| Affiliation: | 1. Sabaragamuwa University of Sri Lanka, P.O. Box 02, Belihuloya, Sri Lanka School of Applied Sciences, RMIT University, Bundoora West Campus, Melbourne, Vic., 3001 Australia;2. Glyn O. Philips Hydrocolloid Research Centre at HUT, Hubei University of Technology, Wuhan, 430068 China;3. Institute of Nuclear Agricultural Sciences, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, 310029 China;4. Department of Food Science & Technology, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, 200240 China;5. Sabaragamuwa University of Sri Lanka, P.O. Box 02, Belihuloya, Sri Lanka;6. Rice Research and Development Institute, Batalagoda, Sri Lanka;7. School of Applied Sciences, RMIT University, Bundoora West Campus, Melbourne, Vic., 3001 Australia |
| Abstract: | Gelatinization, pasting, digestibility and estimated glycaemic index of six high amylose rice varieties differing in length/width ratio were studied. Amylose content ranged narrowly (27.8–29.1%). Resistant starch content ranged from 0.44% to 1.4%. In contrast to gelatinisation enthalpy, gelatinisation temperature (GT) ranged narrowly (76.7–77.4 °C). For all rice varieties, melting temperature of amylose-lipid complex I and II was around 99 °C and 110 °C, respectively. The enthalpy of amylose-lipid complex I and II ranged between 0.18–0.87 and 0.23–0.55, respectively. Expected in vitro glycaemic index (GI) of all tested varieties was similar (88.2–92.4). The results showed that the size of the rice grain (length/width) and resistant starch content had no apparent impact on the GI of high amylose rice. The dominant factors determining the digestibility and glycaemic response of the tested high amylose rice varieties seemed to be amylose content and the GT. Besides the pasting temperature, other pasting properties varied significantly but were not correlated to starch digestibility and estimated GI among the six rice varieties. Thus, RVA pasting properties, except for pasting temperature, may not be good predictors for the GI of these high amylose rice. |
