Investigations of commercial sodium copper chlorophyllin degradation after ultraviolet irradiation

Abstract

Chlorophyllins are naturally derived colors that provide green hues to food products in oil- and water-based systems. Due to their good antimicrobial activity, in order not to contaminate the surface of food products and to increase product expiration dates and safety, the use of commercial chlorophyllin is common in the form of antimicrobial films that could cover fresh or processed food. UV irradiation effects on commercial sodium copper chlorophyllin are examined to estimate the potential application risk of this chlorophyll derivative for use in foods and cosmetics. Photodegradation of an aqueous 1 × 10-4 M commercial sodium copper chlorophyllin solution was monitored after ultraviolet irradiation. The samples were irradiated for a period of 0 - 60 min. in a cylindrical photochemical reactor called "Rayonnet" with symmetrically placed lamps that emit an energy flux of 12 W/m2 at 300 nm. Ultrahigh liquid chromatography coupled with a diode array and electrospray ionization mass spectrometry was used to monitor the loss of major components of sodium copper chlorophyllin after irradiation, as well as, to detect possible new products. It is estimated that the photodegradation of all detected compounds follows first-order kinetics. UHPLC analysis showed the loss of the major chlorophyllin component, copper chlorin e6 , at a rate faster than the overall detected components, in the range of 7.02 × 10-2 min-1.The observed photosensitivity of sodium copper chlorophyllin was lower than to the natural chlorophylls, and raising the possibility of its use in food and cosmetics. The main detected photoproducts are oxidized compounds of chlorophyllin. For all these reasons, the rapid loss of copper chlorin e6 , may reduce some of the main commercial sodium copper chlorophyllin dietary benefits, like antimutagenic and antioxidant activity.