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 °C in solution and at −20 °C in the lyophilized products. Lycopene content was monitored at λmax = 482 nm, the limit of detection was 0.41 μg/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 μg/ml for β-CD, HP-β-CD and Me-β-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 μg/ml, respectively. At 4 °C, storage stability of lycopene–cyclodextrin binary systems in water or 5% (w/v) aqueous dextrose solutions, was limited (t1/2 = 1–4 days). Addition of the antioxidant sodium metabisulfite increased the stability of lycopene–HP-β-CD binary system in water. At −20 °C, the lyophilized lycopene–cyclodextrin binary systems were stable for at least 2 weeks.