Produce Color and Appearance 215
of Swiss chard (Beta vulgaris l. ssp.cicla (L.) lef. cv. Bright Lights). Bright Lights
is a mixture cultivar that produces differently colored plants. RP-HPLC and positive
ion electrospray mass spectrometry were used for analyses. Samples of purple, red-
purple, yellow-orange, and orange petioles were freeze-dried, extracted with 80%
aqueous methanol, filtrated, concentrated in vacuum, and subjected to further sep-
aration and identification. Colorimetric measurements of the extracts were also
recorded. Nineteen betaxanthins and nine betacyanins were identified in the extracts.
Histamine-betaxanthin and alanine-betaxanthin were novel compounds not reported
previously. Tyramine-betaxanthin and 3-methoxytyramine-betaxanthin were identi-
fied for the first time in Swiss chard. The compounds identified in purple petioles
included betanin, isobetanin, betanidin, and isobetanidin.
7.6 CONCLUDING REMARKS
In the past few current years significant progress has been made in the chemistry of
pigments and related compounds occurring in fruits and vegetables. Most of the
research has been done in the area of carotenoids and polyphenolic compounds due
to the presence of epidemiological and other data related to promotion of health and
disease prevention, not necessarily due to the color function of these substances. A
significant number of publications in the biochemistry of chlorophylls has been
devoted to photosynthesis. Relatively less work related to betalains has been
reported. To refresh the reader’s memory, at the beginning of each section of this
review short introductory information is included on chemical definitions and struc-
tures of selected pigments. Only a few figures with basic structures considered to
be essential are presented in the text. Numerous and sometimes complex chemical
structures and tables are available in many referenced publications. The introductory
information in each section is followed by summaries of the most current reports.
These reports are not equally distributed among all subjects of the review and are
more or less numerous in some areas depending on the available publications. An effort
was made to provide enough information to reduce the need to read the full articles.
However, readers who are interested in more details will find them in referenced original
publications, which in most instances also contain many citations to the past work in
the specific areas. They may be especially important for those who have an interest in
health aspects of produce pigments and related compounds that were not covered in
this review due to the space limitation. Several monographs that contain comprehensive
coverage of the past work on chemistry of pigments of fruits and vegetables are also
cited here. The purpose of this review will be fulfilled if it contributes at least in part
to the dissemination of current progress in the field of chemistry of produce pigments
and motivates some young researchers to work in this area.
REFERENCES
Alonso-Salces R, Barranco A, Abad B, Berrueta L, Gallo B, and Vicente R (2004). Polyphe-
nolic profiles of basque cider apple cultivars and their technological properties. J.
Agric. Food Chem. 52, 2938–2952.