Use of nanoencapsulated curcumin against vegetative cells and spores of Alicyclobacillus spp. in industrialized orange juice.

Pathogenic and deteriorating bacteria are a great concern to food safety. In this sense, the present study evaluated the fight against microbial contamination through the use of nanoparticles containing curcumin, in addition to analyzing the physical properties of these nanoparticles. Efficient curcumin encapsulation was determined by Fourier transform infrared spectra evaluation and differential scanning calorimetry. Transmission electron microscopy images showed irregular shaped nanoparticles with broad size distribution (20-250 nm). The antibacterial activity was considered satisfactory, since curcumin in the form of nanoparticles demonstrated antimicrobial and antibacterial activity superior to curcumin in its free form, against both pathogenic bacteria, such as Staphylococcus aureus (MIC 125 μg/mL), and deteriorates, such as Alicyclobacillus acidoterrestris (MIC 62.5 μg/mL). Since curcumin nanoparticles may be consumed as a food additive, the bioactive properties of the nanoencapsulated curcumin were also evaluated in relation to antioxidant capacity (Thiobarbituric acid reactive substances (TBARS) and oxidative hemolysis inhibition assays) and cytotoxicity against four carcinoma cell lines, as well as two non-tumor cells. As a proof of concept, nanoparticles were incorporated in orange juice, with the juice maintaining satisfactory pH, °Brix, and color stability, during three days of storage (8 °C).