effects continue to be the focus of studies on these pigments
(Figure 4). For example, microwave and conventional
heating of kiwi led to 42–100% losses in the
chlorophylls [54]. In some vegetables, high pressure treatment
caused no degradation or slight increases, while high
pressure high temperature degraded both chlorophylls
[55]. Chlorophyll b was more stable than chlorophyll a at
70 8C, but both were highly degraded at 117 8C. In processed
green olives, all the chlorophyll pigments were Mgfree
(mostly pheophytins)[56].In pistachio kernels, drastic
losses were observed with pheophytins a and b, which both
decreased by approximately 85% after 60 min of roasting
[57]. Pyropheophytins a and b increased significantly during
roasting and were 10–12 fold higher in the pistachios
roasted for 60 min than in the raw pistachios.
Currently chlorophyll complexes and chlorophyllins are
the only approved chlorophyll colorants [37]. Their use in
food products is often limited by their susceptibility to
photodegradation and instability in acidic pH (3.5–5).