The Role of Starch Physicochemical Properties in Determining the Glycaemic Index of Novel Potato Varieties

• Main Author: Moreira, Tracy Sousa
• Other Authors: Wolever, Thomas M. S.
• Language: en_ca
• Published: 2012
• Subjects: Glycaemic Index; Potatoes; 0570
• Online Access: http://hdl.handle.net/1807/32609

Potatoes are often thought of as high GI. It is known that cooking and cooling affect GI and that these effects may be mediated through the physicochemical properties of their starch. As part of a Canadian initiative to develop low GI potatoes, novel potato varieties which differed in starch composition were tested in 2 separate studies. In study 1, we determined the GI of 8 varieties and found that cooling produced a wide range of effects (0-50% reduction in GI). In study 2, four previously tested varieties were re-examined. A significant variety-x-treatment interaction (p<0.01) was observed with cooling reducing GI in some potatoes. Examination of the starch properties and their role in determining GI showed that RDS was positively associated with GI (r2= 0.85, p= 0.001) and SDS (r2=-0.60, p= 0.02) and amylose (r2=-0.99, p=0.007) negatively associated with GI. No relationship between RS and phosphorous content and GI was observed.