Pengaruh Penyiangan Dan Suhu Penyimpanan Terhadap Mutu Kimiawi, Mikrobiologis Dan Organoleptik Ikan Tongkol (Auxis Tharzard, Lac)

Ikan tongkol merupakan salah satu bahan pangan yang dikonsumsi masyarakat dan jika dibiarkanpada suhu kamar, maka terjadi proses penurunan mutu menjadi busuk. Ikan yang sudah mengalami prosespembusukan, bila dikonsumsi dapat menimbulkan keracunan (Histamine fish poisoning). Keracunan inidisebabkan oleh kontaminasi bakteri pathogen dengan dekarboksilasi asam amino histidin oleh enzimhistidin dekarboksilase menghasilkan histamin. Bakteri ini banyak terdapat pada anggota tubuh manusiayang tidak higienis, kotoran/tinja, isi Perut ikan, insang serta peralatan yang tidak bersih.Penelitian eksperimental dengan pola faktorial, yaitu faktor P adalah faktor penyiangan dengan 2 taraf,tanpa penyiangan dan penyiangan, sedangkan faktor T adalah suhu penyimpanan dengan 3 taraf yaitu suhupenyimpanan 30oC, 15oC dan 0oC.Analisis statistik terhadap mutu kimiawi seperti kadar histamin, kadar total volatil bases (TVB) dantrimetilamin (TMA) menunjukkan perbedaan nyata (P<0,05) pada pengaruh penyiangan dan suhupenyimpanan. Terjadi peningkatan kadar histamin, kadar TVB dan TMA selama penelitian. Selamapenelitian terjadi peningkatan jumlah koloni bakteri, jumlah Coliform, kecuali bakteri Vibrioparahaemolyticus negatif. Perlakuan penyiangan dan suhu penyimpanan 0oC memiliki mutu kimiawi,mikrobiologis terbaik sampai hari ke 10 serta masih diterima panelis.Hubungan antara kadar histamin dengan jumlah bakteri mempunyai hubungan sangat kuat, ditunjukkandengan nilai r ? 0,7 kecuali kadar histamin dengan waktu memiliki hubungan agak lemah r ? 0,5.Keamanan ikan tongkol dengan penerapan teknologi tepat guna berupa tanpa penyiangan danpenyiangan pada suhu 30oC hanya aman untuk dikonsumsi sampai hari ke 0. Perlakuan tanpa penyiangandan suhu penyimpanan 15oC aman sampai hari ke 4, sedangkan dengan penyiangan aman sampai hari ke 6.Untuk perlakuan tanpa penyiangan dan penyiangan dengan suhu penyimpanan 0oC aman sampai hari ke 10

Condensation of Silica Nanoparticles on a Phospholipid Membrane

The structure of the transient layer at the interface between air and the aqueous solution of silica nanoparticles with the size distribution of particles that has been determined from small-angle scattering has been studied by the X-ray reflectometry method. The reconstructed depth profile of the polarizability of the substance indicates the presence of a structure consisting of several layers of nanoparticles with the thickness that is more than twice as large as the thickness of the previously described structure. The adsorption of 1,2-distearoyl-sn-glycero-3-phosphocholine molecules at the hydrosol/air interface is accompanied by the condensation of anion silica nanoparticles at the interface. This phenomenon can be qualitatively explained by the formation of the positive surface potential due to the penetration and accumulation of Na+ cations in the phospholipid membrane.Comment: 7 pages, 5 figure

Gravitational oscillations of a liquid column

We report gravity oscillations of a liquid column partially immersed in a bath of liquid. We stress in particular some peculiarities of this system, namely (i) the fact that the mass of this oscillator constantly changes with time; (ii) the singular character of the beginning of the rise, for which the mass of the oscillator is zero; (iii) the sources of dissipation in this system, which is found to be dominated at low viscosity by the entrance (or exit) effects, leading to a long-range damping of the oscillations. We conclude with some qualitative description of a second-order phenomenon, namely the eruption of a jet at the beginning of the rise.Comment: 22 pages, pdf. Submitted to Physics of Fluid

PENGARUH PENYIANGAN DAN SUHU PENYIMPANAN TERHADAP MUTU KIMIAWI, MIKROBIOLOGIS DAN ORGANOLEPTIK IKAN TONGKOL (Auxis tharzard, Lac)

Ikan tongkol merupakan salah satu bahan pangan yang dikonsumsi masyarakat dan jika dibiarkanpada suhu kamar, maka terjadi proses penurunan mutu menjadi busuk. Ikan yang sudah mengalami prosespembusukan, bila dikonsumsi dapat menimbulkan keracunan (Histamine fish poisoning). Keracunan inidisebabkan oleh kontaminasi bakteri pathogen dengan dekarboksilasi asam amino histidin oleh enzimhistidin dekarboksilase menghasilkan histamin. Bakteri ini banyak terdapat pada anggota tubuh manusiayang tidak higienis, kotoran/tinja, isi perut ikan, insang serta peralatan yang tidak bersih.Penelitian eksperimental dengan pola faktorial, yaitu faktor P adalah faktor penyiangan dengan 2 taraf,tanpa penyiangan dan penyiangan, sedangkan faktor T adalah suhu penyimpanan dengan 3 taraf yaitu suhupenyimpanan 30oC, 15oC dan 0oC.Analisis statistik terhadap mutu kimiawi seperti kadar histamin, kadar total volatil bases (TVB) dantrimetilamin (TMA) menunjukkan perbedaan nyata (P<0,05) pada pengaruh penyiangan dan suhupenyimpanan. Terjadi peningkatan kadar histamin, kadar TVB dan TMA selama penelitian. Selamapenelitian terjadi peningkatan jumlah koloni bakteri, jumlah Coliform, kecuali bakteri Vibrioparahaemolyticus negatif. Perlakuan penyiangan dan suhu penyimpanan 0oC memiliki mutu kimiawi,mikrobiologis terbaik sampai hari ke 10 serta masih diterima panelis.Hubungan antara kadar histamin dengan jumlah bakteri mempunyai hubungan sangat kuat, ditunjukkandengan nilai r ? 0,7 kecuali kadar histamin dengan waktu memiliki hubungan agak lemah r ? 0,5.Keamanan ikan tongkol dengan penerapan teknologi tepat guna berupa tanpa penyiangan danpenyiangan pada suhu 30oC hanya aman untuk dikonsumsi sampai hari ke 0. Perlakuan tanpa penyiangandan suhu penyimpanan 15oC aman sampai hari ke 4, sedangkan dengan penyiangan aman sampai hari ke 6.Untuk perlakuan tanpa penyiangan dan penyiangan dengan suhu penyimpanan 0oC aman sampai hari ke 10

Complete solution of a constrained tropical optimization problem with application to location analysis

We present a multidimensional optimization problem that is formulated and solved in the tropical mathematics setting. The problem consists of minimizing a nonlinear objective function defined on vectors over an idempotent semifield by means of a conjugate transposition operator, subject to constraints in the form of linear vector inequalities. A complete direct solution to the problem under fairly general assumptions is given in a compact vector form suitable for both further analysis and practical implementation. We apply the result to solve a multidimensional minimax single facility location problem with Chebyshev distance and with inequality constraints imposed on the feasible location area.Comment: 20 pages, 3 figure

Relaxation Properties of Small-World Networks

Recently, Watts and Strogatz introduced the so-called small-world networks in order to describe systems which combine simultaneously properties of regular and of random lattices. In this work we study diffusion processes defined on such structures by considering explicitly the probability for a random walker to be present at the origin. The results are intermediate between the corresponding ones for fractals and for Cayley trees.Comment: 16 pages, 6 figure

Wetting of a symmetrical binary fluid mixture on a wall

We study the wetting behaviour of a symmetrical binary fluid below the demixing temperature at a non-selective attractive wall. Although it demixes in the bulk, a sufficiently thin liquid film remains mixed. On approaching liquid/vapour coexistence, however, the thickness of the liquid film increases and it may demix and then wet the substrate. We show that the wetting properties are determined by an interplay of the two length scales related to the density and the composition fluctuations. The problem is analysed within the framework of a generic two component Ginzburg-Landau functional (appropriate for systems with short-ranged interactions). This functional is minimized both numerically and analytically within a piecewise parabolic potential approximation. A number of novel surface transitions are found, including first order demixing and prewetting, continuous demixing, a tricritical point connecting the two regimes, or a critical end point beyond which the prewetting line separates a strongly and a weakly demixed film. Our results are supported by detailed Monte Carlo simulations of a symmetrical binary Lennard-Jones fluid at an attractive wall.Comment: submitted to Phys. Rev.

Small-World Networks: Links with long-tailed distributions

Small-world networks (SWN), obtained by randomly adding to a regular structure additional links (AL), are of current interest. In this article we explore (based on physical models) a new variant of SWN, in which the probability of realizing an AL depends on the chemical distance between the connected sites. We assume a power-law probability distribution and study random walkers on the network, focussing especially on their probability of being at the origin. We connect the results to L\'evy Flights, which follow from a mean field variant of our model.Comment: 11 pages, 4 figures, to appear in Phys.Rev.

Participatory market chain appraisal for the full range of agroforestry products including market trends and growing markets

This paper focuses on the participatory market chain analysis of agroforestry products in six sites of two districts (Kavre and Lamjung) of Nepal. In total, 93 market actors were involved in the study, in which 80 persons were purposively selected from Local Resource Person (LRP) and Local Resource Group (LRG) members and 13 persons were randomly selected from the local, district and national level traders. Primary data on agroforestry products was collected through Participatory Rural Appraisal (PRA) tools following several field visits. Fourteen agroforestry products in Lamjung and 20 agroforestry products in Kavrepalanchok district were selected for analysis. The findings showed that small-scale production and insufficient service to farmers from the village level agriculture collection centers and cooperatives are the major constraints to effective and efficient market chain development and management. The main factors responsible for increasing the production of agroforestry products are the rise in awareness among LRPs/ LRGs about agroforestry practices along with institutional and policy development to facilitate the marketing of agroforestry products. The paper concludes by highlighting the controlling factors in agroforestry business.S. M. Amatya, I. Nuberg, E. Cedamon, K. K. Shrestha, B. H. Pandit, P. Aulia, M. Joshi and B. Dhaka