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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This temperature is known as the cloud point, and is the temperature where crystals begin to form and scatter light. Lipid oxidation is an extremely complex process involving numerous reactions that give rise to a variety of chemical and physical changes in lipids: The terms fat, oil and lipid are analisos used interchangeably by food scientists. Oxidation of unsaturated lipids can be minimized by adding antioxidants, or by flushing containers with nitrogen gas and avoiding exposure to heat and light.
Analisis Pembuatan Asam Lemak Documents. Initially, starch is added to the solution that contains the iodine and the solution goes a dark blue. The surfactants displace the fat globule membrane which surrounds the emulsion droplets in milk and causes them to coalesce and separate. Firstly, peroxides are soxhlte products that are broken down in the latter stages of anslisis oxidation.
Saponification Number The saponification number is a measure of the average molecular weight of the triacylglycerols in a sample.
A pure triacylglycerol has a single melting point that occurs at a specific temperature. Lipid fractions by TLC TLC is used mainly to separate and determine the concentration of different types of lipid groups in foods, e. 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.
As with the Babcock method, it does not determine phospholipids. 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.
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 gaseous products.
A simple test to determine the ability of lipids to withstand cold temperatures without forming crystals, is to ascertain whether or not a sample goes cloudy when stored for 5 hours at 0oC. Extracciones Con Equipo Soxhlet Documents. Desirable physical characteristics of foods, such as appearance, flavor, mouthfeel and texture, depend on the type of lipids present. 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.
The aqueous phase is then decanted off, and the concentration of lipid in the solvent is determined by evaporating the solvent and measuring the mass of lipid remaining: These can be divided into three different categories according to their physicochemical principles: This is not a problem in the Soxhlet method because the sample is always surrounded by solvent.
Many instrumental methods are simple to operate, rapid, reproducible, require little sample preparation and are nondestructive.
The container is shaken vigorously and the organic solvent and aqueous phase are allowed to separate either by gravity or centrifugation. They are a major source of energy and provide essential lipid nutrients. In the later stages of lipid oxidation the conjugated dienes which are primary products are broken down into secondary products which do not adsorb UV-visible light strongly which leads to a decrease in absorbance.
All triacylglycerols are esters of glycerol and three fatty acid molecules, nevertheless, the fatty acids can have different chain lengths, branching, unsaturation, and positions on the glycerol molecule.
It is faster and simpler to carry out than the Babcock method. Disini sampel disimpan dalam alat Soxhlet dan tidak Measurement of bulk physical propertiesDensity: The higher the degree of unsaturation, the more iodine absorbed, and the higher the iodine value. Special instruments are available to carry out solvent extraction at elevated temperatures and pressures.
As the FAMES pass through the column they are separated into a number of peaks based on differences in their molecular weights and polarities, which are quantified using a suitable detector.
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 soxhhlet a fire. This solution is then heated so that the reaction goes to completion. Soxhlet Extractions – Soxhlet Extractions Author: The density of solid fat is higher than the density of liquid oil, and soxhllet there is an increase in ajalisis when a fat crystallizes and a decrease when it melts.
Below a certain stress known as the “yield stress” the product behaves like a solid with an elastic modulus because the crystal network is not disrupted, but above this stress it flows like a liquid because the crystal network is continually disrupted. In a food that contains many different components whose concentration may vary, it is difficult to disentangle the contribution that the fat makes to the overall measurement from that of the other components.
The manufacture of many foods relies on a knowledge of the type of lipids present in order to adjust the processing conditions to their optimum values, e.