Coclodextrina

1878

J. Agric. Food Chem. 2005, 53, 1878−1883

Effect of β-Cyclodextrin in Improving the Correlation between
Lycopene Concentration and ORAC Values
DHARMENDRA V. BANGALORE, WILLIAM MCGLYNN,*

AND

DARREN D. SCOTT

Food and Agricultural Products Research and Technology Center, Oklahoma State University,
Stillwater, Oklahoma 74078-6055

Lycopene, a lipophilic antioxidant, plays acrucial role in biological systems. It may play an important
role in human biological systems by providing protection against cardiovascular disease and some
cancers and by boosting the immune system. The oxygen radical absorbance capacity (ORAC) has
been validated as an index of antioxidant activity for many hydrophilic antioxidants but not for lycopene.
This study validates the ORAC assay fordifferent concentrations of lycopene in the presence of
β-cyclodextrin, a water-solubility enhancer. Lyc-O-Mato 6% extract was used as a source of lycopene
for these experiments. Lycopene was extracted according to a standard spectrophotometric assay
procedure in the presence of β-cyclodextrin at concentrations of 0, 0.4, 0.8, and 1.6%, and the
antioxidant activity of lycopene was measuredwith the ORAC assay. Experiments were conducted
in quadruplicate and statistical pooled correlations analyzed. Statistical analysis showed a very high
correlation (R 2 ) 0.99) between ORAC and ascorbic acid concentrations, validating this method.
Lycopene concentration correlated poorly with ORAC (R 2 ) 0.33) in the absence of β-cyclodextrin.
Correlations improved with increasing levels ofβ-cyclodextrin (R 2 ) 0.58 and 0.91 for 0.4 and 0.8%
β-cyclodextrin, respectively). A very high β-cyclodextrin concentration (1.6%) decreased the correlation
between ORAC and lycopene concentration. Inclusion of β-cyclodextrin in the ORAC assay improves
correlation between ORAC and lycopene concentration, thus expanding the scope of the ORAC assay
to include an additional fat-soluble antioxidant.KEYWORDS: ORAC; lycopene; lipophilic antioxidants; β-cyclodextrin

Lycopene, a lipophilic antioxidant, may play a number of
key health-promoting roles in the human body. Among these
are cancer prevention, reduction of cardiovascular risks, and
regulation of the immune system (1-3). Currently, the most
extensive use of lycopene is as a coloring agent for the food,
cosmetic, and pharmaceuticalindustries (4). However, the high
antioxidant activity and bioavailability of lycopene make it very
attractive as an ingredient in the functional food and nutraceutical products that are increasingly popular in today’s food
marketplace. Potential sources of lycopene and the levels present
in different foods have been previously tabulated (5). The
technology exists to extract and purifylycopene for use as a
functional food ingredient. However, further research is needed
to correlate lycopene concentration in a food product with
antioxidant activity. Such knowledge is critical for determining
effective and economical rates of lycopene addition. One
standardized and well-established method for analyzing antioxidant activity as a function of concentration is the oxygen
radicalabsorbance capacity (ORAC) assay. In the past, this
method has been largely limited to water-soluble antioxidants.
Modifying this method to work with lycopene and perhaps other
* Author to whom correspondence should be addressed [fax (405) 7446313; e-mail mcglynn@okstate.edu].

fat-soluble antioxidants provides a powerful and convenient tool
for quantifying the effectiveness of lycopene as anantioxidant
in foods.
The ORAC assay originally was developed by Cao et al. (6).
Ou et al. (7) enhanced the economy and repeatability of the
method by substituting fluoresein for the phycoerythrin originally used as a florescent probe. This enhanced assay was termed
ORACFL. Both the ORAC and ORACFL assays employ hydrophilic reagents in an aqueous system. Even so, a number of
recent studies...