Judul: Physical characteristics and shelf life of yellow passion fruit coated by chitosan
Abstrak: Yellow passion fruit is one of the table fresh fruits preferred by Indonesian consumers. One alternative to prolong its shelf life is by chitosan of the whole fruit. The objectives of this research were 1) to determine the shelf life of yellow passion fruit coated by chitosan, 2) to assess the influence of various chitosan concentrations in wax on the physical characterictic changes, and 3) to assess the influence of storage temperature on the fruit weight losses. The shelf life of yellow passion fruit coated by 1.5% chitosan wax was 9 days at room temperature, and 16 days at 150C. Higher chitosan concentrations maintained significantly the total soluble solid, and the organoleptic score, and decreased the weight losses at 150C. However, it did not influence the fruit firmness and color. Lower temperature storage decreased significantly the respiration of passion fruits causing the reduction of the fruit weight losses.
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Judul: Penggunaan Kitosan dan Lilin Lebah sebagai Bahan Pelapis untuk Meningkatkan Masa Simpan dan Mempertahankan Kualitas Buah Pepaya
Abstrak: Papaya is a climacteric fruit with increased respiration rate during ripening process. Respiration rate papaya can be inhibited by providing a coating on the surface of the fruit. Coating materials that can be used include chitosan and beeswax. The purpose of this research is to study the effect of chitosan and beeswax coating on the shelf life and quality of Callina papaya fruit during storage. Experiment was carried from November 2014 until March 2015 at the Experimental Field of PKHT, Tajur and Postharvest Laboratory, Department of Agronomy and Horticulture, Faculty of Agriculture, Bogor Agricultural University. The experimental design used was completely randomized design with 3 treatments and 3 replications, there are chitosan 0.75%, beeswax 6%, and the control (without coating). Data were analyzed by F test and treatments that affect were analyzed by Duncan Multiple Range Test (DMRT). Parameters measured were shelf life, the index of fruit skin color scale, respiration rate, weight loss, skin firmness, pulp firmness, total soluble solids, total titratable acids, and the content of vitamin C. Results of the experiments showed that chitosan and beeswax treatments can extend the shelf life of papaya Callina 4–5 days compared to control because it inhibits respiration rate papaya during storage. The use of chitosan and beeswax can maintain the physical and chemical quality of papaya fruit Callina.
Keyword: Callina, chemical quality, physical quality, postharvest ripening, respiration rate

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