The Effect of Potato Varieties and Processing Methods on Glycemic Response

In order to identify those potatoes which exert a low glycemic impact after processing, eight early potato varieties and four processing methods were evaluated for their total starch content, amylose content, rapidly digestible starch (RDS), slowly digestible starch (SDS), and resistant starch (RS), estimated glycemic index (eGI), glycemic load (eGL) as well as their relationship among each other. While all these profiles were highly dependent on the potato variety and processing methods, all the eight varieties were classified as low GL foods (p ≤ 0.05). A strong positive correlation was observed between eGI and RDS (r = 0.84, 0.79, and 0.74) for retrograded and reheated, baked and microwaved varieties, respectively), whereas a moderate negative correlation was observed between eGI and RS for retrograded and reheated (r = -0.39) and microwaved (-0.37) varieties (p ≤ 0.05). On the basis of these findings, it can be concluded that potato variety, processing methods, and starch characteristics define the eGI and eGL. Furthermore, for the varieties examined, the present study identified RDS as a major starch factor contributing to eGI.