PREPARASI SAMPEL Pengeringan sampel. Analisis Kadar Lemak dalam Bahan Pangan. PERALATAN SOXHLET Analisis Sifat Fisiko-Kimia Lemak atau. Berat lemak diperoleh dengan cara memisahkan lemak dengan pelarutnya. dll. dietil ksi Soxhlet Prinsip Analisis • Ekstraksi lemak dengan pelarut. Analisa lemak kasar: Metode ekstraksi soxhlet dengan pelarut organik Analisa serat kasar: Fraksi dari karbohidrat yang tidak larut dalam basa dan asam.
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Thus the total lipid content determined by solvent extraction depends on the nature of the organic solvent used to carry out the extraction: The amount of ICl remaining is determined by adding excess potassium iodide to the solution to liberate iodine, and then titrating with a sodium thiosulfate Na2S2O3 solution in the presence of starch to determine the concentration of iodine released: In many foods the lipid component plays a major role in determining the overall physical characteristics, such as flavor, texture, mouthfeel and appearance.
The temperature at which the fat just starts to move downwards due to its weight is called the “slip point”. The terms fat, oil and lipid are often used interchangeably by food scientists. This group of substances includes triacylglycercols, diacylglycercols, monoacylglycercols, free fatty acids, phospholipids, sterols, caretonoids and vitamins A and D. Normally, oxidation can take a long time to occur, e.
A pure triacylglycerol has a single melting point that occurs at a specific temperature. If the solid fat content or crystal structure is important it may be necessary to carefully control the temperature and handling of the sample.
The saponification number is then calculated from a knowledge of the weight of sample and the amount of KOH which reacted. It is possible to monitor the loss of reactants e.
Polar lipids such as glycolipids or phospholipids are more soluble in polar solvents such as alcoholsthan in non-polar solvents such as hexane. This solution is then heated so that the reaction goes to completion. Some of the ICl reacts with the double bonds in the unsaturated lipids, while the rest remains: Lipid oxidation is one of the major forms of spoilage in foods, because it leads to the formation of off-flavors and potentially toxic compounds. Finally, many fats are prone to lipid oxidation, which leads to the formation of off-flavors and potentially harmful products.
The Soxhlet method is the most commonly used example of a semi-continuous method. This technique is therefore an example of a measurement of the reduction in the concentration of reactants.
Praktikum Analisa Pangan – dan Alat Bahan: A variety of methods have been developed to measure the temperature dependence of the solid fat content. Massa jenis densitas hasil ekstraksi dihitung dengan mennggunakan persamaan: The plasticity of a lipid is due to the fact that fat crystals can form a anallsis network that gives the product some solid-like characteristics.
This is not a problem in the Soxhlet method because the sample is always surrounded by solvent. Chromatography can be used to determine the complete profile of molecules present in a lipid. The acid value is defined as the mg of KOH necessary to neutralize the fatty acids present in 1g of lipid. The lipid is dissolved in a suitable organic solvent and an excess of KI is lema These can be divided into three different categories according to their physicochemical principles: The most powerful of these is nuclear magnetic resonance NMR spectroscopy.
Ekstraksi soxhlet ini juga dapat disebut dengan ekstraksi padat-cair.
The flash point is the temperature at which a flash appears at any point on the surface of the sample due to the ignition of volatile lemk products. Analisa Hasil Metode ekstraksi soxhlet digunakan untuk mengekstrak senyawa yang kelaarutannya terbatas dalam suatu pelarut dan wnalisis tidak larut dalam pelarut tersebut.
Instrumental Techniques A variety of instrumental methods can also be used to provide information about lipid composition. The lipid to be analyzed is weighed and dissolved in a suitable organic solvent, to which a known excess of iodine chloride is added.
For this reason, starch is usually used as an indicator because it forms a molecular complex with the iodine that has a deep blue color.
Kedua, ditempatkan kedalam kertas saring. For this reason lipids are usually derivitized prior to analysis to increase their volatility. Bahan Adapaun bahan0bahan yang kami gunakan dalam percobaan ekstraksi soxhlet antara lain: The surfactants displace the fat globule abalisis which surrounds the emulsion droplets in milk and causes them to coalesce and separate.
For high moisture content foods it is often sxhlet to use batch solvent or nonsolvent extraction techniques.
They are particularly important for selecting lipids that are going to be used at high temperatures, e. The concentration of different volatile fatty acid methyl esters FAMEs present in the sample is then analyzed using GC.
Valuable information about the lipid oxidation process is obtained by measuring changes in this profile with time, especially when peaks are identified using mass spectrometry or NMR. The CO2 extracts the lipid, and forms a separate solvent layer, which is separated from the aqueous components.
The lipid content of a food is determined by weighing the percentage of lipid extracted from the original sample. The fatty acids normally found in foods vary in chain length, degree of unsaturation and position on the glycerol molecule. The density is usually measured by density bottles or dilatometry. Dalam percobaan ini kami menggunakan sampel kemiri.