Judul: Kandungan Aflatoksin dan Analisis Titik Kritis pada Pengelolaan Pascapanen Jagung di Kabupaten Garut
Abstrak: Corn is the major ingredients feedstuff. Feed ration in feedmill industry is based on corn-soya. Postharvested corn is susceptible to fungal invasion which able to produce fungal metabolites such as aflatoxin. The objectives of the research are (1) to get a description aflatoxin contamination in farmer, collecting sellers and whole sellers (2) to get a description of critical points an aflatoxin contamination (3) to get a correlation and regression between aflatoxin and moisture content, ash, organic matter, water activity both in corn kernel and corn meal. A total of 57 samples of corn which collected from farmers, collecting sellers and whole sellers in Garut regency have been investigated for the aflatoxin contamination and the critical points of its occurrence in postharvested corn. Sampling was done with purposive sampling method and aflatoxin content was detected by Enzyme Linked Imunosorbent Assay (ELISA). Other parameters were moisture content, ash, organic matter, water activity both in corn kernel and corn meal. The results showed that the highest contamination was found in whole sellers level. The critical points at farmers stage were due to spoilage corn from field unproper, shelling procedure and sun drying dependence . Critical points at collecting sellers stage were due to improper storage and sun drying dependence. Whereas critical point at whole seller stage was due to the improper mixing practice. Based on statistical analysis (SPSS 13.0), there was a positive correlation between percentage of damage kernels and aflatoxin content, coefficient correlation (r) = 0.552 in farmer level. In collecting sellers, between moisture content and aflatoxin content were negatively corelated with coefficient correlation (r) = -0.630 but organic matter and aflatoxin content were positively corelated with coefficient correlation (r) = 0.662. In whole sellers, there was no corelation which significan (alpha: 0.05) between aflatoxin and other parameter.
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Judul: Pengaruh Kadar Air Dan Metode Penyimpanan Tongkol  Jagung (Zea Mays, L.) Terhadap Pertumbuhan Aspergillus Flavus  Dan Pembentukan Aflatoksin
Abstrak: Corn is one of agricultural commodity that has been cultivated in high quantity in Indonesia. Until now, the utilization of corn has been limited to the seed, which used as feeds and foods. It caused by product, in the form of corncob has been reach 46% from all corn varieties (Sapoetra, 1994), so it has been started to expand the using of corncob to be a more useful product. One alternative of the corncob utilization is xilosa, as the raw material in xilitol production. Xilitol has been used on candy and sweetener product. Corn is agricultural commodity which susceptible to fungal infection, so it was need right condition during storage. A. flavus is one of mold that often contaminate corn. This fungy can produce aflatoxin, a toxin which was dangerous for human and animals health, if they eat the product which contaminated of aflatoxin. In low concentrations (not more than 20 ppb), aflatoxin cause liver and kidney cancer, while in high concentration (20 ppb or more), aflatoxin can cause death. Maximum aflatoxin concentration that was permitted to be consumed according to Food and Drug Administration, USA was no more than 20 ppb. The goal of this research were to get the best water content and the right storage method which can inhibite A. flavus growth and aflatoxin formation. Water content that applied in this research were 11%, 15% and 19%, while the storage method that used were ruged and packed use gunny sack. The duration of storage was 30 days with three times sampling, that were 0 day, 15 day and 30 day. The corn variety that used was Bisma. This research consist of two steps. First was preparation of raw material that include corncob characterizations and conditioning of water content. Corncob characterizations consist of carbohydrate, protein, fat, crude fiber, ash and water content, while conditioning of water content was done with moisting and drying the corncob to get the water content at 11%, 15% and 19%. In main research the measured parameters were water content, A. flavus population and aflatoxin concentration. The analyze of statistic method that used in this research were Completely Randomize Design with two factors and Completely Randomize Design with three factors. Completely Randomize Design with two factors was used to analyze water content data, while Completely Randomize Design with three factors was used to analyze A. flavus population data. The results of corncob characterizations were : water content 11.80±0.06%, ash content 1.59±0.010%, protein content 1.62±0.07%, crude fiber content 34.02±0.09, carbohydrate (by diff.) 95.65±0.01 and fat content 1.14±0.04%. In main research, the corncob water content was decrease during storage. The highest decrease of water content was occured on the storage with ruged method and 19% water content, while the lowest decrease was occured on the corncob which was packed use gunny sack and 11% water content. The storage method that gave the lowest population of A. flavus was the corncob which was packed use gunny sack and 11% water content. From each storage method, the lowest population of A. flavus was obtained on 11% water content and the
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Judul: Hamiltonian formulation for linear waves motion in two layers fluid
Abstrak: The surface wave could be considered as a wave that separates two fluids, namely water and air. Based on this assumption, it is introduced the interfacial wave, a wave between two layers of fluid with different density. The formulation of interfacial waves motion begins with deriving the base equation of irrotational ideal fluid. Furthermore, according to irrotational fluid assumption, the base equation can be stated in velocity potential. In this derivation, the fluids domain is assumed to be restricted by rigid lid boundary conditions, both at the upper and lower limit. Therefore, the interfacial waves motion can be explained in a hamiltonian formulation. In the hamiltonian formulation, total energy is defined as the sum of kinetic and potential energy. The hamiltonian system is obtained from reduction of kinetic energy by using the Dirichlet Neumann Operator. The resulted kinetic energy equation is nonlinear. Therefore, this form is linearized by first part of the Taylor expansion. This linearization gives a dispersion relation of linear wave. Based on this dispersion relation, the phase speed of the linear wave depends on the density ratio of the two layers fluid.
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