Figure 2: FMC whole fruit extractor
The FMC juice extractor has two inter-meshing jaws which encom- pass the fruit, crushing it between them. The juice exits through a mesh screen which penetrates the center of the fruit and the juice is separated from the peel, pith and seeds. This crushing action is suffi cient to force the oil out of the glands on the surface of the fl avado. The FMC machine sprays water onto the surface of the fruit, and the oil-water emulsion is subjected to centrifugation.
Traces of water and waxy material are separated by keeping low temperature.
About 75% of citrus oil production utilizes this technology. The odor of cold pressed oil is true in nature and similar to that of the oil present in fruit.
Fat possesses a high power of absorption of volatile oil and, if brought in contact with fragrant fl owers, it absorbs the perfume. This princi- ple methodically applied on large scale constitutes enfl eurage. The quality of the fat base is important for the quality of the fl ower oil. It must be odor- less and of proper consistency. If the crops (fat) is too hard, the blossoms will not have suffi cient contact with it, the absorption will be insuffi cient, and the quality and yield will be poor. If the crops is loose, it may engulf the fl owers so that exhausted ones are diffi cult to remove and retain adhering fat when removed. The crops must have a consistency suitable to produce a semihard surface from which exhausted fl owers can be removed easily.
Saturated fragrant fat extract is known as pomade. Enfl eurage process of cold extraction is carried out in Bulgaria, Egypt, Algeria, Sicily (Italy), and Grasse (France). France remains the main centre of production of highly prized so-called natural fl ower oil. Natural fl ower oil does not include the distilled essential oil but applies only to fl ower oils obtained by enfl eurage, maceration or solvent extraction. The whole process is carried out in cold atmosphere cellars (cold rooms). The mixture of one part highly purifi ed tal- low and two parts lard is best suited for enfl eurage.
Different bases have been used in the preparation of crops.
For example, vegetable fat, mineral oil, esters of polyhydric aliphatic alcohol (ester of glycol, glycerol, mannitol, hexitol), and fatty acids of high molecular weight have been tried, but the best results were from the old-fashioned mixture of lard and tallow. To purify tallow, it is melted after cleaning, wash- ing and removing blood and muscles; the skin is beaten and cleaned, and benzoin (0.6%) and alum (0.15%-0.30%) are added. Benzoin is a preserva- tive while alum causes impurities to coagulate during heating. Warm melted fat is fi ltered through cloth and left to cool.
The vehicle for holding the fat crops during the process is a specially designed “chassis”. These are rectangular wooden frames (2 in.
high, 20 in. long and 16 in. wide) that hold a glass plate (Figure 3). The fat crops is applied to both sides of the glass with a spatula at the beginning of enfl eurage: 360 g crops on each side is required. When 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 (Figure 4). Every morning, freshly picked fl owers are cleaned by removing the leaves and stalks and eliminating the moisture from dew or rain. The fl owers are strewn (Figure 3) by hand on top of the fat layer of each glass plate. Traces of moisture will cause the crops to go rancid, so precaution must be taken.
Figure 4: Pile of chassis
When chassis are piled one above the other, fl owers remain in contact with the lower fat crops which acts as direct solvent, whereas the upper fat layer (beneath the glass plate of the chassis) absorbs only the volatile perfume given off by the fl owers. After 24 h, the fl owers are removed from the chassis. The time of removal, however, depends on type of the fl ow- ers. Removal of the fl owers from the crops is known as defl eurage. Immedi- ately following defl eurage, the chassis are recharged with fresh fl owers. For this purpose, the chassis are turned over, thus the fat layer which in the pre- vious operation formed on top (ceiling) of the small chamber is now directly charged with fresh fl owers. When the fat crops becomes saturated with fragrance (pomade), the crops is removed from the chassis with a spatula.
The pomades are extracted with absolute alcohol in a process called extrait.
At the beginning and several times during the harvest, the fat on the chas- sis is scratched over with a metal comb and tiny furrows are drawn in order to change and increase the surface area available for maximum absorption.
The most highly saturated pomade is pomade no. 36, meaning the crops on the chassis has been treated with fresh fl owers 36 times during the whole process of enfl eurage. In the case of jasmine, every kilogram of fat is charged with 3 kg fl owers during the entire period. The alcohol washing of pomade no. 36 are called extrait no. 36, which reproduces the natural fl ower oil to a remarkable degree. Sometimes a fatty note is present in the extrait, which can be removed by freezing and fi ltering the alcoholic washes.
Figure 5: Batteuses
Pomades are processed during winter in cool cellars called batteuses (Figure 5) made of copper and equipped with stirrers. Several batteuses are arranged serially. The alcohol driven from one batteuse is poured in second, third and fi rst washings of successive batteuses. For the last washing, fresh alcohol is used. Extrait no. 36 is cooled in a refrigerator to separate the fat. The exhausted fat is odorless and used for the manu- facture of soap. Complete concentration of extrait is done under vacuum at low temperature to remove alcohol, producing absolute of enfl eurage which is semisolid in nature. The fl owers removed from the chassis are extracted with solvents (petroleum ether) and the concentrated residue is dissolved in absolute alcohol. The fat is removed by freezing. This preparation is known as absolute of chassis. Absolute of enfl eurage and absolute of chassis logically supplement one another because each represents only part of the total oil present in the fl owers but, due to cost difference, they are kept separately.