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):||1 January 2012|
|PDF File Size:||9.16 Mb|
|ePub File Size:||4.3 Mb|
|Price:||Free* [*Free Regsitration Required]|
Then, the solution is titrated with a sodium thiosulfate solution of known molarity. Kemudian padatan yang telah halus dibungkus dengan kertas saring.
This procedure is inexpensive and allows rapid analysis of lipids in fatty foods. Some of the ICl reacts with the double bonds in the unsaturated lipids, while the rest remains: Foods which contain high concentrations of unsaturated lipids are particularly susceptible to lipid oxidation, which can lead to theformation of undesirable off-flavors and aromas, as well as potentially toxic compounds e.
Grinding is often skxhlet out at low temperatures to reduce the tendency for lipid oxidation to occur. Komposisi kimia dalam biji dan minyak kemiri setiap gram daging biji kemiri mengandung Ketaren.
Published on Jul View 6. The sample is heated in the injection chamber to volatilize the FAMES and then carried into the separating column by a heated carrier gas. Thus even a lipid which consists of only triacylglycerols may contain a huge number of different chemical species. This temperature is known as the cloud point, and is the temperature where crystals begin to form and scatter light. Spots can be scraped off and analyzed further using techniques, such as GC, NMR or anailsis spectrometry.
This technique is an example of a measurement of the increase in concentration of primary reaction products. After shaking the aqueous phase soxhldt separated from the non-polar solvent, placed in a test-tube, and heated for 20 minutes in boiling water, which produces a naalisis color. The plasticity of a lipid is due to the fact that fat crystals can form a three-dimensional network that gives the product some solid-like characteristics.
Instrumental Techniques A variety of instrumental methods can also be used to provide information about lipid composition.
The container is shaken vigorously and the organic solvent and aqueous phase are allowed to separate either by gravity or centrifugation. In order, to decide the most appropriate sample preparation procedure it is necessary to have a knowledge of the physical structure and location of the principal lipids present in the food. Introduction It is important to be able to accurately determine the total fat content of foods for a number of reasons: It is often of practical importance to have an oil which does not crystallize when stored at 0oC for prolonged periods.
Although sometimes the term fat is used to describe those lipids that are solid at the specified temperature, whereas the term oil is used to describe those lipids that are liquid at the specified temperature.
A chromatographic analysis involves passing a mixture of the molecules to be separated soxylet a column that contains a matrix capable of selectively retarding the flow of the molecules. Basically, the sample is placed into an NMR instrument and a radio frequency pulse is applied to it. By making these measurements over a range of temperatures it is possible to determine the melting point, the total amount of lipid involved in the transition and the SFC-temperature profile.
The sample is then centrifuged while it is hot oC which causes the liquid fat to rise into the neck of the Babcock bottle.
This reduces the amount of time required to carry out the extraction, but it has the disadvantage that channeling of the solvent can occur, i. Some of the most important reasons for determining the type of lipids present in foods are listed below: For this reason, a number of accelerated oxidation tests have been developed to speed up this process.
A wide variety of experimental techniques are available to characterize the rheological properties of food materials. A small amount of the lipid sample soxlhet be analyzed is spotted onto the Analusis plate. Kedua, menggunakan rotary evaporator unyuk memisahkan antara ektrak kemiri dengan n-heksana pelarutnya dengan menggunkan perbedaan titik didih. Konsentrasi Reaksi refluks Re-kristalisasi Cara Kerja Adapaun langkah-langkah dalam praktikum ekstraksi soxhlet, yaitu yang pertama ditumbuk kemiri dan diambil sebanyak soxulet gram.
Keenam, dipasang kondensor dan dialirkan pendingin melalui pompa. This group of substances includes triacylglycercols, diacylglycercols, monoacylglycercols, free fatty acids, phospholipids, sterols, caretonoids and vitamins A and D. Thiobarbituric acid TBA This is one of the most widely used tests for determining the extent of lipid oxidation.
Many of the textural properties that people perceive when they consume foods are largely rheological in nature, e. By measuring the chemical shift spectra it is possible to determine the concentration of specific types of chemical groups present, which can be used to estimate the concentration of different types of lipids. Food manufacturers analiais measure the variation of SFC with temperature when characterizing lipids that are used in certain foods, e.
If lipid oxidation is a problem it is important to preserve the sample by using a nitrogen atmosphere, cold temperature, low light or adding antioxidants. The isoamyl alcohol is used to prevent charring of the sugars by heat and sulfuric acid which can be a problem in the Babcock method since it makes it difficult to read the fat content from the graduated flask. Solusi Rotary Evaporasi Laboratorium Solusi yang The fat is poured into a metal container and heated at a controlled rate, with a flame being passed over the surface of the sample at regular intervals.
Analysis of the types of lipids present in a food usually requires that the lipid be available in a fairly pure form. The CO2 extracts the lipid, and forms a separate solvent layer, which is separated from the aqueous components.
The density of liquid oil is less than that of most other food components, and so there is a decrease in density of a food as its fat content increases.