530 Produce Degradation: Reaction Pathways and their Prevention
formalin-acetic acid-ethanol [3] or in 3% glutaraldehyde-2% formaldehyde and post-
fixed in 1% osmium tetroxide [4] and dehydrated in a graded series of ethanol [3,4].
The samples were then either cryofractured in liquid nitrogen [5] or sliced under
100% ethanol, critical point dried in a Tousimis Autosamdri 815 (Tousimis, Rock-
ville, MD), sputter coated with gold-palladium in a Denton Desk II sputter coating
unit (Denton Vacuum, Moorestown, NJ), and observed and photographed in an
Hitachi S-4700 field emission scanning electron microscope (Japan).
18.2 INHERENT PRESERVATION IN PLANT ARCHITECTURE
Intact fruits and vegetables are protected from rapid breakdown from environmental
influences by their surrounding outer layers that form a skin. The outermost protec-
tive layer is a thin, continuous waxy layer, the cuticle [6], which slows dehydration
and serves as an effective barrier against the entry of pathogens and insects [7] and
is, therefore, the natural package giving a first layer of protection. Beneath the cuticle
FIGURE 18.1Schematic representation of the various parts of plants consumed as food.
(Adapted from Jewell, G.G., Fruits and vegetables, in Food Microscopy, Food Science and
Technology, Vaughn, J.G., Ed., Academic Press, New York, 1979.)