Abstract
In this study, steamed rice cakes prepared with different particle sized flour were used to investigate how the structures of rice cakes affected masticatory properties and bolus starch hydrolysis. Decreasing the particle size increased the surface areas requiring hydration, resulting in a loose structure and fluffy starch network during gelatinization. Increasing the particle size led to a tight and firm network, but was easily melted in the oral cavity. The chewing cycle and time differed among the samples. The conditions of inter-individual salivary flow rate and salivary α-amylase were diverse. The oral carbohydrate hydrolysis in the bolus before swallowing showed no significant differences in reducing sugar levels among particle sizes. However, salivary concentration was related to initial starch hydrolysis in the oral cavity, indicating the food structures affected mastication factors and physiological conditions. This study provides food structure and physiological factor information that could help design customized foods in industry.