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Although the starch digestibility of cooked white rice has been investigated with regard to its relation to starch structure, it is not yet clear how starch molecular structure and water content affect its digestion rate. To investigate this, the in vitro starch digestibility and molecular structure of 10 rice varieties with a range of rice-to-water cooking ratios were investigated. As expected, starch digestibility varied with different conditions. Typically, a higher amylose content resulted in a lower maximum digestion extent for a given water content. Having relatively more and longer amylopectin intermediate chains caused a slower starch digestion rate, but only with rice-to-water ratios between 1:1 and 1:1.2. These results could prove useful to find combinations of starch fine molecular structures and water contents to produce cooked rice with low glycemic index.

Development of wheat bread with slow starch digestibility is of great importance in terms of generally improving human health. Many factors can be used to determine starch digestibility in wheat bread, including the composition and structure of different bread micro- and macronutrients such as starch, protein, lipid, fiber and polyphenol. Processing conditions including dough hydration, kneading, fermentation, baking and storage parameters are also important factors in determining starch digestibility in wheat bread. This review aimed to summarize these factors from the literature and corresponding mechanisms how they determine starch digestibility. It provides opportunities to reduce starch digestibility in wheat bread by selecting a desirable combination of raw bread ingredients and processing conditions. Considering the global epidemic of chronic diseases such as type 2 diabetes, this review contains important information that can turn wheat bread into a much healthier food product with a lower glycemic index.

Chinese steamed bread (CSB) is one of the staple foods in China, although it has a high glycemic index (GI) value. Development of CSB with a slower starch digestibility is thus of great importance for the improvement of human health. Many factors are related to the starch digestibility in CSB. Most currently available strategies are focusing on the incorporation of other whole flours with high dietary fiber or polyphenols to reduce the starch digestibility. Although successful in reducing starch digestibility, the incorporation of these flours also deteriorated textural attributes and sensory characteristics of CSB. Much more strategies have been applied for the reduction of starch digestibility in breads, which should be further explored to confirm if they are applicable for CSB. This review contains important information, that could potentially turn CSB into a much healthier food product with slower starch digestibility.

White rice is the staple food for more than half of the world's population, but it has a high glycemic index and minor resistant starch (RS) content. The consumption of cooked white rice has thus been associated with the global epidemic of chronic diseases such as type 2 diabetes. RS is beneficial for human health in many aspects such as antidiabetic function. However, the development of cooked white rice with high RS content is challenging, due to the high starch gelatinization degree. In this review, main factors affecting RS content of cooked white rice were critically evaluated, with the aim to help food industry develop strategy to increase the RS content in cooked white rice. It was shown that RS content can be manipulated by starch genetic and structural modifications. Starch hierarchical structures, protein compositions and physical barriers, lipid compositions and amylose-lipid complex, cell wall architecture and compositions can all affect the RS content. Additionally, storage and ageing, degree of milling, cooking and cooling conditions, food additives, chemical and enzymatic modifications and physical modifications are other critical factors. Considering the popularity of white rice around the world, this review contains information that could generally improve human health by turning cooked white rice into a healthier food with high RS content.