Produce Degradation Pathways and Prevention

Role of Cuticles in Produce Quality and Preservation 23

FIGURE 2.1

Model of cuticle structure in produce. The epidermal cell layer (EC) consists

of epidermal cells. The cell contents are contained within the cell by the cell membrane(ECM) and cell wall (CW). The cuticular membrane (CM) consists of a lamellar region (LR)composed of a cutin-rich matrix and some cellulose and pectin material. The cutin matrix isin

filtrated with waxes that may be extruded on the cuticle surface to form an epicuticular wax

layer (EW). Some crystalline wax structures may also form on the cuticle surface. Thecuticular membrane adheres to the epidermal cell wall by pectins (P). The cuticular membrane,pectin region, and epidermal cell layer taken together form the bulk of the skin tissue.FIGURE 2.2

Photomicrograph of a cross-sectional view of cherry fruit stained for carbohy-

drates using periodic acid-Schiff’s reagent. Note the carbohydrate-rich cell wall, especiallyin the epidermal layer.FIGURE 2.3

Photomicrograph of a cross-sectional view of cherry fruit stained for lipids

using sudan black. Note the dark staining of the cuticular membrane on the fruit surface.FIGURE 2.4

Photomicrograph of the surface of a cherry fruit. Note the reticulate pattern of

epicuticular wax on the cuticle surface. The structure was most prominent on the stylar endof the fruit and varied in quantity from one fruit to another.FIGURE 2.5

Photomicrograph of the cuticular membrane of cherry fruit isolated using

enzymes. Note the reticulate pattern of epicuticular wax similar to that shown in Figure 2.4.