Development of a realistic food model describing the fate of glucosinolates during food processing
PhD-fellow: Dipl. Oect. Irmela Kruse
Irmela.Kruse@wur.nl
Supervisors:
Dr. ir. M. Dekker (PDQ), Dr. R. Verkerk (PDQ), Prof.dr.ir. M.A.J.S. van Boekel (PDQ)
Project term: December 2009 – december 2013
Sponsor: EU-FP7 DREAM
Introduction
Epidemiologic studies, prospective cohort studies as well as case control studies have been carried out on the correlation between a diet high in Brassica vegetables which contain glucosinolates, and the formation and development of cancer. Even if the metabolism is not entirely understood it is assumed that degradation products of glucosinolates have the potential to reduce the risk of cancer. After cell rupture e.g. while chewing or thermal treatment the glucosinolates come in contact with the enzyme myrosinase which is locally secluded in the intact plant. The myrosinase separates the glucosinolate into glucose and an unstable aglycon which is transformed into either nitrile, isothiocyanate or thiocyanate depending on the reaction environment. These products are highly bioactive and especially isothiocyanates have shown in animal and cell studies cancer preventive properties.
Aim
The aim of this project is to design and develop a realistic food model of the fate of glucosinolates while processing food. With the aid of mathematical modelling the changes in the concentration and availability of glucosinolates during processing can be described and the content in the ready produced food predicted. This could help to quantify the intake of glucosinolates in studies. The model can calculate the glucosinolate contents of foods made by different processing methods and therewith take consumer behaviour into account. By this the statistical power of studies already carried out or planned studies about the correlation between intake of Brassica vegetables and reduction of cancer risk may be increased. It should be possible with limited additional experimental research to apply such a model to other bioactive plant components.
Future research
To characterise 3 to 5 different vegetables of the family Brassicaceae. Their morphology/micro¬structure, cell wall characteristics, enzyme activity and stability, glucosinolate levels, profiles and stability, cell lysis, leaching, decompartmentalisation, bioaccessibility and bioavailability will be determined as input for the model. Based on experimental studies a mathematical model will be developed to predict the contents of glucosinolates and their degradation products in the processed food. Depending on the surrounding conditions like pH or temperature during the breakdown of glucosinolates the reaction products will vary. Hence different mechanisms have to be covered by the model including heating up of the processing water, thermal lysis of cells, leaching of glucosinolates from the vegetable matrix, enzymatic breakdown of glucosinolates, denaturation of myrosinase, thermal degradation of glucosinolates in the vegetable and in the processing water.
Conclusion
It should be possible to use the mathematical model not only for foods containing Brassica vegetables, but also for other plant-based foods, with limited additional effort. If the degradation mechanism of a food component is known the content in the processed food can be estimated with such a model for all kinds of nutrients. Therefore it would be a useful tool for food producing companies to estimate the content of e.g. phytonutrients for health claims as well as for researchers to estimate the actual content in prepared foods of phytonutrients in their studies.
