Protein oxidation in processed cheese slices treated with pulsed light technology

Abstract

The effect of pulsed light technology on protein oxidation was studied in sliced processed cheese by measuring the protein-bound carbonyls with a spectrophotometric DNPH assay. Bovine serum albumin was also tested as a protein standard. Fluences of 0.7, 2.1, 4.2, 8.4 and 11.9 J/cm(2) were applied to vacuum-packaged cheese slices and to an aqueous solution of the protein. Treatments up to 4.2 J/cm(2) did not promote protein oxidation immediately after flashing either in cheese or in the standard. Samples treated with 8.4 and 11.9 J/cm(2) showed significantly higher carbonyl amounts than non-treated ones. Protein oxidation increased along cheese storage at 4°C, and differences among treatments remained. Further studies on the sensory properties will be needed to clarify the impact of pulsed light on processed cheese quality.

Keywords: Carbonyls; DNPH assay; Processed cheese; Protein oxidation; Pulsed light.