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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The signal from the solid fat decays much more rapidly than the signal ahalisis the liquid oil and therefore it is possible to distinguish between these two components. Lipids are an extremely diverse group of compounds consisting of tri- diand monoacylglycercols, free fatty acids, phospholipids, sterols, caretonoids and vitamins A and D.
It is difficult to find a single solvent which meets all of these requirements. Separation and Analysis by Chromatography Chromatography is one of the most powerful analytical procedures for separating and analyzing the properties of lipids, especially when combined with techniques which can be used to identify the chemical structure of the peaks, e. Analisis Lemak Metode Soxhlet Documents. Nevertheless, over-consumption of certain lipid components can be detrimental to our health, e.
The acid value is defined as the mg of KOH necessary to neutralize the fatty acids present in 1g of lipid. Thus the lipid content of foods can be determined by measuring their density.
Lipids can sometimes be extracted by simply applying pressure to a food to squeeze out the oil, e. Prisip kerja dak ekstraksi soxhlet adalah memisahkan senyawa tertentu dari sampel padat dengan menggunakan titik didih tertentu dan senyawa tertentu.
Analisa Hasil Metode ekstraksi soxhlet digunakan untuk mengekstrak senyawa yang kelaarutannya terbatas dalam suatu pelarut dan pengotor-pengotor tidak larut dalam pelarut tersebut. 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.
A number of instrument manufacturers have designed modified versions of the Soxhlet method that can be used to determine the total lipid content analsiis easily and rapidly e. Massa jenis densitas hasil ekstraksi dihitung dengan mennggunakan persamaan: Sampel yang digunakan dan yang dipisahkan dengan metode ini berbentuk padatan.
The fire point is the temperature at which evolution of volatiles due to the thermal decomposition of the lipids proceeds so quickly that continuous combustion occurs a fire. 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. The lipids then remain in the flask because of their low volatility.
These instruments are finding greater use because of the cost and environmental problems associated with the usage and disposal of organic solvents. Bahan Adapaun bahan0bahan yang kami gunakan dalam percobaan ekstraksi soxhlet antara lain: Food manufacturers often measure the variation of SFC with temperature when characterizing lipids that are used in certain foods, e.
The acid value may be overestimated if other acid components are present in the system, e. Economic not to give away expensive ingredients Legal soxhllet conform to standards of identity and nutritional labeling laws Health development of low fat foods Quality food properties depend on the total lipid content Processing processing conditions depend on the total lipid content The principle physicochemical characteristics of lipids the “analyte” used to distinguish them from the other components in foods the “matrix” are their solubility in organic solvents, immiscibility with water, physical characteristics e.
For this reason, a number of accelerated oxidation tests have been developed to speed up this process. The thimble is placed in an extraction chamber, which is suspended above a flask containing the solvent and below a condenser.
In a food that contains many different components whose concentration may vary, it is difficult to lrmak the sohlet that the fat makes to the overall measurement from that of the other components. The main disadvantages of the technique are that a relatively dry sample is needed to allow the solvent to penetrateit is destructive, and it is time consuming.
The sample is then cooled at a controlled rate and the temperature at which the liquid just goes cloudy is determined. 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.
Instrumental methods are most useful for rapid measurements of fat content on-line or in quality assurance laboratories of food factories where many samples must be measured rapidly. These techniques are muchcruder than chromatography techniques, because they only give information about the average properties of the lipid components present, e.
Saponification is the process of breaking down a neutral fat into glycerol and fatty acids by treatment with alkali: Thus the lipid content can be determined by measuring its ultrasonic velocity. Many of the textural properties that people perceive when they consume foods are largely rheological in nature, e.
Lipid oxidation is an extremely complex process involving numerous reactions that give rise to a variety of chemical and physical changes in lipids: Dalam percobaan ini kami menggunakan sampel kemiri.
Thus, a change in solution appearance from blue to colorless can be used as the end-point of the titration. The lipid content is determined by measuring the area under a peak in an NMR chemical shift spectra that corresponds to the lipid fraction. Official methods have been developed for specific types soxxhlet foods that stipulate the precise sample preparation procedure that should be followed. Detergent Method This method was developed to overcome the doxhlet and safety concerns associated with the use of highly corrosive acids.
The temperature at which the fat analisia melts and becomes transparent is called the “clear point”. For this reason, this test is now usually referred to as the thiobarbituric acid reactive substances TBARS method. IntroductionLipids are one of the major constituents of foods, and are important in our diet for a number of reasons. By measuring the chemical shift leak 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.
If lipid oxidation is a problem it leemak important to preserve the lejak by using a nitrogen atmosphere, cold temperature, low light or adding antioxidants. The saponification number is then calculated from a knowledge of the weight of sample and the amount of KOH which reacted. Basically, the sample is placed into an NMR instrument and a radio frequency pulse is applied to it.
Eventually, the solvent builds up in the extraction chamber and completely surrounds the sample. A number of these instrumental methods have major advantages over the extraction techniques mentioned above because they are nondestructive, require little or no sample preparation, and measurements are usually rapid, precise and simple.
The flask is heated and the solvent evaporates and moves up into the condenser where it is converted into a liquid that trickles into the extraction chamber containing the sample. The tests reflect the amount of volatile organic material in oils and fats such as free fatty acids. There are a number of problems with the use of peroxide value as an indication of lipid oxidation.
Each instrumental methods has its own advantages and disadvantages, and range of foods to which it can be applied.