Judul: Aplikasi coating kitosan untuk memperpanjang umur simpan buah salak pondoh (Salacca edulis Reinw.)
Abstrak: Pondoh snake fruit is a tropical commodity which rapidly damaged during storage. The rain causes of damage due to respiration and fungal infection. Chitosan can be a coating material and inhibit the growth of fungal. Plastic has a permeabilities for O2, CO2, and H₂O ansfer. The purpose of this research is to know influences of chitosan coating and plastics packaging for shelf-life and qualities of pondoh snake fruit in some maturities level (80%, 90%, hatch) during storage. There are three steps of the methods, that was preparation chitosan coating Chitosan:acetic acid 1%) (b/v) 0.3:100; 0.5:100; 0.7:100, spray chitosan coating, and type of packaging material i.e. polypropyhlene without holes, polypropyhlene holes, polyetyhlene without oles, polyetyhlene holes and no packaging) then storage at temperature 16°C. The results howed that 80% maturity of pondoh snake fruit which coated by chitosan 0.5:100 chitosan:acetic acid 1%) (b/v) and packaged by polypropylene without holes have shelf-life until days, 90% maturity of pondoh snake fruit which coated by chitosan 0.7:100 (chitosan:acetic id 1%) (b/v) and packaged by polypropylene without holes have shelf-life until 12 days, batch maturity of pondoh snake fruit which coated by chitosan 0.5:100 (chitosan:acetic acid 1%) (b/v) and packaged by polypropylene without holes have shelf-life until 12 days. Pondoh snake fruit without treatment in room temperature was damaged until 100% in 6 days of storage. Qualities of pondoh snake fruit was decrease as storage in level of damage, weight loss, vitamin C, total acid, otal soluble solids, and organoleptic.
Keyword: Pondoh snake fruit, Chitosan coating, Polyethylene, Polyprophylene, cold storage

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: igenvalues and Eigenvectors of Tridiagonal Matrix with Non Constant and Recurrent Diagonal Entries.
Abstrak: Matriks tridiagonal adalah suatu matriks yang mempunyai entri-entri bernilai nol kecuali pada diagonal utama, di bawah diagonal utama (subdiagonal) dan di atas diagonal utama (superdiagonal). Entri pada diagonal utama tidak konstan dan berulang. Setiap entri pada matriks tridiagonal ini adalah bilangan kompleks. Dalam karya ilmiah ini, akan dibuktikan 3 teorema untuk menentukan nilai eigen dengan 2 kasus dan 1 teorema untuk menentukan vektor eigen. Teorema pertama menentukan polinomial karakteristik dari matriks tridiagonal. Polinomial karakteristik dari matriks tridiagonal tersebut digunakan untuk menentukan nilai eigen pada teorema kedua dan ketiga serta menentukan vektor eigen pada teorema keempat
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