With the advent of improved analytical techniques, statistical experiment design, computers and knowledge of food constituents, there have been significant advances in our knowledge of the impact of processing on food constituents. Unfortunately some of this information has not contributed significantly to our ability to predict the influence of processing or resulted in refined predictive equations. This paper reviews our current ability to predict the influence of processing on food constituents. Traditional and potential processes are examined and research needs are identified so that food quality quantification and prediction advances. (C) 2002 Elsevier Science Ltd. All rights reserved.