Therefore, the bioactive glucosinolates (glucoraphanin and indolyl glu-
cosinolates) play an important role for broccoli quality. The content of
glucoraphanin increased with decreasing daily mean temperature. Ad-
ditionally, the daily mean of PPFD at nearly 275 mol m^2 s^1 led to
a minimum of glucoraphanin content at every temperature level (Figure
5.4). Production of glucosinolates and carotenoids is strongly tempera-
ture dependent with an increase in temperature inhibiting biosynthesis
of carotenoids and glucosinolates.
INTERACTION OF CLIMATIC CONDITIONS
IN PRE- AND POSTHARVEST
According to our results, varying weather conditions and agro man-
agement modified the chemical composition of vegetables, that is, cutin
accumulation in the cuticula of the leaves and suberin embedded in the
secondary tissue of roots and tubers, which directly influences the tran-
spiration rate and indirectly influences the external appearance of the
product. The alteration rate of product compounds due to preharvest fac-
tors strongly determines postharvest behavior and shelf life.
The seasonal transpiration behavior in postharvest storage will be il-
lustrated by studies on small radish. Figure 5.5 shows the seasonal tran-
90 ENVIRONMENTAL EFFECTS ON PRODUCT QUALITY
FIGURE 5.5Seasonal transpiration rate of small radish separated in leaves and tubers.