1. The University of Reading, School of Food Biosciences, PO Box 226, Whiteknights, Reading, RG6 6AP, UK.
2. United Biscuits (UK) Limited, Group Research & Development, Lane End Road, Sands, High Wycombe, HP12 4JX, UK.
3. Corresponding author: E-mail: M.H.Gordon@reading.ac.uk Phone: +(44) 1189316723. Fax: +(44) 1189310080.