Judul: Kinetics of Quality Change of Carotenoids-rich Fat Powder Made From Red Palm Oil
Abstrak: Vitamin A Deficiency (VAD) has been a serious problem in Indonesia and the underlying cause is a diet which is insufficient in vitamin A. Food fortification is one of the strategy that can be implemented in Indonesia to reduce the burden of VAD and to improve vitamin A intake. Red palm oil, Indonesia’s abundant natural resource rich in carotenoids, is very potential to be used as food fortificant. Red palm oil can be used by direct addition to food product or by transforming it into carotenoids-rich fat powder before use. This study was to investigate the kinetics of quality changes of carotenoids-rich fat powder during storage and to determine the product shelf life, using Arrhenius accelerated method. Samples of fat powder were stored at 26C (ambient/room temperature) and at elevated temperatures of 35C, 40C, and 55C for 30 days, and samples were taken and analyzed every 5 days. As a reference, samples of fat powder were also stored at refrigeration of 12C. The results showed that fat powder underwent (i) some color changes, (ii) increase in free fatty acid and peroxide value, and (iii) decrease in carotene content and powder flowability. With carotene tolerance 50% of initial carotene, carotenoids-rich fat powder can be stored for 3 months and 11 days at ambient/room temperature with light protection.
Keyword: Bogor Agricultural University (IPB), Arrhenius accelerated method, Spray chilling, Palm Stearin, Red Palm Oil, Fat powder

Judul: Studi kinetika perubahan mutu mikroenkapsulat minyak sawit merah selama penyimpanan
Abstrak: One of the alternatives of red palm oil utilization is to transform it into red palm oil microencapsulate (RPOM). Some indicators for RPOM quality damaged during storage are free fatty acids, peroxide value, total carotenes, and colours. Besides, its angle of repose also becomes main parameter because RPOM used is powdery product. In this research, RPOM had stored for 40 days in incubator with 35 oC, 44 oC, and 55 oC temperatures to analyzed the change of its quality characteristics. The result shows that the higher the temperature of storage, the faster RPOM get physical and chemical damages. Rate of increase of peroxide value and total rate of decrease of total carotenes are following first order reaction with each value of k are 0.0370 day-1 and 0.0067 day-1 respectively, while the rate of increase of free fatty acids and decrease of yellow colours are following zero order reaction with value of k are 0.0039% day-1 and 0.1720 unit day-1. Activation energy value for various quality parameters which derived from this study are 117327.17 J mol-1 for increase of free fatty acid; 27955.825 J mol-1 for increase of peroxide value; 69638.895 J mol-1 for decrease of carotene total; and 66194.405 J mol-1 for decrease of yellow colour.
Keyword: Bogor Agricultural University (IPB), RPOM, palm oil, order reaction, k value, energy activation value

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