PROPERTIES OF STARCHES FROM AUSTRALIAN WHEATS .3. IN-VITRO DIGESTIBILITY AND HYDROXYPROPYL DERIVATIVES

The in vitro digestibilities of starches isolated from 21 Australian w heat varieties were measured after gelatinisation, using porcine pancr eatic alpha-amylase. The starches were also converted into their hydro xypropyl derivatives and levels of substitution, and freeze-thaw stabi lity of the products assessed. Digestibilities varied between samples and were significantly correlated negatively with fat content of the s tarches. No significant correlations between digestibilities and any o f amylose content, grain hardness or granule crystallinity were found. Efficiency of reagent usage during derivatisation and freeze-thaw sta bility also varied between starches. Levels of substitution were not r eflected in relative freeze-thaw stabilities of the starch derivatives .