and fruit husk colour, ratch vision, taste, and flavour). Based on regretion analysis result visual sheath and weight reduce, the third maturity degree has slope value (2,443 and 0,008). that result have smaller vvalue than others. Result of that maturitie’s organoleptyc test was accepted by consumer in cool storage temperature until 12 days. While room storage until 9 days. The 6% concentration of beeswax coating has smaller slope value at parameters sheath, reduce weight, and hardness husk than others (2,109; 0,007; 0,017). Not only that parameters but also organoleptyc test knowed that consentration had higher accepted consumer than others. The 10 ppm concentration of giberelic acid coating has smaller slope value at parameters sheath, reduce weight, and hardness husk than others (2,453; 0,001; 1,579). According organoleptyc test knowed that consentration had higher accepted consumer than others. The 1000 ppm concentration of benomyl coating has smaller slope value at parameters sheath, reduce weight, and hardness husk than others (2,237; 0,009; 0,179). Not only that parameters but also organoleptyc test knowed that consentration had higher accepted consumer than others.
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Judul: Best Difference Equation Aproximation to Duffing 's Equation
Abstrak: Persamaan Duffing merupakan persamaan yang sering muncul sebagai model masalah sistem ayun mekanis atau pada masalah rangkaian listrik. Umumnya penyelesaian persamaan ini secara numerik memberikan hampiran dengan gala! yang tinggi, seperti dengan metode Runge-Kutta. Tulisan ini mengkonstruksi suatu persamaan beda untuk menghampiri persamaan Duffing tersebut. Penyelesaian dari persamaan beda ini melibatkan fungsi-fungsi eliptik Jacobi. Berdasarkan penyelesaian ini diperoleh basil bahwa penyelesaian hampirannya persis sama dengan penyelesaian analitiknya. Penyelesaian analitik yang diperolehjuga melibalkan fungsi-fungsi eliptik Jacobi.
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