Peeling expression

Bergamot Citrus aurantium ssp. bergamia (Rutaceae) fresh fruit peel (expression) 0.5 limonene (42) linalyl acetate (27) y-terpinene (8) linalool (7) flavouring, aromatherapy, perfumery also contains the furocoumarin bergapten (up to 5%) and may cause severe photosensitization (see page 146)... 

Box 7.7 IFRA Guideline for Bitter Orange Peel Expressed... 

Sponge squeezed into a terracotta bowl, the concolina After decantation, the oil was collected in metal containers. This was an extremely laborious process characterized by substantial oil losses. A later improvement of the fruit peel expression process was the scodella method. The apparatus was a metallic hemisphere lined inside with small spikes, with a tube attached at its center. The fruit placed inside the hemisphere was rotated while being squeezed against the spikes thus breaking the oil cells. The oil emulsion, containing some of the wax coating the fruit, flowed into the central tube was collected, and the oil was subsequently separated by centrifugation. 

The filter usually has an endless cloth, traveling intermittently between the plates via roUers, to peel off cakes. Unfortunately, if the cloth is damaged anywhere, the whole cloth must be replaced, which is a difficult process. Each time the filter cloth zigzags through the filter, the filtering direction is reversed this tends to keep the cloth clean. Most of these filters incorporate membranes for mechanical expression, and cakes sometimes stick to the membranes and remain in the chamber after discharge. Some vertical filters are available with a separate cloth for each frame. The cloths maybe disposable and such filters are designed to operate with or without filter aids. 

In one extractor (FMC Inc.), the fmit is located between two cups having sharp-edged metal tubes at their base. The upper cup descends and the many fingers on each cup mesh to express the juice as the tubes cut holes in the top and bottom of the fmit. On further compression, the rag, seeds, and juice sacs are compressed into the bottom tube between the two plugs of peel. A piston moves up inside the bottom tube forcing the juice through perforations in the tube wall. A simultaneous water spray washes the peel oil expressed during extraction away from the peel as an oil—water emulsion the peel oil is recovered separately from the emulsion. 

In another extractor (Automatic Machinery and Electronics Inc. (AMC)) the individual fmits are cut in half as they pass a stationary knife. The halves are oriented in a vertical plane, picked up by synthetic mbber cups, and positioned across plastic serrated reamers revolving in a synchronized carrier in a vertical plane. As the fmit halves progress around the extractor turntable, the rotating reamers exert increasing pressure and express the juice. The oil and pulp contents in the juice increase with greater reaming pressure. The recoverable oil is removed in a separate step prior to juice extraction. Needle-sharp spikes prick the peel of the whole fmit, releasing oil that is washed away with water and recovered from the oil—water emulsion. 

In the extraction of citms juices it is desirable to have as gende an extraction pressure as possible. There should be minimal contact time between juice and pulp to reduce the amount of bitter substances expressed from the peel into the juice. The amount of suspended soHds in citms juice is controlled in a subsequent separation in a finisher. A screw action is used to force the juice through a perforated screen and separate the larger pulp particles from the juice. The oil level in the juice is adjusted by vaporizing under a vacuum (10). The separated pulp is washed and finished several times to produce a solution which is then either added back to the juice to increase juice yield, or concentrated to produce pulp wash soHds, also called water extract of orange soHds, which can be used as a cloudy beverage base. 

Lime Oil. This oil is obtained from the fmit Citrus aurantijolia Swingle the Key, Mexican, or West Indian lime or C latijolia Tanaka, the Persian lime, either by steam distillation or expression. Either the entire cmshed fmit or only the peel may be used, depending on the specific properties desired. A typical commercial distilled lime oil contains the constituents shown in Table 10 (25). 

Bergamot. Bergamot oil is produced by cold expression from peels of fmits from the small citms tree. Citrus bergamia. The fmits are inedible and of httle value. Bergamot is grown mainly in southern Italy and northern and western Africa. The oil is used to impart a sweet freshness to perfumes. Its largest chemical constituent, to the extent of 35—40%, is linalyl acetate [115-95-7] (1), with a much smaller amount of citral [5392-40-5] (2) as an important odor contributor. 

Fig. 15. Adhesion expressed as peel strength of poly(vinyl alcohol) film on polyester film (8). To convert N/m to ppi, divide by 175.

The United. States Department of -bgrieultarc have recontly devised a machine for the peeling ol cilriii fruits and the expression therefrom of the eaaential oil. Although only iu the experimental stage, it piomiaea to be very auecesstnl. 

Without going into details we shall quote the final result of the orbital peeling method which expresses the EPI as a sum of terms involving the zeroes and the poles of peeled Green functions (G/j,, ) Gij k) denotes IJ block of the Green function corresponding to the Hamiltonian, where two atoms I and J are embedded at sites i and j and the orbitals from 1 to (k-1) are deleted at the site i.) ... 

The two variable terms should yield very abrupt variations in the Ej(r)-modulus, since the generally large differences between the moduli of the inclusions and the matrix must be accomodated in very thin peels for the mesophases. The appropriate functions for such steep variations are power functions of radii r with large adhesion exponentsq. Then, the Ej(r)-modulus may be expressed by ... 

For properties such as peel strength and elongation to break, which decrease with oxidation, a different empirical relation has to be used. We have found that elongation to break and peel strength retention data can be fit to the following expression [15] ... 

In a previous publication (1) we reported that the pretreatment of fresh fhiit waste using microwave heating ensured a better extraction of pectin, resulting in an increase in the yield of pectin from 10 to 50 %. It was established that this microwave pretreatment ensured retention of the degree of esterification of the extracted pectin, better expressed in citrus peels... 

If a section cut through a small sulfur-burned area of a lemon injured on the tree is examined microscopically, coagulation of protoplasm and cell collapse are apparent. Also, the injured tissue stains abnormally dark with safranin indicating the protoplasm has become more acidic than in normal tissue (18). Sides of the peel of lemons burned by sulfur on the tree were found to be higher in total sulfate than were uninjured sides of the same peel. The high total sulfate content of the peel was subsequently found to be due in part to soluble sulfate, as shown by analyses of the expressed cell solution (18). 

Karim FD, Rubin GM 1998 Ectopic expression of activated Rasl induces hyperplastic growth and increased cell death in Drosophila imaginal tissues. Development 125 1-9 Kawamura K, Shibata T, Saget O, Peel D, Bryant PJ 1999 A new family of growth factors produced by the fat body and active on Drosophila imaginal disc cells. Development 126 211-219... 

Much of the FLS biochemical and structure/fimction analysis has focused on a protein from C. unshiu (mandarin). A cDNA was isolated based on sequence homology to an Arabidopsis FLS EST (153O10T7) and used as a probe to determine regulation of gene expression [92]. Higher expression was observed in young leaf, flower, peel, and juice sac/segment epidermis tissues. Expression decreased with tissue age, as has been observed for citrus CHS, CHI, and F3H [57]. Southern analysis... 

The overproduction of an enzyme at a rate-limiting step to increase levels of specific flavonoids is well illustrated by the Forsythia ANS example described earlier, and also by the use of CaMV35S CF[I increase flavonol levels in A. thalicma and L. esculentum. In particular, fruit of L. esculentum plants expressing P. hybrida CHI had up to a 78-fold increase in flavonol content, principally rutin, in fruit peel. 

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