Glycemic Index of a Novel High-Fiber White Rice Variety Developed in India - A Randomized Control Trial Study

Abstract

Background: White rice, a common Indian staple, has a high glycemic response and is associated with high risk of type 2 diabetes. The aim of this study was to compare the Glycemic Index (GI) of a newly developed high-fiber white rice (HFWR) with that of commercial white rice (WR). Materials and Methods: HFWR was developed using biochemical screening approaches and classical plant breeding techniques. The GI of HFWR was determined using a validated protocol in 30 healthy participants in the year 2013 and repeated in a subsample of 15 participants in the year 2014; the results were compared with the value for WR. The incremental area under the curve was calculated geometrically by applying the trapezoid rule for both reference food (glucose) and the test foods (HFWR and WR). Proximate principles along with dietary fiber, resistant starch, and amylose content were analyzed using standardized methods. Results: The dietary fiber content of HFWR was fivefold higher (8.0 ± 0.1 vs. 1.58 ± 0.17 g%), resistant starch content was 6.5-fold higher (3.9 ± 0.2 vs. 0.6 ± 0.03 g%) (P < 0.001), and amylose content was significantly higher (32.8 ± 1.1 vs. 26.0 ± 0.2 g%) (P < 0.001), compared with WR. HFWR was found to be of medium GI (61.3 ± 2.8), whereas WR was of high GI (79.2 ± 4.8). Overall, HFWR had 23% lower GI compared with WR (P = 0.002). Conclusions: The new HFWR variety can be considered as a potentially healthier alternative to commercial WR in rice-eating populations, on account of its lower GI and high fiber content.