Judul: Studi Keamanan Pangan Buah Apel Impor Melalui Pemantauan Kandungan Formalin Pada Rantai Pemasok di Jakarta
Abstrak: Apple (Malus Sylvestris Mil) has been frequently consumed due to many health benefit including reducing the risk of non-communicable diseases or degenerative diseases. The objective of this study was to evaluate the food safety level of imported apples through formaldehyde sampled test on apple supply chain in Jakarta. The apple were purposively randomized from grocery level in sub district Kramat Jati, East Jakarta and from distributor level in grocery market Kramat Jati, East Jakarta. Apple sample were taken to laboratorium for formaldehyde analysis. Fuji and Washington apple taken from grocery level contained 3.4 ppm and 2 ppm formalin respectively. Fuji apple and Washington apple taken from distributor level had 2 ppm and 7.7 ppm of formalin. Peeling may reduce the formalin content in apple, Peeled Fuji and Washington apple from grocery level contain 1.9 ppm and 1.9 ppm formalin, while peeled Fuji and Washington apple taken from distributor level contain 1.9 amd 1.1 formalin. The formaldehyde contents in apples sold in Karamat Jati were in normal range,which means, there is no formaldehyde added to the apple sold in market and therefore, its safe to consume.
Keyword: Bogor Agricultural University (IPB), market, import, apple, formalin

Judul: Estimation of Physico-chemical Characteristics of Apple Fruit Using Near Infrared Spectroscopy
Abstrak: Apel (Malus sylvestris.) merupakan buah yang memiliki nilai ekonomi cukup tinggi di Indonesia. Apel banyak digemari oleh masyarakat Indonesia karena memiliki cita rasa yang khas dan menimbulkan efek segar pada orang yang mengonsumsinya. Cita rasa apel terbaik diperoleh ketika buah sudah matang sempurna dan apel merupakan buah klimaterik sehingga tingkat kematangan dipengaruhi oleh ketuaan buah saat dipanen. Namun penentuan ketuaan apel masih dilakukan secara visual tanpa alat bantu sehingga hasilnya kurang akurat, kurang objektif sehingga berpotensi kematangan tidak sempurna. Metode spektroskopi NIR (Near Infrared Spectroscopy) memberikan alternatif dalam menentukan tingkat ketuaan buah apel tanpa merusak bagian buah tersebut. Penelitian ini bertujuan untuk menduga sifat fisiko-kimia buah apel manalagi dengan tiga umur panen berbeda (130, 140, dan 150 hari setelah bunga mekar, HSBM) secara nondestruktif dengan menggunakan metode spektroskopi NIR. Sifat atau kandungan fisiko-kimia buah apel terkait dengan tingkat ketuaan buah apel. Parameter yang diuji untuk menentukan kandungan fisiko-kimia buah apel adalah total padatan terlarut, kekerasan daging, dan kadar air. Hasil penelitian menunjukkan hasil terbaik untuk pendugaan total padatan terlarut buah apel didapatkan menggunakan pra-pengolahan data Smoothing Savitzky-Golay (SGs) dengan nilai koefisien korelasi sebesar 0.93; standard error of calibration (SEC) sebesar 0.81 %brix; standard error of prediction (SEP) sebesar 0.86 %brix dan ratio of standard error of prediction to deviaton (RPD)sebesar 2.61. Untuk parameter kekerasan buah hasil terbaik didapatkan dengan pra-pengolahan data Multiplicative Scatter Correction (MSC) dengan nilai koefisien korelasi sebesar 0.78; SEC sebesar 0.47 N; SEP sebesar 0.45 N dan RPD sebesar 1.53. Untuk parameter kadar air didapatkan hasil terbaik dengan pra-pengolahan data Standard Normal Variate (SNV) dengan nilai koefisien korelasi sebesar 0.75; SEC sebesar 0.92%; SEP sebesar 0.85% dan RPD sebesar 1.50., Apple (Malus sylvestris.) is a fruit with high economic value in Indonesia. Apples are much favored by people in Indonesia because they have a distinctive taste and have a fresh effect on people who consume them. The best apple taste is obtained when the fruit is fully ripe and the apple is a climacteric fruit so that the level of maturity is influenced by the age of the fruit when it is harvested. However, the determination of the aging of apples is still done visually without any tools so that the results are less accurate, less objective so that the potential for ripeness is not perfect. The NIRS (Near Infrared spectroscopy) method provides an alternative to determine the level of maturity of apples without damaging the fruit. This study aims to estimate the physico-chemical properties of manalagi apples with three different harvest ages (130, 140, and 150 days after blooming, DAB) nondestructively by using the NIR spectroscopy method. The properties or physicochemical properties of apples are related to the level of maturity of apples. The parameters tested to determine the physico-chemical content of apples were total dissolved solids, flesh hardness, and moisture content. The results showed that the best results for estimating total soluble solids of apples were obtained using Smoothing Savitzky-Golay (SGs) data pre-processing with a correlation coefficient of 0.93; standard error of calibration (SEC) of 0.81 %brix; standard error of prediction (SEP) is 0.86 %brix and ratio
Keyword: Apple, flesh hardness, moisture content, NIRS, total dissolved solids

Judul: Penentuan Nilai Eigen dan Vektor Eigen dari Matriks Tridiagonal 2-Toeplitz dengan Pendekatan Polinomial Chebyshev
Abstrak: The eigenvalues and eigenvectors of a matrix can be determined by finding its characteristic polynomials. The characteristic polynomials of a tridiagonal 2-Toeplitz matrix is shown to be closely connected to polynomials which satisfy the Chebyshev recurrence relationship. If the order of the matrix is odd, then the eigenvalues are found explicitly in terms of the Chebyshev zeros and the eigenvectors are found in terms of the polynomials satisfying the recurrence relationship. For even ordered matrices, the situation is more complicated. The problem in these cases is that although the Chebyshev recurrence formula is still applied, its initial values are not generating Chebyshev polynomials
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