Study On Preparation And Application Of Waxy Maize Starch With Freeze-thaw Stabilization

Waxy foodstuff is a kind of traditional food in china, thousand years of development history. Many people like waxy foodstuff for its soft texture,various kinds, particular flavor. With the improvement of people's life, people gradually put forward high demand for waxy foodstuff.In this work, the waxy maize starch was used to produce the hydroxypropylated waxy maize starch with freeze-thaw stabilization by the chemical method. Freeze-thaw separate water's velocity(SWV) and molar substitution, as criterions. Then, the hydroxypropylated waxy maize starch was used to produce the hydroxypropylated-phosphate monoester compound modification starch with freeze-thaw stabilization, and freeze-thaw SWV and phosphate molecule substitution were used as criterions;whereas the products'properties were analyzed. Fucose,salt, xanthic glue were added into maize mochi which is a kind waxy foodstuff to get better freeze-thaw stabilization. Detailed results were as fellows:The waxy maize starch was used to produce the hydroxypropylated waxy maize starch which had freeze-thaw stabilization. The concentration of starch slurry, amount of propylene oxide, reaction temperature, reaction time, dosage of NaOH, dosage of Na2SO4 which affecte- d freeze-thaw stabilization and molar substitution of hydroxypropylated waxy maize starch were studied. The following optimum conditions were obtained: 40% of starch slurry,12% of propylene oxide,1.3% of NaOH,14% of Na2SO4 at 50℃for 25h. Under the conditions, freeze-thaw SWV of starch is 48.5%, whereas molar substitution is 1.51.The hydroxypropylated waxy maize starch was used to produce the hydroxypropylated- phosphate monoester compound modified starch which had freeze-thaw stabilization. Concentration of orthophosphate, the substitution of hydroxypropylated waxy maize starch, reaction temperature, reaction time, pH, amount of urea, proportion of tow kinds of orthopho- sphate which affected freeze-thaw stabilization and phosphate substitution of hydroxyprop -ylated-phosphate monoester waxy maize starch were studied. These results demonstrated that the optimum conditions were: concentration of orthophosphate 30% , substitution of hy- droxypropylated waxy maize starch 0.12, reaction temperature 140℃, reaction time 120min, pH 5.5, amount of urea 4% , NaH2PO4:Na2HPO4 3:1. Under the condition, freeze-thaw SWV of starch is 9.2%, whereas phosphate substitution is 0.073.Compared to the waxy maize starch in stability,luminosity, antiaging, viscidity degree, microstructure ect, These propertied of the modified starch all were improved.Finally, The flavor, exquisite degree, spring and rigidity of maize mochi added the modified starch with freeze-thaw stabilization were greatly improved.