Epicarp

In the case of specimens such as apples, it may be appropriate to remove the epicarp (skin) in the region being tested. 

In citrus fruits, where the outer skin or epicarp is a composite structure containing certain flavouring substances, it would be detrimental to juice quality if the fruit were subjected to direct pressure as is the case with the fleshy fruits, that is, soft fruits, pome fruits and stone fruits. Stone fruits, before being processed for juice separation, must first be separated from their stones, or pits, in order to facilitate ease of handling and to avoid unwanted notes in the finished... 

The epicarp, composed of a layer of colourless cells, polygonal in surface view with thin sinuous walls and a faintly and irregularly striated cuticule stomata are fairly frequent and, very occasionally, cicatrices may be present. Underlying... 

The covering trichomes, which are usually found attached to small fragments of the epicarp, are pluricellular, multi-seriate and rounded at the apex, vary in length and are composed of fairly thick-walled cells. 

On transverse section of the pedicel, two kinds of laticifers, a convex arc and a concave one, were observed in the peripheral bundle and in the central one, respectively. The placenta traces (placentae) and the valve traces (valves) through the capsule wall appeared light microscopically as dense masses of branching vascular tissues in chlorenchyma within the epicarp. The former were fewer in number and smaller in diameter than the latter. The placenta traces contained laticifers but no fibers. The valve traces became the main source of latex. No laticifers were detected in the ovule however, the terminals of the laticifers were observed near the junction of the placenta and ovule. Laticifers appeared in the phloem of the sepals and petals during blooming. Laticifers were detected in the stamen traces in the thalamus but not in the stamens. The ends of laticifers were detected in ovule traces. The diameters of laticifers in the ovary 2 weeks before petal fall were as large as those in the mature capsule. 

The fmit of the olive tree is an egg-shaped dmpe, consisting of a pericarp and an endocarp. The pericarp includes an epicarp (skin) of variable thickness according to the variety, and a mesocarp (pulp) surrounding the endocarp (woody pit) in which... 

In addition to oil, the pulp and epicarp contain a variety of natural components soluble in the oil. As will be seen later, the oil is obtained from the olive by a variety of techniques, always physical, leaving a residue (pomace) that contains up to 8% oil, which is then extracted by solvent (usually hexane) and named pomace oil. 

The epicarp contains a number of components of relatively high polarity that are not removed by mechanical extraction and remain in the pomace. Removal of these components along with the oil by solvent extraction of the pomace accounts for the higher unsaponifiable content of olive-pomace oil. 

Straight Long Chain Alcohols. Linear long-chain alcohols with carbon numbers between C22 and C32 are present in olive oil both free and esterihed (waxes). The components are abundant in the epicarp of the fruit and concentrate in solvent extracted oil. Phytol, probably derived from biodegradation of chlorophyll, is also present along with geranyl (38). 

Cyclic Dihydroxy Compounds. Pentacyclic triterpenes in olive oil include 3p,17p-dihydroxy-12-oleanene (erythrodiol) and its parent compound uvaol, obtained largely from the epicarp and therefore characteristic of solvent extracted oils (42, 65). 

Frequently the pericarp consists for the most part of other elements than the ripened ovarian wall and is then termed a pseudocarp or anthotarp. The pericarp consists of three layers of different texture, viz. epicarp, mesocarp and endocarp. The epicarp is the outer layer. The mesocarp the middle, and the endocarp the inner Digitized by Microsoft ... 

IV. Baccate Fruits (Succulent fruits in which the endocarp is always succulent and the mesocarp sometimes).— The Berry is a small fleshy fruit with a thin membranous epicarp and a succulent interior in which the seeds are imbedded. Examples Capsicum, Tomato, Belladonna, Grape, Currant, etc. 

Pig. 102.—Baccate fruits, i, berry (uva) of Belladonna with adherent calyx 2, Pumpkin, cut transversely illustrating a pepo fruit (ft).alocule 3, hesperidium fruit of the Orange cut transversely showing epicarp (e), mesocarp (m), endocarp (en), pulp (p), and seed (s). 

The Hesperidium is a large thick-skinned succulent fruit with seeds embedded in the pulp but from a superior ovary. Examples Orange, Grape-fruit, Lemon, etc. In each of these there is to be noted a glandular leathery epicarp, a sub-leathery mesocarp and an endocarp in the form of separate carpels. From the endocarp hairs grow inward into the carpellary cavities and become filled with succulence. The seeds lie amid the hair cells. Fig. 102 (3). 

Fig. 103.—I, Drupe of cocoanut cut vertically, showing epicarp (e), mesocarp (m), stony endocarp (rf) seed coat (5), endosperm end), and embryo sac cavity (e,5.) which in the mature seed contains a nutritive fluid. 2. Pome of an apple cut vertically to show core composed of 5 ripened carpels and flesh of matured torus. 3, Eaetrio of raspberry. 4, Same, cut vertically to show arrangement of the little drupes on fleshy receptacle.

Epicarp, consisting of epidermis and hypodermis. The epider-. mis consists of a layer of thick-walled epidermal cells whose outer... 

Fig. 105.—Photomicrograph of a transverse section of a mericarp of Foeni-culum vulgare, showing epicarp (A), mesocarp (B), endocarp (F), vitta (C). endosperm of seed (D), carpophore (G) and fibro-vascular bundle in primary rib (E). (Highly magnified.) ...

Epicarp, or outer covering tissue, composed of colorless epidermal cells and small stomata. The epidermal cells in cross-section appear rectangular, while in surface view they are both polygonal and rectangular. 

The Pericarp or ripened ovarian wall which, alike with all other grains, adheres firmly to the wall of the seed forming a portion of the skin of the grain. The pericarp comprises an outer epicarp of elongated cells with thin cuticle, a mesocarp of thicker walled cells without, becoming thinner within, and a layer of tube cells. 

II. Order Principles.—Palmew or Palm Family.—Tropical or subtropical shrubs, rarely trees, having unbranched trunks which are terminated by a crown of leaves, in the axils of which the flowers are produced. The leaves are well developed with pinnate or palmate blades and a fibrous sheathed clasping petiole. The flowers are small, of one or two sexes, and crowded on a spike or spadix, which is subtended by a large bract, or spathe which may become woody, as in the Cocoanut Palm. The perianth consists of 6 parts in 2 whorls (3 sepals and 3 petals) or it may be inconspicuous or absent. The stamens are 6 in number, rarely 3, inserted below the ovary. The ovary is superior, of 3 cells, with central placenta. The fruit is either a nut, with leathery epicarp, fibrous or cellular mesocarp and thin membranous endocarp, or a drupe (Cocoanut) with leathery epicarp, broadly fibrous mesocarp and stony endocarp, or a berry as in the Date Palm, Phoenix, with membranous epicarp, succulent mesocarp and soft succulent endocarp. The seeds are albuminous with the reserve food frequently in the form of hard cellulose (ivory-nut-palm). 

The baobab fruit is composed of an outer shell (epicarp) (45%), fruit pulp (15%) and seeds (40%) (5). The woody epicarp or pod contains the internal fruit pulp (endocarp) which is split in small floury, dehydrated and powdery slides that enclose multiple seeds and filaments, the red fibres, that subdivide the pulp in segments (Nour et ai, 1980, cited in (20)) (Figure 1). 

Fig. 1 SEM photographs of broken surface olives, adapted from Mafra et al. [7] (a) details of green olive thin-walled parenchyma cells tightly packed (cell adhesion) (b) overview, showing tissues fracturing through the cells of epicarp and mesocarp with no cell separation at the middle lamella (c) details of the black olive parenchyma showing cell separation (by the dissolution of pectic polysaccharides) (d) overview, showing a smaller region of broken cells in comparison to (b), involving only the epicarp and the first layers of the mesocarp...

The major phytoalexins formed by green tissues (cotyledons, leaves, bracts, and the epicarp of bolls) are the cadal.enes and lacinilines shown in Fig. 2 (12, 18). About 75% of these compounds are methylated in the cultivate 6. hirsutum (19), whereas methylation is either greatly restricted or absenfln the other cultivated cottons (G. arboreum, . herbaceum and Gi. barbadense). These compounds have been demonstFated Tn palisade parenchyma cel Is... 

In order to get oil from citrus fruits, such as oranges, lemons or tangerines, cold expression is preferred, due to the thermal instability of the main constituents of the essential oil. The oil cells are located below the epicarp surface. The fruit must be washed and sliced into two halves, the pulp withdrawn and then the peel must be softly pressed to break the oil glands, which can be removed with water. 

Product obtained from vegetable raw material—either by distillation with water or steam or—from the epicarp of Citrus fruits by a mechanical process, or—by dry distillation (ISO/ DIS 9235.2, 1997, p. 2). Steam distillation can be carried out with or without added water in a still. By contrast, dry distillation of plant material is carried out without the addition of any water or steam to the still (ISO 9235, 1997). Note 2 in Section 3.1.1 of ISO/DIS 9235.2 is of importance. It states that Essential oils may undergo physical treatments (e.g., re distillation, aeration) which do not involve signi cant changes in their composition (ISO/DIS 9235.2, 1997, p. 2). 

The history of the expression of essential oils from the epicarp of citrus fruits is not nearly as interesting as that of hydrodistillation. This can be attributed to the fact that these expressed fragrance concentrates were more readily available in antiquity as expression could be effected by implements made of wood or stone. The chief requirement for this method was manpower, and that was available in unlimited amount. The growth of the industry led to the invention of new mechanical machinery, followed by automation and reduction of manpower. But this topic will be dealt with later on. 

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