Judul: Karakterisasi Gel Cincau Hijau Kemasan Selama Penyimpanan Dingin
Abstrak: Green grass jelly without heat treatment has a very short shelf life, which is one day if stored at ambient temperature. In the previous research, green grass jelly with addition of hydrocolloid had been made to maintain its physical characteristic after heat treatment. The objective of this research is to study the characteristic of pasteurized (CHP) and steamed (CHK) green grass jelly at cool storage (5-10oC) for 15 days. The product had been analyzed for its physical (gel strength, colour, syneresis rate, and pH value), microbiological (TPC), and functional properties (total chlorophyll, phenolic compound, antioxidant capacity, dietary fiber) every three days. The result showed that CHP and CHK commonly have similar pattern of changes, which had increased in syneresis rate, dietary fiber, and total microbes, whereas green colour intensity, pH value, total chlorophyll, total phenolic compound, and antioxidant capacity decreased after stored within 15 days. In the end of storage period, syneresis rate of CHP (6,66%) was higher than CHK (4,90%). pH value were relatively stable during storage for both products. CHK had higher green colour intensity (a* value more negative) than CHP, which prominently showed at the beginning of storage. All functional properties of CHP and CHK slightly decreased during storage. CHK complied SNI 7388:2009 without storage, while CHP complied SNI until 12 days of storage.
Keyword: pasteurization, steaming, cool storage, green grass jelly

Judul: Gel Cincau Hijau (Premna oblongifolia Merr.) Manis yang Diperkaya dengan Antioksidan dan Flavor Ekstrak Pandan, Lemon, dan Suji
Abstrak: Green grass jelly is a functional food that has many beneficial healt effects, such as an anticancer. Traditional green grass jelly is susceptible to syneresis and of microbial contamination, resulting in a decrease in quality. Previous studies showed that the addition of carrageenan and NaHCO3 has resulted in pasteurized green grass jelly with exterded shelf life. The purpose of this study were to obtain the best formulation of green grass jelly with the addition of pandan, lemon, and suji extracts based on its physical and sensory properties, and to study its functional and microbiological characteristic. Jelly with 10% pandan extract and 5% lemon juice were known to have lower syneresis and was accepted by the panelist. Therefore, were selected as the best product. Lemon flavored jelly was better than pandan jelly in term of antioxidant and total phenol. The antioxidant capacity in green grass jelly with lemon juice was 0.5184 mg AEAC/g w.b and total phenol was 29.6407 mg GAE/g w.b. The antioxidant capacity of green grass jelly with pandan extract was 0.3375 mg AEAC/g w.b and total phenols was 21.9382 mg GAE/g w.b. However, pandan jelly contain a higher amount of chlorophyll (0.0230 mg/g w.b) than the lemon jelly (0.0185 mg/g w.b). Total plate count result showed the bacterial content was < 2,5 x 102 CFU/g, this value met the requirement of SNI that is < 1,0 x 104 CFU/g.
Keyword: antioxidants, pandan leave extract, lemon juice, green grass jelly

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