224 Produce Degradation: Reaction Pathways and their Prevention
8.9 Produce Treatment and Nutrient Quality .................................................... 243
8.9.1 Preharvest Treatment........................................................................ 243
8.9.2 Postharvest Treatment ...................................................................... 244
8.9.2.1 Heat Treatments ................................................................ 244
8.9.3 Chilling Treatments.......................................................................... 247
8.9.4 Waxing.............................................................................................. 248
8.9.5 Coating with Edible Films ............................................................... 248
8.10 Nutritional Implications of Produce Processing.......................................... 248
8.10.1 Blanching ......................................................................................... 250
8.10.2 Refrigeration and Freezing .............................................................. 250
8.10.3 Dehydration ...................................................................................... 251
8.10.4 Fermentation..................................................................................... 252
8.10.4.1 Lactic Acid Fermentation ................................................. 252
8.10.4.2 Acetic Acid Fermentation................................................. 253
8.10.4.3 Alkaline Fermentation ...................................................... 254
8.10.5 Probiotics.......................................................................................... 254
8.10.6 Use of Additives............................................................................... 256
8.10.7 Radurization ..................................................................................... 257
8.11 Summary ...................................................................................................... 258
References.............................................................................................................. 259
8.1 INTRODUCTION
Fruits and vegetables contain small to significant amounts of several key nutrient
(e.g., carbohydrates, vitamins, and minerals) and nonnutrient substances (e.g., phy-
tochemicals) that are critical to human health. In addition, fruits and vegetables are
composed of living tissues that are metabolically active and for this reason their
composition changes constantly. The rate and extent of such changes depend on the
physiological role of the substances involved and the stage of maturity of the fruits
and vegetables (Salunkhe et al., 1991). Although fruits and vegetables can make a
significant contribution to human nutrition, they are not recommended as the sole
source of nourishment. Rather, they are used advantageously to correct nutrition
deficiencies (e.g., the role of citrus fruits in the correction of scurvy) or to comple-
ment other foods.
Several of the compounds in fruits and vegetables are very sensitive to produce
handling and the treatment processes that occur between the time produce leaves
the farm to the time of purchase/consumption. Therefore, when the nutritional
content of fruits and vegetables is considered, pre- and postharvest handling and
treatment factors that influence nutrient composition should be taken into account.
A few of the factors of importance in this respect include stage of maturity and
ripening of fruits and vegetables during harvesting, disinfecting treatments, storage,
and processing treatments.
The maturity or ripening of fruits and vegetables as described by Salunkhe et
al. (1991) is accompanied by a series of changes in color, texture, flavor, and chemical
composition. These changes may or may not be associated with degradative or
synthetic processes. In this chapter, nutrients common in fruits and vegetables and