Preparative Conditions of Shiratama Mochi Cake (Mechanical Properties of Waxy Rice Cake (Mochi) Part I)

Abstract

Mochi, a unique product in Japan, shows typical visco-elastic behavior after cooking. Four key preparative conditions of mochi were examined to a method employing shiratama flour which prepared by wet milling of waxy rice. a) Steaming a large lump of shiratama flour dough was better than boiling small lumps because the mochi of the former always resulted in a constant apparent viscosity value, measured with a penetrometer. b) Dough steamed for 15 min was kneaded and forced into a polyvinylidene chloride film casing or a hard rectangular case through a hand-worked extruder. c) The molded mochi in these containers was cooled in a refrigerator for more than 48 hr. Since the apparent viscosity increased sigmoidally (104~105 poise) with an elapse in cooling time, the mochi cake become easier to cut for testing with a relaxometer on successive examinations. d) The optimum concentration of the solid matter was about 45%, for ease of handling. Thus, this study established a moisture determination method for waxy rice products. The important feature was the pre-drying in which the mochi lump was puffed up between heated iron plates. © 1980, Japan Society for Bioscience, Biotechnology, and Agrochemistry. All rights reserved.