Feasible methods to control starch digestibility: strategies for reducing glycemic index of rice noodles

Diabetes has become the most common chronic disease threatening the health of people in China and even the world. Consumers are paying more and more attention to the glycemic index (GI) of food, especially staple foods. As a traditional staple food, rice noodle has been popular with Chinese consumers. Therefore, the strategies to reduce the GI of rice noodles attract increased research attention. Starch is the most abundant component in rice noodles. The rapid digestion of starch can lead to a significant increase in post prandial blood glucose levels. This review summarizes the effects of material characteristics, exogenous additives and processing methods on starch digestibility of rice noodles. Additionally, strategies to reduce the GI of rice noodles are discussed. The variety of material species, due to the structural differences of starch and other components, will lead to large differences in the GI of rice noodles. The ordered multiscale structure and crystal structure of starch provide resistance to enzyme attack, inhibiting the digestion of starch. Some bioactive phytochemicals, such as dietary fiber and polyphenols, can also inhibit starch digestion, which are more abundant in coarse cereals. The deficiency of these phytochemicals can be supplemented by exogenous addition. In addition, processing methods such as extrusion and retrogradation can induce crosslinking of biopolymers or reassembling ordered structures of starch, thereby slowing down the digestion. This paper provides a theoretical basis for the exploration of nutritious rice noodles suitable for consumption by people with diabetes and hyperglycemia.