393 Studies on structure-function relationships of friabilin.

F. M. ANJUM and J. D. Schofield. Department of Food Science and Technology, University of Reading, Reading RG6 6AP, UK.

Puroindolines (Pins) were extracted from starch and flour of soft and hard wheat cultivars, and puroindoline a (Pin a) and puroindoline b (Pin b) variants were isolated by using chromatography of Mono S. Differences were found in the presence/concentration of puroindoline a and puroindoline b between hard and soft wheat cultivars. Variations in the ability of hard and soft wheat starches to bind Pins have been examined and, conversely variation in the ability of Pins from hard and soft wheats, including Pin b variants, to bind to the surface of a particular wheat starch has been explored. The involvement of particular amino acids in the binding of Pins to the starch granule surface has been assessed using specific chemical modification techniques.