Fruit and Vegetable Quality

traceuticals have gained some attention in relation to genetic engineer-
ing attempts to improve or modify the quality of agricultural and horti-
cultural produce. Table 2.3 gives an as yet incomplete summary of
known phytonutrients and attempts towards their modification via ge-
netic engineering.
For example, by genetically manipulating the carotenoid pathway a
range of different quality parameters such as contents of solids, vitamin
A, antioxidative compounds, or fruit color may be altered. This has been

Genetic Engineering of Traits Affecting Quality 33

Phytochemical Ascribed Effect

Carotenoids cancersimmune system;UV protection;

antioxidant; some are vitamin A precursors

(-, - and ε-carotene)

Vitamin A antioxidant; essential nutritive

Desaturated fatty acids LDL-choleresterol

Resveratrol cardiovascular disease

Tocopherol antioxidant;liver detoxification enzyme

activity

Phytoestrogens breast cancer

Hemicellulose binding of gallic acid

Glucosinolates liver detoxification;immune

response;cancers

L-carnitine fatty acid transport across mitochondrial

membranes

Epitopes of surface immune response (“edible vaccines”)

proteins from

pathogenic microbes

Epitopes of auto- immune response (“edible vaccines”)

antigenes

Other applications

Elimination of allergens transgenic elimination of known potent food

allergens (e.g., rice allergen; glutene in

wheat flour)

Increase of phytase digestibility of feed and food;availability

of phosphorous

Table 2.3. Current Genetic Engineering of Plants for Higher

Contents of Phytochemicals.

,Increasing or decreasing effect, respectively.