Judul: Assessment of current hygienic manufacturing practices and evaluation of additional food preservatives effect in Nam Prik Mushroom
Abstrak: Nam Prik Mushroom is ready-to-eat food product in Thailand which made from edible mushroom Schizophyllum commune with curry paste. It is produced by Chaiyo Farm, one of Thailand small-medium enterprise. Current hygienic and manufacturing practices in Chaiyo Farm and effectiveness of combination chemical food preservatives, propyl-paraben and calcium propionate, of Nam Prik Mushroom’s shelf life was assessed. Assessment of manufacturing practices at Chaiyo Farm resulted in total conformity of 25.83% based on Thailand Primary Good Manufacturing Practices. Propyl-paraben and calcium propionate did not influence pH, color, and water activity of Nam Prik Mushroom. The effectiveness combination of propyl-paraben and calcium propionate to extend the shelf life Nam Prik Mushroom was not proven. Either non-preserved or preserved Nam Prik Mushroom could not be accepted organically after 3 days storage at room temperature.
Keyword: Bogor Agricultural University (IPB), shelf life, Schizophyllum commune, calcium propionate, propyl-paraben, GMP

Judul: Good Manufacturing Practices Assessment and Shelf-life Analysis of Chili Paste Mushroom in Chaiyo Farm
Abstrak: Mushroom as food product has big potential to be used. The nutritional content of mushroom that suitable for low energy diet and good source of protein become the reason of mushroom popularity. Schizophyllum commune has been known as one of edible mushroom that has functional properties. In Southern of Thailand, this mushroom becomes one of the famous food that been sold commercially with chili or curry paste seasoning. In this research, we assessed the Thailand’s GMP application of the producer. Besides that, this research also measured the shelf-life of chili paste mushroom product in room temperature and made a comparison with the addition of mixed preservative (propyl-parabens 500 ppm and calcium propionate 1000 ppm). From the GMP application, Chaiyo Farm as a producer still needs great numbers of improvement due to a lot of nonconformities. The longest shelf-life of product, chili paste mushroom, was estimated less than six days with addition of preservative at room temperature.
Keyword: GMP, calcium propionate, propyl-paraben, Schizophyllum commune

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