Lycopene-rich watermelon concentrate used as a natural food colorant: Stability during processing and storage

A lycopene-rich watermelon (Citrullus lanatus) concentrate was incorporated into snack cracker, fusilli pasta, and extruded snacks for coloring purposes. Changes in the L* and a* color coordinates and in the lycopene content were evaluated before and after thermal processes and monitored through 90 days of storage at ambient tem-perature. The products with the maximum lycopene degradation during processing were snack cracker and extruded snack (between 30 and 45%) whereas no degradation was observed in the fusilli pasta, except during cooking into boiling water (reduction up to 41%). The change in color during processing varied substantially depending on the product, but, in general, thermal treatments applied reduced the a* values (less reddish). The degradation kinetics of the lycopene and the color during storage followed first-order kinetics, with a half-life time of 25 to 315 days for lycopene content and 65 to 210 days for a* coordinate. Snack cracker was the most stable and had more than a 4-month period before losing half of the pigment content.