Judul: Aplikasi Gel Lidah Buaya (Aloe vera L.) sebagai Pelapis Buah Salak Pondoh (Salacca edulis Reinw.).
Abstrak: Pondoh salacca is one type of fruit that damaged quickly during storage. Application of coating as gas barrier could do to prolong the shelf life. Aloe vera gel can used as oxygen barrier that reduce respiration rate of pondoh salacca. This research performed to study the effect of aloe vera gel coating in preventing damage to physical, chemical, and microbiological pondoh salacca during storage. Packaging material used are a plastic polypropylene (PP) and polyethylene terephthalate (PET) that applied in normal (without vacuum) and vacuum condition. Fruits that have been sorted and cleaned, sprayed with a coating solution aloe vera gel : solvent ratio of 0:1, 1:4, and 1:2, then dried with the aid of a fan to dry. Once packed, pondoh salacca stored at cold temperature range 15-20 oC and RH 90-99 %, and observed on accordance with the conditions of the fruit. The parameters observed are of the weight loss, the percentage of damage, Vitamin C, total dissolved solids, and total acidity. The results of the analysis found that the ratio of coating is best able to withstand the decline in the quality of pondoh salacca is aloe vera gel : solvent ratio of 1:2. The type and condition of the best packs to maintain the quality of fruits is a kind of plastic PP and normal conditions (without vacuum). The combination of treatments both can also reduce damage fruits, it is evident that the treatment aloe vera gel : solvent ratio of 1:2 and the type of plastic PP with normal conditions can last up to 26 days of storage the level of damage by 37 % and amounted to 0.61 % weight losses. The content of Vitamin C fruits amounted to 1.84 mg/100 g of fruit, and the amount of total dissolved solids and total acid are 15.5 oBrix and 0.48 %.
Keyword: pondoh salacca, coating, aloe vera gel, packaging, shelf life

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: Penentuan Nilai Eigen dan Vektor Eigen dari Matriks Tridiagonal 2-Toeplitz dengan Pendekatan Polinomial Chebyshev
Abstrak: The eigenvalues and eigenvectors of a matrix can be determined by finding its characteristic polynomials. The characteristic polynomials of a tridiagonal 2-Toeplitz matrix is shown to be closely connected to polynomials which satisfy the Chebyshev recurrence relationship. If the order of the matrix is odd, then the eigenvalues are found explicitly in terms of the Chebyshev zeros and the eigenvectors are found in terms of the polynomials satisfying the recurrence relationship. For even ordered matrices, the situation is more complicated. The problem in these cases is that although the Chebyshev recurrence formula is still applied, its initial values are not generating Chebyshev polynomials
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