Judul: Aplikasi Edible Coating Lidah Buaya dan Suhu Penyimpanan untuk Menjaga Mutu Salak Pondoh (Salacca edulis Reinw.) Terolah Minimal.
Abstrak: Application of edible coating and storage temperature are common to maintain fruit’s quality. A source that can be used as edible coating is aloe vera which contains antimicrobial substance. Unfortunately extra effort is needed to prepare aloe vera to be edible coating (peeling, crushing, and filtering) that causes difficulties in application. Formulation of aloe vera edible coating in powder form could ease the application. This research aimed to know the effect of spray drying process on aloe vera edible coating characteristics and its effectiveness to maintain minimally processed salak pondoh. Furtheremore, this research aimed to get information about the effect of aloe vera edible coating and storage temperature on minimally processed salak pondoh (Salacca edulis Reinw.). Fruits quality parameters in this research were firmness, weight loss, percentage of damage, and visual changes. Statistical analysis used was Completely Randomized Design with twice replications. The result showed that spray drying process decreased aloe vera edible coating viscosity, total soluble solid (TSS), and titratable acidity, while its pH value increased. Aloe vera edible coating color changed to be yellowish from smooth green. Furtheremore storage temperature gave significant (α=0.01) effect on all parameters, while aloe vera edible coating did not give significant effect on all parameters analyzed, but uncoated fruits were contaminated by molds sooner than coated ones.
Keyword: Edible coating, aloe vera, polysaccharides, minimally processed fruit, spray dry

Judul: Formulasi dan aplikasi pelapis gel Lidah Buaya pada buah Salak Pondoh (Salacca edulis Reinw.)
Abstrak: Salacca edulis as agricultural commodities is highly perishable and has short shelf life. Reduction of respiration rate can extend shelf life of Salacca edulis. Coating and packaging could reduce respiration rate as these inhibit the transfer of CO2, O2, and water vapour. Aloe vera gel is potential to be applied as coating material. Aloe vera gel composed of polysaccharides that can inhibit the transfer of CO2 and O2 gas, and contains anti microbial function components that can inhibit microbial spoilage. The objectives of this research were to formulate and characterize the Aloe vera gel coating solution; and to observe the effect of application Aloe vera coating solution on the quality changes of Salacca edulis var. pondoh. This research was conducted in four steps. At the first step is characterize Salacca edulis var. pondoh. The next step are formulate and then characterize the coating solution. Formula Aloe vera gel coating solution with etanol 70% solvent, CMC 0.5% (w/w), gliserol 0.5% (w/w), potassium sorbate 0.05% (w/w) and ratio 1:2, 1:1, and 3:2 (gel: solvent) have characteristics viscosity 610-885 cP; pH number 5; moisture content 98.35-98.60 %, and total dissolved solid 7-9°Brix. The last step is application of aloe vera gel coating. That application has influence the quality changes of Salacca edulis var. pondoh. Application of Aloe vera gel coating and non perforated Poly Propylene (PP) packaging can extend Salacca edulis var. pondoh shelf life until 22 days with the decay percentage below 50% in cold storage temprature.
Keyword: Salacca edulis, Gel aloe vera, Coating, Packaging, Shelf life

Judul: Invers dari Matriks Tridiagonal Jacobi
Abstrak: Suatu matriks berukuran n×n dinamakan matriks tridiagonal jika untuk . Karya ilmiah ini memberikan algoritma yang mudah untuk menemukan invers ( dari matriks tridiagonal Jacobi yang simetrik dan nonsimetrik. Setiap elemen pada matriks tridiagonal ini adalah bilangan real. Terdapat 3 lema dan 2 teorema untuk menentukan . Lema pertama menunjukkan persamaan utama dalam membuktikan lema-lema dan teorema-teorema selanjutnya. Invers dari matriks yang simetrik dibuktikan oleh lema kedua yang menunjukkan elemen-elemen baris ke- dari . Selanjutnya, lema kedua dilengkapi dengan teorema pertama yang menunjukkan elemen-elemen dengan . Invers dari matriks yang nonsimetrik dibuktikan oleh lema ketiga yang menunjukkan elemen-elemen dengan dan elemen-elemen dengan dibuktikankan oleh teorema kedua.
Keyword: symmetric, nonsymmetric, matrix