Antioxidants and Bioactive Compounds in Fruits - Fruit Ripening: Physiology, Signalling and Genomics - page 100

yet the relationship between common
quality attributes and phytochemical pro-
fi les has not been examined in great detail.
Quality evaluation is an important issue
in the fruit industry and in breeding
programmes, whilst studies of phyto-
chemical attributes (e.g. carotenoids,
tocopherols and phenolics) related to
antioxidant properties have recently
commenced in breeding populations. The
exploitation of natural populations is an
integral part of modern marker-assisted
breeding, with special reference to
nutritional quality and bioactive com-
pounds. Recently, phytochemicals present
in green, yellow and red wild relatives of
tomato have been analysed during fruit
development and ripening, and noticeable
differences in terms of antioxidant prop-
erties have been monitored (Mélendez-
Martinez et al. , 2010).
Over the last decade, numerous studies
have quantifi ed the phytochemical content
and/or the total antioxidant capacity with
an array of in vitro assays in cultivars/
genotypes of the same species. Such
analyses are usually conducted with
samples from a single maturity stage
(physiological or commercial), and only
later studies have measured quantities of
such compounds during fruit ripening both
on and off the vine. As a result, infor-
mation regarding phytochemical profi les of
fruit during maturation and ripening under
various postharvest conditions represents
an ongoing research emphasis.
Testing methods employed to monitor
the phytochemical composition and anti-
oxidant properties of fruits are another
critical factor. Most studies determine the
total content of phenolic compounds,
carotenoids and fl avonoids using relatively
simple spectrophotometric methods. How-
ever, it should be noted that, due to the
complex nature of bioactive compounds in
fruit, one-step characterization of such
compounds is diffi cult. The selection of the
solvent, drying and extraction method is of
critical importance in phytochemical
analysis (Goulas and Manganaris, 2012).
Hyphenated techniques, such as high-
performance liquid chromatography with

UV detection (HPLC-UV) and liquid
chromatography-mass spectrometry (LC-
MS) or spectroscopic techniques such as
nuclear magnetic resonance (NMR) and
Fourier transform infrared spectroscopy
(FT-IR) offer insights in to the composition
of specifi c bioactive compounds in fruit.
Emerging research is employing meta-
bolomic platforms to monitor fruit
antioxidant/phytochemical profi les (Lom-
bardo et al. , 2011; Rohrmann et al. , 2011).
The antioxidant levels of fruit crops
may be attributed to on- and off-the-vine
factors including environmental conditions
during growth and development, as well as
those in the postharvest environment. In
addition to fruit manipulation and post-
harvest environmental conditions, the
accumulation and degradation of anti-
oxidant compounds of fruits during the
ripening process may also be attributed to
both genetic and environmental factors,
such as cultivar, cultural practices,
environmental factors and developmental
stage (Vicente et al. , 2009). Duration of
holding at room temperature, in cold
storage and other postharvest treatments
including controlled storage temperature
and modifi ed atmospheres and/or other
physical treatments all have the potential
to change the phytochemical profi le of the
fruit under study. A recent review high-
lighted changes that occurred in phyto-
chemical concentration during on-tree
ripening or after the employment of several
postharvest technologies and processing
methods (Serrano et al. , 2011). Tech-
nologies such as heat and calcium
treatments, modifi ed atmosphere packaging
and ethylene action inhibition through
application of 1-methylcyclopropene (1-
MCP) and polyamine can be applied before
or along with cold storage. Intriguingly,
these specifi c treatments increased the
bioactive content of fruit commodities
compared with conventional cold storage
alone (Serrano et al. , 2011).
An overview of the health-promoting
properties of horticultural commodities on
a species basis as well as on general
aspects of fruit nutritional quality has been
published recently (Vicente et al. , 2009;