Encapsulation of tomato juice by freeze-drying: physicochemical and antioxidant characterization and stability

Abstract

Tomatoes are an important dietary source of lycopene, a natural antioxidant compound that contributes to reducing reactive oxygen species (ROS); however, the lack of a food matrix can result in their rapid degradation during storage. Therefore, the aim of this work was to evaluate the physicochemical, antioxidant, and stability properties of lycopene and β-carotene in encapsulated tomato juice (TJ) obtained by freeze-drying. Maltodextrin (MD) and gum arabic (GA) were used as wall materials. Two formulations were obtained: MD:GA:TJ (3:1:14) and MD:GA:TJ (1:3:14), and were both compared with three controls: MD:GA (3:1), MD:GA (1:3), and freeze-dried TJ without wall materials. The physicochemical properties, lycopene, and β-carotene content were evaluated; also, antioxidant activity was measured by DPPH and ABTS assays. Carotenoid stability during storage was also evaluated. The encapsulates presented maximum concentrations of lycopene and β-carotene of 17.86 and 1.90 mg/100 g, respectively, and an antioxidant activity that varied from 5.14 to 20.98 μM Trolox/g. Good hydration, water solubiliza- tion, and color properties were observed in the encapsulates. The MD:GA:TJ (3:1:14) treatment presented the best antioxidant and stability characteristics during storage.