Effects of high-pressure treatment and soaking on the cooked rice

• Published in: Nihon Shokuhin Kagaku Kōgaku kaishi Vol. 52; no. 2
• Main Authors: Yamakura, M. (Ochanomizu Univ., Tokyo (Japan)), Okadome, H, Suzuki, K, Tran, U.T, Homma, S, Sasagawa, A, Yamazaki, A, Ohtsubo, K
• Format: Journal Article
• Language: Japanese
• Published: 01.01.2005
• Subjects: CHEMICOPHYSICAL PROPERTIES; COOKING; HIGH PRESSURE TECHNOLOGY; RICE; SOAKING
• ISSN: 1341-027X
• DOI: 10.3136/nskkk.52.60

High- pressure (HP) treatment is a novel technique, which has been applied by food industry, including the processing of cooked rice. In Japan, before cooking, rice is usually soaked in water for a short time, about 1 h. In this report, researches on changes of properties of rice samples, which were presoaked in water for 30min at either 25 deg C or 55 deg C, then subjected to HP at 400 MPa for a minute, thereafter soaked in water for different periods of times, were carried out. The effects of presoaking temperature, HP treatment, and soaking duration on the physicochemical and biological properties of rice, were evaluated. The results demonstrated that the surface of cooked rice treated by HP was more sticky and had a higher "balance degree" (ratio of stickiness to hardness), than that of non-treated one. The contents of sugars and free amino acids were increased with the increase of presoaking temperature, soaking time, and HP. In addition, the number of Bacillus cereus was reduced, when rice had been presoaked at high temperature or treated by HP. Therefore, HP processing is an advantage one method, which can be applied in processing of rice, with aims of better palatability and safety.