Judul: Aplikasi Teknik Pengemasan dan Coating Khitosan untuk Memperpanjang Umur Simpan Buah Salak Pondoh (Salacca edulis Reinw)
Abstrak: During the storage, performance of snake fruit will be spoiled quickly. Due to enzimatic reaction, chemical reaction, and microorganism activity. The purpose of this research was to determine the shelf life of snake fruit with chitosan coating packed in PP and PE bag. Snake fruit was cleaned and sprayed with 0.7% Chitosan water solution. Water used in this research was distilled water, bottled drinking water and tap water. Coated snake fruit the was packed in PP and PE bag in normal and vacuum condition. Once packed, snake fruit was stored at 16-17°C then it was analysed in every of 2-5 days. The parameters observed was Vitamin C, total acid, percentage of weights loss, total dissolved solid, and panels preference. snake fruit that coated with chitosan distilled water packed in PP bag gave the longest shelf life ie. 31 days, performance of snake fruit with best treatment was vitamin C of 1.37 mg/100g, total acid content of 0.003%, the percentage of weights loss of 0.01%, TSS of 14 °brix and the percentage of spoiled of 43% and by panels preference test samples are preferred PPTB (PP bag normal with bottled drinking water solution).
Keyword: Snake Fruit, Chitosan, Coating

Judul: Penggunaan Kitosan dan Kemasan Plastik Film untuk Memperpanjang Masa Simpan Salak Pondoh.
Abstrak: Snake fruit is a tropical fruit which easily damaged during transportation and storage. The main causes of damage were due to mechanical impact, respiration and fungal microbe infection. The purpose of this research was to analyze the effect of chitosan coating and plastic film on shelf-life of snake fruit var. pondoh during storage. Snake fruit var. pondoh was harvested at farmer orchards in Sleman with condition of 80 percent maturity level. After the harvesting stage, sample of fruit were cleaned and sorted. Snake fruit samples were transported to the packing house in Semarang. Snake fruit samples were then coated by solution with concentration of 0.5 % chitosan substance. Sample of fruits were packed with three different packaging materials. The packaging materials were polypropylene plastic, polyethylene plastic and white stretch film the weight of each packed was 500 grams. Sample of fruits were transported to laboratory at ambient temperature condition for 24 hours. After arriving at laboratory fruits were stored at 15oC and ambient temperature. The parameters of quality in this research were weight loss, water content, total soluble solids, firmness value and organoleptic. The results showed the polyethylene has maximum shelf-life up to 24 days at temperature 15oC. Plastic packaging at room temperature has shelf-life up to 9 days of storage. The fruits that stored at room temperature without treatment it was observed that fruits over-ripe at 6 days and the fruits that stored at 15oC without packaging was in good conditions up to 18 days.
Keyword: Bogor Agricultural University (IPB), shelf-life., packaging, plastic film, natural coating agent, snake fruits var. pondoh, chitosan

Judul: Metrik Einstein (Anti-) Self-Dual Berdimensi Empat dengan Metode Cartan
Abstrak: Gravitational field equation can be formulated in differential forms (differential geometry), which describes gravity as a manifestation of the curvature of space-time. Curvature of space-time is characterized by a metric that satisfies the gravitational field equation. With differential forms it can be formulated the (anti-) self-dual Einstein equation, which is a modification of the Cartan structure in (anti-) self-dual basis. Calculation of (anti-) self-dual metric with (anti-) self-dual Einstein equation is simpler than the calculation using Christoffel symbols.
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