Solubilization and quantification of lycopene in aqueous media in the form of cyclodextrin binary systems

An optimized kneading method for the preparation of lycopene-cyclodextrin binary systems was developed leading to solubilization of lycopene in water and 5% (w/v) dextrose solution. Lycopene quantification in the prepared binary systems was performed by a developed spectrometric method that followed a successful single-step extraction with dichloromethane. Storage stability characteristics of the binary systems were studied at 4 degrees C in solution and at -20 degrees C in the lyophilized products. Lycopene content was monitored at lambda(max)=482 nm, the limit of detection was 0.41 microg/ml and relative standard deviation was less than 3.1%. The results obtained with the spectrometric method were confirmed by a HPLC method. In the presence of cyclodextrins, lycopene concentration in water was 8.0+/-1.0, 27.1+/-3.2 and 16.0+/-2.2 microg/ml for beta-CD, HP-beta-CD and Me-beta-CD, respectively. In 5% (w/v) aqueous dextrose solutions the corresponding values were 16.0+/-1.8, 48.0+/-5.1 and 4.0+/-0.5 microg/ml, respectively. At 4 degrees C, storage stability of lycopene-cyclodextrin binary systems in water or 5% (w/v) aqueous dextrose solutions, was limited (t(1/2)=1-4 days). Addition of the antioxidant sodium metabisulfite increased the stability of lycopene-HP-beta-CD binary system in water. At -20 degrees C, the lyophilized lycopene-cyclodextrin binary systems were stable for at least 2 weeks.