Color improvement and metallo-chlorophyll complexes in continuous flow aseptically processed peas

Fresh and frozen green peas were blanched in zinc solution (50 to 500 mg/L) and thermally processed in a particle cell reactor, which simulates a cont inuous flow aseptic processing system. The thermal process temperatures ran ged from 121 to 145 degrees C at holding times from 0 to 20 min. The degrad ation of chlorophyll and the resulting formation of Zn-pheophytin a and Zn- pyropheophytin a were monitored. Quantitative analysis of the metallo-chlor ophyll complexes was performed by high-performance liquid chromatography, C omplex formation increased during heat processing and was dependent on the zinc concentration absorbed within the peas during blanching. At 130 to 145 degrees C, the formation of Zn-pyropheophytin a increased and processing b etween 121 to 125 degrees C promoted the formation of Zn-pheophytin a. Impr ovements in color relative to control samples suggested that the process mi ght be applicable to two-phase continuous aseptic processing of vegetables.