Influences of Drying and Storage of Lycopene-Rich Carrots on the Carotenoid Content

The stability of β-carotene and lycopene was investigated during convective air and inert gas drying, microwave vacuum drying, and freeze-drying for lycopene containing carrots (Daucus carota L. cv. Nutri Red). After convection drying at temperatures below 70°C, β-carotene and lycopene contents remained unchanged independent of the drying medium. Freeze-drying did not show any advantage to convection-drying regarding carotenoid retention. Microwave vacuum–drying led to dry products with high carotenoid retention within very short drying times of about 2 h. Storage in air and in inert gas (nitrogen) containers was studied for convection-dried products, observing a better retention of carotenoids when using inert gas for a period of up to 6 months. After convection- and microwave vacuum–drying, an even better carotenoid extractability could be observed. No changes in the isomere fractions could be detected in any case.