Resistant starch in cooled white rice reduce glycaemic index

Abstract

Introduction: Not only the amount but types of ingested carbohydrates play a role in glycaemic index. Cooking process makes the starch granules to hydrate and swell (gelatinization) and easy to digest. On cooling, gelatinized starch recrystallises (retro gradation) and become more resistant to enzymatic process, this resistant starch is not digested and absorbed in intestinal, therefore glycaemic index can be reduced. Besides white rice, there is red rice consumed by Indonesian people. The aim of this study was to assess the glycaemic index in cooled white and red rice on healthy subjects. Methods: Twenty five healthy male subjects, aged 18—21, were recruited in the experimental study. The participants were divided into 4 groups by block randomization. The groups were given 50 g carbohydrate in warm white rice (WW), cool white rice (CW), warm red rice (WR), and cool red rice (CR) dish, respectively. Blood glucose on fasting was measured, in 15, 30, 45, 60, 90 and 120min after meal. Glycaemic response was calculated based on area under the curve of blood glucose. Result: This study showed that in WW group had a higher glycaemic response compared to the CW group, 3166.04± 142.95 and 2497.76± 406.78 respectively (p = 0,01). In contrary, there was no statistical difference between group WR and CR, 2899.57± 516.78 vs. 2649.80± 545.52, respectively (p = 0.319). Conclusion: This study indicates that cooled rice has a lower glycaemic index, compared to the warm rice.