Α-Cyclodextrin encapsulation of supercritical CO₂ extracted oleoresins from different plant matrices: A stability study

Abstract

Here we describe the encapsulation in α-cyclodextrins (α-CDs) of wheat bran, pumpkin and tomato oleoresins, extracted by supercritical carbon dioxide, to obtain freeze-dried powders useful as ready-to-mix ingredients for novel functional food formulation. The stability of tocochromanols, carotenoids and fatty acids in the oleoresin/α-CD complexes, compared to the corresponding free oleoresins, was also monitored over time in different combinations of storage conditions. Regardless of light, storage at 25°C of free oleoresins determined a rapid decrease in carotenoids, tocochromanols and PUFAs. α-CD encapsulation improved the stability of most bioactive compounds. Storage at 4°C synergized with encapsulation in preventing degradation of bioactives. Unlike all other antioxidants, lycopene in tomato oleoresin/α-CD complex resulted to be more susceptible to oxidation than in free oleoresin, likely due to its selective sequestration from the interaction with other lipophilic molecules of the oleoresin.

Keywords: Carotenoids; Cucurbita moschata (Duch.); Differential scanning calorimetry; Fatty acids; Fourier transform infrared spectroscopy – attenuated total reflectance; Solanum lycopersicum (L.); Supercritical fluid extraction; Tocochromanols; Triticum durum (Desf.).