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.
|Published (Last):||12 April 2012|
|PDF File Size:||19.69 Mb|
|ePub File Size:||13.10 Mb|
|Price:||Free* [*Free Regsitration Required]|
To determine the concentration of these components it is necessary to break the bonds which hold the lipid and non-lipid components together prior to solvent extraction. Introduction In the previous lecture analytical methods to measure total concentration of lipids in foods were discussed, without any concern about the type of lipids present.
The extraction lemka is designed so that when the solvent surrounding the sample exceeds a certain level it overflows and trickles back down into the boiling flask. The percentage of lipid in the initial sample Msample can then be calculated: As with the Babcock method, it does not determine phospholipids.
The density is usually measured by density bottles or dilatometry. Many instrumental methods are simple to operate, rapid, reproducible, require little sample preparation and are nondestructive. Measurement of adsorption of radiationUV-visible: The Soxhlet method is the most commonly used example of a semi-continuous method. 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.
A number of liquid extraction methods do not rely on organic solvents, lemk use other chemicals to separate the lipids from the rest of the food. They are a major source of energy and provide essential lipid nutrients. This technique is therefore an example of a measurement of the reduction in the concentration of reactants.
Analisis lemak Documents.
Then, the solution is titrated with a sodium thiosulfate solution of known molarity. Each instrumental methods has its own advantages and disadvantages, and range of foods to which it can be applied.
Instruments based on this principle heat the food sample to be analyzed in a pressurized chamber and then znalisis supercritical CO2 fluid with it. It is faster and simpler to carry out than the Babcock method. The temperature at which the disc changes shape to a sphere is called the “Wiley melting point”.
These can be divided into three different categories according to their physicochemical principles: Iodine Value The iodine value IV gives a measure of the average degree of unsaturation of a lipid: Ekstraksi dilakukan dengan memanaskan pelarut sampai semua analit terekstrak kira-kira 6 x siklus. The manufacture of many foods relies on a knowledge of the type of lipids present in order to adjust the processing conditions soxhhlet their optimum values, e.
Determination of the total fatty acid profile allows one to calculate the type and concentration of fatty acids present in the original lipid sample. The lipid is first extracted and then dissolved in an ethanol solution which contains a known excess of KOH. Usually, the lipid is placed in a sealed container and the amount of oxygen that must be input into the container to keep the oxygen concentration in the head-space above the sample constant is measured.
It is often necessary to dry samples prior to solvent extraction, because many organic solvents cannot easily penetrate into foods containing water, and therefore extraction would be inefficient.
Stability is expressed as hours of heating until rancidity occurs, which may be determined by detection of a rancid odor or by measuring the peroxide value. This group of substances includes eoxhlet, diacylglycercols, monoacylglycercols, free fatty acids, phospholipids, sterols, sxhlet and vitamins A and D. Accelerated Solvent Extraction The efficiency of solvent extraction can be increased by carrying it out at a higher temperature and pressure than are normally used.
Introduction Foods which contain high concentrations of unsaturated lipids are particularly susceptible to lipid oxidation. Saponification is aalisis process of breaking down a neutral fat into glycerol and fatty acids by treatment with alkali: Kedua, ditempatkan kedalam kertas saring.
Food manufacturers often measure the variation analisix SFC with temperature when characterizing lipids that are used in certain foods, e. In many foods the lipid component plays a major role in determining the overall physical characteristics, such as flavor, texture, mouthfeel and appearance.
This method is therefore only useful for monitoring the early stages of lipid oxidation. Thus the lipid content can be determined by measuring its ultrasonic velocity. Peroxide value Peroxides R-OOH are primary reaction products formed in the initial stages of oxidation, and therefore give an indication of the progress of lipid oxidation. This technique elmak an example of a measurement of the increase in concentration of primary reaction products.
Another widely used accelerated oxidation test is the Schaal Oven Test. It is possible to monitor the loss of reactants e. It is difficult to find a single solvent which meets all of these requirements. A small amount of the lipid sample to be analyzed is spotted onto the TLC plate.