Extraction and rheological properties of pectin from fresh peach pomace

This paper reports a study of the extraction of pectin from fresh peach pomace at different conditions of temperature (40 degrees C, 60 degrees C and 80 degrees C), acidity (pH 1.30-2.53) and time (10-80 min). The highest yields of extracted pectin were obtained at the highest temperatures and at the lowest assayed pH. The yields of extracted pectin were correlated with pH of extraction by a polynomial third degree equation. Moreover, with each assayed pH and temperature a global kinetics of extraction has been supposed consisting of two stages: pectin extraction and then pectin degradation. Both stages are supposed to be of first order and provide the mean of getting an expression which adequately describes the global process of extraction. Rheological characteristics of the sample extracted at highest yield conditions were also studied. (C) 1999 Elsevier Science Ltd. All rights reserved.