Quality changes of carrots thermally processed in a large size (5 kg) retort pouch during 52 weeks of storage were investigated under different packaging methods and package shapes. To improve the efficiency of thermal processing (121.1oC, 0.15 MPa), the carrot (i.e., solid) and the broth (i.e., liquid) of the carrot soup were separately packed and sterilized. The quality changes of carrot packed without liquid were compared with those with liquid. Two different package shapes such as rectangular parallelepiped and cube were also evaluated to figure out the efficiency of the heat penetration rate for a large-sized pouch. The TTT (F0-values = 6) were 27, 54, and 114 min from the rectangular parallelepiped, cube, and solid/liquid mixed groups, respectively. In the mixed groups, the hardness and chewiness of solids (carrot) were significantly smaller than those measured in the other groups as TTT increased. Carrots treated in the rectangular parallelepiped shape showed a significantly higher texture than the cube shape. The CV of hardness and chewiness in the rectangular parallelepiped and the cube shape were calculated as 7.56 and 47.19, and 29.16 and 65.28, respectively. This demonstrated that a more uniform quality can be obtained from the rectangular parallelepiped shape.

Quality changes of carrots thermally processed in a large size (5 kg) retort pouch during 52 weeks of storage period were investigated upon different packaging methods and package shapes. To improve the efficiency of thermal processing (121.1°C, 0.15 MPa), the carrot (i.e., solid) and the broth (i.e., liquid) of carrot soup were separately packed and sterilized. The quality changes of carrot packed without liquid were compared with those with liquid. Two different package shapes such as rectangular parallelepiped and cube were also evaluate to figure out the efficiency of the heat penetration rate for the large size of pouch. The location of cold points and the total thermal processing time (TTT) were different upon the treatment. Fo-values, satisfying the TTT to at least 6 min, were 27, 54, and 114 min from the rectangular parallelepiped, cube and solid/liquid mixed group, respectively. In the mixed groups, the hardness and chewiness of solids (carrot) was significantly smaller than that measured in the other groups as TTT increased. Carrots treated in the rectangular parallelepiped shape showed a significantly higher texture than the cube shape for both immediately after the thermal treatment and during the storage period. Coefficient of variation (CV), which indicates the quality variation within the same treatment, of texture properties obtained from the outside and the center of the sample were compared to evaluate the quality variation within the same treatment. The CV of hardness and chewiness of the rectangular parallelepiped and the cube shape were calculated 7.56 and 47.19, and 29.16 and 65.28, respectively. This demonstrated that more uniform quality could be expected from the thermal treatment in the rectangular parallelepiped shape

The effect of temperature distribution in the retort on the degree of sterilization and the product quality was investigated. The temperature distribution in the retort chamber in an industrial scale of retort was evaluated. The target processing temperature was set to 121.1°C based on the standard sterilization process for C. botulinum. The temperature distributions at several points in the retort chamber were measured during the sterilization process, such as the heating (25°C to 121.1°C), holding (121.1°C), and cooling (121.1°C to 25°C) processes. Fo-values at different positions in the chamber were evaluated and compared. Potato cubes were used as a control sample to obtain the heat penetration curve for evaluating the degree of sterilization and the quality changes. Potato samples in cube shape (13×13×13 mm) were prepared and packed in 5 kg of retort pouch pack. A significant temperature deviation occurred during the cooling process and it significantly affected the degree of sterilization.