Evaluation of Alternative Colorants to Citrus Red II and Their Application on Citrus Fruit

The humid subtropical climate of Florida citrus groves contributes to poor peel quality of oranges and their hybrids early in the season, and has resulted in fresh fruit packers using dye to increase their product’s marketability. Citrus Red II (CR2), the most widely used commercial citrus dye in Florida, has been listed by the European Union (EU) and the International Agency for Research on Cancer (IARC) as a group 2B carcinogen. This has generated a negative perception in the mind of consumers, and increased the desire to find natural or food grade colorants to replace CR2 for use on citrus. In this research, three natural red/orange colorants, including annatto extract, paprika extract and paprika oleoresin, were selected based on their perceived favorable appearance on orange fruit.  The relative stability of the natural colorants, with respect to CR2, was evaluated by applying them on test papers and orange fruits. All evaluated natural colorants were rapidly oxidized and faded when applied on test papers. Application of a carnauba wax after application of the colorants substantially reduced the oxidation rates of the natural dyes, resulting in slower decoloration. When applying the natural colorants to ‘Hamlin’ oranges before waxing, the treatments retained the improved color after storage in the dark at 5 °C, simulating cold storage, however, only annatto extract maintained a stable color when stored in a simulated market condition, at 23 °C under room light exposure.