Changes in the Palatability of Foods by Hydrostatic Pressurizing

Abstract

Eleven kinds of foods (rice, soy bean, potato, sweet potato, Japanese radish, carrot, apple, pear, persimmon beef and chicken) were pressurized at hydrostatic pressure of 5000kg/cm² at room temperature for 10min. Effect of pressurizing on appearance, odor, taste and texture of food was evaluated by sensory tests. Changes in hardness and color were measured by a Texturometer and a Color difference meter, respectively. The fracture load and fracture deformation of Japanese radish were also measured by a Rheoner. The surface structures before and after pressurizing were observed by SEM. Furthermore, after pressurizing, the permeation rate of sodium chloride into Japanese radish during NaCl aqueous solution soaking and the browning rate of potato were studied. The appearance, odor, taste and texture of almost all foods changed by pressurizing except rice and soy bean. The texture of potato and sweet potato turned to pliable and the sweetness of sweet potato increased. Taproot vegetables increasd in transparency and became pliable. The transparency and sweetness of the fruits increased. Pear and persimmon softened. The color of meats was tinged with white and their hardness increased. Gelatinization in potato starch was not observed. Pressurized Japanese radish absorbed more sodium chloride than controlled one. The browning rate of potato was accelerated by pressurizing. From these results, it is suggested that hydrostatic pressure will become one of the useful way for new food processing or cooking.