Pretreatment process of quick-freezing broccoli

The effects of different blanching temperatures and blanching time on broccoli quality were investegated with response surface methodology. The changes of chlorophyll and texture of broccoli after freezing were studied when treated with CaCl₂ solution of different concentrations, and the optimization of pretreatment process was also researched. Experimental results showed that the optimized pretreatment process was as follows: blanching time 2 min, blanching temperature 96℃ and CaCl₂0.8%(m/v). Compared with the non-optimized process, it was found that the intensity of the texture of the bud increased by 26.9%, caudex increased by 16.8%; chlorophyll content increased by 26.5%; peroxidase activity decreased to the level required by the process; vitamin C, protein content and water activity all had no significant changes when the quick-freezing broccoli was treated under the optimized pretreatment condition.