Search

Copyright of Journal of Chinese Institute of Food Science & Technology / Zhongguo Shipin Xuebao is the property of Journal of Chinese Institute of Food Science & Technology Periodical Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

More cost-saving and efficient freezing is required to enhance the performance of quick freezing for blueberries. In this study, a new system was proposed to utilize a multi-outlet array nozzle for spraying blueberries with dry ice particles. Experimental tests were conducted to investigate the variations in the thermal properties of blueberries with temperature during the freezing process. These parameters were then input into Fluent software. A quick-freezing model was established for the dry ice particle spray inside the chamber. Numerical simulation was conducted to simulate the blueberry quick freezing using Fluent software. The optimal inlet flow velocity was successfully obtained to optimize the nozzle outlet diameter after the simulation. The results indicate that the better precooling of blueberries in cold water was to a temperature of 1℃. The nozzle was designed with six outlets in a circular array, where the central lines of the outlets were inclined at a 60° angle from the central line of the nozzle inlet, while the aperture size was 5.2 mm, and the nozzle was designed in a circular aperture shape with a contraction form. Additionally, four outlets were arranged at the center position of the nozzle's entrance axis, each with a diameter of 2 mm. The nozzle was configured with a spraying height of 120 mm, an entrance aperture measuring 30 mm, and an inlet velocity of 0.25 m/s. The center temperature of all the blueberries decreased from 1℃ to −18℃ in a total of 129 s, indicating the more uniform and quick freezing of the blueberries. Experimental testing was conducted to validate the simulation. An optimal combination was achieved in the freezing process of 127 s at the slowest cooling rate, with a time of 36 s for the formation of the maximum ice crystal generation zone. The cooling curves of the experimental process and the simulation process match well. The thawed blueberries were then subjected to physicochemical property testing after three days of storage. The results show that the blueberries subjected to quick freezing using dry ice particle spraying exhibited superior changes in their quality before and after freezing, compared with the CXS 103-1981 standard for frozen blueberries. A comparative experiment show that the blueberries were subsequently subjected to quick freezing using direct spraying of liquid nitrogen at −80℃. However, the dry ice cost much less for the quick freezing of blueberries, compared with the direct spraying with −80℃ liquid nitrogen. This low cost further enhanced the feasibility and economic viability of dry ice for blueberry freezing. The physicochemical property tests showed that there was almost no difference with the dry ice. The research findings can provide a solid foundation for the widespread application of the quick freezing of blueberries using dry ice spray. [ABSTRACT FROM AUTHOR]

Copyright of Food & Machinery is the property of Food & Machinery Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Food & Machinery is the property of Food & Machinery Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Shipin Kexue/ Food Science is the property of Food Science Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Harbin Institute of Technology. Social Sciences Edition / Haerbin Gongye Daxue Xuebao. Shehui Kexue Ban is the property of Harbin Institute of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Harbin Institute of Technology. Social Sciences Edition / Haerbin Gongye Daxue Xuebao. Shehui Kexue Ban is the property of Harbin Institute of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Natural Gas Industry is the property of Natural Gas Industry Journal Agency and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Quick-frozen fruits and vegetables have a high demand on the processing device for rapid freezing, due to the ever-increasing requirements for the high quality and nutritional value to taste of consumers in food production. The purpose of this study is to use the sublimation process of dry ice particles, further to form the superfast freezing in low temperature environment, in order to adequately keep the original color, flavor, and high quality nutrition of frozen products, while, shorten the freezing time and improve the freezing efficiency. Taking the strawberry as the research material, natural dry ice particles were sprayed into a quick-freezing room, concurrently skimmed quickly the surface of strawberry, and fully contacted with the strawberry to exchange the heat. Therefore, a new innovated platform was designed, including the fabrication of dry ice pellet, spraying system, a quick-freezing room, and a feasible pallet. A thermomechanical model of strawberry in the quick-freezing room was established, to simulate the distribution of temperature, velocity, and pressure during the dry ice spraying using the Comsol multiphysics software. The inlet radius of dry ice jet was set under the conditions of 18, 20, 23, 25 and 30 mm, and the injection velocity was set as 0.10, 0.15, 0.20, 0.25, 0.30, 0.40, 0.50 m/s, thereby to determine the time when the core temperature and surface temperature of strawberry met the requirements of quick freezing. The solid fraction of dry ice in different time was compared, when the injection velocities of dry ice were 0.20 and 0.30 m/s. The results showed that the freezing time of strawberry decreased, while the freezing efficiency increased, with the increase of the inlet radius and the spray speed of dry ice. When the inlet radius was 25 mm and the flow velocity was 0.30 m/s, the core temperature of all strawberries reached -18℃ at 350s, indicating the uniform distribution of temperature, and the shortest duration between the strawberry surface to -35 ℃ and the strawberry core to -18 ℃. In this case, it was expected to effectively prevent the surface cracking caused by the excessive difference of internal and external temperature in a strawberry. Meanwhile, the solid fraction of exported dry ice was less than others, indicating the quick freezing of strawberry realized with the maximum efficiency. Compared with liquid nitrogen spraying, the zone of the maximum ice crystal formation and the freezing time of dry frozen strawberry reduced by 63.9% and 41.7%, respectively, indicating the excellent cooling performance using dry ice spray. In addition, the quick-frozen quality of strawberry was significantly improved, due to the less freezing time, the improved freezing efficiency, and the reduced energy consumption of system operation, meanwhile, to better preserve the strawberry juice, original color, flavor, and nutrition. An experiment was also used to verify the optimal parameters, where the experimental and simulation errors were 3.70% and 6.03%, respectively, when the surface temperature and core temperature reached the standard value. Specifically, the physical and chemical properties of strawberries were better than the standard after quick-freezing. The finding can lay a sound foundation for further development of energy-saving and environment-friendly dry frozen devices for fruits and vegetables. [ABSTRACT FROM AUTHOR]

Copyright of Journal of China University of Petroleum is the property of China University of Petroleum and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)