pH in Action

Based on fundamental chemical relations, well-established in chemical engineering and chemical technology over almost a century, the effects of pH in food and agricultural products will be deduced for different situations and processes. Based on simple equilibria and dissociation of water, salts, acids and bases, and considering the reaction of hydrogen ions in these food-related systems, simple and reliable formulations are developed capable of describing surprisingly well the discoloration of blanched vegetables and the activity of enzymes in different buffered and unbuffered systems. The line of reasoning is generic and can be applied repeatedly to different problems, situations and processes

pH Effects in Foods: Development, Validation and Calibration of a Fundamental Model

The effects of pH observed in the activity of a number of enzymes from different origins and the degradation of green colour in blanched vegetables, was modelled based on fundamental kinetic principles by considering hydrogen ions as an integral part of the reaction mechanism. Parameters were estimated by non-linear regression analysis with explained parts (R2adj) was in all cases except for the enzyme lipase, well over 95°and frequently well over 98&Eth;Applying fundamental models in integral data analysis made it possible to pinpoint aberrations at high and low pH ranges in the discoloration of vegetables, which remained unnoticed using classical analysis procedures. The model on enzyme activity was successfully applied to analyse and to describe a double optimal pH region when iso-enzymes are present in the total pool of active enzymes

Methoden voor de karakterisering van de grondstof aardappel : tweede verwerkingstijdstip

Dit rapport geeft een overzicht van de methoden die gebruikt worden voor bet bepalen van de grondstofeigenschappen tijdens het tweede verwerkingstijdstip in het kader van het VAVI-programma