Hydrolytic Maceration and Cold Fat ExtractionA. K. Singh

Extraction of active constituents from raw material is an important and one of the most critical steps in order to maintain desired phytoconstituents. Excellent active constituents will give an excellent quality product for some food, flavors, cosmetics, and pharmaceutical industries. A suitable method for extraction is very important in the development of natural products. A very simple extraction, like we do every day is when you brew your coffee in a hot water, which tannins and caffeine were extracted from coffee beans into hot water. There are numbers of extraction techniques that can be use to extract desired constituents from plants. The choice among them is due to physicochemical properties and stability of the phytoconstituents to be obtained. The present article deals with extraction by hydrolytic maceration, expression and cold fat extraction.1. Hydrolytic MacerationHydrolytic maceration is a method which refers to preparation of solution by soaking a plant material with various suitable solvent, vegetable oil, or water. The differences with percolation is depends on the flow of solvents through bulk material. The rate of extraction depends upon the following: The rate of transport of solvent into the mass to be leached. The rate of solubilization of soluble constituents into solvent. The rate of transport of solute out of the insoluble material and from the surface of the insoluble material into the solution.In this process, a solid material is placed in a closed bottle and then add the suitable solvent (menstruum). After that, this process is allowed to stand for a long time which varying from several hours to days depends on how long took the solvent to menstruum all the constituent with diffuse through materials cell walls and dilute them. Sometimes adding an alcohol was needed prior to prevent microbial growth.

2. ExpressionEssential oils are mostly obtained by distillation in different plant parts. However, a few essential oils such as citrus oil which present in citrus peel are, obtained by expression, in order to give a product with superior quality. This type of oil will give a small yield of oil and does not represent of oil that occurred originally in the plant, if obtained by distillation process. Its due to the long action of heat which leads to hydrolysis, polymerization, and resinification that decompose the substances in oil. In citrus plants, the citrus peel contains numerous of oil sacs and glands, where the citrus oil contained, and this is a basic reason why expression technique is the most suitable method for extracting a citrus oils. And also there is a albedo, which on maturation stage will elongated and branched, which give the ripe peel spongy texture. This spongy layer plays an important role in this technique, but it easily absorbs the oil that ejected from expression and hold it with greater tenacity, which makes the fruit peel needed to soak in water first before being expressed because spongy layer will absorb the water instead of oil, which makes the process will exerted an oil and water emulsion.2.1. Process of Expression2.1.1. Hand Process In this process, the fruits are cut divided in two pieces. The fruit pulp removed by sharp edged spoon and then peel immersed in water for several hours and finally pressed by hands. First, hold a sponge in left hand and place it in a wooden crossbar, place the peels, and then place the other sponge above it and squeeze the sponge. This process requires much labor and the yield of this method is 50%-70% of the total oil present in the peel. The quality of oil obtained from hand pressing is near to the quality present in fruit peel2.1.2. Equelle ProcessEquelle is a process which using a shallow brass-nailed bowl of copper with a hollow central tube. The fruits is rolled by hand with some pressure and exerted a water oil emulsion which separated by decantation.2.1.3. Hand MachinesIn this process, the peel is placed or trapped in two sponge by hand and fitted with a funnel through which oil and watery material pass to receiving vessels. 2.1.4. Sfumatrici and PelatriciSfumatrici is a machines which treat only the peel after removal of juice and pulp, while pelatrici is a same process but with the whole fruit. Special sfumatrice is a roller type machine which fruit peel is bent and pressed to expel the maximum quantity of oil. The emulsion is filtered by wool or sponge to yield water and oil separation mixtures. Pelatrici is a whole fruit processing. These machines crush whole fruit and separate oil and aqueous phases by distillation or centrifugation. Oil is removed by lightly punctured the surface of fruit with a million sharp stainless steel points in rotating rolls. There is also a Food Machinery Corporation(FMC) Whole Fruit Extractor which extracts citrus oils from the whole fruit without any mix of emulsion extract and fruit juice. FMC juice extractor is equipped with two inter-meshing jaws which encompass the fruit, crushing it between them, and the juice will exits through a mesh skin. The peel then crushed, so that oil will expelled and the emulsion is separated by centrifugation. This process is give the odor of cold pressed oil is true in nature and similar to that of the oil present in fruit.3. Cold Fat ExtractionSome high-price essential oils from jasmine, tuberose, and gardenia are only produce a small quantity of oil and cannot be obtained by distillation methods, because the oil components were thermolabile and yield a very small quantity of perfume. The oil from these type of flowers will produce high yield perfume quantity with cold fat extraction methodCold fat extraction or enfleurage basically using fat as medium for extraction. fats possess a high power of absorption of volatile oil, if there is a contact with flowers, it will absorbs the perfume and leave the flower exhausted. The important thing from this method is the quality of fat base which leads to quality of flower oil. It must be odorless and proper consistency. If the crops (fat) is too hard, it will hardly absorbs the perfume because the flowers not have a sufficient contact with it and the oil yield will be poor. If the crops is loose, it may retain adhering on the flowers and difficult to removing the exhausted flowers. Two part of lard and one part of tallow is a suitable mixture of good consistency of corps that still used in perfume industries. In this method, fat was placed in a square wooden frame glass named chassis and flowers will placed on a fat surface and the chassis were piled one above the other, the chassis form an air-tight compartment with a layer of fat on the upper and lower sides of each glass. Every morning the exhausted flowers will be removed and replace it with new fresh pick of flowers, and this step will repeat until the fat is highly saturated. And then the fat was collected by spatula and dilute it with solvent like alcohol which extracts the oil from fat. After that, separate the solvent with filtering the fat with freezing the fat. These used fat from enfleurage process is called pomade that used in several cosmetics products. The mixture of oil and solvent which called extrait were distillated or evaporated until the flower oil were obtained.