It has been reported in Ball et al., (1998) study that the amylose content in rice varies from 15-35%. Based on amylose content (%), Juliano (1992) categorized rice lines into different categories such as waxy (0-2% amylose), very low (2-12% amylose), low (12-20% amylose), intermediate (20-25% amylose), and high (25-33% amylose). Low amylose rice cultivars are usually tender, cohesive and glossy, while higher amylose cultivars are dry, fluffy and separated when cooked. It has also been studied that these percentages are mediated by the proportion of amylose to amylopectin in starch granules. According to Unnevehr et al. (1992), Malaysian rice belongs to intermediate to high amylose categories. However, local consumers prefer to consume rice with intermediate amylose content. Hence, in order to satisfy consumer’s taste, the high amylose content (not more than 30%) of the locally produced rice should be improved.
Another previous study (Widowati et al. 2007a) has reported that milled rice of low amylose varieties tends to have high GI (≥70) values, whereas high amylose rice varieties has low GI (≤55) values. However, people in many countries like in Indonesia, like to eat sticky rice with high GI although it is not recommended for diabetic patient. Therefore, a rice processing technology is needed that produces low GI sticky rice to overcome these problems. Based on eating trials, it has been observed that parboiled rice has a lower GI compared with milled rice (Foster-Powell et al. 2002). A previous In vitro study led to the conclusion that an increase in amylose and dietary fiber contents and also decrease in starch digestibility causes declining in GI values (Sri Widowati et al. 2010). However, rice lines with low amylose and low GI has not been found yet. A detailed investigation is therefore required whether such lines exist at all and if, their impacts on diabetics should also be examined.
The differences in starch digestibility might be caused due to various factors, including the botanical source, food processing, physiochemical properties, particle size, amylose/amylopectin ratio and the presence of lipid-amylose complexes (Goddard et al., 1984, Guraya, Kadan, & Champagne, 1997).
As rice is considered as one of the primary dietary sources of carbohydrates...