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: Pengaruh Pelapisan Edibel Terhadap Umur Simpan dan Mutu Buah Naga Terolah Minimal yang Disimpan dalam Kemasan Atmosfer Termodifikasi
Abstrak: Minimally processed dragon fruit has a limited shelf life which can be extended if the fruits are subjected to edible coating and modified atmosphere packaging combined with low temperature storage. The objective of this study was to determine the influence of edible coating used for minimally processed dragon fruit on its quality and shelf life. Objective and organoleptic tests were conducted every two days observing the critical quality parameters of edible coated minimally processed fruits. The results indicated that selected glucomannan concentration for edible coating solution was 0.55%. The study recommended that edible coated minimally processed dragon fruits stored in a packaging made out of LDP no.4 as the bottom container with a ratio of 229 g fruits/180 cm2 areal, and stored at 5°C using stretch film for the modified atmosphere packaging. At the validated packaging design, edible coated minimally processed dragon fruits had four day shelf life with an organoleptic score of 3.5 in the range of 1-5.
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Judul: Invers Drazin dari Matriks Toeplitz Singular
Abstrak: Matriks Toeplitz adalah matriks yang setiap unsur pada diagonal utama bernilai sama dan setiap unsur pada subdiagonal yang bersesuaian dengan diagonal utama juga bernilai sama. Matriks singular adalah matriks yang tidak bisa ditentukan inversnya. Akan tetapi, dapat diupayakan untuk ditentukan inversnya menggunakan invers matriks yang diperumum. Invers Drazin merupakan salah satu jenis invers matriks yang diperumum. Pada karya ilmiah ini ditentukan invers Drazin dari matriks Toeplitz singular dengan menggunakan metode Leverrier Faddeev. Kemudian, ditentukan invers Drazin dari matriks Toeplitz singular yang direpresentasikan sebagai penjumlahan segitiga bawah dan segitiga atas matriks Toeplitz berdasar pada teorema Gohberg dan Semencul., Toeplitz matrix is a matrix in with element on the main diagonal has the same value and on the subdiagonal corresponding to the main diagonal also has the same value. Singular matrix is a matrix that has no inverse. However, it can be attempted to determine the inverse using a generalized inverse matrix. Inverse Drazin is a type of generalized matrix inverse. This paper discussed the inverse Drazin for a singular Toeplitz matrix using the Leverrier Faddeev method. Then, the Drazin inverse of the singular Toeplitz matrix which is represented as a sum of products of lower and upper triangular Toeplitz matrix based on Gohberg and Semencul theorem.
Keyword: inverse Drazine, singular Toeplitz matrix