Study On Technology And Mechanism Of Pretreatments Affecting Qualities Of Dehydrated Cabbage

This study mainly focoused on technology and mechanism of pretreatments whichaffect the qualities of dehydrated cabbage. Blanching conditions and additives in osmotictreatment were investigated in order to extend the course of glucose accumulation on thesurface of dehydrated cabbages during storage. In addition, Pretreatments in the productionof cabbage paper were also investigated. Two key technical parameters, for prevention ofdiscoloration and proper hardness, were determined after a lot of experiments.Firstly, in order to reduce the cost of pretreatment and improved its quality in storage,low priced additivs, such as high maltose syrup and maltose dextrine, were tested inosmotic treatment in production of dehydrated cabbage. The resuluts showed that solidgain/original solid of cabbage during osmotic treatment with high maltose syrup was lessthan with glucose, but far better than with maltose dextrine and fructose. In term of waterloss gain/original solid of cabbage, pretreatment with high maltose syrup was prior to withother additives. Therefore, it is possible that high maltose syrup substitutes for fructose inosmotic treatment in production of dehydrated cabbage.Secondly, in order to improve the quality of dehydrated cabbage during storage,effects of pretreatment with different methods on its quality were investigated with days ofglucose accumulation as an experiment index. Better result was obtained in pretreatmenwith high maltose syrup than with fructose. It was determined that a longer storge andbetter appearances can be achieved when glucose, fructose and high maltose syrup wereadded as much as 16%, 8% and 4%.Finally, pretreatment technics were investigated in production of cabbage paper in themethod of rolling so as to get natural green color and proper hardness. After blanched inalkalescent aqueous solution adjusted with NaHCO3 for 4min, cabbage was immersed in3% Na2 S2O3 aqueous solution for 2min, and then in 200mg/mL ZnSO4 aqueous solutionfor 5min, made into paste after washing remnants on its surface. Cabbage paste, togetherwith 5% potato paste and 0.5% potato starch, was dried at 65℃ in oven with fans for 4hours into vagetable paper, which owned natural green color and proper hardness.