Glycaemic Index and Glycaemic Load of Newly Developed Rice Varieties in Sri Lanka

Abstract

Five existing and newly developed rice varieties (Super kernel, Purple queen, Rathu suduru, Red fragrant, and White slender (parboiled)) were tested for glycaemic index (GI) and glycaemic load (GL). Sixteen healthy volunteers were recruited. After overnight fasting, each of them was given a 50 g available carbohydrate portion of glucose (reference food) or different varieties of cooked rice (test foods) on separate occasions. At each occasion, the fasting and post-prandial capillary blood glucose responses were determined over 2 h, and the incremental area under the curve (IAUC) was calculated. The GI value was calculated as the IAUC of the test food / IAUC of the reference food Ö 100. The GI values of Super kernel (40 ± 5.5%) and Rathu suduru (61 ± 5.5%) were found to be significantly different (P < 0.05) and GI values for Purple queen (47 ± 4.9%), Red fragrant (54 ± 3.8%) and White slender (parboiled) (49 ± 3.8%) were found to be not significantly different (P > 0.05). GI values of Red fragrant at 40% and 100% polishing levels were 54 ± 5.7% and 53 ± 5.5%, respectively and they were found to be not significantly different (P > 0.05). The GL values of Rathu suduru (12 ± 1.1%) and Super kernel (8 ± 1.0%) were found to be significantly different (P¡0.05) while that of Purple queen (9 ± 0.9%), Red fragrant (10 ± 0.7%) and White slender (parboiled) (9 ± 0.7%) were found to be not significantly different (P > 0.05). All the rice varieties tested could be classified as low GI and low GL except Rathu suduru (Medium GI and GL). Therefore, the low GI and GL rice varieties may confer potential benefits in terms of glycaemic control and as a guide to food selection among people with diabetes.