Glycemic Index and Amylose Content of 25 Japonica Rice Italian Cultivar

The glycemic index (GI) was developed to classify foods according to their ability to increase postprandial blood glucose. The literature reports that the GI of rice varieties ranges from 48 to 93. All studies evaluate Indica rice but none evaluates the GI of Japonica rice. Furthermore, no studies have been conducted to assess the relationship between amylose content and GI in Japonica rice. The aim of this study is to evaluate the GI and amylose content of 25 Japonica rice genotypes. This study is based on the standard method for GI determination according to the international standard ISO 26642; it includes two men and eight women (mean age 28.3 ± 3.7, Body Mass Index – BMI – 21.4 ± 2.6). Five rice genotypes show low GI (Selenio, Argo, Enr18215, Enr18328, Enr18433), 10 medium GI (Carnaroli, CL12, CL388, CRLB1, Elio, Enr18126, Iarim, S. Andrea, Tiberio, and Valente), and 10 high GI (Arborio, Lince, Duilio, Castelmochi, Padano, Puma, Baldo, CL18, CL35, CL71). A negative association is also observed between medium GI and amylose (r = −0.528). As the amylose content increases, the mean GI decreases. Five rice genotypes have a low GI and are therefore suitable for a healthy diet and for diabetics.