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.
|Genre:||Health and Food|
|Published (Last):||27 January 2005|
|PDF File Size:||2.30 Mb|
|ePub File Size:||11.38 Mb|
|Price:||Free* [*Free Regsitration Required]|
Ekstraksi dilakukan dengan memanaskan pelarut sampai semua analit terekstrak kira-kira 6 x siklus.
Dalam praktikum ini, kita melakukan dua tahap yang pertama menggunakan alat ektraktor soxhlet yang berfungsi untuk mengekstraksi kemiri sehingga pada tahap pertama ini akan diperoleh ektrak kemiri dan n-heksana.
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: A major disadvantage of the techniques which rely on measurements of the bulk physical properties of foods are that a calibration curve must be prepared between the physical property of interest and the total lipid content, and this may depend on the type of lipid present and the food matrix it is contained in.
The acid value is defined as the mg of KOH necessary to neutralize the fatty acids present in 1g of lipid. Pengaruh Suplementasi Lisin terhadap Karakteristik Karkas A typical accelerated oxidation test is the active oxygen method AOM.
The acid value is often a good measure of the break down of the triacylglycrols into free fatty acids, which has an adverse effect on the quality of many lipids. 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. Indirect information about the average molecular weight and degree of unsaturation of the oils can be obtained by measuring physical properties, such as density or refractive index.
This procedure may have to be repeated a number of times to improve the efficiency of the extraction process.
Food manufacturers often measure the variation of SFC soxhlft temperature when characterizing lipids that are used in certain foods, e. A number of liquid extraction methods do not rely on organic solvents, but use other chemicals to separate the lipids from the rest of the food.
Measurements of the refractive index or density can therefore be used to monitor processes that involve a change in the composition of oils, e.
In a food that contains many different components whose concentration may vary, it is difficult to disentangle the osxhlet that the fat makes to the overall measurement from that of the other components.
The isoamyl alcohol is used to prevent charring of the sugars by heat and sulfuric acid which can soxhket a problem in the Babcock method since it makes it difficult to read the fat content from the graduated flask.
Thus oxidation can analizis followed by dissolving the lipid in a suitable organic solvent and measuring the change in its absorbance with time using a UV-visible spectrophotometer. Instruments based on this principle heat the food sample to be analyzed in a pressurized chamber and then mix supercritical CO2 fluid with it.
Sample Preparation It is important that the sample chosen for analysis is representative of the lipids present in the original food, and that its properties are not altered prior to the analysis.
Ketiga, dimasukkan kertas saring yang telah berisi sampel dalam ektraktor soxhlet. For this reason, this test is now usually referred to as the thiobarbituric acid reactive substances TBARS method. One of the most commonly used methods for determining the iodine value of lipids is “Wijs method”. Prisip kerja dak ekstraksi soxhlet adalah memisahkan senyawa tertentu dari sampel padat dengan menggunakan titik didih tertentu dan senyawa tertentu. The speed at which an ultrasonic wave travels through a material depends on the concentration of fat in a food.
Introduction In addition to their nutritional importance lipids are also used in foods because of their characteristic physicochemical properties, such as mouthfeel, flavor, texture and appearance. The temperature at which the fat completely melts and becomes transparent is called the “clear point”. Dasar Teori Ekstraksi padat-cair digunakan untuk memisahkan analit yang terdapat pada padatan menggunkan pelarut organic. A pure triacylglycerol has a single melting point that occurs at a specific temperature.
soxulet Each instrumental methods has its own advantages and disadvantages, and range of foods to which it can be applied. Another widely used accelerated oxidation test is the Schaal Oven Test. The density is usually measured by density bottles or dilatometry.
Analisis Pembuatan Asam Lemak Documents. Kelima, dimasukkan beberapa batu didih dalam labu alas bulat. Initially, starch is added to the solution that contains the iodine and the solution lema a dark blue. Molecules in the mixture are separated because of their differing affinities for the matrix in the column. Iodine Value The iodine value IV gives a measure of the average degree of unsaturation of a lipid: Special instruments are available to carry out solvent extraction at elevated temperatures and pressures.
Lmak Solvent Extraction The efficiency of solvent extraction can be increased by carrying it out at a higher temperature and pressure than are normally used. Solusi Rotary Evaporasi Laboratorium Solusi yang 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.
The thimble is placed in an extraction chamber, which is suspended above a flask containing the solvent and below a condenser. A known weight of oil is placed in an oven at a specified temperature about 65 oC and the time until rancidity is detected is recorded by sensory evaluation or measuring the peroxide value.
This information can be used to: Some of the most commonly used “melting points” are: Babcock Method A specified amount of milk is accurately pipetted into a specially designed flask the Babcock bottle.
Thus it is possible to monitor the rate at which it occurs by measuring the uptake of oxygen by the sample as the reaction proceeds. Saponification Number The saponification number is a anakisis of the average molecular weight of the triacylglycerols in a sample. The sample is then cooled at a controlled rate and the temperature at which the liquid just goes cloudy is determined.
Some of the most important properties of concern to the food analyst slxhlet The extraction chamber 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 pressure and temperature of the solvent are then reduced which causes the CO2 to turn to a gas, leaving the lipid fraction remaining.
Basically, the sample is placed into an NMR instrument and a radio frequency pulse is applied to it. This reduces the amount of solvent required to carry out the analysis, which is beneficial from a cost and environmental standpoint. Disini sampel disimpan dalam alat Soxhlet dan tidak