Design and experiment of vacuum-steam pulsed blancher for fruits and vegetables

Blanching is an essential thermal processing using hot water or steam to treat fruits and vegetables, which is often carried out prior to the preservation process like drying, canning and freezing. Blanching can effectively inactivate enzymes in products such as polyphenol oxidase (PPO) and peroxidase (POD) enzymes, which cause deterioration reactions, off-flavor and undesirable changes in color. Under the condition of blanching, fruits and vegetables can keep their original colors, flavors and nutritional ingredients. Hot water and steam are by far the most widely used blanching methods. In order to ensure the uniformity of the internal flow field, the flow field of inner blanching body was simulated by computational fluid dynamic (CFD) software Fluent, and the steam jet structure was optimally designed by adding interceptor in the bottom of the blanching body. In this paper, the designed vacuum-steam pulsed blancher for fruits and vegetables has improved blanching loading capacity and uniformity, which has