Physicochemical Properties of Soft and Hard-type Rice Flour According to Moisture Content and High Hydrostatic Pressure Treatment

Abstract

This study investigated the effects of high hydrostatic pressure (HHP) treatment on the physicochemical properties of rice flour according to its moisture levels in order to develop new materials for processed rice foods. The rice varieties used were the Samkwang variety (normal and hard type) and the Shingil variety (processing and soft type). The moisture content of the rice flour was adjusted to 35–55% and it was treated with the HHP treatment at 400–600 MPa. The water absorption capacity, solubility, and swelling power of the rice flour increased as the moisture levels and pressure increased. The 600 MPa enzymatic hydrolysis-treated rice flour showed similar results to the heat-treated rice flour. Scanning electron microscopy showed few cavities, resulting in a dense structure. X-ray diffraction confirmed that the 23° peak, which indicates the degree of gelatinization, decreased with increasing moisture levels and pressure. The HHP treatment of the rice flour changed its physicochemical properties according to the moisture levels and pressure applied. These results can provide important information on the development and production of various foods.

Keywords

• rice flour
• ultra high pressure
• physical properties
• gelatinization